The Convair B-36 "Peacemaker" is a strategic bomber built by Convair and operated by the United States Air Force (USAF) from 1949 to 1959. The B-36 is the largest mass-produced piston-engined aircraft ever built, although it was exceeded in span and weight by the one-off Hughes H-4 Hercules (commonly known as the Spruce Goose). It has the longest wingspan of any combat aircraft. The B-36 was capable of intercontinental flight without refueling.
Entering service in 1948, the B-36 was the primary nuclear weapons delivery vehicle of Strategic Air Command (SAC) until it was replaced by the jet-powered Boeing B-52 Stratofortress beginning in 1955. Production of the B-36 ceased in 1954. All but four aircraft have been scrapped.
The propulsion system of the B-36 was unique, with six 28-cylinder Pratt & Whitney R-4360 Wasp Major radial engines mounted in an unusual pusher configuration, rather than the conventional tractor propeller layout of other heavy bombers. The large, slow-turning propellers interacted with the high-pressure airflow behind the wings to produce an easily recognizable very-low-frequency pulse at ground level that betrayed approaching flights. Beginning with the B-36D, Convair added a pair of General Electric J47-19 jet engines suspended near the end of each wing which were also retrofitted to surviving B-36Bs. Consequently, the B-36 was configured to have 10 engines, six radial propeller engines and four jet engines, leading to the B-36 slogan of "six turnin' and four burnin'". The B-36 had more engines than any other mass-produced aircraft. The two pods with four turbojets and the six piston engines combined gave the B-36 a total of 40,000 hp (30,000 kW) for short periods of time.
