Sideward Flight, High-Altitude Evaluation, and Simulated Engine Failures KingCobra Model 309 Attack Helicopter
Final rept. 7 Jul-8 Aug 1972
ARMY AVIATION SYSTEMS TEST ACTIVITY EDWARDS AFB CA
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A limited evaluation was conducted of the performance and handling qualities of the Model 309 helicopter. The evaluation required 7 hours of flight time. Previous testing had been accomplished and a report was submitted. Except as noted in this report, the performance and handling qualities were essentially unchanged from those observed during the previous testing. The tail rotor horsepower limitation previously reported as a deficiency no longer exists due to an uprating of the tail rotor drive system from 350 to 450 shaft horsepower. The increase in sideward flight airspeeds to 60 knots in left sideward flight and 50 knots in right sideward flight at low altitude, and 50 and 40 knots in left and right sideward flight at high altitude, enhances the ability to hover in gusty winds. The standard-day out-of-ground-effect hover ceiling at the TOW mission gross weight of 12,385 pounds is 14,340 feet and at the maximum allowable gross weight of 14,000 pouns, is 9950 feet. The hot day 95 F out-of- ground-effect ceiling is 4300 feet at maximum gross weight. Lateral acceleration maneuvers were conducted at both high- and low-altitude sites. Left lateral acceleration was limited to by the transmission torque limit to 0.33g at the low-altitude site and 0.24g at the high-altitude site. Right lateral accelerations were limited by directional control to 0.28g and 0.14g at the low- and high-altitude sites, respectively. The helicopter response characteristics following simulated engine failures were significantly milder than that of the standard AH-1G and are satisfactory. One shortcoming, the excessive pilot workload during lateral accelerations and reversals, was identified.
- Jet and Gas Turbine Engines