Bell had been leading the way in attack helicopters with the first
purpose-designed Bell 207 Sioux Scout, first flown in July 1963 and
the Bell 209 AH-1 HueyCobra first flown on September 7, 1965, the
latter becoming the first attack helicopter to go in
series-production. Already in 1971 the company had developed an
advanced attack helicopter, the Bell 309 KingCobra.
As the 207 and 209 prototypes, the two KingCobra prototypes were
company funded, the first flying on September 10, 1971 powered by a
Pratt & Whitney Twin Pac turbine engine and intended as an
replacement for the USMC AH-1J SeaCobra. The second flew
with a Lycoming T-55 turbine engine for the first time in January
1972 and was to be offered to the US Army.
However the second prototype suffered from an accident in the spring,
so to participate in an Army evaluation of potential gunships, the
first prototype had its Twin Pac engine replaced by the Lycoming
engine to suit the Army requirements. One other evaluated helicopter
was the Sikorsky S-67 Blackhawk but neither of these types were ordered.
In November 1972 the US Army issued a request for proposals for their
Advanced Attack Helicopter developing programme to which Bell
responded with the Model 409, resulting in June 1973 in a contract
for two prototypes and a ground test vehicle. The two KingCobras have
been used as research vehicles for this and other programmes.
The KingCobra had the general configuration of the HueyCobra but had
the wing stubs enlarged to a span of 13 ft (3.96 m), 5 ft (1.52 m)
enlarged new designed rotor, 4 ft 7 in (1.40 m) longer fuselage and a
tailboom extension. The General Electric chin barbette could mount a
0.79 in (20 mm) or 1.18 in (30 mm) rotary cannon, the wings had four
hard points for various weapons like up to eight Hughes TOW missiles
and up to 38 2.75 in (70 mm) rockets. The multi-sensor fire control
system comprised infra-red, laser and low-light-level television systems.