An Active Flow Circulation Controlled Flap Concept for General Aviation Aircraft Applications

G. S. Jones* S. A. Viken* A.E. Washburn* L. N. Jenkins* C.M. Cagle**Flow Physics & Control BranchNASA Langley Research CenterAbstractA recent focus on revolutionary aerodynamic concepts has highlighted the technology needs of general aviationand personal aircraft. New and stringent restrictions on these types of aircraft have placed high demands onaerodynamic performance, noise, and environmental issues. Improved high lift performance of these aircraft canlead to slower takeoff and landing speeds that can be related to reduced noise and crash survivability issues.Circulation Control technologies have been around for 65 years, yet have been avoided due to trade offs of massflow, pitching moment, perceived noise etc. The need to improve the circulation control technology for generalaviation and personal air-vehicle applications is the focus of this paper. This report will describe the developmentof a 2-D General Aviation Circulation Control (GACC) wing concept that utilizes a pulsed pneumatic flap.SymbolsA Area (_)b Span (inches)CL Uft CoefficientCo Drag CoefficientCa Moment CoefficientC,, Momentum CoefficientC Chord (inches)CCW Circulation Controlled WingD Drag (Ibs)DC Duty Cycle (Time On/Time Off)E Mean Voltagee' Fluctuating Voltageh Slot height (inches)LE Leading EdgeL Lift (Ibs)M Pitching Moment (in-lbs)m mass flow (Ib/sec)P Pressure (Ib/in 2or Ib/tt 2)p' FluctUating Pressure (Ib/in 2or Ib/ft2)r Trailing edge radius (inches)U Velocity (ft/sec)u' Fluctuating Velocity (ft/sec)q Dynamic Pressure (Ib/ft 2)S Wing plan form area (_)SCFM Standard Mass Flow (ft3/min)(Expanded to 14.7 psia & 72°F)SPL Sound Pressure Level (dB)TE Trailing EdgeT Static Temperature (°R)w Slot Width (inches)Angle of attack (degrees)p density (Lbm/ft 3)r Circulation