Empennage Design of Solar-Electric Powered High Altitude Long Endurance Unmanned Aerial Vehicle

Abstract

KARI is developing a solar-electric powered HALE UAV(EAV-3). For demonstrating the technology, EAV-2H, a down-scaled version of EAV-3, is developed and after EAV-2H's initial flight test, the directional stability and control need to be improved. Thus, the vertical tail and rudder of EAV-2H are redesigned with Advanced Aircraft Analysis(AAA).Size of the rudder is increased from mean chord ratio of rudder to vertical tail,      =30 to     =60 and size of the vertical tail is reduced 15%. As a result, the directional control to side wind(  ) is improved to sideslip angle,  deg=25°and   (m/sec)=3.54. Also, variation of airplane side force coefficient with sideslip angle(   ) and variation of airplane side force coefficient with dimensionless rate of change of yaw rate (   ) are reduced 15% and 22%, respectively to minimize the effect of side wind. The empennage design of EAV-2H is verified with flight tests and applied to design of KARI's solar-electric-powered EAV-3.

Aerodynamic Design of the Solar-Powered High Altitude Long Endurance (HALE) Unmanned Aerial Vehicle (UAV)

“…The size of the vertical tail is reduced 15% to cut down 15% of the variation of airplane side force coefficient with sideslip angle, C yβ , and 22% of the variation of airplane side force coefficient with dimensionless rate of change of yaw rate, C yr . Also, the vertical tail to rudder ratio, C r /C v , is increased from 30% to 60% to secure the directional stability at the least, the variation of airplane yawing moment coefficient with angle of sideslip (C nβ ) = 0.0588rad -1 [6,7].…”