YAH-63
The Bell (model 409) YAH-63 (1976) was Bell Helicopter's entry in the Advance Attack Helicopter (AAH) competition against the Hughes YAH-64.
The Bell (model 309) KingCobra was a scaled-up version of the AH-1G Cobra attack helicopter. It had a lengthened and strengthened fuselage and changes in the nose to accept a stabilized multi-sensor gun sight. It was evaluated against the AH-56A Cheyenne and the Sikorsky S-67 Blackhawk in 1972, but none were accepted by the Army. The Bell (model 309) KingCobra had a laser day and night sight, infrared fire control system, and night vision TV. Armament was similar to that of the Cheyenne and the Blackhawk. The KingCobra was powered by a single Lycoming T55-L-7C 2850 shp engine. One of only two prototypes crashed. The other took part in comparative trials in 1972 with the Lockheed AH-56A Cheyenne and the Sikorsky (S-67) Blackhawk, but the U.S. Army decided none matched its requirement. The Bell (model 309) KingCobra evolved into the Bell (model 409) YAH-63.
From the Model 309, Bell derived a new prototype attack helicopter, the Model 409 (US Army designation YAH-63), which it entered for the AAH (Advanced Attack Helicopter) competition won by the aircraft proposed by Hughes. The YAH-63 had a different profile from the Kingcobra, including a conspicuous ventral fin and a tail plane at the top of the tail fin.
In November 1972 the Army solicited design proposals for a new Advanced Attack Helicopter (AAH) intended for the all-weather anti-armor role. The Army's specifications required that the new aircraft be powered by twin General Electric T700 turboshaft engines and armed with up to sixteen Hellfire or TOW anti-tank missiles in addition to a single 30mm cannon. Preliminary design proposals were submitted by Boeing-Vertol, Bell, Hughes, Lockheed, and Sikorsky, and in June 1973 Bell and Hughes were selected as finalists and were each awarded contracts for the construction of two prototype aircraft.
The first prototype YAH-63 (serial 73-22246) made its maiden flight on 1 October 1975, but crashed during a test flight the following June. The aircraft was repaired and, along with the second prototype (73-22247), entered the official Army 'fly-off' against the YAH-64. On 10 December 1976 the Hughes machine was selected as the winning AAH design, and both YAH-63 prototypes were subsequently returned to Bell for disposal.
