This limited flight test program defined the hover and takeoff performance of the HH-53C helicopter at high altitude and included an evaluation of the increased tail rotor power provided by a new tail rotor bellcrank. Hover and takeoff performance were satisfactory during high altitude testing. Operating at 105% rotor speed at high altitude, heavy gross weight combinations provided a more rapid response of the aircraft to control inputs than operation at 100% where control response was somewhat sluggish. In addition, it provided increased performance, prevented reaching mechanical control stops from limiting performance and lowered cruise guide readings. The new tail rotor bellcrank increased the HH-53C lift capability approximately 4,500 pounds by preventing tail rotor authority from limiting aircraft performance. A compromise between maximum performance and safety resulted in recommendation of a 35 knot indicated airspeed for takeoff. (Author)
Limited High Altitude Performance Evaluation of the HH-53C Helicopter
1971
58 pages
Report
No indication
English
Aircraft , Helicopters , Performance(Engineering) , High altitude , Flight testing , Hovering , Takeoff , Lift , Tail helicopter rotors , Rotor blades(Rotary wings) , Flight speeds , Climbing , Flight control systems , Response , Helicopter engines , Gas turbines , Hh-53c aircraft , H-53 aircraft , T-64 engines , T-64-ge-7 engines