At the commencement of the Korean War in 1950, the USAF realised it lacked an all-weather interdiction aircraft, therefore in September 1950 the USAF issued a requirement for a jet-powered bomber with a top speed of 630 mph and a minimum service ceiling of 40,000 feet and a range of 1,150 miles. As the need was urgent, only designs based on existing airframes were considered, the winner was based on the existing English Electric Canberra, the decision was probably influenced by the fact that a British Canberra B.2 was flown non stop without being refuelled across the Atlantic Ocean for evaluation, this was the first time any jet aircraft had done this. English Electric was already fully committed with existing orders so a licence was issued to Martin to build an American version of the Canbera the B-57 using Wright J65's, a licence built Armstrong Siddeley Sapphire engine.
Unfortunately after entering USAF service in August 1953 the B-57 proved to be unreliable, mainly a result of engine problems and production was terminated in 1957 after 403 aircraft had been produced, USAF tactical squadrons were due to change to supersonic F-100 Super Sabres, and the Martin B-57's were to be withdrawn, but the onset of the Vietnam War delayed this decision. A significant number of B-57's ended there operational lives serving with the air forces of Pakistan and Taiwan. Specifications: Martin B-57B Crew: Pilot and navigator/observer/bomb-aimer Length: 65 ft 6 in (20.0 m) Wingspan: 64 ft 0 in (19.5 m) Height: 14 ft 10 in (4.52 m) Empty weight: 27,090 lb (12,285 kg) Max takeoff weight: 53,720 lb (24,365 kg) Engines: Twin 7,220 lbf (32.1 kN) Wright J65-W-5 turbojets Maximum speed: Mach 0.79 (598 mph, 960 km/h) at 2,500 ft (760 m) Combat radius: 950 mi (825 nm, 1,530 km) with 5,250 lb (2,380 kg) of bombs Service ceiling: 45,100 ft (13,745 m) Rate of climb: 6,180 ft/min (31.4 m/s)
Armament: Guns: Four 20 mm (0.787 in) M39 cannon Bombs: 4,500 lb (2,000 kg) in bomb bay, including nuclear bombs - 2,800 lb (1,300 kg) on four external hard-points, or unguided rocket projectiles
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