The B-36 is the largest mass-produced piston-engined aircraft ever built. It had the longest wingspan of any combat aircraft ever built, at 230 ft (70.1 m). The B-36 was the first bomber capable of delivering any of the nuclear weapons in the U.S. arsenal from inside its four bomb bays without aircraft modifications. With a range of 10,000 mi (16,000 km) and a maximum payload of 87,200 lb (39,600 kg), the B-36 was capable of intercontinental flight without refuelling. 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. All but four aircraft have been scrapped. The B-36 took shape as an aircraft of immense proportions. It was two-thirds longer than the previous "superbomber", the B-29. The wingspan and tail height of the B-36 exceeded those of the 1960s Soviet Union's Antonov An-22 Antheus military transport, the largest ever propeller-driven aircraft put into production. Only with the advent of the Boeing 747 and the Lockheed C-5 Galaxy, both designed two decades later, did American aircraft capable of lifting a heavier payload become commonplace. 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 four-engine, tractor propeller layout of other heavy bombers. The prototype R-4360s delivered a total of 18,000 hp (13,000 kW). While early B-36s required long takeoff runs, this situation was improved with later versions, delivering a significantly increased power output of 22,800 hp (17,000 kW) total.[25] Each engine drove a three-bladed propeller, 19 feet (5.8 m) in diameter, mounted in the pusher configuration, thought to be the second-largest diameter propeller design ever used to power a piston-engined aircraft (after that of the Linke-Hofmann R.II). This unusual configuration prevented propeller turbulence from interfering with airflow over the wing, but could also lead to engine overheating due to insufficient airflow around the engines, resulting in inflight engine fires. 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; these were also retrofitted to all extant 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. Number built: 384 For more information on the development, design, operarional history and variants, click here.
