Engineering Flight Test of the YCH-47C Medium Transport Helicopter. Army Preliminary Evaluation I
Final rept. Jun 1966-Jun 1968
ARMY AVIATION SYSTEMS TEST ACTIVITY EDWARDS AFB CA
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Army Preliminary Evaluation I was conducted to verify the performance guarantees, obtain limited handbook data and evaluate the mission effectiveness of the YCH-47C helicopter. The maximum cruise speed capability was 155 KTAS and limited by heavy cockpit vibration. The outstanding 95 degree Fahrenheit day in ground effect and out of ground effect hover capability enhances the mission effectiveness of the aircraft. The flight envelope release VNE for all gross weights tested at 245 rpm rotor speed and low and high altitudes was not attained. The airspeed was limited by as much as 15 KTAS due to heavy cockpit vibration, but not to the extent that the mission effectiveness of the helicopter would be seriously degraded. The VNE was easily exceeded for all gross weights tested at 235 rpm rotor speed-high altitudes with no vibration limitations encountered.