The US Army actively used helicopters during the Korean War. First of all, for performing transport tasks. After the war, Bell Helicopter decided to develop a gunship helicopter. The first projects were only armed versions of conventional helicopters, but the AH-1 Cobra was originally developed as a combat one.
The AH-1 was designed on the basis of the UH-1 Iroquois (they took the engine, bearing and steering screws). The fuselage became narrower, a small wing was added, 2 crew members sat in tandem. The Lycoming T53-L-13 engine (1100 hp) allowed to reach a speed of up to 276 km/h. The flight range was 570 km. The armament could include 7.62 mm machine guns, a 20 mm cannon, a 40 mm grenade launcher + guided / unguided missiles. September 7, 1965-the first flight of the Bell AH-1 Cobra attack helicopter (aka Model 209).
The AH-1 Cobra became the world's first mass-produced combat helicopter, and its layout is a kind of standard. 1116 AH-1s produced were operated in more than 10 countries around the world — from Israel to the Philippines.