A new propelled wing aircraft configuration

This paper investigates by an energetic approach possible new configurations of aircrafts, which can rival in low speed operations against helicopters. It starts from an effective energy balance of helicopters during fundamental operations: takeoff, horizontal flight, hovering, and landing. The energy state of a helicopter can be written as:

E = ½ mV2 + mgh + ½ I ω2 (1)

where m is mass of helicopter, I is total rotor inertia, ω is rotor rotational speed. By taking the partial derivative with respect to time of equation 1, the power is expressed as

dE/dt = ΔP = mV dV/dt + mg dh/dt (2)

By optimizing the energy balance of the helicopter a new aircraft configuration has been obtained that allow a very high lift even at very low speed, but drastically reducing the energy consumption during horizontal flight. The total power required is obtained by rotor power and overall efficiency factor (η) and HPreq total = η HPreq rotor.

By equations (1) and (2) it has been produced a preliminary optimization in different operative conditions considering a speed range from 0.5 (hovering conditions) to 50 m/s. By an accurate balance of the results, it has been identified that the most disadvantageous situation for a helicopter is forward flight. A new powered wing architecture has been specifically studied for replicating the behaviour of helicopters. Preliminary it has been defined by starting from the energy equations the main characteristics of the propelled wing. From those numerical results it has been defined a new configuration of propelled wing and the new aircraft configuration which allow adequate performance against helicopter. Those wings take a large advantage of two not common features: symmetry with respect to a vertical axis and possibility of optimizing the shape for specific missions.

It has been designed and optimized in different configurations by CFD. In particular, an accurate analysis of fluiddynamic of the system allows quantifying the different effects that allows realizing an extraordinary ratio between lift and thrust producing an effective vehicle that can rival against helicopter also at very low speeds with a morphing configuration that will be presented in the final paper because of patenting reasons. Results show that the proposed innovative aircraft configuration allows hovering and very low speed flight. In particular, the conditions and the design for this kind of operation are presented even if still in initial design stage. The presented aircraft architecture can also allow inverting the direction of motion just by inverting the direction of the thrust. In this case, it will allow overcoming completely the performances of helicopters. The energetic balance of flight has been evaluated and the advantages with respect to helicopters have been finally expressed with surprising results.

Attribution-NoDerivs 3.0 United States