The paper presents a theory for flight-dynamic analysis of highly flexible flying-wing configurations. The analysis takes into account large aircraft motion coupled with geometrically nonlinear structural deformation subject only to a restriction to small strain. A large motion aerodynamic loads model is integrated into the analysis. The analysis can be used for complete aircraft analysis including trim, stability analysis linearized about the trimmed-state, and nonlinear simulation. Results are generated for a typical high-aspect-ratio "flying-wing" configuration. The results indicate that the aircraft undergoes large deformation during trim. The flight-dynamic characteristics of the deformed aircraft are completely different as compared with a rigid aircraft. When the example aircraft is loaded sufficiently, the pair of complex-conjugate short-period roots merges to become two real roots, and the phugoid mode goes unstable. Furthermore, nonlinear flight simulation of the aircraft indicates that the phugoid instability leads to catastrophic consequences.

Flight Dynamics of Highly Flexible Flying Wings

Challenges of future aircraft propulsion: A review of distributed propulsion technology and its potential application for the all electric commercial aircraft

This thesis deals with airplanes using solar energy as their only source of energy for more than 24 hours flight. Using solar panels, they collect it during the day for immediate use but also store the remaining part for the night flight. This work presents a new analytical methodology for the conceptual design of such airplane. Its major advantage lies in the fact that it is simple and versatile, which makes it applicable to a large range of airplanes of different wingspans, from the small MAV to the large manned aircraft. The design methodology is based on power and mass balances occurring during level flight. An extensive study was done on the mathematical modeling of the subparts, for example concerning electric motors the question being to know how their mass and their efficiency vary with power. Empirical data over a large range were used in this study. Finally, the analytical method contains 5 mission parameters and 25 others linked to the various technologies involved that the user can vary in order to see on a graph the dependencies between the 3 layout variables (aspect ratio, wingspan and total mass) for all the feasible solutions. The final selection can then be easily made. Sky-Sailor, a 3.2 meters wingspan solar powered airplane, was then designed using this methodology. A prototype, with an ultra lightweight structure covered by silicon solar cells was built in order to validate the process. We also developed in this framework dedicated electronics for the autonomous navigation and the efficient solar power management. The final 2.44 kg airplane was tested with success during several autonomous flights, showing capabilities that were very close to the one calculated in theory. The longest flight achieved lasted more than 27 hours within a circuit length of more than 874 kilometers and proved the feasibility of solar powered continuous flight. In addition to the first application example on Sky-Sailor, other designs are presented and discussed, like the case of a 70 cm solar UAV but also a 60 m manned solar airplane. It is then very interesting to see how things evolve with scaling. In fact, going in each direction removes and adds its batch of

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Design of Solar Powered Airplanes for Continuous Flight

AIAA Guidance, Navigation, and Control Conference

Applications of the unsteady vortex-lattice method in aircraft aeroelasticity and flight dynamics

In the last ten years, different concepts of electric vertical take-off and landing aircrafts (eVTOLs) have been tested. This article addresses the problem of the choice of the best configuration. VTOLs built since the fifties are presented and their advantages, disadvantages, and problems are discussed. Three representative eVTOLs, one for each main configuration, are compared on five main parameters and three reference missions. The parameters are disk loading, total hover time, cruise speed, practical range, and flight time. The performance of the eVTOLs on the urban, extra-urban, and long-range mission is evaluated computing the time and energy required. The results show that the best configuration depends on the mission. The multirotor is more efficient in hover. The vectored thrust jet is more efficient in cruise and has a higher range. The lift + cruise is a compromise.

Electric VTOL Configurations Comparison

Design of solar high altitude long endurance aircraft for multi payload & operations

This paper presents the design and manufacture of the first European Very Long-Endurance Stratospheric Unmanned Air Vehicle, HeliPlat® (HELIos PLATform). This vehicle is a monoplane with eight brushless motors, a twin-boom tail type and two rudders. A computer program has been developed to carry out the platform design. To minimize airframe weight, high modulus carbon fibre composite material has been used extensively. Airfoil coordinates and wing planform have been optimized in order to achieve the best possible aerodynamic efficiency by using integral panel/boundary-layer methods and also to obtain the minimum possible induced drag with respect to local Reynolds airfoil. To this effect, several wind-tunnel tests were carried out so as to compare the analytically predicted airfoil performances. After an initial configuration had been worked out, a scale technological demonstrator (wing span 24 m) was designed, manufactured, and tested under shear, bending, and torsion loads. Finite element analysis was also carried out in order to predict the static and dynamic behaviour of both the full-size and scale model versions of the HeliPlat structure. The preliminary static test resulted in a high correspondence.

HELIPLAT: Design, aerodynamic, structural analysis of long-endurance solar-powered stratospheric platform

Several researches are being carried out at the Politecnico di Torino with the aim of designing a high altitude very-long endurance/unmanned air vehicle (HAVE/UAV). Being able to fly in the stratosphere (15-20 km) and with an endurance of about 4 months offers an advantage and possibility that is presently not available with conventional aircraft or satellites. A computer program has been developed to design the platform. The change in solar radiation over a period of a year, the altitude, masses, and efficiencies of the solar and fuel cells, as well as the aerodynamic, structural, flight mechanics, and aeroelastic performances have all been taken into account. Extensive use has been made of high modulus graphite/epoxy when designing the structure in order to minimize the airframe weight, but also to guarantee the required stiffness and aeroelastic performance.A blended wing body (BWB) configuration has been selected for solar HAVE aircraft multi payload and operation (SHAMPO) with eight brushless...

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Enrico Cestino

Papers

Electric VTOL Configurations Comparison

Design of solar high altitude long endurance aircraft for multi payload & operations

HELIPLAT: Design, aerodynamic, structural analysis of long-endurance solar-powered stratospheric platform

Design of a High-Altitude Long-Endurance Solar-Powered Unmanned Air Vehicle for Multi-Payload and Operations

ENFICA-FC: Design of transport aircraft powered by fuel cell & flight test of zero emission 2-seater aircraft powered by fuel cells fueled by hydrogen