Boeing engine started in 1943 and Boeing's gas turbines were designated models 502 (T50), 520 (T60), 540, 551 and 553. Boeing built 2,461 engines before production ceased in April 1968. Many applications of the Boeing gas turbine engines were considered to be firsts, including the first turbine-powered helicopter and boat. Vertol Aircraft Corporation was acquired by Boeing in 1960, and was reorganized as Boeing's Vertol division. The twin-rotor CH-47 Chinook, produced by Vertol, took its first flight in 1961. This heavy-lift helicopter remains a work-horse vehicle to the present day. In 1964, Vertol also began production of the CH-46 Sea Knight.
Armed helicopter and support them on the ground. They were used successfully during the Scud Hunt. Other Army Special Operations include the MH-6 and AH-6 "Little Birds". The MH-6 carries special operators on benches outside the helicopters, from which they can move quickly. The AH-6 is for close air support. The MH-47 Chinook helicopter has been used to carry special operators using long-wheelbase Land Rovers and other vehicles in and out of an area of operations. For longer-range special operations, the Air Force had operated the MH-53 Pave Low helicopter with extensive avionics for navigation, flying at very low altitude, and electronic