The Martin B-57 Canberra was a United States-built, twin jet engine light bomber and reconnaissance aircraft, which entered service with the United States Air Force (USAF) in 1953. The B-57 was initially a version of the English Electric Canberra built under license. However, the Glenn L. Martin Company significantly modified the design and produced several unique variants.
The world's last two remaining flight worthy WB-57Fs are assigned to the NASA Johnson Space Center at Ellington Field, Houston, TX as high altitude scientific research aircraft.At the outbreak of the Korean War in 1950, the USAF found itself in dire need of an all-weather interdiction aircraft. The piston-engined Douglas A-26 Invaders were limited to daytime and fair weather operations and were in short supply. Consequently, on 16 September 1950, the USAF issued a request for a jet-powered bomber with a top speed of 630 mph (1,020 km/h), ceiling of 40,000 feet (12,190 m), and range of 1,150 miles (1,850 km). Full all-weather capability and secondary reconnaissance role had to be included in the design. To expedite the process, only projects based on existing aircraft were considered. The contenders included the Martin XB-51, and the North American B-45 Tornado and J Savage.
Foreign aircraft including the Canadian Avro Canada CF-100 Canuck and the new Canberra, which had not officially entered service with the Royal Air Force (RAF) at the time, were also considered, an extremely rare move. The AJ and B-45 were quickly dismissed because their outdated designs had limited growth potential. The CF-100, an all-weather interceptor, was too small and lacked sufficient range. The XB-51, while very promising and much faster, had limited maneuverability, a small weapons bay and limited range and endurance.
On 21 February 1951, a British Canberra B.2 (flown by Roland Beamont) became the first-ever jet to make a non-stop unrefuelled flight across the Atlantic Ocean, arriving in the United States for USAF evaluation. In a 26 February flyoff against the XB-51, the Canberra emerged a clear winner. It was officially taken up by the USAF on 25 May 1951.
However, because their production lines were working at full capacity to meet the Royal Air Force orders, English Electric was unable to produce additional aircraft quickly enough for USAF requirements, and on 3 April 1951, Martin was granted a license to build Canberras, designated B-57 (Martin Model 272) in the United States. To expedite production, the first B-57As were largely identical to the Canberra B.2, with the exception of more powerful Armstrong Siddeley Sapphire engines of 7,200 lbf (32 kN) of thrust instead of Rolls-Royce Avons, also license-built in the United States as Wright J65s. In addition, canopy and fuselage windows were slightly revised, the crew was reduced from three to two, wingtip fuel tanks were added, engine nacelles were modified with additional cooling scoops, and the conventional "clamshell" bomb bay doors were replaced with a low-drag rotating door originally designed for the XB-51.
The first production aircraft flew on 20 July 1953, and was accepted by USAF on 20 August 1953. During the production run from 1953 to 1957, a total of 403 B-57s were built.
General characteristics
- Crew: 2
- Length: 65 ft 6 in (20.0 m)
- Wingspan: 64 ft 0 in (19.5 m)
- Height: 14 ft 10 in (4.52 m)
- Wing area: 960 ft² (89 m²)
- Empty weight: 27,090 lb (12,285 kg)
- Loaded weight: 40,345 lb (18,300 kg)
- Max takeoff weight: 53,720 lb (24,365 kg)
- Powerplant: 2 × Wright J65-W-5 turbojets, 7,220 lbf (32.1 kN) each
- * Zero-lift drag coefficient: 0.0119
- Drag area: 11.45 ft² (1.06 m²)
- Aspect ratio: 4.27
Performance
- Maximum speed: Mach 0.79 (598 mph, 960 km/h) at 2,500 ft (760 m)
- Cruise speed: 476 mph (414 knots, 765 km/h)
- Stall speed: 124 mph (108 knots, 200 km/h)
- Combat radius: 950 mi (825 nm, 1,530 km) with 5,250 lb (2,380 kg) of bombs
- Ferry range: 2,720 mi (2,360 nm, 4,380 km)
- Service ceiling: 45,100 ft (13,745 m)
- Rate of climb: 6,180 ft/min (31.4 m/s)
- Wing loading: 42 lb/ft² (205 kg/m²)
- Thrust/weight: 0.36
- Lift-to-drag ratio: 15.0
Armament
- Guns: 4× 20 mm (0.787 in) M39 cannon, 290 rounds/gun
- Bombs:
- 4,500 lb (2,000 kg) in bomb bay, including nuclear bombs
- 2,800 lb (1,300 kg) on four external hardpoints, including unguided rockets
Avionics
- APW-11 Bombing Air Radar Guidance System
- SHORAN bombing system
- APS-54 Radar Warning Receiver
