Towards the Low Speed and Highly Agile UAV through a Novel Fuselage Design, Slender Leading Edge Extensions and the Wake Ingestion Concept

Nowadays there is a strong demand for light,economical and high maneuverable UAVs that when operating in a swarm formation they can infer a considerable military impact. This group of Aircrafts (A/C) can act complementary to conventional airforce as a means to saturate the hostile defense system with dispensible units. To this end, a new low subsonic fixed wing UAV concept is proposed herein which aims at high maneuverability for its category of low subsonic speed and light (up to 200 kgs) UAVs. Its characteristics are a variation of the prolate speroid (6:1 aspect ratio) fuselage for low drag cruise flight, the non-slender delta main wing for high struc- tural strength, and the integration of the powerplant, i.e. the Electric Ducted Fans (EDFs), close to the wing for enhancement of the aero/propulsive performance of the A/C. The latter is achieved through the proper manipu- lation of generation and evolution of the Leading Edge Vortices (LEVs) over the wing by the suction produced by the EDFs. The Computational Fluid Dynamics (CFD) code being used herein is the Openfoam-v2412 while the simulations are implemented on a High Performance Computing platform. The numerical simulation hints that the proposed A/C which uses concepts such as the Leading Edge Extension (LEX) for lift augmentation, the wake ingestion and a novel LEV manipulation method can be highly agile and at the same time economical in the sense that it is inherently stable, not requiring expensive flight control systems for its stabilization. On top of its aerodynamic performance, the A/C uses also design concepts that conduce to low Radar Cross Section (RCS).