Performance of a 0.27-scale rotor model designed for the AH-64 Apache helicopter (alternate rotor) was measured in hover and forward flight compared with an AH-64 baseline rotor model. Thrust, rotor tip Mach number, advance ratio, and ground proximity were varied. In hover, at a nominal thrust coefficient of 0.0064, the alternate rotor used about 6.4% less power than the baseline rotor. The corresponding thrust increase at this representative hover power condition was approximately 4.5%, which represents an equivalent full-scale increase in lift capability of about 660 lb. Comparable results were noted in forward flight, except for the high-thrust, high-speed cases investigated (Advance ratio = 0.30), where the baseline rotor was slightly superior. Reduced performance at the higher thrusts and speeds was probably caused by Reynolds number effects and blade elasticity differences. Keywords: Rotor blades rotary wings; Blade tips; Attack helicopters; Helicopter rotor performance; Model rotor testing; Tapered rotor blades; Ground effects. (edc)
Aerodynamic Performance of a 0.27-Scale Model of an AH-64 Helicopter with Baseline and Alternate Rotor Blade Sets
1990
25 pages
Report
Keine Angabe
Englisch
Aircraft , Aerodynamics , Aerodynamic characteristics , Helicopter rotors , Rotor blades(Rotary wings) , Attack helicopters , Blade tips , Elastic properties , Ground effect , Helicopters , Hovering , Level flight , Lift , Model tests , Performance(Engineering) , Power , Ratios , Reduction , Reynolds number , Scale models , Taper , Thrust , AH-64 Aircraft , ASH7A
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