Martin 234 / XB-51
In World War lithe USAAF made widespread and effective use of the attack bomber for battlefield tasks. For post-war service the USAAF wanted a higher-speed successor, and the specification produced two types in the Douglas XB-43 and Martin Model 234 XB-51.
The Martin was designed originally to meet a US Army Air Force requirement for a close-support bomber, being allocated the designation XA-45. However, it was developed instead as a medium bomber with turbojet power-plant and two prototypes were ordered under the designation XB-51.
The XB-51 featured a tandem-unit landing gear arrangement, a thin variable -incidence wing whose leading edges were swept at 35 degrees, a swept T-tail. It was powered by three 2640kg thrust General Electric J47-GE-7 or -13 turbo-jets, one pylon-mounted low on each side of the forward fuselage and the third within the rear fuselage.
Other features included pressurised accommodation for the two-man crew, provisisions for JATO (jet-assisted take-off) units, and a braking parachute.
The first of two aircraft flew in October 1949, and although flight trials confirmed that the XB-51 had very good performance, they revealed that the type had poor handling qualities in the air. The XB-51 did not proceed past the prototype stage and the USAF opted instead for licence-production of the English Electric Canberra as the Martin B-57.
Engines: 3 x 2360kg General Electric J47-GE-13
Max take-off weight: 25393 kg / 55982 lb
Empty weight: 13431 kg / 29610 lb
Wingspan: 16.18 m / 53 ft 1 in
Length: 25.93 m / 85 ft 1 in
Height: 5.28 m / 17 ft 4 in
Wing area: 50.91 sq.m / 547.99 sq ft
Max. speed: 1038 km/h / 645 mph
Cruise speed: 857 km/h / 533 mph
Ceiling: 12344 m / 40500 ft
Range: 2576 km / 1601 miles