Preliminary Airworthiness Evaluation of the AH-1S (Modernized Cobra) with the HELLFIRE, TOW, and Stinger Missiles Installed

摘要

The aircraft was operated at gross weights up to 10,400 lb, up to 11,340 feet density altitude and at a lateral center of gravity (cg) range from one inch right to approximately three inches left. The asymmetric loadings were caused by the various combinations of armament configurations. The change in equivalent flat plate area compared to the clean aircraft for each configuration varied as a function of airspeed. At 130 knots true airspeed (KTAS), the increased flat plate area was 4.2 square feet for the Launcher configuration, 4.8 square feet for the TOW configuration, 6.6 square feet for the Hellfire and Hellfire/TOW configurations, and 7.8 square feet for the Stinger/Hellfire/TOW configuration. The increase in flat plate area for the Stinger/Hellfire/TOW configuration reduced maximum level flight speed for normal rated power by approximatley 8 KTAS. With the exception of the two armament related shortcomings listed below, the handling qualities and the reactions to system failures of the AH-1S (MC) were not significantly changed by the asymmetric loading of the various armament configurations. Four shortcomings were noted and follow in decreasing order of importance: (1) the high left rolling response to a sudden engine failure at power settings above 75% torque; (2) the undesirable maneuvering stability characteristics above 1.4 g's; (3) insufficient left pedal margin available in right sideward flight above 10 knots in the Hellfire and Hellfire/TOW configurations; and (4) insufficient left pedal margin available for ball-centered forward flight below 30 KCAS in the armament configurations with left lateral cf offset. A CAUTION is recommended for inclusion in the operator's manual dealing with.