[Elenco soci]


Piancastelli Luca

Professore Ordinario


Università degli Studi di Bologna
luca.piancastelli@unibo.it

Sito istituzionale
SCOPUS ID: 6506020256



Pubblicazioni scientifiche

[1] Piancastelli L., Sali M., Leon-Cardenas C., Basic Considerations and Conceptual Design of a VSTOL Vehicle for Urban Transportation, Drones, 6(5), (2022). Abstract
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On-demand air transport is an air-taxi service concept that should ideally use small, autonomous, Vertical Short Takeoff and Landing (VSTOL), “green”, battery-powered electric aircraft (eVSTOL). In addition, these aircraft should be competitive with modern helicopters, which are exceptionally reliable machines capable of the same task. For certification and economic purposes, mobile tilting parts should be avoided. The concept introduced in this paper simplifies the aircraft and makes it economical to build, certify and maintain. Four contrarotating propellers with eight electric motors are installed. During cruise, only two of the eight rotors available are not feathered and active. In the first step, a commercial, certified, jet-fueled APU and an available back-up battery are used. A second solution uses a CNG APU and the same back-up battery. Finally, the third solution has a high-density dual battery that is currently not available. A conceptual design is shown in this paper.

Keywords: attitude control | cost-effectiveness | electric–thermal hybrid aerial | vertical short takeoff landing

[2] Piancastelli L., Pezzuti E., Cassani S., POWER PLANT RELIABILITY ISSUES AND WEAR MONITORING IN AIRCRAFT PISTON ENGINES. PART I: ENGINE WEAR AND TBO REAL-TIME EXTENSION, ARPN Journal of Engineering and Applied Sciences, 17(7), 806-814, (2022). Abstract
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This paper introduces a method to prepare an engine for very long flights without maintenance. It also gives criteria to estimate time between overhaul by using the sensor data to have an estimation of the engine condition. In-flight refueling has introduced new challenges to UAV (Unmanned Aerial Vehicle) propulsion systems. It is now possible to run continuously an UAV without landing for long periods. For this task, it is necessary to carry a quantity of lubricant sufficient for at least one month (approximately 800h). For extremely long flights, diesel piston engines are better than spark ignition ones due to extremely low fuel consumption. A selection in the assembly line individuates those engines that are suitable for long endurance flight. This is possible because automotive engines are manufactured in thousands per day and many quality controls take place in the assembly process. Moreover, mass produced automotive engines pass several tests during the assembly process including a very short run. The results of these tests are useful for an initial selection. Then, a 25-hour trial with a very thin lubricant is sufficient to forecast the oil consumption up to 1,000 hours. The 25 hours run corresponds to the time necessary to stabilize the oil consumption rate. In addition, during the 25 hours run also the electronic infancy failures are detected. In modern engines, the electronic on board diagnosis, the full redundancy of vital sensors, electronic control units and batteries/generators, make it possible to fly safely without emergencies with random electronic failures of components and wiring. Another major requirement is to forecast the engine failure or an unacceptable deterioration in terms of mechanical performance. This paper introduced a method to evaluate the state of wear of the engine starting from a digital monitoring system. A wear model of the engine based on the real duty cycle is proposed. It is then possible to prolong the life of the engine and to increase the time between overhaul. It is also possible schedule the overhaul operation

Keywords: 800h flight | Aircraft | Piston engine | Tbo evaluation

[3] Piancastelli L., Pezzuti E., Cassani S., POWER SPEED REDUCTION UNITS FOR GENERAL AVIATION PART 8: CASING DESIGN FOR METAL DIRECT ADDITIVE MANUFACTURING, ARPN Journal of Engineering and Applied Sciences, 17(6), 661-669, (2022). Abstract
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This paper introduces a practical design procedure for Direct Metal Addictive Manufacturing (AM) by Hybrid Selective Laser Sintering or Melting (SLS/SLM). Theoretically AM frees the designer from many design constraints, practically it introduces new problems and it requires a brand new design of the part. Hybrid manufacturing reduces the problems without solving them totally. Supports can be introduced but represent a waste of time during manufacturing and during the post-mill removal. Before a 3D-printed metal part becomes usable, it has already undergone significant postprocessing in the form of CNC milling, hot-hyping, shot-peening or sand-blasting. Powder-bed fusion parts shows a quite rough surface finish. Considering that post-milling will be necessary in any case, surface finish is less important than other issues metal 3D printing. For example, very small cavities form within the part as it is being built. These defects lead to cracks during the part life cycle. Too few power applied by the wiper, too low laser intensity, excessive or inefficient cooling are the most common causes. Geometry of the part, optimized printing pattern and machine parameters are used to address these problems. AM machine operators have to tune their machines for a given material and print job. In the SLS/SLM process, density is achieved with quality powders, optimized build parameters and controlled machine environment. Hot isostatic pressing treatment as a post-process removes the porosity and reveals excessive defect by deforming the part. Residual stress is a result of the printing process. As the powder is melted and cooled, expansion and contraction occur. The residual stress is compressive at the center of the part and tensile at the boundary surfaces. Therefore, thin walled continuous parts are to be preferred. In fact, the classical ribbed structure has several thickness discontinuity requiring continuous adjustment in the build pattern and in laser modulation. To ensure the quality of the part material, the initial layers of the print are removed via CNC milling after the build is complete. Unfortunately, the thermal stress of the substrate will cause the part itself to warp modifying its geometry. Support structures are positioned in the right locations to prevent distortion or warpage. In addition, overhanging surfaces or down-skins faces have poorer surface finish ad are subjected to warping. For this reason, they also need additional supports. For these reasons, the Direct Metal AM part may have a completely different geometry than a cast component. An example of redesigning of a PSRU (Power Speed Reduction Unit) is provided in this paper.

Keywords: Aircraft | Direct metal additive manufacturing | Gear drive | Helicopter | Housing | Psru | Transmission

[4] Piancastelli L., Calzini F., Cassani S., VALIDATION OF AN EXPERIMENTAL METHOD FOR PEAK TEMPERATURES EVALUATION ON A RR MERLIN XX HEAD, ARPN Journal of Engineering and Applied Sciences, 15(22), 2631-2638, (2020). Abstract
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Aluminum alloy properties are hugely influenced by temperatures and stress gradients. In piston engines, temperatures vary slowly when compared to operating pressure and stress. Therefore, averaging the temperature values is a valid assumption. This paper compares the experimental head temperatures of a Rolls-Royce-Merlin-XX-head with the ones of a NACA paper on a very similar Merlin-Packard-V-1650-7. This experimental method in based on residual hardness measurement on a head of a RR Merlin that crashed in Italy during WWII. The first part is to define the “working life” in hours of the engine. A few samples from a “cool” part of the head give the initial “thermally intact” hardness. Then the hardness of a few samples from a known temperature part is measured. In our case, it is the part of the head that is directly exposed to coolant. The time interval that gives a residual hardness equal to the one of the part of the head that is directly exposed to coolant gives the engine working life. For this purpose, a set of “cool part” samples are kept in at the maximum constant temperature of the coolant (135 degrees C). Then, a few specimens are kept at higher temperatures and are extracted from the oven at regular time intervals. The residual hardness is measured on these specimens. A further set of specimens is subjected to random thermal cycling to verify that the alloy hardness reduction is influenced by the time at high temperature and not by the thermal cycle history. In this way, a correlation between residual hardness and temperature is obtained for the specific engine alloy. It is then possible to measure the residual hardness of various points of the head and to obtain the maximum temperature reached in a specific point. In general, experimental tests have confirmed the cost-effectiveness of this approach. The NACA TM 2069 data and the ones measured with this method show an extremely good correlation. It is then possible to affirm that, also for the alloy used for the Merlin head, a modified Hiduminium RR50, this method of test is valid. Other positive tests were performed in the past with the much more common AlSi9 alloy used for the head of FIAT-1900jtd-8V automotive engine. The method of the residual hardness is old and has met several critics in the scientific community. This paper demonstrates that, for at least a few aluminum alloys, it is still valid. It is a very inexpensive method to evaluate temperatures in new engines using disposed units with a known load history and time. The results are precious to verify that the simulation results used in the head design led to reasonable results. In this way, the development time of new engines can be significantly reduced.

Keywords: head | measurement | piston engine | RR Merlin | temperature

[5] Piancastelli L., Calzini F., Cassani S., OFF-DESIGN PERFORMANCE OF AUTOMOTIVE DERIVED CENTRIFUGAL COMPRESSORS, ARPN Journal of Engineering and Applied Sciences, 15(19), 2174-2181, (2020). Abstract
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The traditional method to draw automotive-turbocharger compressor maps is based on equivalent chocking conditions. In this way, theoretically, the compressor chocking conditions would be exactly evaluated with the new ambient (inlet) conditions. Unfortunately, chocking is not the worst working condition for turbochargers in piston engine applications. In addition, most available compressor maps are interpolated from very few CFD (Computational Fluid Dynamics) or experimental data. The result is that many designers convert the map into a “row” one with the volumetric max flow on the x-axis. However, even this approach has many limitations, since compressor performance depends on Mach and Re numbers. To clarify the concept, a simplified CFD method to draw the compressor map is introduced in this paper. An example, based on a true turbocharger, shows the limitations of most interpolated-maps that can be found in literature. This initial “raw” map has a volumetric flow rate in input (x-axis) and an absolute pressure ratio in output (yaxis). The islands of constant efficiency are then calculated by assuming that the diffuser has a unitary efficiency. Then a new method based on invariants is introduced to calculate the new map with different input ambient conditions [1]. It is based on the ambient sound speed. This method is then corrected in this paper by introducing more accurate values for density and Mach speed. In particular the correction due to the air moisture content is particularly critical. The new invariant map obtained in this way takes into account of variations in inlet air for Re and Mach numbers. The method is valid for automotive and aerospace applications up to 3,000m. Unfortunately, for higher altitudes, even this new method shows its limitations, with the necessity to recalculate the maps with CFD simulation. In fact, rarified air and lower inlet temperature reduce compressor performance in term of efficiency and compression ratio. On the contrary, turbines tend to transfer more power to the shaft. In this way, the compressor to turbine match is far from ideal.

Keywords: altitude | compressor | map | turbine | turbocharger | water content

[6] Piancastelli L., Cassani S., Next generation main battle tank. Part iii: An air transportable, upgradable and flexibleweapon system integrated in the future warfare, ARPN Journal of Engineering and Applied Sciences, 15(15), 1687-1694, (2020). Abstract
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With a foreseen life of more than 30 years, the future Main Battle Tanks (MBT) will face continuous upgrades in and will challenge ever-changing threats. The armament, the armor, the information and the communication suite will be upgraded/changed depending on the scenario and on the technology available. Like in moder cars, the huge hardware/software/sensors is the most changing package. This continuous upgrade should be included in the design of new vehicle, than should be conceived more as a modular, vehicle family than as a single vehicle. The new battle tank is closer to a car platform that is the base for a family of vehicles, in which a major revision of any single model should be performed every two years. The old option-less approach like the Ford T model, which remained in production from 1908 to 1927, belongs to the past. A very desirable requirement would be to host the new vehicle in the bay of the latest C130 for rapid deployment. Even if it is time to update the venerable C130 to something newer and more capable, the basic concept remains. The always-growing 100-ton pan-tank approach is becoming obsolete, along with the idea to add hardware to improve firepower, protection and battlefield effectiveness. This third part introduces a few concepts to design a new MBT or better, a new MBT family, in which a modular concept makes it possible to adapt the vehicle to a specific scenario and to update it with ease. Flexibility and update capability are the new key words. The old concept of the mobile bunker with tracks should be substituted by a hierarchical protection system. This approach is inherited from the attack helicopters. The best-protected part of the tank should be a very small crew compartment. It should be completely separated from the weapon compartment with the main and secondary armaments equipped with automatic loading systems. The NBC (Nuclear Bacteriological Chemical) air filtering system can then be reduced to serve only the humans. The crew should travel secured by safety belts and should be equipped with ejection seats. Air-bag should be considered to reduce the shock of a direct hit from APFSDS penetrator or other high energy threats. These seats are conceptually different from aircraft ones since they will assure a simple exit from the tank, not a true ejection. A multiengine-multimotor approach may be used for traction with two or more powered sprockets. The small powerpacks will occupy less room inside the vehicle. A drive by wire system with an enhanced stability and direction system should be implemented. The ground pressure should be kept well under 900 kPa. Tracks should be narrow and long to reduce power requirements. Only the frontal arc of the MBT should be protected with passive "direct kill" armor. The remaining part of the vehicle should rely on hard-kill active systems except for "light" automatic fire. Since armor is an accessory, it should be added to the basic MBT structure. The "adding" from the outside approach should be extended to as many items as possible to simplify maintenance, equipment and update. The basic vehicle structure is closer to the frame of an F1 car with all the parts and accessories added to it. Similarly to F1 racing cars, it can be made with lightweight materials and aircraft technologies, like Carbon Fiber Reinforced Plastic or aluminum alloy monocoque structure. Finally, an on-board electronic diagnosis system should be implemented to simplify maintenance and increase availability and reliability.

Keywords: Automated turret | Modular | New generation mbt | Upgradable

[7] Piancastelli L., Pezzuti E., Cassani S., Next generation main battle tank. Part II: Converting old MBTS into unmanned MBTS (UMBT), ARPN Journal of Engineering and Applied Sciences, 15(14), 1582-1591, (2020). Abstract
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Modern MBTs (Main Battle Tank) are extremely expensive. Many outdated MBTs and other armored vehicles, often lacking the required armor protection, are still kept in depots. It is now convenient to upgrade them to optionally unmanned weapons by adding a humanoid driver, and a robotic arm as a loader. Sensors, an optional automatic driving system, a control and communication suite would complete the transformation. The main armament and secondary armament may be also changed or upgraded. The off-the-shelf huge electronic equipment can be installed wireless inside the hull. The old crew compartment may be spoiled of all the human related parts. Only the driver seat may be kept in order to leave the capability to remove the humanoid, robotized driver and reinstate the human one. This upgrade should also include a diagnostic system for the vehicle, the sensors and the additional systems to reduce the maintenance burden. An additional, specialized, lightweight armor suite should be focused to protect the mobilization system, the robots, the control and the communication system. This second part of the paper introduces a few options to convert the Leopard 1 MBT to an optionally piloted UMBT (Unmanned Main Battle Tank). A first, minimal step, is just the automation of the original tank. In a second step, the weight is reduced by installing a smaller 60mm cannon with a lighter, but more numerous ammunition storage. A third step increases the firepower by installing on the main turret an automated turret with a 12.7 or 30mm cannon with an optional additional 7.62 machinegun. It is also highly advisable to add an APU (Auxiliary Power Unit) and a battery to reduce IR (infrared) signature, improve main engine life and reduce maintenance.

Keywords: Automated turret | Leopard 1 | MBT | UCV | UMBT | Update

[8] Piancastelli L., Pezzuti E., Cassani S., NEXT GENERATION MAIN BATTLE TANK. PART I: UPGRADING THE “PAN” TANKS, ARPN Journal of Engineering and Applied Sciences, 15(11), 1297-1305, (2020). Abstract
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Modern MBTs (Main Battle Tanks) last more than 30 years. During this period, they will be periodically upgraded in any aspect except the basic structure. Even the main armor is becoming an upgraded accessory that depends on the nature of the threat. The main armament may be also changed or upgraded. The huge electronic equipment is the most upgraded part. The crew compartment may be upgraded in internal armor (for example for spalling), interfaces (optics, displays, commands), safety and protection devices (fire detection and suppression, ejection seats..). This continuous upgrade process should be included in the design of new vehicle, than can be modular for these mid-life upgrades. The vehicle is designed by adding items to the crew compartment and to the mobilization system. As an example, this first part introduces a few options to retrofit the ARIETE MBT. The retrofit cannot be reduced to engine and armor upgrade. A reasoned step approach is outlined in this paper. The first minimal step is based on an active armor and an HMD (Helmet Mounted Display) visual system. The weight increase is compensated by reducing road wheels weight. A second step increases firepower by installing on the main turret an automated turret with an automatic small cannon and a machinegun. The weight increase is compensated by limiting the internal ammunition storage of the main cannon to the anti-tank ones. A third step converts the turret internal ammunition storage into an automatic reloading system. In this way, the crew is reduced from 4 to 3. A fourth step increases crew safety by relocating the driver in the turret and by installing ejection seats. Solutions to reduce ground pressure and to increase the effective “power” available by replacing the final-drives and adding two electric motors on the front sprockets are also briefly examined. It is also highly advisable to add an APU (Auxiliary Power Unit) to reduce IR (infrared) signature, improve main engine life and reduce maintenance.

Keywords: ARIETE | automated turret | MBT | power | updated

[9] Piancastelli L., Cassani S., Energy transfer from airborne high altitude wind turbines: Part III. performance evaluation of a small, mass-produced, fixed wing generator, ARPN Journal of Engineering and Applied Sciences, 15(12), 1355-1365, (2020). Abstract
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High altitude, airborne, wind-energy extraction-systems are the only true alternative to carbon and nuclear produced energy. Airborne Wind Turbines are very efficient due to the possibility to search the altitude with the nominal wind velocity. Winds are very stable and fast at altitudes from 4,000m (13,000ft)-11,000m (36,000ft). It is possible have many airborne generators near consumers in restricted airspace regions. In the first two parts, autogiro solutions demonstrated to be fully feasible but not economically convenient. This third part of the paper deals with the design of a mass-produced fixed wing system for power generation. A fixed wing drone with a minimal airframe was conceptually designed for this purpose. The power generated is 220 kW at 13,600ft (4.15 km) as in the first parts of this paper. 13,600ft (4.15 km) is statistically the best altitude for high power availability and reasonable tether length. The drone is a simplified, unmanned ultralight aircraft. Therefore, it has all the advantages of ultralights: the simplified design rules, the vast knowledge and the mass-produced commercial parts and subsystems. Ballistic parachutes are also available for emergency. As in the first two parts of this paper, the airborne system is tethered to transfer the electric energy to the national grid. On ultralight-generator deployment, the reversible electric generator works as a motor and the airborne generator flies as an aircraft. This UAV (Unmanned Aerial vehicle) can take off from a very short grass field due to the low wing loading. The UAVs unfolds and holds the tether up the required altitude. In the climbing phase, the tether powers the aircraft using the national grid electric power. Once the airplane reaches the operating position, as the nose is turned into the wind, the wind provides the lift and the propeller is reversed to windmill. In this way, it is possible to convert the electric motor into a generator. The autopilot keeps the airplane in the desired position. In nominal attitude and altitude (100km/h@4,150m-54kn@13,600ft), the rotor-generator outputs 0.22 MW. A preliminary design of a mass produced prototype is introduced in this paper with a cost per kWh competitive with fossil generated energy.

Keywords: Airborne wind turbine | Electric power generation | Fixed wing | Green energy | High altitude

[10] Piancastelli L., Cassani S., Energy transfer from airborne high altitude wind turbines: Part I, A feasibility study of an autogirogenerator from an existing helicopter, ARPN Journal of Engineering and Applied Sciences, 14(7), 1407-1413, (2019). Abstract
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Current designs of ground based, wind energy extraction systems have limitations of wind instability and high cost of installations. The efficiency of these systems is optimal for a nominal speed and decrease sharply for higher or lower winds. This paper introduces large air rotors at high altitude for powerful and relatively stable air stream out of ground effect. This first part deals with an existing helicopter that is transformed to an autogiro for power generation. The helicopter is linked to the ground with a cable that connects the airborne generator to the ground power grid. In our case the air rotor system flies at an altitude of about 4 km that is statistically the best compromise between power available and altitude. Two versions of the helicopter are considered: electrical (motors-generators) and hybrid (turboshafts + generators). In the electrical version, the electric motors power the helicopter that climbs up the required altitude and lift the cables. At this point, the motors are switched to generator-mode and the helicopter keeps altitude as an autogiro and generates energy. The hybrid solution adds the generator(s) to the helicopter. The hybrid-helicopter climbs with the turboshafts and then trip-off the engines to work as an autogiro-generator. We used is the largest available helicopter: the CH47 Chinook. This choice is because it is economically convenient to use the largest wind generator possible. Both fully electric and hybrid solutions proved to be technically feasible. However, the pure electric solution requires a huge amount of power from the power grid (7 MW), therefore has relatively high installation costs. For this reason, the hybrid solution is more practical. The average power produced is more than 0.8 MW. Unfortunately, the cost per kWh is two order of magnitude higher than the carbon produced one. Therefore, this solution is convenient only when you have problems to take the fuel or the grid to the place where energy is needed. Helicopter/autogiro stability and control systems enable to change altitude and to deal with emergencies. This airborne system provides the following main advantages: power production capacity higher than conventional ground-based small rotor designs; the installation is environmentally friendly also for the propeller noise.

Keywords: Airborne wind turbine | Autogiro | Electric power generation | Green energy | Hybrid helicopter

[11] Piancastelli L., Cassani S., Energy transfer from airborne high altitude wind turbines: Part II performance evaluation of a autogiro-generator, ARPN Journal of Engineering and Applied Sciences, 14(17), 2972-2979, (2019). Abstract
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High altitude, airborne, wind-energy extraction-systems have the advantage of larger wind stability and higher power production. The efficiency of these systems is optimal because the nominal speed can be searched by varying altitude. Several airborne generators can be grouped in restricted airspace regions near consumer sites. This second part of the paper deals with the design of the simplest and cheapest autogiro for power generation. A single rotor autogiro with a minimal airframe was conceptually designed for this purpose. The power generated is 800 kW at 13,600ft (4.15 km) as in the first part of this paper. The rotor of a known helicopter, the CH-53E Super stallion, was used for the design. Generalpurpose equations for helicopters were adapted to evaluate the weight of the system. As in the first part of this paper, the airborne system is tethered to bring the power to the national electric grid. The altitude of 13,600ft (4.15 km) is statistically the best compromise between power available and tether length. On autogiro-generator deployment, the reversible electric generator works as a motor and the autogiro becomes a helicopter. This helicopter hold the tether and climbs up the required altitude. In this phase, the tether supplies the power from the national grid. Once the helicopter reaches an altitude slightly higher than the desired one, the power is turned off and the helicopter begins the autorotation. The electric motor becomes a generator. The autogiro begins to work with the rotor inclined. The control system inclines the autogiro to the required angle of attack into the incoming wind. In this configuration, the rotor produces electric power and provides the necessary lift to the airborne generator. In this configuration, the generator outputs 0.8 MW with a wind velocity of 54 knots (100 km/h). Unfortunately, the cost per kWh is one order of magnitude higher than the carbon produced one. This solution is more convenient than the one of the previous paper in which the cost was an order of magnitude higher. Still, it is not competitive with traditional energy production.

Keywords: Airborne wind turbine | Autogiro | Electric power generation | Green energy | High altitude

[12] Piancastelli L., Sportiello L., Pezzuti E., Cassani S., Study and optimization of advanced heat sinks for processors, ARPN Journal of Engineering and Applied Sciences, 14(5), 1082-1088, (2019). Abstract
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The main task of this project is the development of a modular heat exchanger to dissipate a TDP (Total Dissipated Power) of 140-180 W on a microprocessor. This exchanger should be able to dissipate the reference target TDP respecting the maximum operating temperatures (above these temperatures the CPU goes into thermal throttle) and the longevity temperatures (lower than the thermal throttle temperatures). This result should be achieved while providing product versatility (based on the concept to adapt the exchanger to each socket), acceptable noise, acceptable size and cost. The heart of the project is the design of a suitable fin surface to protect processors with high TDP. In this case, a significant increase in fan speed and in the size of the finned body is inevitable. In this way, an increase in the heat removal is obtained by larger airflow rate (high number of revolutions of the fan) and the large exchange surface. Considering the impact of these changes, the design of the exchanger is extremely critical in terms of size and noise level. Another physical limit is represented by the progressive and unavoidable phenomenon of electro migration that afflicts each circuit, the more the temperatures separate from those of longevity, the lower the useful life of the CPU. Once the longevity temperature is exceeded, the useful life of the processor decreases with increasing temperatures until the thermal throttle temperature is reached, which causes an abnormal system shutdown. The processors with a TDP from 65W to 95W are the most numerous. For this reason, most aftermarket solutions are designed to dissipate this TDP. The main purpose of this study is to examine the best geometry for a modular exchanger that is able to effectively dissipate the higher TDP (up to 180W) typical of modern high performance processors. For this purpose the Golden-section search is introduced for optimizing the number of fins. The heat exchange is simulated with fluid dynamic simulations (CFD). This new study allows obtaining an optimal design for the construction of the exchanger. The use of an optimal finned surface avoids the use of heat pipes. This approach simplifies the design. Moreover, by using materials with high thermal conductivity (such as copper alloys instead of aluminium alloys) we can certify the heat exchanger for TDP larger than the design one and therefore cope with even higher thermal loads. In this way, we can also effectively dissipate very performant CPUs (very uncommon) with extremely high TDPs such as FX-9590 with a 220W TDP (declared by the manufacturer AMD), maintaining in any case temperatures below the maximum thermal specifications.

Keywords: CFD | CPU | Golden-section search | Microprocessors | Thermal analysis

[13] Piancastelli L., Colautti D., Cremonini M., Cassani S., Torre A., Pezzuti E., Feasibility study and preliminary design of a Ram-Pulsejet for hypersonic passenger Air Transport, ARPN Journal of Engineering and Applied Sciences, 13(20), 8356-8365, (2018). Abstract
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In hypersonic aircrafts, the necessity of operating at speed lower than Mach 1.0 obliged the designers to use the complicate propulsion plant of the mixed compression turbojet. Fast commercial passenger transportation will probably shorten the flight time by a factor 5, from the actual 6 hours to 1 hours for the London-NYC flight route. Therefore, the engine will work for a shorter time. The subsonic part of the flight is very limited. For this reason, a possible solution can be to substitute the turbojet with a pulsejet in the ramjet duct. Valveless pulsejets are extremely, simple, reliable, lightweight, fully throttable jet engines. The main limitations of the pulsejet are very low efficiency, relatively low "thrust density" and noise. Noise is naturally reduced as the main working frequency passes from the 150Hz of small pulsejet to the 40Hz of larger ones. Efficiency can be increased inserting the pulsejet in a ramjet-duct. This solution increases the pressure at the pulsejet intake and efficiently recovers heat from the pulsejet walls. Finally, it is possible to decelerate the jet with an ejector exhaust thrust augmenter. The feasibility of this concept is investigated in this paper. For this purpose, it was imagined to develop a transport aircraft with the aerodynamic of the Valkyrie and the new propulsion system. A cruise speed of MACH 3.5@25,000m was simulated with CFD. In this cruise condition the pulsejet works as a combustion stabilizer for the ramjet. Also, the take-off condition was simulated. At take off the thrust is obtained only by the pulsejet.

Keywords: CFD | Hypersonic transportation | Pulsejet | Ramjet | Simulation | Thrust

[14] Piancastelli L., Bragaglia L., Cremonini M., Cassani S., Pezzuti E., Feasibility study of the installation of an additional "over lift" wing on the ch47 Chinook for cruise performance improvement through the lift-compound approach, ARPN Journal of Engineering and Applied Sciences, 13(19), 8142-8149, (2018). Abstract
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The tandem rotor configuration is particularly convenient for the lift-compound approach in helicopters. In fact, the additional wing is positioned between the two rotors in an area that is marginally interested by the airflow in vertical flight. On the contrary, in horizontal flight, the airflow accelerated by the frontal rotor directly invest the wing improving its lift. A very thin wing with a short chord and a relatively large span can be manufactured with the same technology of the rotor blades. If this wing is fixed without control surfaces, the additional weight can be extremely limited. A concaveconvex high lift airfoil can be used. This airfoil is relatively stiff due to the large bending moment of inertia. A skin stressed structure can be used for the additional wing to obtain also a large torsional stiffness. This lightweight wing can be installed on the helicopter when required and it can be optimized to a defined flight condition. In our case the optimization was performed for cruise. With a very limited weight increment and with a lift penalty within the simulation approximations, the cruise fuel consumption can be halved. The result is impressive for ferrying and long range passenger transport operations, where load capacity can be fully exploited only by increasing the fuel load. In this case a helicopter like the Chinook can perform long range missions with a significant increase in operational capability.

Keywords: Cruise | Helicopter | Lift-compound | Range | Tandem rotor

[15] Piancastelli L., Cremonini M., Cassani S., Calzini F., Pezzuti E., Intake and exhaust position optimization in the cooling duct of diesel helicopters, ARPN Journal of Engineering and Applied Sciences, 13(17), 4811-4819, (2018). Abstract
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CRDID (Common Rail Direct Injection Diesel), automotive derived engine, main advantage is the enormous amount of experimental data. These engines are produced in millions of units and reliability data based trillions of hours are available. It is also possible to run automotive CRDIDs with jet fuel. It is also possible to mix the two fuels with a proper ECU (Electronic Central Unit) mapping. Therefore, the necessity to refuel in airports can be eliminated. Moreover, the additional mass of CRDIDs is largely compensated by the reduced fuel amount necessary to exploit the same mission/flight. However, an additional cooling system duct should be added. For this purpose, fans are replaced by ejector exhaust (augmenter) that does not need fan additional power. Solid Works Flow Simulation confirmed the feasibility of an ejector-exhaust-powered cooling. However, pressure fields around the helicopter varies in a very significant way in the different flight conditions. High cooling duct efficiency requires pressure and clean air at the intake port and negative pressure at the duct nozzle. Therefore, a optimization of the cooling duct positioning has been carried out on a common light helicopter (Eurocopter EC 120). Several different solutions have been simulated with Solid Works Flow Simulation. CFD confirms the ejector choice and the design criteria. The best configuration is a derivation of a Formula 1 intake duct. This solution proved to be the most effective for the CRDID-exhaust powered cooling duct. The result is that the ejector exhaust (augmenter) is extremely effective. With two small intakes at the side of the mast, the pressure differential between the intake and the nozzle of the duct proved to be extremely stable in every flight condition, even with crosswind.

Keywords: CFD | Cooling | Diesel | Efficiency | Exhaust augmenter | Helicopter

[16] Piancastelli L., Cassani S., Pezzuti E., Pompei L., Multi-objective optimization of the cooling system of a diesel helicopter, ARPN Journal of Engineering and Applied Sciences, 13(16), 4610-4616, (2018). Abstract
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CRDID (Common Rail Diesel Engine) main advantage is the extremely high efficiency (up to 52%), the enormous amount of hours run and the flight readiness. Moreover, diesel fuel is safer than jet fuel and it is available everywhere. Therefore, refuelling flights to airports or dedicated supply lines can be avoided. However, diesel engines are generally heavier than turboshafts and require an additional cooling system. This requirement is particularly stringent during near stationary operations of the helicopter. In fact, if fans are used for the cooling system, the available power is reduced with an increased penalty weight for the installation. For this reason the ejector exhaust system can be successfully used in CRDID powered helicopters. A feasibility study of the cooling system for a CRDID (Common Rail Diesel Engine) on a common light helicopter (Eurocopter EC 120-class) is introduced. Optimization of this system is performed. The total mass available for the CRDID is evaluated starting from fuel consumption and helicopter data. A derivative of an automotive engine is proposed for the turboshaft replacement. The result is that the ejector exhaust (augmenter) is extremely effective. Solid Works Flow Simulation confirms the ejector choice and the design criteria.

Keywords: CFD | Cooling | Diesel | Efficiency | Exhaust augmenter | Helicopter

[17] Piancastelli L., Bernabeo R.A., Cremonini M., Cassani S., Calzini F., Pezzuti E., Optimized parachute recovery systems for remote piloted aerial systems, ARPN Journal of Engineering and Applied Sciences, 13(16), 4590-4597, (2018). Abstract
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The new RPAS (remotely piloted aerial systems) are mostly video cameras with wings whose ownership isn't enshrined in any constitution. Rulers are rushing to do regulate the lack of safety and accountability for RPAS. In Italy ENAC (aviation authority) legislated against random acts of stupidity and probable failures. For the current year of 2015, there is a forecast to sell $1bn worth of RPAS product. For these reasons the installation of RPS (Recovery Parachute System) on commercial RPAS is particularly interesting. A few RPS manufacturers have manufactured specific RPS systems for "drones" both rotary and fixed wing. However, these systems are designed with the same criteria of manned aerial vehicle. This paper demonstrates that the design criteria of RPAS are sensibly different from other applications. In particular the rate of descent during recovery should be reduced from 6m/s to 2m/s. This fact poses new challenges in parachute design. In fact RPS mass depends on parachute diameter that increases with low descent rates. This paper demonstrates that it is possible to design effectively RPS for RPAS up to 80kg by using nonwoven fabric in parachutes. In this way the RPS mass is a small fraction of the RPAS one. Deployment systems are not a problem for RPAS since masses are extremely small and the power necessity are accordingly limited.

Keywords: Parachute | Recovery | Remotely piloted aerial systems | Unmanned aerial vehicles

[18] Piancastelli L., Pirazzini A., Cremonini M., Cassani S., Calzini F., Pezzuti E., The optimization of power generation in low-cost Massproduced wheeled wind turbines, ARPN Journal of Engineering and Applied Sciences, 13(15), 4466-4474, (2018). Abstract
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In fixed wind turbine installations, the optimal wind location is difficult to individuate, permissions are difficult to obtain and the production site is distant from the costumers. The large production scale of small wheeled wind turbines keep the cost at minimum and give the possibility to install the windmill close to the final costumers. CFD simulation makes it possible to optimize the matching of a small mobile wind turbine with an automotive commercial alternator. This paper proposes an innovative device to furl the wind turbine around the pole axis in such a way to optimize energy production and avoid over-speed. For this purpose a commercial shock-absorber and a cam mechanism are used. The CFD simulation, in this case with Flow Simulation of Solid Works, makes it possible to design the turbine, the tail vane and the mechanism to maximize energy production. The device includes a shock absorber and a cam mechanism. The system provides optimum matching of the turbine torque output to the generator shaft. The same mechanism also determines the cut-out speed. The automotive generator includes a system to charge a 24V standard battery. Then, a power inverter outputs the electric energy to the grid. The 4m-diameter three-blades-rotor is connected to the 3.6kW automotive alternator through a commercial 2.5:1 speed multiplier.

Keywords: Cam furling mechanism | Energy production | Generator matching | Low cost | Wind turbine

[19] Piancastelli L., Errani V., Cassani S., Calzini F., Pezzuti E., An analytical solution for the determination of the loads acting on a semi-elliptical wing: The case of the Reggiane Re 2005 WWII fighter, ARPN Journal of Engineering and Applied Sciences, 13(14), 4393-4400, (2018). Abstract
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Many papers for the analytical solution of the lift distribution on a semi in semi-elliptical wing have been published. These works [1] usually approximate the solution by series expansion. This paper introduces an original method for the closed-form solution of this problem. The solution is possible through the use of symbolic manipulators. The wing of the WWII fighter "Reggiane Re 2005" has been solved analytically with the proposed method. The results are similar to the ones obtained by the panel-method and CFD. A CFD simulation of the Re 2005 at maximum speed demonstrates that these results are reasonable.

Keywords: Analytical closed solution | Elliptical wing | Lift | Load

[20] Piancastelli L., Cassani S., Calzini F., Pezzuti E., The decisive advantage of CRDID on spark-ignition piston engines for general aviation: Propeller and engine matching for a specific aircraft, ARPN Journal of Engineering and Applied Sciences, 13(13), 4244-4252, (2018). Abstract
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Aircraft fuel consumption depends on engine, engine installation, propeller and aircraft efficiency. The matching of the installed propeller is optimized for a design point and it is a compromise for the other working points. The matching of aircraft optimum lift/drag, the minimum engine fuel consumption and the maximum propeller efficiency is rarely achieved. The hyper simplified model on books does not reach the result. Practically very few aircrafts truly match the three conditions The champion of matching are current airliners that, at least in cruise and with half the fuel, reach the optimum at least at the nominal density altitude. In addition, a few fighters and record aircrafts also achieve the maximum possible speed at the nominal conditions. The large majority of the general aviation aircrafts are far from the optimum matching. Even Unmanned Aerial Vehicles are not champions of propulsion efficiency. Ultralight and sport aircraft are the worst. Turbines are very difficult for matching since their optimum efficiency is reached in a very limited working area. Even spark ignition engines are not efficient in off-design conditions. In fact, the spark ignition engine works with an air to fuel ratio by mass that can ran from 16:1 (lean mixture) down to 12:1 (rich mixture). Even spark ignition direct injection engines the combustion takes place within this range. At the relatively high torque settings typical of aircraft engines, the air inside the combustion chamber is burnt entirely and the power output depends on the engine volumetric efficiency. In diesel engines, the air inside the combustion chamber is never burnt entirely. The minimum air to fuel ratio is around 17:1, but the engine works well with any air to fuel ratio below this value. This means that CRDID (Common Rail Direct Injection Diesel) efficiency or BSFC (Brake Specific Fuel Consumption) curve is flatter than the spark ignition engine one. This fact gives a decisive advantage in the propeller matching and in the fuel consumption. In fact, off-design performance is the strongest point in favour of CRDIDs in general aviation. Therefore, the fuel consumption of CRDID takes advantage not only from the extremely high efficiency of the engine, but also from the better matching. In fact, it is possible to map the CRDID FADEC (Full Authority Digital Electronic Control) to optimize SFC (Specific Fuel Consumption). In the example shown in this paper, a CRDID needs nearly half the fuel necessary to a very good spark ignition engine.

Keywords: Aircraft matching | Diesel engine | Power plant installation efficiency | Propeller | Propeller efficiency | Spark ignition engine

[21] Bernabeo R.A., Piancastelli L., Malik Z.H., Al Azad A., Yaseen J.A., Study and testing of a green trainer to transform small general aviation aircraft for training into a no-emission aerial vehicles, 2018 Advances in Science and Engineering Technology International Conferences, ASET 2018, 1-3, (2018). Abstract
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The large majority of current trainers are piston engine aircrafts. Their engine lasts 2,000 hours maximum. The idea is to substitute the engine with a green electric powerpack with the same performance of the original unit, but with no emission and basically with no maintenance. The powerpack should be easy to install, safe and should provide sufficient autonomy. This last part is particularly easy for trainers, since they fly in a very standard way. At morning, with the battery fully charged, the instructor and the student perform a flight that lasts typically from 20 minutes to 2 hours. On landing a de-briefing of the student takes place. This phase is followed by the briefing of the new student. These two steps take at minimum of 30 minutes. During this time the battery can be partially recharged. The process will continue for a full day, with a longer recharge during break times. Therefore, it is perfectly possible to have a one day autonomy (about 10 hours). This project is intended to develop an experimental green trainer to validate the best configuration for this power pack and to find-out critical issues on installation, safety, reliability and maintenance. Finally, a minimum number of 300 hours of flight will be performed to perform an accelerated test to individuate critical safety issues on the new proposal. This part should be considered as in integral part of the University Career for those aviation students who want to get involved in testing and engineering, rather than only flying. At the same time, converting powerplants from the combustion ones into the electric ones will contribute to reduce the polluting emissions in the air that produce micro-climate changes.

Keywords: aircraft trainers | Electric engines | emissions | maintenance

[22] Piancastelli L., Powerplant reliability issues and wear monitoring in aircraft piston engines. Part II: Engine diagnostic, Drones, 2(1), 1-15, (2018). Abstract
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This paper introduces a method to efficiently monitor the status of a piston engine during flight. ECUs (Electronic Control Units) make it possible to fly safely without emergencies or urgencies with random electronic failures of components and connections. The same can be easily done on older engines by adding a reliable digital monitoring system and an automated calibration of the carburetors. In fact, their reliability is several order of magnitude inferior to modern turboshafts. In modern engines with FADEC (Full Authority Digital Electronic Control) as the “on” button is pressed the sensors and actuators are checked. The CPUs will then run start-up during the cranking phase (engine running without ignition). If everything is all right, then the engine starts and the post start checks are also performed. During flight, the ECU checks CPUs, sensors and actuators. Therefore, the electronic system can be monitored with high reliability without much effort. The sensors may crosscheck the engine situation and may output very reliable early diagnosis of incoming failures. Statistical data on spare parts are invaluable for monitoring application, signaling weak or not-lasting components and failure modes. This is another advantage of automotive piston engines conversions to aircraft use.

Keywords: Aircraft | Monitoring | Piston engine | Reliability

[23] Piancastelli L., Cassani S., Calzini F., Pezzuti E., Mobility improvement of heavy tracked vehicles: The "pan" tank experience, ARPN Journal of Engineering and Applied Sciences, 13(22), 8937-8944, (2018). Abstract
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This paper shows that the sinkage of the tracked vehicle is the most important parameter in its mobility. Power and fuel consumption follow cubic power law with sinkage. So the usual strategy to increase power is not the more convenient way to improve vehicle off road performance. The Ground Pressure (GP) is the critical parameter. Power requirement goes with the cubic power of sinkage. GP above 0.9 daN/cm2 should be avoided at all costs. The best way to obtain this result on an existing design is to increase track length. However it is easier to work on track width. The easiest modification is to add "Duckbill extensions" in the outer part of the shoe. This system was used on the Sherman Tank when additional armor was added. With modern technology it is perfectly possible to perform experimental tests with new shoes. This can be done by manufacturing prototypes of high stress nitrided steel shoes, usually with 300M high strength steel. Comparative fuel consumption is a good index of vehicle performance. Also wheel diameter and width can be increased to improve off-road performance. Specialized tracks for different terrains should also be designed. The gravity center should be kept slightly rearward. This attitude should not be excessive to keep the pressure value more even possible along the track. In any case the vehicle naturally assumes the backward inclination due to terrain compression. Another important improvement is the addition of computer controlled directional control to improve the accuracy of trajectories. This is particularly important for tracked vehicles where turning involves extremely high energy consumption.

Keywords: Ground pressure | Mobility | Tracked vehicles

[24] Piancastelli L., Pezzuti E., Cassani S., Flow analysis of multiple injectors in high-power-density HSDI CR diesel engines, Defect and Diffusion Forum, 388, 1-13, (2018). Abstract
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The primary task in DI (Direct Injection) diesel engines design is the fulfilment of the required emission limits. This result should be achieved while still providing optimum torque-to-rpm curves, acceptable fuel consumption, acceptable power density and affordable purchase and maintenance costs. One method to achieve these objectives is the downsizing. In this case a significant increase in the crankshaft speed and boost pressure is unavoidable. In this way an increase in air flow rate through the intake and exhaust ducts is obtained. Considering the impact of these changes, the duct design is extremely critical due to Mach number. Another physical limit is the CR (Common Rail) injector dynamic performance. This performance decreases with injector size and maximum fuel flow for inertia problems. Automotive engines in the range of 10 to 100 HP per cylinder are the most numerous. For this reason, these injectors are the most updated. Furthermore, their small inertia favors a better dynamic performance. The larger number of nozzles improves combustion performance. In fact, the better surface to volume ratio or the spray improves heat transfer. For this reason, it is convenient to use multiple injectors systems in modern HSDI (High Speed Direct Injection) CR large diesels, as it was common in the past. The primary purpose of this study is to examine the best duct geometry on a modern two-injectors-per-cylinder truck engine. For this purpose a new promising, patented concept is introduced. The study includes flow simulations during the intake phase. This new-patented design enables the formation of two extremely strong homogeneous swirls centered to the injectors, with excellent swirl and flow coefficients. The use of swirl generators on the manifolds avoids the necessity to design helical intake ducts. This approach simplifies head design. Moreover, using a VG (Variable Geometry) arrangement for the volutes (swirl generators) it is possible to tune the swirl index at the optimum for every crankshaft velocity and every load. In this way, the vehicle fuel consumption is reduced.

Keywords: Common Rail | Diesel | Direct injection | Multiple injectors | Swirl index

[25] Piancastelli L., Cassani S., Tribological problem solving in medium heavy-duty marine diesel engines part 1: Journal bearings, ARPN Journal of Engineering and Applied Sciences, 12(22), 6533-6541, (2017). Abstract
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Tribological problems are extremely common in classical DI (Mechanical Direct Injection Diesels) and those update to CR (Common Rail) technology. These engines are still widely used in Power Generation, Diesel-electric locomotives and Marine applications. The original design of the first prototype, in a few cases, was conceived just after the First World War The marine environment and the continuous increase of performances and TBO provoked several tribological problems that have been partially solved through the years. However, significant improvements are still possible with modern technology in journal bearings, lubrication systems and lubricants. The journal bearing should float before applying load, for this reason start up originated problems cause 90% of the bearings failure. The relative speed between journal and bearing should be over a well-defined value to avoid boundary lubrication. For this reason, compression reduction devices can be used at star or the geometrical compression ratio should be reduced in favour of turbo-charging induced compression. Start velocity should be controlled and the lubrication system should be checked. Finally, a suitable lubricant should be used.

Keywords: Cold start | Direct injection diesel | Friction | Journal bearings | Lubricant | Seizure | Tribology | Wear

[26] Piancastelli L., Ammoniaci L., Cassani S., Convertiplane cruise performance optimization with contra-rotating propellers, ARPN Journal of Engineering and Applied Sciences, 12(19), 5554-5559, (2017). Abstract
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A major problem of convertiplanes is that they need high disk-loading for efficiency in cruise and very low diskloading for lift at vertical take-off. Contra-Rotating Propeller (CRP) seems to be a convenient solution for the tilt-rotor convertiplanes derived from the tilt-motor V22/BA609. With this propeller arrangement the rotor diameter can be significantly reduced. In this way the disk-loading for vertical take-off is the same of the traditional propeller. In the case of an aerial vehicle similar to the V22 the rotor diameter can be reduced from 11.6m down to 7m. The lower diameter and disk area significantly reduces the drag at cruise speed. In this way propulsion efficiency is increased. In the V22 case a secondary reason for using contra-rotating propellers is to increase the propeller disk-area, and achieve higher vertical lift efficiency, within a propeller diameter limited by the height of the aircraft's undercarriage. In this way the emergency "conventional" horizontal landing is possible by giving a small amount of dihedral to the wings (8 DEG). This is easy to implement due to the absence, in the contra-propeller version, of the interconnecting transmissions between the two rotors at the wingtips. Moreover, the huge gyroscopic moments of the V-22/BA609 propulsion system that induces slow response on these aerial vehicles is annulled by the contra-rotating solution. Finally, the contra rotating propellers are less subject to the roughness zone of the VRS (Vortex Ring State) as demonstrated in wind tunnel tests. The higher complication of the two contra-rotating rotors is compensated by the fact that only the blade feathering DOF is implemented in the hub. In helicopter mode, the advancing blades of each rotor operate at higher pitch angles to produce more lift without prejudice to roll trim, since the difference in lift between the advancing and retreating blades of the upper propeller are balanced by the equal and opposite lift distribution of the lower one. This concept is called the Advancing Blade Concept (ABC) and has been successfully implemented in the Sikorsky's X2 high-speed technology demonstrator. Flutter due to lack of stiffness of the contra-rotating solution have been successfully solved in the fifties (see the nearly sonic Tu95 Bear). In this paper the cruise performance of the contra rotating solution is fully analysed with Solid Woks Flow Simulation. As expected the propulsion cruise efficiency is significantly higher than the traditional propeller solution.

Keywords: Contrarotating propellers | Convertiplane | Cruise | Efficiency

[27] Piancastelli L., Cassani S., On the conversion of automotive engines for general aviation, ARPN Journal of Engineering and Applied Sciences, 12(13), 4196-4203, (2017). Abstract
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Automotive engines have outstanding quality controls and extremely high cost-effectiveness. This is typical to lean, mass production. For this reason, the application of these engines on aircraft is most appealing. Ultralight-sport aircraft have pioneered this approach. A few automotive-aircraft certified engines are already available on the market. However, this approach has not been as successful as foresaw a few years ago. This is due to the differences between the automotive application and the aircraft use. These differences have lead to teething problems that have been solved in almost 20 years of research work. The level now reached and the experience achieved makes it possible to convert any "successful" automotive engine into an aircraft engine. This work starts with the description of the data available from automotive manufacturers. Automotive engines have a huge background of statistical data on performance, reliability and TBO (Time between Overhaul). The correlation of these data to an aircraft application is not straightforward. Then the performance curves obtainable from the new aircraft engine are introduced. Finally, an algorithm calculates the residual life to TBO (Time between Overhaul) of an automotive engine. The method was tested on a few small last-generation CRDIDs (Common Rail Direct Injection Diesels) and spark ignition (gasoline) engines. These engines were also converted for use into small aircrafts with power ranging from 60 to 200HP. This very simple method is implemented directly in the FADEC (Full Authority Digital Electronic Control) or E-ECU (Engine Electronic Control Unit) of the engine with very few lines of C-Code (C-Language Code). It is assumed that the engine undergoes regular maintenance schedule and OBD (On Board Diagnostic) is implemented. OBD is perfectly able to foresee the imminent failure of the accessories like the starting motor, the generator, the turbocharger, the injector(s), the HPP (High Pressure Pump), etc. These parts are external to the engine and can be changed during field maintenance. Accidents, like prolonged under/overcooling, crankshaft damper failure, overspeed are monitored by the OBD and require specific maintenance actions. Ordinary problems like excessive fuel, lubricant, coolant consumption, pressures out of range... are also dealt by the OBD-related service system.

Keywords: Aircraft | Automotive | General aviation | Piston engine | TBO

[28] Piancastelli L., Fiumana L., Cassani S., Study and optimization of a contra-rotating propeller hub for convertiplanes part 1: VTO and hovering, ARPN Journal of Engineering and Applied Sciences, 12(11), 3451-3457, (2017). Abstract
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Contra-rotating propeller seems to be a convenient solution for the tilt-rotor convertiplanes of the V22/BA609 type. With this propeller arrangement the rotor diameter is significantly reduced. In the case of an aerial vehicle similar to the V22 the rotor diameter can be reduced from 11.6m down to 7m. In this case the emergency horizontal landing is possible by giving a small amount of dihedral to the wings (8 DEG). This is easy to implement due to the absence, in the contra-propeller version, of the interconnecting transmissions between the two rotors at the wingtips. The V-22/BA609 configuration has a high roll polar moment of inertia with roll control implemented through differential rotor thrust. VRS is then particularly critical. The contrarotating propellers are less subject to the roughness zone of the VRS as demonstrated in wind tunnel tests. Furthermore, the airfoil chosen (NACA 0006) is particularly suited to have a smooth transition from the propeller working state to the windmill brake state. The stability of the contrarotating propellers and the possibility of the two hubs to rotate at different speed in windmill brake state, make it easier to enter into a stable autorotation state. The autogyro (autorotation) and the airplane mode landing are fundamental requirements for the certification of V22/BA609 as civilian transport. To make the certification easier it is possible to identify three flying modes for the aerial vehicle: VTOL with the hubs tilted vertically, STOL with the hubs at an intermediate angle and aircraft (horizontal hubs) for cruise. The transition can be restricted to most favorable conditions. The turboshafts may have two working conditions: in the cruise one the maximum pressure (and maximum efficiency) of the reference Brayton cycle is necessary. This pressure is achieved with the contribution of the air intake. In this mode the propeller tip speed can be near 0.5M. The lower disk diameter of the contra-rotating propeller guarantees better propulsion efficiency. The VSTOL mode is with maximum power, with lower maximum pressure in the turboshaft and with higher propeller tip speed (0.91M). The hub can be simplified with the Advancing Blade Concept (ABC) that requires only the blade feathering DOF. The upper and lower rotors require about 1 DEG of difference in AOA (Angle Of Attack) in most conditions. The gyroscopic effects are neutralized and the force necessary to tilt the rotors is much lower than the single rotor solution. This assures also better handling in most flying conditions. Finally, the two-contra-rotating-rotors-tilting mechanism is not more complicated than the single rotor one.

Keywords: Contrarotating propeller | Convertiplane | Efficiency | Handling | Lift | Safety | VRS

[29] Piancastelli L., Gardella M., Cassani S., Cooling system optimization for light diesel helicopters, ARPN Journal of Engineering and Applied Sciences, 12(9), 2803-2808, (2017). Abstract
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CRDID (Common Rail Diesel Engine) main advantage is the reduced fuel consumption, the safety and the flight readiness. In fact, diesel fuel is available everywhere and flights to airports just for refueling can be avoided. However, diesel engines are generally heavier than turbo shaft and require cooling. This necessity is particularly important during near stationary operations of the helicopter. If fans are used for the cooling system, the available power is reduced with an increased penalty weight for the installation. For this reason the ejector exhaust system can be successfully used in CRDID powered helicopters. A feasibility study for the installation of a CRDID (Common Rail Diesel Engine) on a common light helicopter (AB 206) is introduced. The total mass available for the CRDID is evaluated starting from fuel consumption and helicopter data. A derivative of an automotive engine can be used for the turbo shaft to CRDID powered plant conversion. The result is that the installation is indeed possible and the payload can be slightly increased in the diesel powered helicopter due to more power available.

Keywords: Diesel cooling helicopter ejector exhaust

[30] Piancastelli L., Clarke R.V., Cassani S., Diffuser augmentedrun the river and tidal picohydropower generation system, ARPN Journal of Engineering and Applied Sciences, 12(8), 2678-2688, (2017). Abstract
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At our current state of technological development, the designs being proposed for the "channeling of a turbine" based on wind power, commonly called DAWT (Diffuser-Augmented) or CWAT (Compact-Acceleration), utilize a diffuser (divergent) shaped as an airfoil. Further developments of the concept have brought about the introduction of other wingedprofiled ring structures behind or in front of the entrance to the divergent making the design more complicated as well as more expensive due to the difficulty of producing correct contours. Even though this results in an increase in power, it usually is limited to slightly more than a four-fold increase at most. In addition, brims (wing-lens) have been recently added around the external edges of the diffuser. Nonetheless, brims thus designed, are not suitable for use in a river due to the significant stress that the structure as a whole needs to withstand. No design, proposed until now, includes a convergent at the entrance to a turbine due to the obstruction effect that it has on the flow of water into the turbine, slowing it down and thereby reducing the acceleration produced by the "channelizing" divergent. This article will introduce an innovative convergent-divergent to which can be inserted a hydro-kinetic turbine which will increase the maximum output power available 12.7 times compared with a free turbine.

Keywords: Compact-acceleration | Diffuser-augmented | Hydro-power | Low head | Run the river | Water powered turbines

[31] Piancastelli L., Cassani S., Mapping optimization for partial loads of common rail diesel piston engines, ARPN Journal of Engineering and Applied Sciences, 12(7), 2223-2229, (2017). Abstract
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Theoretically, from a control design point of view, modern diesel engines are dynamic, nonlinear, MIMO (multiple-input and multiple-output) systems. This paper demonstrates that this assumption is not correct and a suitable model for predictive control (MPC) of power (torque), NOx and soot emissions based on temperature feedback is perfectly possible on SCR (Selective Catalytic Reduction) CRDITDs (Common Rail Direct Injection Turbocharged Diesel). The method optimizes the temperature at a selected point of the engine exhaust. This reference point is the turbocharger intake for Euro 0 (aircraft). For Euro 6+/US Tier 3a+ SCR diesels, the reference point is the intake of the "emission control system" usually at the outlet of turbocharging system. The traditional five-inputs are only theoretically independent. In fact, fuel injection duration depends on torque (load) and efficiency. Fuel advance is retarded to obtain the required reference temperature. HPEGR (high pressure exhaust gas recirculation) is adopted only when the emissions cannot be controlled by the fuel advance. VGT (variable geometry turbo) valve positions and low pressure LPEGR maximize the air flow (efficiency) at the engine intake. On the outputs, peak pressure and peak pressure derivative should be kept within structural limits. Soot and NOx are two faces of the same problems. In fact, high NOx means low soot and good combustion efficiency. Temperature and air flow are the keys to obtain optimum engine performance. Air flow is controlled by the turbocharger, while temperature depends on injection. This paper demonstrates that CRDITDs mapping is much easier when the fundamentals of diesel combustion and SCR are simplified to basic concepts. The strategy to retard the injection advance increases efficiency of 30% over traditional LPP (Optimal Location of Peak Pressure)- mapping at low loads.

Keywords: Control unit | Diesel | Electronic | Emission | Mapping | Optimization

[32] Piancastelli L., Cassani S., High altitude operations with piston engines power plant design optimization: Nozzle design and ramjet general considerations, ARPN Journal of Engineering and Applied Sciences, 12(7), 2242-2247, (2017). Abstract
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In stratospheric flights with piston powered aircrafts, the cooling system takes part to the vehicle design optimization process. An integrated design of the cooling duct(s) is strictly necessary. At high altitudes, the cooling air is taken from high-pressure areas into a subsonic ramjet: the Meredith cooling duct. A diffuser reduces the airspeed and increases the pressure of the cooling air. Then a group of high performance finned radiators rejects the heat from coolant, air charge and lubricant. A variable geometry nozzle transforms the added enthalpy into speed and thrust. The nozzle is positioned in a low pressure, high turbulence area. The nozzle design and the duct thrust are discussed in this paper. At first the results from Parts I to IV are summarized and discussed. The resulting data are also exposed and summarized. The pressure recovery and heat rejection are evaluated in function of aircraft speed for a 1-m2vertical-radiator circular duct. The nozzle is then optimized and the total thrust is evaluated.

Keywords: HALE | Meredith effect | Nozzle | Optimization | Ramjet | UAV

[33] Piancastelli L., Migliano S., Cassani S., An extremely compact, high torque continuously variable power transmission for large hybrid terrain vehicles, ARPN Journal of Engineering and Applied Sciences, 12(6), 1796-1800, (2017). Abstract
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The planetary gear hybrid power train (PGHP) is known as one of the most compact speed reduction system. The PGHCVT (Planetary Gear Hybrid Continuous Variable Transmission) introduced in this paper varies continuously the reduction ratio by using an additional external, speed controlled, power source to the traditional thermal engine. The movement of the annular gear in the opposite way to the carrier P (Figure-2). In this way, when the annular is still, the minimum speed ratio is achieved. As the annular speeds up the speed ratio increases up to obtaining a still carrier. Theoretically, reverse ratio is possible by further increasing annular speed. However, speed limits on the annular gearing usually prevent the obtainment of a still carrier or a reverse motion. In any case, even a single stage planetary gearing obtains an extremely large transmission ratio variation. An example of 4WD (four Wheel Drive) vehicle is introduced in this paper with a preliminary design of the gearing system. The efficiency of the transmission is extremely high due to the very limited number of sliding contacts.

Keywords: CVT | Hybrid electric vehicle | Planetary gearing

[34] Piancastelli L., Burnelli A., Cassani S., Validation of a simplified method for the evaluation of pressure and temperature on a RR Merlin XX head, International Journal of Heat and Technology, 35(3), 549-558, (2017). Abstract
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Material behavior depends on average peak temperature, stress magnitude and stress gradient. This assumption is valid since temperatures varies slowly when compared to pressure (stress). In this paper, a RR Merlin head is simulated with a few mathematical models used in Formula 1 racing. These extremely simplified models make it possible to evaluate temperatures and pressures starting from very few data. The method is described in detail, along with the many experimental coefficients available from several years of design activity. A step by step approach is used to allow the comprehension of this method that was developed by the Authors. The choice of the RR Merlin was dictated by the public availability of experimental data on temperatures. In fact, in the case of the RR Merlin XX, very reliable experimental results are available in NACA TN 2069. A reverse engineering process was applied on a rescued RR Merlin XX head. An accurate redesign was performed to obtain a 3D model. Assembly instructions and tolerances were found on original Rolls Royce overhaul manuals. In this way assembly and working loads were calculated and simulated. Nonlinear FEA analysis was performed on this CAD model with extremely satisfactory results for the thermal loads. Well known criticalities of the original design were found. The results were compared with NACA results both for heat rejection and temperatures. However, the mechanical stresses proved to be more critical for simulation and evaluation. Therefore, they will be discussed in another, dedicated paper.

Keywords: CAD | FEA | Geometry | Optimization | Piston engine | Simulation | Thermal analysis

[35] Piancastelli L., Frizziero L., Cremonini M., GA multi-objective and experimental optimization for a tail-sitter small UAV, Lecture Notes in Mechanical Engineering, 0, 597-604, (2017). Abstract
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This paper introduces a Montecarlo Genetic Algorithm, hierarchical, multiobjective optimization of a Vertical Take Off landing Unmanned Aerial Vehicle having a tail sitter configuration. An optimization of the hierarchical type is introduced in place of the methods generally used multi-objective optimization, such as Pareto and “arbitrary” weighted sums. A Montecarlo method optimizes the weights of the final objective function used by the Genetic Algorithm. A very simple “spreadsheet based” algorithm defines the CAD model of the Genetic Algorithm individuals in order to evaluate the performance of the candidates. The optimization method described in this study appears to be very effective. Then experimental tests were conducted with scaled-down prototypes. Four flight tests were performed: Take Off, Cruise, Slow flight, Landing. A Taguchi matrix was defined for each experiment. The tests started from a prototype that comes directly from the Montecarlo Genetic Algorithm optimization and led to the final prototype shown along the paper (page 7, right figure). Unfortunately, the tail sitter approach proved poor control authority in the final phase of the vertical landing. Even the “final” prototype showed unsatisfactory behavior in case of erratic wind gusts. This unsolved problem is common to the tail sitter configuration that requires a power control by air jets or additional propeller to control the aircraft in the final phase of landing. Unfortunately, this necessity renders the tail sitter configuration inconvenient for small Unmanned Aerial Vehicles.

Keywords: Genetic algorithm | Montecarlo random optimization | Tail sitter | UAV

[36] Piancastelli L., Cassani S., Power speed reduction units for general aviation part 4: Simplified gear design for piston-powered, propeller-driven "heavy duty" aircrafts and helicopters, ARPN Journal of Engineering and Applied Sciences, 12(5), 1533-1539, (2017). Abstract
X

Bending fatigue (Strength) or surface compression/lubrication (Hertz stress) and scuffing resistance define aerospace gearing design and optimization. In addition, a correct design method must include adequate ability to resist all these types of failures. Of all the failures modes, tooth bending has the most severe consequences, whereas pitting and scuffing are durability-type failures that can be (theoretically) anticipated and corrected before final failure. However, in helicopter transmission pitting and scuffing are the main failure cause. Therefore, it is important for the designer to understand the criticalities of the different application. The third paper dealt with the general problem of designing the PSRU (Power Speed Reduction Unit) gear drives on a general aviation propeller-driven aircraft. This fourth part deals with aerobatic/racing/STOL-utility "heavy duty" aircrafts and with helicopters. In the first part of this paper, a verification method of a "general aviation PSRU" for a heavy duty aircraft is introduced. Then helicopter transmissions are discussed, starting from the most suitable gear types, the transmission architecture and the main problems. Bevel gearing are briefly introduced by defining design criteria, suitable materials properties and selection method. Then the flash temperature concept is briefly summarized along with experimental data on the most advanced steel alloys available on the market.

Keywords: Aircraft | Gear drive | Involute | Piston engine | PSRU

[37] Piancastelli L., Cassani S., Power speed reduction units for general aviation part 3: Simplified gear design piston-powered, propeller-driven general aviation aircrafts, ARPN Journal of Engineering and Applied Sciences, 12(3), 869-874, (2017). Abstract
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The power speed reduction unit (PSRU) is the device that is loaded by the piston engine and the thruster. The thruster, a propeller of a fan, acts on the PSRU to extract the required power at the optimum speed for the aerial vehicle. Inertia, thrust and vibrations load the PRSU. PSRU has been "the problem" of the years before WWII. These problems periodically come back from common design errors or from the introduction of new technologies. For historical reasons, FAR and JAR do not allow the use of belt and chain transmissions in PRSUs for aircrafts. However, recent advances in timing belts make it possible to manufacture lubrication free PRSUs. Multi-Groove-V belts have also been used successfully in helicopters and homebuilt aircrafts. Belt PRSU are critical in design and they will be fully analyzed in another paper. This third paper deals with the general problem of designing the PRSU gear drives on a general aviation aircraft [1-2].

Keywords: Aircraft | Gear drive | Involute | Piston engine | PRSU

[38] Piancastelli L., Cassani S., Power Speed Reduction units for general aviation part 5: Housing/casing optimized design for propeller-driven aircrafts and helicopters, ARPN Journal of Engineering and Applied Sciences, 12(2), 602-608, (2017). Abstract
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The purpose of this paper is to focus on the design of casings for aircrafts and helicopters PSRU (Power Speed Reduction Unit). This paper introduces a rigorous and practical design procedure for gearboxes. The work starts from the experience of the Authors in Formula 1 and Aircraft gearboxes. For certification, safety and durability reasons, aircraft and helicopter gearboxes did not have the same development rate of the Formula 1 counterparts. A brief history of Formula 1 PRSU/gearboxes forms the first part of this paper. This part includes also an introduction to material and manufacturing technologies. Then the modal analysis of the gearbox is discussed, along with the influence of tolerances and operating temperatures. Then cooling is briefly introduced. The gear train is focus of the PSRU. Proper gear meshing in any load and environmental condition is the main requirement of the PSRU. Unfortunately gears and transmissions are the source of many forcing time-varying forces that act on the housing. This forces not only vary with tolerances, temperatures and loads, but also with wear. Therefore, a comparison of the natural frequency of the housing, the torsional critical speed of rotor system and the flexural critical speeds of each of the shafts with the exciting frequency clearly may be used to qualify the gearbox housing. A finite element modelling of the gearbox housing can be carried out to obtain its natural frequency, stress distribution and forced response. Unfortunately, the excitation frequencies vary with tolerances and operating conditions. Furthermore, in aircraft PRSUs, it is common practice to vary the transmission ratio (and the gears) in the same housing. Therefore, the housing should dampen a fairly large number of exciting frequencies. This result is obtained by curved surfaces, ribbing and double walling. This approach also reduces the noise produced by the transmission. In fact, noise radiated by a gearbox is directly related to the vibratory level of its housing. Therefore, an additional aim of this study is to analyze the transfer mechanisms between the static transmission error of a gear pair and the dynamic responses of gear and housing of a gearbox. Aerospace and Formula 1 transmissions have many similarities, with Aerospace engineers working on both sides and importing solution. The great advantage of Formula 1 gearboxes was (until the unlucky Regulations of 2010) that it was extremely easy to make experiments. This is due to the fact that all Formula 1 cars are prototypes with test pilots on board. Therefore, this paper will take advantage of the knowledge achieved in Formula 1 to transfer these data to aerospace PSRU and transmissions [1-2].

Keywords: Aircraft | Gear drive | Helicopter | Housing | PSRU | Transmission

[39] Piancastelli L., Cassani S., Maximum peak pressure evaluation of an automotive common rail diesel piston engine head, ARPN Journal of Engineering and Applied Sciences, 12(1), 212-218, (2017). Abstract
X

This paper introduces a method to linearize a FE (Finite Element) nonlinear problem. This method reduces calculation time by several orders of magnitude. Therefore, head geometry is optimized without supercomputers. In this paper the method is applied to a very critical component: the aluminum alloy piston head of a modern Common Rail Direct Injection Diesel (CRDID) [1-2]. The method consists in the subdivision of the head, in several volumes, that have approximately a uniform temperature. Each volume has an ad-hoc material model that takes into account of temperature, pressure and pressure derivative. Therefore, material behavior depends on average volume temperature, stress magnitude and stress gradient. This assumption is valid since temperatures vary slowly when compared to pressure (stress). In this paper, a known head is analyzed and validated with this method. The head comes from an engine that has run at full load for a known period (60h). It was therefore possible to evaluate true temperatures on head from residual Rockwell B hardness (HRB). This procedure can be considered a reverse engineering approach to evaluate the evaluate the temperature on the engine head. The test was aimed to evaluate the maximum peak pressure possible for the cylinder head. This relatively easy procedure outputted a reasonable maximum value for the engine. In general, experimental tests have confirmed the cost-effectiveness of this approach. This method can be successfully used in many other applications. From the design to the optimization of new or existing critical engine components.

[40] Piancastelli L., Cassani S., Power speed reduction units for general aviation part 2: General design, optimum bearing selection for propeller driven aircrafts with piston engines, ARPN Journal of Engineering and Applied Sciences, 12(2), 544-550, (2017). Abstract
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The power speed reduction unit (PSRU) is the device that is loaded by the generating unit and the thrusters. Propeller induced, gyroscopic and inertia loads are extremely important for PRSU bearing selection and life evaluation. Engine powers become easily a secondary factor for bearings and housing design. For this reason, it is important to select the best bearing assembly for the specific application with the required propeller. After a general discussion about PRSU and housing design, a very simplified method for bearing life calculation is introduced in this paper. It is based on similar, proven and extremely successful design of existing PRSUs. This method compares the life of this design with the new one. Aerobatics and general aviation loads are also compared. This paper demonstrates that the selection of a CFRP fixed pitch propeller for aerobatics keeps the load approximately to the same level of a general aviation aircraft. This is true in the case of plywood-reinforced off-the-shelf propeller for the general aviation load history. Aluminum alloy propellers are to be discarded for aerobatic use [1-2].

Keywords: Bearings | General design | Piston engines | Propeller | PRSU

[41] Piancastelli L., Frizziero L., Pica S., Donnici G., High altitude operations with piston engines powerplant design optimization part IV: Radiators optimum design, ARPN Journal of Engineering and Applied Sciences, 11(9), 5650-5660, (2016). Abstract
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In high altitude operations, the cooling system takes part to the vehicle design optimization process. An integrated design of the cooling ducts is strictly necessary. At high altitudes, the cooling air is taken from high-pressure areas into an alternate, extremely optimized, path. A diffuser reduces the airspeed and increases pressure of the cooling air. Then a group of high performance finned radiators rejects the heat from coolant, air charge and oil. The high altitude, after diffuser radiator performance is discussed in this paper. At first high performance Formula 1 radiators are introduced and discussed. Experimental data are also exposed and summarized. The pressure drop and heat rejection are expressed in function or Re and Pr numbers of cooling air. Then the radiator performance at high altitude is extrapolated from the ground test data. Finally a few suggestions on radiator and cooling ducts arrangement are introduced.

Keywords: Cooling | HALE | Meredith effect | Optimization | Radiators | UAV

[42] Piancastelli L., Pica S., Donnici G., High altitude operations with piston engines powerplant design optimization part III: The diffuser critical design, ARPN Journal of Engineering and Applied Sciences, 11(7), 4461-4470, (2016). Abstract
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Low BSFC (Brake Specific Fuel Consumption) and flat-altitude-rating make piston engines ideal choice for subsonic flight at altitudes up to 20, 000m-65, 000ft. These propulsion systems are more complex than traditional applications that are normally limited to 5, 000-7, 000m (16, 000-23, 000ft). In fact, the air propulsion (propeller or fan), the air intake and the cooling system take part have huge volumes. Therefore, their design influences vehicle aerodynamics as a whole. The cooling system is an integral part of aircraft design. As assessed from WWII design heritage, the cooling duct can be a static subsonic ramjet: the Meredith cooling duct. At high altitudes, the Meredith duct air is taken from highpressure areas into an alternate, extremely optimized, path. This path should end with a nozzle in a low pressure, high turbulence area of the aerial vehicle. In subsonic ramjet cooling ducts, the "static compressor" or diffuser is the most critical part. In fact the maximum compression ratio is below 1.5. Its efficiency highly influences the total thrust and the cooling efficacy of the duct. The Meredith duct should be embedded in the fuselage or in the wing to avoid excessive external drag. Only the air intake is positioned outside. In propeller systems, the intake is positioned in the lower part of the aircraft at about 2/3 of the wing chord, where the pressure reaches its maximum. In propeller systems, the high altitude engine intake can be positioned at the end of diffuser to increase the engine boost. In this way the turbomachinery mass and volume is reduced and the power to mass ratio of the propulsion system is increased. In fan systems, higher pressure is present inside the fan duct. In this paper, the preliminary design of the cooling duct is introduced. However, a CFD/wind tunnel optimization is strictly necessary to achieve a fully effective system. In any case, the requirements of low weight, high reliability and long endurance HALE (High Altitude Long Endurance) UAVs (Unmanned Aerial Vehicle) requires further work on this specific subject.

Keywords: Cooling | Diffuser | HALE | Meredith effect | Optimization | UAV

[43] Piancastelli L., Pica S., Donnici G., High altitude operations with piston engines powerplant design optimization part II: Turbo-charging, turbo matching, efficiency and serial arrangement optimization, ARPN Journal of Engineering and Applied Sciences, 11(7), 4333-4345, (2016). Abstract
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Low BSFC (Brake Specific Fuel Consumption) and flat-altitude-rating make piston engines ideal choice for altitudes up to 20,000m-65,000ft. These propulsion systems are more complex than traditional applications that are normally limited to 5,000-7,000m (16,000-23,000ft). In fact, the air propulsion (propeller or fan), the air intake, the fuel system, the turbocharging, the exhaust and the cooling system take part to the design optimization process. An integrated design is strictly necessary. At high altitudes, the intake air is taken from high-pressure areas into an alternate, extremely optimized, path. In propeller systems, a diffuser is usually positioned in the lower part of the aircraft. It converts kinetic energy into pressure. In fan systems, a little amount of "high pressure" air is taken from the high-pressure area of the fan. In lower power units, automotive-derived turbochargers can achieve the required pressure ratio. However, this option is limited by the maximum amount of volumetric flow rate. Moreover, automotive turbocharger housings have to be redesigned to use low-weight inconel alloys instead of heavier cast-iron. A complete redesign of the high pressure turbocharger (the unit closer to the engine manifold) can achieve pressure ratios from 8:1 to 10:1. This expensive process increases the power to mass ratio of the propulsion system. For higher power rating over about 200 kW axial compressorturbine assemblies derived from small turboshafts can be used as a turbocharging unit. In this case the burner is substituted by the piston engine. Especially for diesel engines, the advantage lies in the efficiency (BSFC). In fact, the maximum temperature reached in the diesel combustion chamber is about 4200K and the air flow is much lower than traditional turboshafts. Hybrid and turbocompound solutions are also possible. The exhaust and the intake of the piston engine have to be redesigned. However, the requirements of low weight, high reliability and long endurance HALE (High Altitude Long Endurance) UAVs (Unmanned Aerial Vehicle) requires further work on this specific subject.

Keywords: HALE | Optimization | Propulsion | Serial cascade arrangement | Turbochargers | UAV

[44] Piancastelli L., Frizziero L., The installation of a common rail diesel engine on a light helicopter of the Eurocopter EC120 class, Ingenieria e Investigacion, 36(1), 6-13, (2016). Abstract
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A feasibility study for the installation of a CRDID (Common Rail Direct Injection Diesel) on a light helicopter is introduced. The total mass available for the CRDID is evaluated starting from fuel consumption and helicopter data. The conversion of an automotive unit was discarded to excessive mass and excessive costs of the conversion. A derivative of an automotive engine was then considered. This solution proved to be feasible. The installation of the new CRDID was then studied. The turbocharger and the cooling system were defined for the application. The result was the evaluation of the power plant installation mass that proved to be much lower than the maximum admissible. The installation is then possible.

Keywords: Common rail | Diesel | Helicopter

[45] Piancastelli L., Frizziero L., Pica S., Donnici G., High altitude operations with piston engines powerplant design optimization, ARPN Journal of Engineering and Applied Sciences, 11(5), 3525-3533, (2016). Abstract
X

Diesel and spark-ignition piston engines are an ideal choice for long endurance, high altitude operations (10, 000m/33, 000ft) and extremely high altitude operations (20,000m-65,000ft). These systems are more complex than traditional applications that are normally limited to 5, 000-7, 000m (16, 000-23, 000ft). In fact, the air propulsion system (propeller or fan), the air intake, the fuel system, the turbo charging, the exhaust and the cooling system take part to the design optimization process. An integrated design is strictly necessary. Since prop-fan is currently under development, the design should start from the choice between propeller and fan. This choice will influence optimum cruise speed, critical altitude and aircraft design as a whole. The air induction system is extremely important to improve efficiency, endurance and critical altitude. At low altitude, a filtered induction system is used for takeoff. At high altitudes, the intake air is taken from high-pressure areas into an alternate, extremely optimized, path. This induction system recovers as much pressure as possible, air kinetic energy at cruise speed. In propeller systems, the intake is usually positioned in the lower part of the aircraft. On fan systems, a little amount of "high pressure" air is taken from the high-pressure area of the fan. The exhaust system is also critical with the choice between pressure recovery and thrust. Exhaust-pressure-recovery reduces backpressure and temperature at exhaust. However, the improvement in critical altitude is marginal. In more common, thrust driven exhaust systems, the exhaust energy is converted into speed and thrust. At the relatively high speed of high altitude cruise, also the cooling system adds a small amount of thrust through the Meredith's effect. The piston engine power plant design is then extremely critical. Many different components should find the correct position for maximum performance. The power-plants of WWII water-cooled fighters and bombers are good examples, even if their design cruise altitude is below 10, 000m (33, 000ft). Modern turbofan and turbojet air intakes are also of help. However, the requirements of low weight, high reliability and long endurance HALE (High Altitude Long Endurance) UAVs (Unmanned Aerial Vehicle) requires further work on this specific subject.

Keywords: Cooling | HALE | Meredith effect | Optimization | Thruster | UAV

[46] Ceruti A., Bombardi T., Piancastelli L., Visual flight rules pilots into instrumental meteorological conditions: A proposal for a mobile application to increase in-flight survivability, International Review of Aerospace Engineering, 9(5), 144-151, (2016). Abstract
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This paper describes a handheld application to help pilots when entering degraded visibility conditions. In this case, the loss of control is a typical emergency situation from which a pilot should be able to recover, but often he/she doesn’t do owing to problems of situation awareness. A new instrument, based on the use of accelerometers/GPS equipping modern handheld devices has been designed, virtually tested in flight simulators and finally tested in flight. Attention has been given to show essential information in a very simple and intuitive way, so that the instrument can be useful in case of pilot disorientation, panic or high stress levels. After a testing phase, the instrument showed useful to provide an indication about the attitude of the plane and to provide the pilot an indication of the stick and throttle movements needed to restore a safe levelled flight. The use of this application by pilots in emergency situation can enhance the survivability in Instrument Meteorological Conditions also without a specific training. This paper shows how the high computation capability and advanced visualization devices typical of smartphones can be useful to increase the flight safety by developing a new class of emergency not-certified instruments. A further testing phase of the instrument in critical conditions like gusty environment or deteriorated weather will be carried out as a future development of this work to better evaluate the limits of the instrument herein described.

Keywords: Flight safety | Flight simulation | Human machine interfaces | IMC | VMC

[47] Piancastelli L., Frizziero L., Pica S., Donnici G., TBO evaluation of naval and aircraft diesel engines, ARPN Journal of Engineering and Applied Sciences, 11(1), 716-725, (2016). Abstract
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This paper demonstrates that the experience from Formula 1 and watercraft racing can be applied directly to assess and improve the aircraft/maritime conversion of automotive commercial engines. A direct comparison of the main parameters that characterizes modern CRDID (Common Rail Direct Injection Diesel) and Formula 1 racing engine demonstrates that the similarities are hidden inside the design criteria. In fact, CRDIDs should output high torque at low rpm (1000-3000rpm) while racing engine should have top torque at 9000-11000 rpm. This fact introduces much shorter strokes in racing engines that reduce inertia loads. Since pressures are higher for CRDIDs the combustion loads are similar. The techniques used to improve the TBO of Formula 1 spark ignition engine and racing watercraft diesel can then be directly applied to naval and aircraft engines where the low-cost requirements are not so stringent as in mass-produced automotive CRDIDs (millions of items). The same technology that prolongs the Formula 1 TBO from a single race to the whole season can then be successfully used in aircraft/naval CRDIDs. A quantitative assessment of the TBO increase is included in this paper for the various systems that compose a CRDID.

Keywords: Common rail | Friction | Load factor method | Piston engines | TBO | Wear

[48] Piancastelli L., Frizziero L., Pica S., Donnici G., Optimal intercooler layout arrangement for Formula 1 racing engines, ARPN Journal of Engineering and Applied Sciences, 11(3), 1443-1450, (2016). Abstract
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This paper demonstrates that efficiency and torque output of the actual Formula 1 power units depends mostly on the turbocharger (TC) efficiency. Compressor and turbine off-design efficiency and turbine energy recovery capability should be maximized to maximize the torque to fuel ratio. Since larger TCs increase turbolag, a new layout for the intercooler is proposed in this paper. This solution reduces turbolag and make it possible to focus on the TC efficiency as a thermal machine. In fact, not only the TC design choices can radically alter the efficiency of the TC itself, but also influence the efficiency of the ICE and of the MGU (Motor Generator Units). Energy evaluation of the TC readily exploits the concept.

Keywords: Compressor | ERS | Formula 1 | Intercooler | Turbine | Turbocharger

[49] Piancastelli L., Castagnoli A., Frizziero L., Design and optimization of an aircraft propeller for tuned torsional vibration damping, ARPN Journal of Engineering and Applied Sciences, 10(16), 6725-6731, (2015). Abstract
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This paper analyzes the design process of an aircraft propeller for a piston engine. The propeller should also damp the main critical torsional frequency of the crankshaft. The first step was the calculation of the geometrical parameters of two different blades: one according to Larrabee's procedure and the other one according to the Theodorsen's theory. The evaluation of the effect of aerodynamics and centrifugal loads has required the union of the results come from CFD (Computational Fluid Dynamics) and the ones come from the CSM (Computational Structural Mechanics), through the execution of several one way FSI (Fluid Structure Interaction) analyses. The results allowed making pre-stressed modal analyses, which gave the opportunity to identify the kinds of propeller having the fundamental frequency coincident with the main resonance frequency of the crankshaft. The final design is a blade having the deformed shape of the optimum aerodynamic design.

Keywords: Aircraft propeller | Crankshaft | Torsional vibrations | Tuned damper

[50] Piancastelli L., Castagnoli A., Frizziero L., Donnici G., Pica S., Direct comparison of fsi optimized theodorsen and larrabee propellers, ARPN Journal of Engineering and Applied Sciences, 10(16), 7250-7258, (2015). Abstract
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The goal of this study is the analysis of the design process of aircraft propellers which are coupled to a piston engine, aiming to find the best design approach. The first design step is the calculation of the initial geometry. This phase is particularly critical since it will affect the following optimization. Several theories for blade design have been proposed during the years. The most popular are the Larrabee's procedure and the Theodorsen's theory. The Larrabee theory is the most used in recent years, while the Theodorsen was most popular in the WWII era. This work focuses on the differences on the results of the two approaches for a general aviation propeller for light aircrafts. For this aerial vehicle category both the strength and efficiency should be considered, since the production technology cannot be as refined as for larger propellers. As it will be seen, the subsonic nature of these aerial vehicles makes it possible to use both initial design approaches. In a second phase, the evaluation of the effect of aerodynamics and centrifugal loads requires the union of the results that come from CFD (Computational Fluid Dynamics) and the ones come from the CSM (Computational Structural Mechanics), through the execution of several one way FSI (Fluid Structure Interaction) analyses. However the starting point proved to be critical for the final result. The Larrabee procedure proves to be ideal for high speed aircraft propellers manufactured with up-to-date materials and procedures. The "old" Theodorsen theory leads to a stronger blade that can be easily manufactured with wood or simplified technologies. The Theodorsen blade is superior for the centrifugal load bearing capacity. This geometry leads to lighter blades. The efficiency of the Larrabee blade seems to be superior. However, experience proved that the CFD analysis can be tricky and unreliable for efficiency evaluation. The pressures are better distributed along the Larrabee's blade with better results at high airspeed. Eventually two geometrically optimized blades have been designed, which have a deformed shape (at cruise conditions) similar to the best aerodynamic geometry and comparable technological characteristics. The Larrabee and Theodorsen designs lead to different optimized blades even after the FSI simulation, demonstrating that the optimization procedure is largely influenced by the initial propeller blade design.

Keywords: Aircraft propeller | CFD | FEA | FSI | Optimization | Starting design

[51] Piancastelli L., Frizziero L., Fuel consumption reduction and power downsize via robotized multiple speed gearbox and automatic selection system for an automotive application, JP Journal of Heat and Mass Transfer, 12(2), 197-210, (2015). Abstract
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Multiple-speed gearboxes with computer controlled automatic gear selection devices are a common possible choice in cars. Robotized gear insertion of one tenth of a second is possible. Economical and weight consideration are to be made to verify if it is convenient to use a smaller engine and a larger gearbox with a wider choice of speeds. In this paper, an automotive application for a public transport vehicle based on a Class S chassis with the choice of common-rail direct injection engines. This choice is particular unfavorable for the multispeed gearbox since common-rail engines have very flat specific fuel consumption curves. The lumped mass model implemented is conceived to estimate velocity, acceleration and fuel consumption starting from aerodynamic, inertia and thermodynamic data of the vehicle. The estimated data of performance and fuel consumption were compared with measured values. A Genetic elitarian Algorithm (GA) was used to optimise the engine choice and the gearbox speeds distribution. A maximum reduction of 15% was then calculated with a 16-speeds gearbox and a 140 HP/300Nm engine in comparison with the standard 5-speeds 204 HP/500Nm engine. This fuel reduction was obtained on the mixed city-motorway cycle. In this case, maximum speed is limited to 180km/h and the 0-100km/h acceleration is reduced to 11s (from the original 8.6s). The weight remains almost unaltered since the 204 HP engine is heavier than the 140 HP and this largely compensates the gearbox weight increase. The multiple speed solution seems to be very interesting also for public transports vehicles and for trucks.

Keywords: Automatic selection system | Automotive | Multiple-speed gearbox

[52] Piancastelli L., Frizziero L., Diesel ecu mapping optimization for aircraft and helicopter applications, JP Journal of Heat and Mass Transfer, 11(2), 151-167, (2015). Abstract
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Starting from a good automotive engine is always a good idea, also for brand new automotive design. In the case of automotive to aircraft conversions, the automotive engine is modified as little as possible. This approach has several advantages: reduced development time, good reliability and availability of cheap and worldwide spare parts. What it may appear a good idea is to tune up the original ECU (electronic control unit) by using one of the several softwares available on the market. However, this approach is not feasible even for ultra light aircrafts. This is due to the lack of control on the software of these ECUs. In fact, automotive software timing or ECU set-up is performed in the following way. The final ECU manufacturer (who holds the responsibility of the hardware and the software in the final car ECU) supplies to the car manufacturer a “development ECU” with a “development Software”. This system is tuned on the engine and on the car to fulfill the car manufacturer requirement. When the tuning is considered satisfactory, the “maps” (the data inputted by the manufactured) are given to the ECU manufacturer. This later translates the data into the software of a “production ECU”, that is given back to the car manufacturer for final validation prior to serial production of ECU and car. In this case, even the car manufacturer does not have a full control of what happens inside his ECU. This is logical since the full responsibility is given to the ECU part supplier. So the tuning of a serial production ECU is more than a true programming. Results are unpredictable to a certain extent that depends on the level of knowledge of the person who performed the tuning and of the software house that implemented the software. The software that truly runs on serial production ECU is a well kept secret of the ECU manufacturer, since it is the knowledge of ECU. The simpler is the software the less expensive will be the ECU and the larger the profits of the ECU supplier. Tricks are hidden inside the ECU to obtain these results; these tricks multiplied per millions of ECU give the supplier a competitive advantage. So, even the car manufacturer has a limited control on what happens inside the real-time software of the ECU, what emerges is the engine and the car behavior. Aircraft conversions require the replacement of ECU, wirings and sensors with appropriate units. This assembly with its own software constitutes the aircraft FADEC.

Keywords: Aircraft | Diesel | Electronic control unit | Helicopters | Mapping optimization

[53] Piancastelli L., Frizziero L., Donnici G., Di Giacomo G., Gattii A., Optimized FSI flow simulation using modern up-to-date software systems: A direct comparison between simulated and tunnel results, ARPN Journal of Engineering and Applied Sciences, 10(20), 9174-9182, (2015). Abstract
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The goal of this study is the analysis of the CFD/FSI simulation accuracy of complex shapes with standard CADembedded software packages. In a PLM (Product Lifecycle Management) system, the continuous improvement of CADembedded FSI (Fluid System Interaction) software packages has progressively reduced the necessity for highly specialized external partners. These simulation software packages are designed to keep pace with the unavoidable design development. To make FSI and CFD usable for mechanical designers and design engineers from other engineering disciplines, CFD software package have been largely automated. The specialist expertise required to operate traditional CFD software may be negligible However, the capabilities of CAD-embedded CFD to handle complex geometries and to simulate complex industrial turbulent flows with heat and mass transfer raise question of the accuracy on the results obtainable by a nonspecialized designer. In this paper, a paraglider wing from NASA TN D3442 was used as a case study. This wing was modelled inside commercial CAD software and then thoroughly analysed by using the simulation tools with their default settings. The accuracy of results was then evaluated.

Keywords: CFD | FEA | FSI | Paraglider wing

[54] Piancastelli L., Forghieri M., Frizziero L., Chinni L., Cremonini M., Large HSDI CR diesel engines multiple injections and multiple swirls concept, ARPN Journal of Engineering and Applied Sciences, 10(18), 7919-7928, (2015). Abstract
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All future power developments should consider as primary tasks the achievement of the required emission levels and CO2-values, while still providing optimum torque-to-rpm curves, the lowest SFC (Specific Fuel Consumption) over the widest range possible, good power-to-weight and affordable costs. One method to achieve these objectives is the downsizing. To achieve the levels of engine performance that are required, a significant increase in the rated speed and in the boost pressure is mandatory. In this case, the result is an increase in the flow rate through the intake and exhaust ports and valves. Considering the impact of these changes, the port layout of the system is reanalyzed. Another physical limit to the maximum speed depends on the CR (Common Rail) injector dynamic performances. These performances decrease with size for inertia problems and they depend on the amount of effort involved in their development. Automotive engines in the range of 10 to 100 HP per cylinder are the most common. For this reason, these injectors are the most advanced and costeffective. Furthermore, their small size and inertia is favorable to the best dynamic performance. The larger number of nozzles improves combustion performance. In fact the better surface to volume ratio or the spray improves heat transfer. For this reason, multiple injection systems can be used in the modern HSDI (High Speed Direct Injection) CR large diesels. This solution was commonplace before WWII, but has been progressively abandoned with the introduction of mechanical high-pressure injection systems and the bowl combustion chamber. In this paper, a dual combustion chamber per cylinder engine is considered. The primary purpose of this study is to examine the best port layout on a modern diesel combustion system and to introduce a new promising concept. The study included flow measurements of intake flow and CFD simulations of the flow field during intake. This design enables the formation of two homogenous swirls centered onto the injectors, with excellent flow coefficient. The design also allows an increase in volumetric efficiency combined with a reduction in flow losses.

Keywords: Diesel engines | Multiple injections | Multiple swirls

[55] Piancastelli L., Gatti A., Frizziero L., Ragazzi L., Cremonini M., CFD analysis of the Zimmerman's V173 stol aircraft, ARPN Journal of Engineering and Applied Sciences, 10(18), 8063-8070, (2015). Abstract
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The present work had as its main aim to carry out a study of the high lift of an unconventional aircraft of the '40s, the Vought V-173 Flying Pancake. To obtain this result the Authors used the Computational Fluid Dynamics (CFD) software SolidWorks Flow Simulation. In particular, the CL-αand CD-αcurves have been interpolated from the points obtained from the simulations for different configurations of the V173 aircraft CAD model. In a first phase the aerodynamics of the aircraft was evaluated 'clean' without the presence of the propellers was analysed. In a second phase, the influence of the two large propellers was taken into account. The effect of the propeller was clearly shown especially at high AOA. These results were obtained from the direct comparison of the Lift-AOA and Drag-AOA curves for the unpowered and the powered condition. The CFD results confirmed the impression of high controllability of the powered aircraft up to AOA of 50°. This behavior with the extremely smooth stall gave the impression of an aircraft impossible to stall or to spin.

Keywords: CAD | CFD | Flying pancake | STOL | V173

[56] Piancastelli L., Frizziero L., Donnici G., Common rail diesel-automotive to aerial vehicle conversions: An update (Part III), ARPN Journal of Engineering and Applied Sciences, 10(14), 5823-5830, (2015). Abstract
X

Back to the 1997 when this activity began, it was generally though that CRDIDs (Common Rail Direct Injection Diesel) would have completely replaced the piston gasoline engines used in aircrafts within a decade. This fact did not happen for several reasons. This paper tries to individuate these reasons. The more updated solutions to the many problems that almost stopped this application are also introduced. In this third part, maintenance and cost effectiveness related issues are introduced. Automotive OBD concept is described as a method to reduce maintenance costs and risks.

Keywords: Automotive and aerial-vehicle | Common rail direct injection diesel | On board diagnostic (OBD)

[57] Piancastelli L., Frizziero L., Donnici G., A new concept for low inertia electric turbocompounding in racing spark ignition engines, JP Journal of Heat and Mass Transfer, 12(1), 1-14, (2015). Abstract
X

Electric turbocompounding in racing spark ignition engine is focused on transient operation. Classical compressor and turbine maps should be adapted for this particular condition. Electric turbocompounding has limited torque and power available on the electric side. For this reason, an ad hoc solution should be devised. A low inertia solution is proposed in this paper with the advantage of minor modifications on existing commercial highly optimized turbochargers. A large advantage over the current solution may be achieved. In this solution, a very low inertia electric/motor generator is magnetically coupled to the turbocharger on the compressor side of the shaft. The electromagnetic coupling acts also as a torque limiter allowing extremely large slips between turbocharger and generator shafts.

Keywords: Electric turbocompound | Spark ignition engines

[58] Piancastelli L., Frizziero L., Rotondi A., Optimum installation of a common rail diesel engine on a “classical” helicopter: The UH1, JP Journal of Heat and Mass Transfer, 12(1), 45-64, (2015). Abstract
X

A feasibility study for the installation of a CRDID (Common Rail Diesel Engine) on a medium helicopter is introduced. The total mass available for the CRDID is evaluated starting from fuel consumption and helicopter data. A derivative of an automotive engine was considered. The installation of the new CRDID was then studied. The result was the evaluation of the power plant installation mass that proved to be lower than the maximum admissible. The installation is then possible. Care should be taken in the cooling system to avoid large penalties in power and efficiency. For CRDID powered helicopters, the ejector exhaust system can be successfully used. With CRDIDs, huge advantages can be obtained on operating costs due to reduced fuel consumption, safety and helicopter availability. In fact, diesel fuel is available everywhere and flights to airports just for refueling can be avoided.

Keywords: Common rail diesel | Helicopter power unit

[59] Frizziero L., Piancastelli L., Bombardi T., Graphically enhanced visual concealment of large objects, ARPN Journal of Engineering and Applied Sciences, 10(12), 5157-5163, (2015). Abstract
X

Inexpensive, flicker free, flat, large, extremely bright LCD panels can be effectively used to conceal very large objects both stationary and moving. CCDC (Charge Coupled Device Camera) may capture the surrounding environment and reproduce it on the LCD screens. LCDs may easily be installed on the surface of the objects. It is also possible to use the video cards of personal computers and laptops to digitally process the image captured with the CCDS and obtain patterns to disguise the real appearance of the object or the way it is moving. The visual CCD (Camouflage, Concealment, and Deception) system so obtained is extremely effective. In this paper, it is demonstrated that the digital image processing techniques necessary to obtain a successful concealment are elementary and already embedded in the hardware of video card for real time image processing. It is also possible to superimpose patterns at defined frequencies that will obscure the image to the human observer especially in case of use of magnifying optics. The CCD effect in the visual and ultralight field is extremely effective. An example of active CCD of the Ariete MBT (Main Battle Tank) is shown in this paper.

Keywords: Graphically enhancement | Visual concealment

[60] Piancastelli L., Frizziero L., Donnici G., The meredith ramjet: An efficient way to recover the heat wasted in piston engine cooling, ARPN Journal of Engineering and Applied Sciences, 10(12), 5327-5333, (2015). Abstract
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Piston engines with power up to 1000HP (735.5 kW) are becoming popular in the aeronautical field for the high efficiency and the possibility to work with Diesel, jp4 and jp8 fuels up to altitudes up to 20,000m (65,000 ft). This paper updates a secondary advantage of piston engines: the Meredith effect. The Meredith duct is a ramjet powered by the heat wasted in cooling. In this way the efficiency of the original piston engine that can be higher than 50% which is the normal in common rail diesel engines. Even if the efficiency of this ramjet is lower than 30%, an accurate Design of this secondary engine can add a significant amount of thrust to the fan or the propeller powered by the piston engine. This effect, well known since the beginning of WWII, is being thoroughly analysed in this paper with regard of the efficiency. Previous papers introduced and a new radiator, with wing section tubes. As it will be seen the main design variable for the Meredith ramjet it the air temperature increase. This paper demonstrates that it is not convenient to increase this temperature over 200°C for aircrafts flying at about 600km/h@6000m (~330knots@20,000ft). The in-wing duct appears to be slightly better than the in-fuselage or the in-nacelle ones.

Keywords: Piston engine cooling

[61] Piancastelli L., Frizziero L., Preliminary optimization of a common rail direct injection diesel alternative to the AE2100 class turboshafts, ARPN Journal of Engineering and Applied Sciences, 10(11), 4738-4747, (2015). Abstract
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It is shown that a CRDID (Common Rail Direct Injection Diesel) turbo compound design is a highly over constrained problem. Very few options are available to the designer, even from the metallurgical point of view. The process of the preliminary design is fully described and the preliminary performance evaluation is fully described. A comparison with the original turbo shaft installation of a Hercules C130J aircraft is performed and the results are analyzed. The CRDID turbo compound seems an extremely convenient option since it can halve the fuel consumption, with increased safety and reduced logistical problems. CRDID emissions, with SCR (Selective Catalytic Reduction) may easily reach the automotive Euro 6 standard.

Keywords: AE2100 | Common rail direct injection diesel (CRDID)

[62] Piancastelli L., Bernabeo R.A., Frizziero L., UAV remote control distraction prevention trough synthetic augmented virtual imaging and oculus rift-style headsets, ARPN Journal of Engineering and Applied Sciences, 10(10), 4359-4365, (2015). Abstract
X

A remote control station for Unmanned Aerial Vehicles (UAV) based on oculus Rift-style headsets and joysticks is proposed in this paper. With this solution situation awareness and distraction can be controlled and measured during the flight. With Virtual Augmented Reality (VAR) software it is possible reproduce accurately both the cockpit and the external view thanks to the helmet tracking system. Also the head-up display (HUD) and up-to-date flight instruments can be reproduced. In this way the PF (Pilot Flyng) station can be reduced to helmet, throttle/stick joysticks with force feedback and a few additional LCDs. Another main advantage of VAR headsets is the possibility of reconfiguring the cockpit via software and to use it for several different UAVs. In Figure-5 it is possible to see a logical schema of a VAR station: the pilot inputs via helmets (line of sight direction), flight controls (stick and throttle) and switches on joysticks the data in the AVCS software (Aircraft Visualization and Control System): The Aircraft Visualization and Control System take the data from the aerial vehicles, elaborates them and outputs the external view (external visual system) and the view of instruments (instrument visualization system). These two "images" are overlapped and mixed in a highly hierarchical visualization system, where only the relevant objects are depicted. To do so the external camera images from the aerial vehicle are analyzed and cleaned of all non-relevant data. The data from the sensors are also to be included in the synthesizing process. The application of these ideas as discussed in this paper consists of the realisation of a VAR display system for a remotely piloted aerial vehicle. All the instruments are modelled via Head Up Display (HUD) while the external scenery is analyzed and only relevant elements for mission accomplishment or collision avoidance are represented. The PF have the possibility of a 360° field of view. Sound realism and true situation awareness can be then achieved. Software for distraction control and situation awareness can be easily implemented in the system. A synthetic audio interrogation system can keep track of the current state of alert of the PF.

Keywords: Augmented reality | Remote control | UAV

[63] Frizziero L., Piancastelli L., An over constrained optimization problem: The prolonged autonomy bike (PA bike), ARPN Journal of Engineering and Applied Sciences, 10(10), 4563-4570, (2015). Abstract
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The Prolonged Autonomy e-bike o PA-bike is a e-bike that can use a traditional fuel to charge the battery during run or at rest. In this way it is possible to prolong the autonomy of the e-bike. A fuel cell with a reformer or a traditional very small catalyzed piston engine can be used. In both cases the emissions are very limited and the efficiency is very high, since the "traditional fuel" motors work at constant optimum condition. This paper tries to optimize the PA-bike by assembling commercial components. Outsourcing for bicycles should be very easy since commercial part availability is very high. Customization is a very common practice for bikers, since it does not require authorizations. However the problem proved to be over constrained. The commercial components, in particular the electric motor, proved to be an important boundary condition. The result is a single possible solution, or a category of solutions, all similar. This is due to the fact that commercial components are highly standardized for marketing reasons.

Keywords: Autonomy | E-bike | Optimization

[64] Piancastelli L., Bernabeo R.A., Noise reduction and control in DCFS FBW with hardware and digital fuzzy filters, ARPN Journal of Engineering and Applied Sciences, 10(8), 3418-3424, (2015). Abstract
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This paper introduces the implementation of a few algorithms based on fuzzy logic to improve the performance of a "Fly-by-wire" (FBW) "Digital Flight Control System" (DCFS). These algorithms have been tested on a flight simulator type "FNPT II". This simulator was entirely developed at the Laboratory of Aerospace Engineering of the University of Bologna (Forlì site). The algorithms should be simple (reliable) and quick in order to avoid response delay. They should also bring a true advantage in the FBW system. The proposed solutions are on the active filtering of the inputs an adaptive tolerance implementation for the identification of faulty sensors and their deactivation. The field in which this study has demonstrated greater effectiveness is in SW filtering of input signals, where a simple and effective algorithm was implemented. Finally, extremely simple hardware techniques to reduce input noise are also described.

Keywords: Digital flight control system (DCFS) | Flight simulator | Fly-by-wire (FBW) | Noise reduction

[65] Piancastelli L., Frizziero L., Donnici G., Common rail diesel - automotive to aerial vehicle conversions: An update (Part II), ARPN Journal of Engineering and Applied Sciences, 10(8), 3286-3294, (2015). Abstract
X

Back to the 1997 when this activity began, it was generally thought that CRDIDs (Common Rail Direct Injection Diesel) would have completely replaced the piston gasoline engines used in aircrafts within a decade. This fact did not happen for several reasons. This paper tries to individuate these reasons. The more updated solutions to the many problems that almost stopped this application are also introduced. In this second part of this paper engine selection concepts and TBO (Time between Overhaul) are introduced.

Keywords: Avionization | Conversion | Diesel common rail

[66] Piancastelli L., Frizziero L., Different approach to robust automatic control for airplanes, ARPN Journal of Engineering and Applied Sciences, 10(6), 2321-2328, (2015). Abstract
X

Current automatic control system uses linear mathematical models to validate automatic flight control for airplanes. Gain scheduling, non linearity and improved feedback through simulation are also introduced. Very computers operate the actuators in order to keep the airplane on the right path, in the current trim and with the proper safety margin. Some engineers are testing fuzzy control logic to control airplanes and UAVs (Unmanned Aerial Vehicles). The result is brilliant, since very simple controllers are able to fulfill the specification with little "knowledge" about the airplane performances. This means that fuzzy controllers are very robust since they are able to operate with much degraded aerodynamics or with reduced thrust. However no one was able to validate the airplane/fuzzy controller with a mathematical proof. So it is not sure that it will works in any condition. By the way the same happens for the airplane/human pilot model. So a mathematical proof is still required also for this later solution. On the other side, very accurate, time based non linear mathematical models are available for flight simulation. These models are used in several fields ranging from development to training. In recent years computers that can run these accurate models in fractions of seconds were marketed at very low prices. The idea introduced in this paper is to run an accurate mathematical model on some of these fast autopilot computer in order to optimize the sequence of commands to be inputted to the FBW system of the airplane in order to keep the path in the safest way possible. For this purpose it is necessary to have enough computing power to calculate this best solution at a rate compatible to a correct control of the airplane. In this paper we will demonstrate that these computing resources are already available and it is predictable that the computing speed of future years will allow running even more sophisticated simulators. The question may be: why use more complicated systems when current control system fulfills satisfactorily the same task in a cheaper and more reliable way? The answers are several. At first it is a matter of robustness, what happens if the yaw damper fails or the actuator of the left ailerons is unable to fulfill its task or the tail is ripped off? In this case standard systems are not able to take the airplane to the ground safely even if it is indeed possible to control the airplane by a coordinate action of the remaining control surfaces. Optimization means that it is possible to reduce the stress on structures in order to improve aircraft life, to find the control sequence that assure the mean fuel consumption or to prefer the shortest time possible to reach the required trim on the right path. In other words it is more flexible. It is also possible to monitor aircraft performance in order to evaluate external or internal disturbances. Air turbulences, wind gusts may be controlled in order to optimize structural integrity or passenger comfort. Internal disturbances, as defective functioning of components or controls, occasional failure of sensors may be diagnosed, in some cases corrected in other simply reported after landing. The reliability improvement is not the latest benefit. As a rule of the thumb more electronics or more components means less reliability with the exception of redundancy and this is the case of this paper.

Keywords: Airplane control | Automatic control

[67] Piancastelli L., Frizziero L., Donnici G., Common rail diesel - Automotive to aerial vehicle conversions: An update (Part I), ARPN Journal of Engineering and Applied Sciences, 10(6), 2479-2487, (2015). Abstract
X

Back to the 1997 when this activity began, it was generally thought that CRDIDs would have completely replaced the piston gasoline engines used in aircrafts within a decade. This fact did not happen for several reasons. This paper tries to individuate these reasons. The more updated solutions to the many problems that almost stopped this application are also introduced. In this first part FADEC related issues are introduced. Torsional vibration control is also briefly discussed.

Keywords: Aeronautical engines | Conversion of automotive engines | Diesel engines

[68] Piancastelli L., Frizziero L., Donnici G., Common rail diesel-electric propulsion for small boats and yachts, ARPN Journal of Engineering and Applied Sciences, 10(6), 2378-2385, (2015). Abstract
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The marine propulsion system is the heart of the ship. Its reliability will directly affect the safe navigation and operating costs of ship and its overall safety. The individuation of the best propulsive solution is one of the key technologies in marine field. Focusing on the study of comprehensive reliability, this study analyses operation environments of the marine propulsion system firstly, and then evaluate the comprehensive reliability of the chosen marine propulsion system. According to the fault tree of the marine propulsion system, a CRDID (Common Rail Direct Injection Diesel) electric hybrid marine engine system is taken as an example The result shows that a new engine CRDID-hybrid system can be reliably installed on small boats and yachts. It is believed that the knowledge gained in this study will provide a theoretical reference for research on comprehensive reliability of hybrid marine propulsion systems.

Keywords: Diesel electric marine propulsion system | Failure probability | Fault tree analysis | Reliability

[69] Piancastelli L., Frizziero L., GA based optimization of the preliminary design of an extremely high pressure centrifugal compressor for a small common rail diesel engine, ARPN Journal of Engineering and Applied Sciences, 10(4), 1623-1630, (2015). Abstract
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A method to perform the preliminary design of an impeller for an extremely high pressure ratio centrifugal compressor is introduced in this paper. The equations used are fully detailed and a design procedure is introduced. This design procedure required a GA (Genetic Algorithm) optimization to obtain an acceptable optimum result. It is demonstrated that a 8:1 compressor can be designed for a mass flow of 500 kg/h. This GA optimized initial design should be then be validated through CFD (Computational Fluid Dynamics) simulation and then tested on a test bench. However, the initial design phase is critical, since a CAD model of the impeller is needed to start the simulation process. In our case this initial phase couldn't be inspired by existing design, since none were found. Aircraft and Helicopter engines do not have the problem of turbo lag, since fan/propeller inertia eliminates this problem. On the contrary these engines necessitate of performance at altitudes (flight levels) much higher than automotive applications. Small turbochargers with high compressor ratio are not available on the market, so a special design is needed.

[70] Piancastelli L., Frizziero L., Mapping optimization for common rail diesel conversions from the automotive to the flying applications, ARPN Journal of Engineering and Applied Sciences, 10(4), 1539-1547, (2015). Abstract
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Performance of electronic controlled diesel engine is depended on quality of the map(s). In this paper, the implementation of an electronic-control map in common rail diesel engine is made, the character of operational profile in diesel engine and rule of typical profile data obtained from experiment is analyzed, a method of developing these surfaces from very few data point is applied. The particular application of aircraft and elicopter common rail direct injection diesel engines is considered. The steps of this experimental optimization activity is presented in order to test to operational profile demand. This demand is very different from the automotive to the aircraft/helicopter application. The preparation of the test engine(s) and of the test electronics for brake tests is completely different. Also the mapping technique differs substantially being the primary objectives widely different.

Keywords: Aircraft | Common rail | Diesel engine | Electronic control | Fitting surface | Helicopter | Mapping

[71] Piancastelli L., Frizziero L., A new approach for energy recovery and turbocompounding systems for high altitude flight with common rail diesel engines, ARPN Journal of Engineering and Applied Sciences, 10(2), 828-834, (2015). Abstract
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This paper introduces an original method for the preliminary calculations and the turbomatching of a dual stage high altitude turbocompounding system. This method is conceived to use modified automotive commercial turbochargers along with electric motor/generators. The method used is innovative and uses only the data commonly available from the manufacturer. In the example described herein, full power and throttle control are achieved up to 10, 000m (32, 000ft). The engine is a Common Rail Direct Injection Diesel engine derived from the automotive market. The calculation method and the problems connected are widely discussed. For this application turbocompunding is a good option that partially compensates the unavoidable increase in TOW (Take Off Weight). In drones that have relatively large batteries, the ERS (Energy Recovery System) does not increase the air vehicle mass.

Keywords: Diesel common rail | Energy recovery | Turbocompunding system

[72] Piancastelli L., Frizziero L., Multistage turbocharging systems for high altitude flight with common rail diesel engines, ARPN Journal of Engineering and Applied Sciences, 10(1), 370-375, (2015). Abstract
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A Fiat 1.9jtd diesel engine has been extensively reviewed to output 300HP. This paper introduces a multiple stage turbocharging system that uses commercial turbocharger, taken from the catalogue of a popular manufacturer. The calculation method and the problem connected are widely discussed. Along with the problem that may arise in using these off the shelf unit. The quite heavy result advice the user to adopt ad-designed turbochargers for this task.

[73] Piancastelli L., Frizziero L., Donnici G., Turbomatching of small aircraft diesel common rail engines derived from the automotive field, ARPN Journal of Engineering and Applied Sciences, 10(1), 172-178, (2015). Abstract
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Common rail automotive (Direct Injection) Diesels (DID) are always turbocharged. This engine works at limited altitude and should output torque at low rotational speeds. Not so for engines that work coupled to propeller and fans. This is the case of aircraft and helicopter engines. In this case it is important to have high output power at high rpm and to keep throttle authority and power at the higher altitude possible. Some basic concepts to achieve this result are introduced in this paper. Single turbocharging systems are introduced and an option to improve the altitude performance is discussed. Far from being exhaustive, this paper is an initial step in the long and awkward technology of turbocharging automotivederived engines. The basic concepts for efficiency are also discussed.

Keywords: Common rail automotive Diesels (DID) | Turbocharging

[74] Piancastelli L., Frizziero L., Supercharging systems in small aircraft diesel common rail engines derived from the automotive field, ARPN Journal of Engineering and Applied Sciences, 10(1), 20-26, (2015). Abstract
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Common rail automotive diesels are always turbocharged. This engine works at limited altitude and should output torque at low rotational speeds. Not so for engines that work coupled to propeller and fans. This is the case of aircraft and helicopter engines. In this case it is important to have high output power at high rpm and to keep throttle authority and power as high as possible. Some basic concepts to achieve this result are introduced in this paper. Single turbocharging systems are introduced and an option to improve the altitude performance is discussed. Far from being exhaustive, this paper is an initial step in the long and awkward technology of aircraft common rail diesels. The basic combustion principles and the basic concepts for efficiency are also discussed.

Keywords: Aircraft | DIDs | Rail automotive diesels | Turbocharging systems

[75] Frizziero L., Piancastelli L., Accelerated FEM analysis for critical engine components, Walailak Journal of Science and Technology, 12(2), 151-165, (2015). Abstract
X

This paper introduces a method to simplify a nonlinear problem in order to use linear finite element analysis. This approach improves calculation time by 2 orders of magnitude. It is then possible to optimize the geometry of the components even without supercomputers. In this paper the method is applied to a very critical component: the aluminium alloy piston of a modern common rail diesel engine. The method consists in the subdivision of the component, in this case the piston, in several volumes, that have approximately a constant temperature. These volumes are then assembled through congruence constraints. To each volume a proper material is then assigned. It is assumed that material behaviour depends on average temperature, load magnitude and load gradient. This assumption is valid since temperatures vary slowly when compared to pressure (load). In fact pressures propagate with the speed of sound. The method is validated by direct comparison with nonlinear simulation of the same component, the piston, taken as an example. In general, experimental tests have confirmed the cost-effectiveness of this approach.

Keywords: CAD | FEA | Geometry | Optimization | Simulation

[76] Piancastelli L., Bombardi T., Persiani C.A., Alberto B.R., An augmented reality interface proposal to improve air transportation safety, Far East Journal of Electronics and Communications, 12(2), 79-97, (2014). Abstract
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Modern airliners are really UAV (Unmanned Aerial Vehicle) that fly with a very limited contribution from the pilots. UAV modern technology is ready to turn to full automatic passenger transportation. The barrier is purely physiological and not technical. This technology is available since a few years. However, the main critical safety issue is still emergency. When everything seems to go wrong, manual control may be the last resource. The emergency, back up, pilot can be comfortably seated several thousands of miles away. His awareness about aircraft situation may be null. He has to grasp immediately the situation and take a proper corrective action. Time is the essential factor. Still, the remote pilot may have not logged many active flying hours. Now, in everyday flight, the normal configuration is AF (Autopilot Flying) + PNF1 (Pilot Not Flying 1) + PM/PNF2 (Pilot Monitoring/Pilot Not Flying 2). The pilot(s) still log(s) these hours as active flying hours, even if, for most of the time, it is the autopilot that is in charge for flying. The pilot training problem is now very serious. Pilots, remote or not, are interfaced to the aircraft system through MFD (Multifunctional Flight Displays): these are Computer Graphic Displays with or without side buttons. What it is seen by the pilot is the GUI (Graphic User Interface): it should then be easy and familiar to the pilots especially when they are called to work. GUI modern WYSIWYG (What You See Is What You Get) Augmented Reality and hierarchical techniques should be used, the more familiar to the average person the better. Basic manual training should be provided to pilots to make them ready to handle critical situations. The actual training based on normal automatic procedures and on air traffic handling is now obsolete. In fact, automatic systems and air traffic can be easily handled even without any human intervention. This fact had been demonstrated by the famous US air traffic controller strike back in the Reagan era (1981). In this paper, several issues about the interface are discussed. An additional, non-certified, graphic interface focused on non-standard or emergency condition flight is proposed in this paper. This augmented reality interface is designed for a smooth transition between automatic and human controlled flight, being human control extraordinary for nowadays airliners.

Keywords: Air transportation safety | Augmented reality | Interface systems

[77] Daidzic N.E., Piancastelli L., Cattini A., Diesel engines for light-to-medium helicopters and airplanes (Editorial), International Journal of Aviation, Aeronautics, and Aerospace, 1(3), (2014).
[78] Piancastelli L., Frizziero L., Design, study and optimization of a semiautomatic pasta cooker for coffee shops and the like, ARPN Journal of Engineering and Applied Sciences, 9(12), 2608-2617, (2014). Abstract
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The advantage to have an automatic pasta machine that cooks dry semolina pasta automatically seems to be several, ranging from energy consumption to freshness and taste. However these machines have proved to be highly problematic. Several problems of pasta cooking machines are diffusively discussed. Also several automatic pasta machine patents are briefly described. The machine described herein is conceived for coffee shop where a hot water reservoir and an operator are available. This makes it possible to simplify the machine and improve the safety of use. Several technical solutions are analyzed in this paper. Energy concepts and concerns are also discussed. Different technical solution to achieve the best compromise between cost, functionally and safety are introduced. Several fashionable designs are analysed and introduced in this paper. At the end a very simple "rocket" patented machine is described. This machine can cook the special patented "geared spaghetti" in less than a minute and every other type of spaghetti in half the time indicated in the box. This solution seems to be the best compromise for taste, safety and performance.

Keywords: Automatic pasta machine | Coffee

[79] Piancastelli L., Frizziero L., Donnici G., The common-rail fuel injection technique in turbocharged di-diesel-engines for aircraft applictions, ARPN Journal of Engineering and Applied Sciences, 9(12), 2493-2499, (2014). Abstract
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In the activity of injection mapping optimization, a good degree of knowledge on how a common rail injection works is strictly necessary. This paper is aimed to summarize the basic knowledge about turbocharged Common Rail Direct-injection Diesel engines (CRDID). It is possible to use automotive CRDIDs on aircrafts and helicopter; however their use is very different for the original car installation. For this reason a complete rethinking of the engine and the way the engine control is performed is strictly necessary. For this reason the engine should be reprogrammed for the new application. To perform this activity it is strictly necessary to know how the original automotive application works. This paper is aimed to this objective, in order to point out the differences with the automotive installation and the new optimization functions. The combustion process of turbocharged CRDID, equipped with high pressure common-rail fuel injection systems, with different boost pressures, injection pressures, and fuel quantities are introduced. The influence of the injection and the swirl mode on the ignition delay and the flame propagation is analyzed. The sac hole nozzles with a variable number of holes and different injector types (electromagnetic/piezoelectric) are also briefly described. An experimental analysis of the combustion process is briefly discussed along with spray penetration, dispersing angle, velocity, the distribution/evaporation of the fuel droplets, ignition delay, ignition location, combustion progression. The applied swirl has not an influence on the spray penetration, but it is extremely important for the ignition and the combustion process. On the contrary the swirl itself is reduced by the injected amount of high pressured fuel. The droplet turbulence increases from the center of the combustion chamber of the spray radial rapidly decreases. The difference in the combustion of CRDIDs, traditional diesel engines and spark ignition engine is also briefly discussed. Finally the difference from automotive and aircraft and helicopter CRDIDs, from the combustion tuning point of view is discussed. Optimum combustion (and mapping) is also introduced as basic concepts.

Keywords: Aircraft | Turbocharged di-diesel-engines

[80] Piancastelli L., Frizziero L., Turbocharging and turbocompounding optimization in automotive racing, ARPN Journal of Engineering and Applied Sciences, 9(11), 2192-2199, (2014). Abstract
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Turbocharged spark ignition engine for automotive racing have a long and controversial history. From the times of high torque at all cost, to the actual F1 era of maximum efficiency. However turbocharging and turbocoumpounding basic concepts have not changed. It is surprising that, through the years, the same identical errors are repeated. Turbocharger (TC) unit design is a highly optimized task, that requires good concepts, good mathematical models, lots of experimental data and a very good optimization. Performances vary completely with design choices, with big differences between even close solutions. Present software for mathematical modeling of performances are far from accurate and should be corrected with experimental data to obtain effective results. Genetic Algorithms are to be used as optimization method to evaluate the best design solution. Even minor errors in design choices result in large penalties on performance.

Keywords: Automotive racing | Turbocharger

[81] Piancastelli L., Frizziero L., Donnici G., Learning by failures: The "Astura II" concept car design process, ARPN Journal of Engineering and Applied Sciences, 9(10), 2009-2015, (2014). Abstract
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Accessibility has always been a problem in sport car. Very low car floors, small doors, almost horizontal seating position with upward cramped legs are the negation of comfort. In marketing clips long legged girls show their knickers for the joy of the potential buyer. In the old times there were rumors that the four seats, automatic transmission Ferrari was made for the Drake himself, who was "obliged" to own and drive a Ferrari. Yet the only place where people with impaired legs are identical to all the others is the car. However the sports cars are usually denied to people with problems of motion. The Ercolani's idea was to overcome these problems by several concurrent solutions. The idea proved to be nice, while the design approach from sketch to 3D-CAD proved to be a complete failure. The final project fulfils many of the requirements, but with a completely different style. This project proved the substantial unfeasibility of the outside-in approach in the automotive field.

Keywords: ASTURA II | Car design

[82] Pezzuti E., Valentini P.P., Piancastelli L., Frizziero L., Development of a modular system for drilling aid for the installation of dental implants, ARPN Journal of Engineering and Applied Sciences, 9(9), 1527-1534, (2014). Abstract
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In oral implantology, proper execution of the holes for the installation of dental implants is directly related to the correct functioning and durability of the system itself. For this reason, the procedure discussed here, which was once performed freehand in all its phases, is now being implemented through aids with more precision. Masks currently in use are created in resin ad hoc; surgical stents are inserted into the holes that will then be used as a guide. These aids are fixed into the jaw by means of micro bone screws in order to prevent movement during surgery. Despite this, we still use the guides as they are, centered properly with the help of drilling jigs. The same technique is also used in partially edentulous cases through smaller jig fixed on teeth near to the implant zone. In this article, we propose a guidance system for milling cutters used in partially edentulous cases involving from one to three adjacent installations. The purpose of the study was to realize a modular model adaptable to most dental implants, as well as efficient, quick, and low cost by pouring the resin into a plaster mold of the teeth, and then drilling the masks into position in the plants at the required angle.

Keywords: Dental implants | Drilling aid

[83] Piancastelli L., Frizziero L., Donnici G., Study and optimization of an innovative CVT concept for bikes, ARPN Journal of Engineering and Applied Sciences, 9(8), 1289-1296, (2014). Abstract
X

The standard bicycle has a well defined form: two same-size in-line wheels with a triangular-shaped frame and an almost vertical riding position. This bike model is the "safety bicycle" 1870's model. May be it is not the most efficient form and, for sure, not the latest developed. The improvement had not been so important. There was indeed a big jump in the late 80's/early 90's, some of which could be attributed both to an increase in time trials and, may be, also to the doping practices of the time. In any case, doping of some form or another has been going on since the beginning of the Tour de France. Time trials are crucial for average speed and it may be they are entirely responsible for the improvement. In any case many other significant advantages have been made on the man-machine. Training and nutrition have been improved through the years. © 2006-2014 Asian Research Publishing Network (ARPN).

Keywords: Bicycle system | Electric facilities | Transportation

[84] Piancastelli L., Frizziero L., Bombardi T., Bézier based shape parameterization in high speed mandrel design, International Journal of Heat and Technology, 32(1-2), 57-63, (2014). Abstract
X

The optimization of bi-dimensional profiles of axisymmetric parts is one of the most commonly addressed problems in engineering. Shafts are a typical example of this basic shape. This work is concerned with the use of Genetic Algorithms (GAs), Finite Elements (FE) and rational Bézier curves for the optimization of high speed mandrels. The design variables of the problem are the weights of the nodes of the Bézier boundary curves used to define the finite element discretization. These values are generated by the GA and handled by a mesh generator which defines a candidate solution to the problem. The value of the natural frequencies for each individual is evaluated. For a given set of values of cross-sectional areas and resulting natural frequencies, the value of the fitness function of an individual is obtained. Is this case of a constrained optimization problem The binary-coded generational GA uses a Gray code, rank-based selection, and elitism. The paper briefly summarizes the basis of the GAs formulation and describes how to use refined genetic operators. The mixed pure cylindrical and Bézier shaped model boundary is discretized by using a beam FEM (Finite Element Method) model. Some selected parts of the boundary are modeled by using curves, in order to allow easy meshing and adaptation of the boundary to optimization process. A numerical examples is presented and discussed in detail, showing that the proposed combinedtechnique is able to optimize the shape of the domains with minimum computational effort. The improvement in confront with the original multiple-cylinder shape is significant, without violating the restrictions imposed to the model.

Keywords: Bézier | FEA | Genetic algorithm | High speed winding mandrel | Natural frequencies

[85] Piancastelli L., Frizziero L., Rocchi I., A low-cost, mass-producible, wheeled wind turbine for easy production of renewableenergy, Far East Journal of Electronics and Communications, 12(1), 19-37, (2014). Abstract
X

Wind turbine farms have many disadvantages: it is hard to identify the best location in terms of wind, permissions are difficult to obtain and the energy needed is produced far away from customers who have network problems. Our idea is to manufacture a large number of very small turbines and install them close to consumers. Mass production would minimize cost. The wind turbine would be self-contained in a wheeled trailer for better transportation and it would require no installation. A "plug & play" approach is employed. If the generator fails to produce a sufficient quantity of energy, the user could easily move the wind turbine to a more suitable position or sell the unit. This paper describes a small 5000 W wind turbine mounted on a wheeled trailer. It is easily transportable, and extremely simple to install. When the system is folded down, the single-blade is contained within the overall dimensions of the retracted column. The electrically powered hydraulic deployment system unfolds and then extends the retractable column (tower) of the windmill. At the end of the column extension the single-blade is released, turning upwards due to gravity imbalance and the system is ready to function. © 2014 Pushpa Publishing House.

Keywords: Plug & play | Transportation | Wheeled trailer | Wind turbine

[86] Piancastelli L., Frizziero L., Donnici G., A highly constrained geometric problem: The inside-outhuman-based approach for the automotive vehicles design, ARPN Journal of Engineering and Applied Sciences, 9(6), 901-906, (2014). Abstract
X

The traditional automotive design process that starts from the sketches and the 2D drawings has been superseded by the modern CAD modeling tools. The step through the clay model and the following digitalization problems can be superseded. It is now possible to construct the inside and to define the ergonomic boundaries of the vehicle in an inside out process. This approach greatly reduces the time to market of the final product by including all the parts and the components that comes from other projects or from outsourcing. However a 1:1 (true scale) physical mock up of the vehicle is, in most the cases, still necessary. In fact the evaluation of the real aesthetics of the new project should be made in a true 3D environment. The inside-out approach optimizes the standardization, the outsourcing, the multi powertrains and the unified "platform" concepts. © 2006-2014 Asian Research Publishing Network (ARPN).

Keywords: Automotive design | Methodology to design | Optimization

[87] Piancastelli L., Frizziero L., How to adopt innovative design in a sportscar factory, ARPN Journal of Engineering and Applied Sciences, 9(6), 859-870, (2014). Abstract
X

Inspired by an article which analyzes the implementation of an innovative system approach to a more sustainable and innovative design, the present paper would like to try to apply the same approach to a real case, inside of a famous Italian sportscar factory. A case study in this factory was developed and decoded gaining improved understanding of innovative system design and those factors that substantially influence its success. All the factors mentioned above are used, into the application presented in this paper, to achieve an ultimate optimization of the system. © 2006-2014 Asian Research Publishing Network (ARPN).

Keywords: Design methods | Design organization | Innovative design | Sportscar factory

[88] Piancastelli L., Frizziero L., Pezzuti E., Kers applications to aerospace diesel propulsion, ARPN Journal of Engineering and Applied Sciences, 9(5), 807-818, (2014). Abstract
X

Surprisingly, the safety of a flight is still not guaranteed to maximum steam ejection of power during take-off. Moreover, modern aircraft require significant amounts of electricity. It could also be argued that today in many respects the automotive industry appears to be a technology leader with respect to the aerospace industry that, instead, is more conservative. Ferrari has developed, and implemented, on their F1 cars, an electronic device, called KERS, which is able to produce electricity, with peaks of 60 KW for 7s, with a mass of 20 kg, including rechargeable batteries. The main goal of this paper is to explore utilization of turbo-charged aerodiesel engines and conduct feasibility study of the F1-derived KERS to assist power generation in normal and critical flight phases. The KERS' reversible brushless electric motor works as a generator for all aircraft power needs and also provides starting power. It is demonstrated here that such design philosophy improves performance and flight safety of light-to-medium airplanes and helicopter. © 2006-2014 Asian Research Publishing Network (ARPN).

Keywords: Diesel engine | Hybrid aircraft | Kinetic energy recovery system | Li-ion battery systems | Turbine engines

[89] Piancastelli L., Frizziero L., Pezzuti E., Aircraft diesel engines controlled by fuzzy logic, ARPN Journal of Engineering and Applied Sciences, 9(1), 30-34, (2014). Abstract
X

Normally in diesel and gasoline engines, common rail systems are employed. The key factors for correct engine power management are pressure, precision and velocity. Digital computers and PID control systems characterize current systems. Recovery strategies are used when anomalies occur and engine performance is significantly reduced. So, restoring normal conditions needs technical assistance. For safety reasons this approach cannot be used in aeronautical, naval and energy-supply applications. In some cases it is necessary to utilize all the possible energy from the power unit causing significant life-reduction of the engine. In this case a progressive reduction strategy should be used and injection law should be reduced accordingly. For this purpose injection control based on fuzzy logic is more effective. In this case, traditional PID control systems are substituted by fuzzy logic control. A reference map is introduced in the Full Authority Digital Electronic Control; this map is interpreted by the fuzzy logic control system that adapts the injection law to the current engine situation. This method has been experimented on a common-rail test bed and results are compared with traditional "binary recovery strategy" FADEC. ©2006-2014 Asian Research Publishing Network (ARPN).

Keywords: Aircraft | Diesel propulsion | Engine control | Fuzzy logic

[90] Piancastelli L., Frizziero L., Rocchi I., Zanuccoli G., Daidzic N.E., The "C-triplex" approach to design of CFRP transport-category airplane structures, International Journal of Heat and Technology, 31(2), 51-59, (2013). Abstract
X

The quality of CFRP composites is highly dependent on the manufacturing process. Laminate performance is greatly affected by the void and resin fractions. Thicker structures result in lower quality. Thin composite laminates manufactured at high pressures offer best quality. However, impact and damage tolerance, buckling and concentrated stresses for rivets and bolts require redundancy which increases the thickness. Thick laminate structures lower CFRP mechanical properties. Composite laminates have advantage of good surface smoothness and low tolerances. A thin laminate tailored for the specific application with good monitoring system and support for buckling prevention with impact protection offers good solution. The bearing laminate is encapsulated between two sup porting layers with excellent outside tolerances and smoothness rep resenting the C-triplex concept. Inserts are included in the constructions for bolts or rivets. On the bearing laminate a monitoring tissue is installed for load history and structural integrity. The three layers are arranged in a way to house foam that provides support for buckling and thermal insulation. The C-triplex macro panels are bolted to a titanium or aluminum alloy skeleton of the aircraft body. C-triplex panels contain all ducts for the wires, pipes, and plug? necessary for the body interior.

Keywords: Aircraft structures | C-triplex | CFRP | Composite material | Modular construction

[91] Piancastelli L., Daidzic N.E., Frizziero L., Rocchi I., Analysis of automotive diesel conversions with KERS for future aerospace applications, International Journal of Heat and Technology, 31(1), 143-153, (2013). Abstract
X

Maximum takeoff or maximum continuous power is surprisingly often insufficient to guarantee absolute flight safety. Modern aircraft also need a conspicuous amount of electric power. The automotive industry in many respects is technology leader while aerospace industry is more conservative due to safety concerns. Ferrari developed an electronic KERS and implemented it in their Formula-One racing cars. KERS is capable of producing peak electrical power of 60 kW for 7s at a mass of 20 kg including rechargeable batteries. The main goal of this article is to explore utilization of turbo-charged aerodiesel engines and conduct feasibility study of the F1-derived KERS to assist power generation in normal and critical flight phases. The KERS' reversible brushless electric motor works as a generator for all aircraft power needs and also provides starting power. It is demonstrated here that such design philosophy improves performance and flight safety of light-to-medium airplanes and helicopters.

Keywords: Diesel engine | Hybrid aircraft | Kinetic energy recovery system | Li-ion battery systems | Turbine engines

[92] Piancastelli L., Frizziero L., Zanuccoli G., Daidzic N.E., Rocchi I., A comparison between CFRP and 2195-FSW for aircraft structural designs, International Journal of Heat and Technology, 31(1), 17-24, (2013). Abstract
X

Composite structures such as CFRP offer significant weight reduction over the conventional aluminum alloys for aircraft. Weight reduction improves fuel efficiency of the aircraft by approximately 20% which results in cost savings and simultaneously reduces the operational environmental footprint. However, the new aluminum-lithium alloys offer significant improvements and are viable alternatives to CFRP. Aluminum lithium alloy 2195 with Friction Stir Welding is introduced as a successful alternative to CFRP primary structures. A "thick skin" monocoque design with integral stringers as crack stoppers is discussed. An old Macchi 205 WWII fighter plane has been redesigned both in CFRP and 2195-FSW for comparison. The final designs are comparable in weight, but 2195-FSW is more competitive based on mass production costs, reparability, and environmental impact. Macchi 205 airplane is used due to in-depth experience with the original aircraft geometry and loads. Knowledge gained here can be directly transferred to larger structures, from corporate jets to large transport category airplanes.

Keywords: 2195-FSW | Aircraft structures | Aluminium alloys | CFRP | Composite material

[93] Dumas A., Trancossi M., Madonia M., Garziera R., Piancastelli L., Pirondi A., Frizziero L., Zero emission temporary habitation: Analysis of a passive container housing system acclimatized by geothermal water, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 6(PARTS A AND B), 1701-1717, (2012). Abstract
X

This paper presents a novel concept of container mobile housing system denominated ZETHa (Zero Energy Temporary Habitation). It is based on the LESP (Low Exergy Structured Panel) concept, in which the acclimatization is realized by water recirculation inside the external walls of the building and the ZEBRA concept (Zero Energy Consumption building. This evaluation will also consider energy needs by appliances. Copyright © 2012 by ASME.

[94] Piancastelli L., Frizziero L., Morganti E., Pezzuti E., Method for evaluating the durability of aircraft piston engines, Walailak Journal of Science and Technology, 9(4), 425-431, (2012). Abstract
X

A significant issue in aircraft engines is quantifying residual life to overhaul. The algorithm described in this paper calculates with a good level of reliability the residual life of a petrol piston engine. The method was tested on small, latest-generation, naturally-aspirated aircraft and racing piston engines, and has been effective in several experiments. This method is implemented directly on the electronic control system of the engine with very few lines of C-code. The method can also be used in many industrial engines. This innovative method assumes that only two main factors (power level and wear) affect engine durability or time between overhauls. These two factors are considered as separate and combined with worst case criteria. The wear is assumed to follow a logarithmic law and a formula similar to the Miner's law for material fatigue is used, making it possible to calculate the power-level curve with knowledge of only two points. The wear-curve is also related to elapsed engine cycles. The algorithm is very simple and can be implemented with just a few lines of software code accessing data collected from existing sensors. The system is currently used to evaluate actual residual life of racing engines.

Keywords: Aircraft | Algorithm | Durability | Engine

[95] Piancastelli L., Frizziero L., Marcoppido S., Pezzuti E., Revised KAD tool to optimize F1 cars through a combined-elitarian genetic-fuzzy algorithm, Journal of King Saud University - Engineering Sciences, 24(2), 165-171, (2012). Abstract
X

The KAD (Knowledge Aided Design) tool is developed to predict the performance of an F1 car in different driving conditions and with different configurations. The regulations to put in trimming a car, also in the exasperated technology of the competitions, still demand a remarkable dose of luck and an elevated number of tests. It is then important to know a set of regulations close to the optimal trim before testing the car on the track. The difficult phase of this process is to evaluate the lap time. As a matter of fact driving style, track conditions and car behavior should be simulated. The optimisation of the fuzzy controller that simulates the pilot for an F1 racing car is difficult due to handling problems and velocity of response. For this purpose a specific Genetic Algorithm (GA) was conceived and tuned to work with a lumped mass model of an F1 racing car for the optimization of the fuzzy controller that simulates the pilot. A new mutation and a new crossover operator were defined to complement the standard crossover and mutation operators of the basic Holland's GA. This was necessary in order to increase the overall performance of the fuzzy pilot. This approach was tested on an F1 car due to the huge amount of data available (Donnarumma, 1998; Moelenbein, 1989; Lee and Takagi, 1993).

Keywords: Control | Fuzzy logic | KAD | Performance

[96] Piancastelli L., Frizziero L., Rocchi I., An innovative method to speed up the finite element analysis of critical engine components, International Journal of Heat and Technology, 30(2), 127-132, (2012). Abstract
X

This paper introduces a method to simplify a non linear problem in order to use linear finite element analysis. This approach improves calculation time by two orders of magnitude. It is then possible to optimize the geometry of the components even without supercomputers. In this paper the method is applied to a very critical component: the aluminium alloy piston of a modern common rail diesel engine. The method consists in the subdivision of the component, in this case the piston, in several volumes, that have approximately a constant temperature. These volumes are then assembled through congruence constraints. To each volume a proper material is then assigned. It is assumed that material behaviour depends on average temperature, stress magnitude and stress gradient. This assumption is valid since temperatures varies slowly when compared to pressure (load & stress). In fact pressure propagates with the speed of sound. The method is validated by direct comparison with non linear simulation of the same component, the piston, taken as an example. In general, experimental tests have confirmed the cost-effectiveness of this approach.

Keywords: CAD | FEA | Geometry | Optimization | Simulation

[97] Piancastelli L., Frizziero L., Rocchi I., Feasible optimum design of a turbocompound Diesel Brayton cycle for diesel-turbo-fan aircraft propulsion, International Journal of Heat and Technology, 30(2), 121-126, (2012). Abstract
X

This paper is conceived to optimize the design of the thermodynamic cycle of a turbine (Brayton cycle) that uses a modern common rail diesel engine as an "active" combustion chamber. In this case the "active" combustion chamber produces the mechanical energy that drives the fan. The incoming air is compressed by the compressor, then is cooled (aftercooler) and inputted in the diesel engine. A high pressure common rail system optimizes the combustion in the diesel combustion chamber and the expansion begins inside the diesel engine. At the exhaust of the combustion chamber a turbine completes the expansion of the hot gases. A nozzle accelerates the exhaust from the turbine to increase the overall thrust. The mechanical energy from the diesel and from the turbine engizes the compressor and the fan. The system can be seen as a turbocharged diesel engine with the turbocharger that outputs energy to the turbofan, increasing the output power and or the efficiency. A diesel-turbine compound can be realized in this way. The coupling of the two system may be obtained in several different ways. The simplest is to put on the same shaft the compressor, the diesel crankshaft and the turbine. In front of the compressor a speed reducer drives the fan. A second example is to connect the turbine and the diesel on to electric generators. Electric engines are connected to the compressor and to the fan. The traditional turbo-diesel has the compressor coupled to the turbine, and the diesel engine that moves the fan. In this latter case, however, the turbine does not energize the fan. Many other hybrid and non hybrid solution are possible. The problem is to optimize temperatures, pressures and rpm to the different machines that form the compound. The availability of many experimental data for diesel and turbines makes it possible to obtain a design of a "true" feasible optimum Diesel-Brayton cycle. The high efficiency justifies the huge manufacturing and development costs of these turbocompound engines.

[98] Piancastelli L., Frizziero L., Morganti E., Canaparo A., Fuzzy control system for aircraft diesel engines, International Journal of Heat and Technology, 30(1), 131-135, (2012). Abstract
X

Common rail systems are conventionally employed in diesel and gasoline engines. Pressure, precision and velocity are key factors for correct engine power management. Current systems are based on digital computers and PID control systems. When anomalies occur, recovery strategies are used and engine performance is significantly reduced. Then technical assistance is required to restore normal condition. For safety reasons this approach cannot be used in aeronautical, naval and energy-supply applications. In some cases it is necessary to utilize all the possible energy from the power unit causing significant life-reduction of the engine. In this case a progressive reduction strategy should be used and injection law should be reduced accordingly. For this purpose injection control based on fuzzy logic is more effective . In this case, traditional PID control systems are substituted by fuzzy logic control. A reference map is introduced in the Full Authority Digital Electronic Control, this map is interpreted by the fuzzy logic control system that adapts the injection law to the current engine situation. For example, if fuel temperature tends to increase over the normal level, injection pressure is reduced by the fuzzy control system and injection time is increased to obtain the maximum possible power output. This approach can be easily implemented with very simple and effective fuzzy logic controllers. This method has been experimented on a commonrail test bed and results are compared with traditional "binary recovery strategy" FADEC. Maximum power output is slightly reduced since fuzzy controllers are less effective than PID in "near reference" conditions. However, when anomalies take place or are simply beginning to appear the fuzzy FADEC behaviour is more effective and preserves engine performance more effectively. Aim of this paper it to define rules and fuzzy controllers to optimize the performance of a diesel engine in various operating conditions with particular attention to the power output.

[99] Piancastelli L., Frizziero L., Diem S.M., Pezzuti E., Methodology to evaluate aircraft piston engine durability, International Journal of Heat and Technology, 30(1), 89-92, (2012). Abstract
X

A main problem in aircraft engines is the evaluation of residual life to TBO. The algorithm described in this paper calculates with good reliability the residual life to TBO of a petrol piston engine. The method was tested on small last-generation naturally-aspirated-avio piston engine, and has demonstrated to be effective in several experimental tests. This method is implemented directly in the FADEC or ECU of the engine with very few lines of C-Code. The method can be used also in many industrial engines. This innovative method assumes that only two main factors (load and wear) affect engine durability or Time Between Overhauls (TBO). These two factors are considered as separate and combined with the worst case criteria. The load is assumed to follow a logarithmic law and a formula similar to the Miner's law for material fatigue is used, making possible to calculate the "load curve" with die knowledge of only two points. The "wear" curve is related to elapsed engine cycles, and is easy to implement since it is related to technological. The resulting algorithm is very simple and can be implemented in very few software lines with data collected from the already existing sensors.

[100] Piancastelli L., Frizziero L., Marcoppido S., Donnarumma A., Pezzuti E., Active antiskid system for handling improvement in motorbikes controlled by fuzzy logic, International Journal of Heat and Technology, 29(2), 95-101, (2011). Abstract
X

Active antiskid systems for high performance motorbikes are difficult to implement due to the necessity to combine performance, equilibrium, handling and safety. In order to design and optimize a fuzzy controlled antiskid system for motorbikes a fuzzy model of the pilot was applied to a lumped-mass model of the motorcycle (two different models have been considered). The fuzzy pilot acts on the steering angle to control trajectory, yaw angle, yaw velocity and roll angle. Throttle position vs. time curve, gear and an adherence model between tire and road are given as input. The fuzzy pilot is implemented with Matlab/Simulink, and simply tries to keep equilibrium. Only measurable inputs were given as input variables of the antiskid fuzzy controller. The output is the percent reduction in throttle position. The motorcycle-fuzzy-pilot model proved to be quite accurate. Motorcycle maximum velocity resulted higher than the real one due to the simplifying hypothesis. In curves the fuzzy pilot is less efficient than the real pilot. In fact there was a low frequency oscillation around the optimum steering angle. This fuzzy controlled antiskid proved to work quite well since equilibrium is attained also in critical situations where the motorcycle-fuzzy-pilot model alone fails to keep equilibrium.

[101] Piancastelli L., Frizziero L., Marcoppido S., Donnarumma A., Pezzuti E., Fuzzy control system for recovering direction after spinning, International Journal of Heat and Technology, 29(2), 87-93, (2011). Abstract
X

The progressive increase of tire-size has concurred to a sensitive improvement of the adherence with consequent increase of car safety. However, the wide tires have problems to expel the water in excess in heavy rain condition. For this reason the phenomenon of the aquaplaning is increasingly felt and is the cause of several automotive accidents. It is not a case that nearly all tire manufacturers supply "rain" tires and adherence in wet conditions is highly advertised. A typical accident happens when aquaplaning occurs in motorway at high speed. One or more tires lose adherence and the car begins to spin. If the pilot is not able to regain the initial direction, the car may hit the guardrail or another car. In this case the modern control systems like the ESP (Electronic Stability Program) and the ASR (Anti Skid Regelung) do not have time or are not able to manage a pre-spin or spin situation at elevated slip-angles. In this paper, a fuzzy control system able to deal with these conditions is introduced. The car has been simulated with a 9 DOF lumped-mass model that does not take into account suspensions and it considers a rigid car on smooth asphalt. The model of adhesion of the tire, instead, takes into account the effect of transverse forces on the longitudinal adherence. An expert pilot controls a high-speed spin with difficulty also. In this paper, a fuzzy control system that is able to control the brake torque on each single tire has been considered. The fuzzy control system works quite well and the car does not even enter in a true spin if enough adherence is present or if the slippery zone on asphalt is limited.

[102] Francia D., Piancastelli L., Renzi C., A very simple and effective method for off-design simulation of modern aircraft piston engines, AIAA Modeling and Simulation Technologies Conference and Exhibit, (2008). Abstract
X

A new generation of aircraft piston engines is currently being introduced on the market. These new engines come directly from the huge experience achieved in the motorcycle and automotive racing and production. However direct use of automotive power unit is not advisable, since car engines work mainly in the first quarter of the power output, while sport motorcycles are used in a very "light" way, with the engines that span several times through the entire range of power outputs and rpm. The other problem is fuel. Aircraft spark ignition engine for ultralight and light aircrafts may continue to use automotive gasoline, while diesel engines for light up to cargo aircraft should use jet(A1) and jp4. However, the large experience obtained from racing/high-performance motorcycles, racing/high-performance cars and common rail engines cannot be ignored. Thousand of hours and billion of Euros have been spent for this development and the results are interesting. This paper tries to calculate the future aircraft engine performance from the many experimental data already available on a certain type of combustion chamber or better from a well defined and experimented cylinder unit. On the other side the "lean-thinking" approach to aircraft engine design may be not applicable. The lean thinking approach tends to prefer the time-to-market to the optimization of the engine unit. With engines that will probably stay on the market for 30 years this approach is not convenient. An important optimization during the design phase is possible with modern CAD tools. Mass and cost reduction may easily reach the 30%. On the other side the "brain storming approach" is not applicable to the heavily-constrained aircraft-engine design, where it is common that inapplicable solutions and ideas seem to be the best during the initial phase even to experts. Our research team developed three different families of engines: the first family uses the cylinder unit of a well proven motorcycle engine, which comes directly from racing and was sold in tenth of thousands in the world market. These spark ignition engines have 4 up to 16 cylinders (Figg. 1, 2), with power from 150 HP to 800 HP. This type of engines have very brilliant power to weight ratios with not superlative fuel consumptions. They are conceived for ultralight aircrafts and helicopters, tilt rotor, tilt shaft and tilt motor power lift V/STOL aircrafts. The second cylinder unit comes directly from the 2 valves FIAT 1900 jtd, that is one of the best two valves turbocharged common rail diesel available on the market. These units span from 4 up to 16 cylinders with power outputs from 175 HP (Fig. 3) up to 1000 HP. They run with jp4, jp8 or jet (A1) and can be bolted directly to the original engine mount of existing light aircraft like Cessna 172/182/337 or can be used in new light aircrafts. The third one is an originally conceived twin combustion chamber diesel family with output power from 600 HP to 4000 HP (hybrid engine) originally conceived for the Hercules C130J, ATR42 or ATR72 aircrafts (Figg. 4, 5). Our hybrid engine is composed by two separate engines: the VD007 diesel and a turboshaft. Each engine moves a separate contra rotating propeller. In ordinary flight the turboshaft works as a turbocharger. In this case the rear propeller is nearly idle. During take off or emergency the turboshaft combustion chamber is activated and additional power is available. In this case pitch is given to the rear propeller that outputs additional useful thrust. All these engines use only the thermo-fluid-dynamics and a few parts of the original cylinder unit, since aircraft application need extended modifications and, in many cases, complete redesign. However on all these engines a large amount of experimental, road and reliability data are available. Their direct application in the aircraft field is a plain mistake, since automotive and motorcycle are very different, but it is not the case to discard all this data that are available for free. For this reason innovative simulation methods were used to obtain engine performance envelope, with the possibility to choose the most convenient off-design solution on a certain aircraft, depending on the use and on the requirements. It is also possible to obtain reliability data for the aircraft FADEC (Full Authority Digital Engine Control) that controls all these new units. It is important to underline that airborne FADECs should be completely different from ground borne FADECs since in the aircraft application recovery strategies are to be chosen by the well trained pilot, while in the automotive field recovery is usually applied automatically in order to preserve engine integrity. A new method for the determination of the engine performance envelope is introduced as an example on the turbo/hybrid diesel unit for the C130J; this engine is called VD007. This approach has been successfully applied on the small diesel jtd family and also to the spark ignition family. © 2008 by the American Institute of Aeronautics and Astronautics, Inc.

[103] Luca P., Marco P., The bonus of aircraft piston engines, an update of the Meredith effect, International Journal of Heat and Technology, 25(2), 51-56, (2007). Abstract
X

Diesel piston engines are becoming popular in the aeronautical field for the high efficiency and the possibility to work with jp4 and jp8 fuels. This paper updates a secondary advantage of piston engine: the Meredith effect. An accurate tuning and design of the cooling system can add a significant additional thrust to the engine plant. This effect, well known since the beginning of WWII, is being refined in this paper. Optimization of the diffuser and the nozzle has been performed and a new radiator, with wing section tubes has been developed. As an example, this new cooling system has been applied to the VD007 hybrid turbo-diesel engine. This power plant has been designed for the C-130J airplanes. The curves of additional thrust vs. speed has been calculated along with size and shape.

[104] Gazzotti D., Piancastelli L., Sartori C., Beneventano D., Fuzzybase: A fuzzy logic aid for relational database queries, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 978, 385-394, (1995). Abstract
X

This paper presents a similarity query generator for DBMSs. A user query which turns out to be too restrictive and returns an empty set of rows is relaxed and transformed into a similar one: the resulting set of tuples will resemble, at some degree, the set defined by the original query. The relaxing activity is based on fuzzy logic and the system provides a user interface to express the query, to obtain suggestions on possible search values and to validate, on the basis of semantic integrity rules, the expressed conditions.

[105] Mirri A., Sangiorgi V., Piancastelli L., Design optimization of a high speed spindle for a take-up winder, Chemiefasern Textilindustrie, 44-96(11-12), (1994). Abstract
X

A novel CFRP (carbon fibre reinforced plastics) take-up spindle of 288mm roller bearing distance L"SUB 1" can be retrofitted to existing winders. Its first natural frequency is at 4950rpm and corresponds to 10 000m/min yarn take-up speed. Bobbin winding time is decreased with both the single-and multi-spindle take-up winder.

[106] Piancastelli L., Some considerations on a four-node finite element for composites with the drilling degrees of freedom, Computers and Structures, 43(2), 337-342, (1992). Abstract
X

A plate-type finite element with six degrees of freedom (DOF) for each of the four nodes is introduced. To obtain this result a Mindlin-type bending-plate element is superimposed on a three DOF per node plane-stress element. Composites are simulated using the YNS theory. A few considerations on some plate-shell elements already tested are reported and the introduction of the drilling DOF is justified. A comparison with the results obtained by using a nine-node reduced-integration isoparametric element is also supplied. © 1992.

[107] De Lollis A., Piancastelli L., Shape and material optimization of the 'Bologna Boot' (a) CFRP skeleton, International SAMPE Technical Conference, 23, 503-513, (1991). Abstract
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The 'Bologna Boot' CFRP othesis was designed to help paraplegics to stand and to walk. The great advantage of the Bolonga Boot when confonted with previous otheses, is the absence of articulation blockage, since the leg is kept straight by moving the patient's center of gravity slightly forward. This displacement is achieved by a sloping sole. A strp transfers the unbalanced weight to a skeleton which includes a wedge of about 5 degrees; a leather sheath completes the boot. This work is focused on skeleton optimization. At the beginning a CFRP design was developed by using a high-modulus-carbon with a PMMA (Poly Methil MethAcrilate) thermoplastic matrix, to allow for minor modifications during test on patients. Then the skeleton was simplified by using a more complete set of measured loads. For this purpose, an high accuracy finite element and a computer program for sandwich optimization were developed. A high-modulus-carbon-epoxy sandwich rod was standardized for various groups of patient sizes; this structure is partially embedded in the polyurethane foam wede by using a low-modulus-carbon-epoxy interface. A PMMA-carbon collar completes the skeleton. This solution permits on-field modification of the skeleton to improve the patient' comfort with half the weight of the previous design.

[108] Granata C., de Lollis A., Campo G., Piancastelli L., Merlini L., Analysis, Design and Development of a Carbon Fibre Reinforced Plastic Knee-Ankle-Foot Orthosis Prototype for Myopathic Patients, Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 204(2), 91-96, (1990). Abstract
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A traditional knee-ankle-foot orthosis (KAFO) for myopathic patients has been studied for the assessment of loads and fatigue resistance. Starting from this basis a thermoplastic matrix carbon fibre reinforced plastic composite (CFRP) KAFO has been developed in order to reduce the weight. A finite-element simulation programme for deformation analysis was used to compare the behaviour of conventional and CFRP orthosis. There were no breakages either of the prototype or of its parts. The CFRP orthosis allows a weight reduction of more than 40 per cent. © 1990, Institution of Mechanical Engineers. All rights reserved.

[109] Bergamaschi S., Bombarda G., Piancastelli L., Sartori C., Expert system for the selection of a composite material, 140-141, (1989). Abstract
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An expert system for composite material selection starting from the user's specification was developed. Since a DBMS database management system was necessary to manage the amount of information for material and application characterization, a logical interface between the Expert 2 system and the relational database was developed. This configuration allows complete separation between the database problem of material characteristic management and the rule-oriented material selection problem handled by the expert system.

[110] De Lollis A., Piancastelli L., Lower limb orthotics, (1989). Abstract
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Carbon fibre composites are being used as strong lightweight materials in knee supports.