Lower surface blowing (LSB) is investigated as an alternative to the variable blade pitch requirement for the X-Wing Circulation Control (CC) rotor concept. Additional trailing edge blowing slots on the lower surfaces of CC airfoils provide a bi-directional lift capability that effectively doubles the control range. The operational requirements (aerodynamic environment) of this rotor system are detailed and compared to the projected performance attributes of LSB airfoils. Analysis shows that, aerodynamically, LSB supplies and fixed-pitch rotor system with the equivalent lift efficiency and rotor control of present CC rotor designs that employ variable blade pitch. Aerodynamic demands of bi-directional lift production are predicted to be within the capabilities of current CC airfoil design methodology. Emphasis in this analysis is given to the high-speed rotary wing flight regime unique to stoppable rotor aircraft. The impact of a fixed-pitch restriction in hover and low-speed (transition) flight is briefly discussed.
Analysis of a Fixed-Pitch X-Wing Rotor Employing Lower Surface Blowing
1987
27 pages
Report
Keine Angabe
Englisch
Aerodynamics , Aerodynamic lift , Rotor blades(Rotary wings) , Aerodynamic characteristics , Airfoils , Blades , Circulation , Control , Efficiency , Helicopters , Hovering , Performance(Engineering) , Pitch(Motion) , Production , Requirements , Rotary wing aircraft , Helicopter rotors , Aerodynamic slots , Stopping , Surfaces , Trailing edges , Variables , Wings , Reprints , X wing aircraft , Circulation control airfoils , Lower surface blowing airfoils , Bidirectional lift , Transition flight , Fixed pitch rotary wing aircraft
Rotor wing device with variable pitch and multi-rotor-wing aircraft
Europäisches Patentamt | 2015
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