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Martin Model 272

B-57 Canberra Tactical Bomber
Variants/Specifications

The twin-jet Canberra was developed for the RAF in the late 1940's by English Electric, Limited. In 1951 it was selected (in preference to the Martin XB-51 - see previous page) as a night-intruder bomber for service in the Korean War. The original intention was to procure Canberras directly from the British production line, but English Electric put RAF orders first. In the interest of speed, the Air Force ordered 250 Canberras from Martin instead, ordering the old B-26 Plant No. 2 at Middle River re-opened for the purpose. They to be built "as is," without extensive modification beyond the addition of forward-firing wing guns and American cockpit equipment. Two RAF Canberras were purchased and sent to the Martin factory as "dog ships."

Although there had been intense disappointment in Middle River over the cancellation of the innovative XB-51, Canberra contracts were to prove both lucrative and long-lasting. Initial production, however, involved a number of serious delays. Conversion of British drawings and specifications to American standards took time. There were also problems with subcontractors. Instead of the Rolls Royce Avon turbojets used in British Canberras, the U.S. Air Force decided to use more powerful J65's, American versions of the Armstrong Siddley Sapphire, licensed to Curtiss-Wright and built by their subcontractor Buick. The early products of this complex collaboration frequently failed to meet Air Force standards. Wing panels subcontracted to Kaiser were delivered late; that subcontract eventually had to be cancelled. Most seriously, one of Martin's British Canberras crashed on a test flight in December 1951. The Martin test engineer on the flight, unable to escape from his seat inside the fuselage, was killed. The resulting re-evaluation of the Canberra's safety caused still more delays. The Air Force was sufficiently concerned to order a competing plane from Douglas in February 1952: the Navy's twin-jet A3D Skywarrior which became the Air Force B-66.

In September 1951 Martin engineers had proposed to add elements of their XB-51 design to a "Super Canberra." This would have had swept wings, plus a T tail, larger cockpit, Shoran navigation system, and rotary bomb-bay. Unwilling to accept delay, the Air Force had turned it down, only to reconsider when the prototype crashed a few weeks later. Wright Field officials demanded that thirty-one specific design flaws be corrected, pointing out the the RAF had submitted a similar list to English Electric. Martin was authorized to install the rotary bomb-bay in all B-57's and to add the new cockpit, along with fuselage dive brakes and external weapons points, after the 75th plane. In compensation the total order was reduced from 250 to 177 planes. An immediate follow-on contract provided for a total of 240 of the improved models: 202 B-57B bombers plus 38 dual-control B-57C trainers.

The first Martin B-57A, almost indistinguishable from a British Canberra, did not fly until July 1953. With the war in Korea just ending, only eight were delivered as bombers; 67 were built as RB-57A tactical reconnaissance planes. The improved B-57B's and C's that followed differed most visibly in their long teardrop canopies, which offered more visibility and also easier ejection for the second crewman in an emergency. A Shoran navigation/bombing system and better radar were also included. The extra weight of the modifications reduced the Martin B-57's speed, range, and ceiling in comparison with the British Canberra, but they added combat capabilities. Further orders included two other models, the RB-57D reconnaissance plane with longer wings for high altitude, and B-57E target tug, capable of streaming targets as high as 30,000 (later 48,000) feet. Twenty of the former and 68 of the latter were ordered.

Beginning in late 1954, two Air Force tactical reconnaissance wings were equipped with RB-57A's, and four tactical bombardment groups traded in their B-26 Invaders for B-57B's. The initial service record was not good. B-57B's suffered a number of fatal crashes and groundings until one of many adjustments to the trim control finally worked. By 1958 the RB-57A's had all been handed down to Air National Guard units; the B-57B's were scheduled to follow them soon afterwards, after less than four years' service.

A series of Cold War crises intervened, however, and kept the Canberra in the Air Force for another decade. In 1958 B-57 groups were dispatched to Turkey to cover U.S. landings in Lebanon and to Okinawa to discourage a Communist Chinese invasion of Taiwan. The 3rd Bombardment Group, stationed in Japan and Korea, was given a nuclear-attack role. Equipped with Low Altitude Bombing System (LABS) computers, crews trained to toss their bombs in a 3.5g climb, then loop over and race away to escape the nuclear blast. In 1964, just as it was relinquishing this mission, the group was ordered to South Vietnam.

For the next five years B-57's were in constant action, flying a variety of daylight bombing, night interdiction, and reconnaissance missions in Southeast Asia. In addition to planes lost to ground fire, fifteen were destroyed on the ground at Bien Hoa air base in a Viet Cong mortar attack and a later runway accident. Replacement planes were recalled from the Air National Guard and from storage at Davis-Monthan Air Force Base. Twenty B-57B's and E's were returned to the Martin factory in 1965 for combat conversion/modernization. General Dynamics loaded another six with high technology nighttime scanners. Designated RB-57E's, these were used in Vietnam under the code-name "Patricia Lynn." The ultimate B-57 night intruder was ordered from Martin in 1969, when sixteen earlier models were converted to "Tropic Moon" B-57G's. Equipped with low-light television cameras mounted below the nose and laser-guided smart bombs, they were used in a high-technology attempt to stop nighttime truck traffic on the Ho Chi Minh Trail.

Canberras saw combat in a variety of situations. A Royal Australian Air Force squadron flew English Electric planes in Vietnam, using optical and radar bombsights for high-altitude level bombing. Canberras flew on both sides in conflicts between India and Pakistan in 1965 and 1971. U.S. military assistance programs supplied 25 B-57B's to Pakistan in 1959, while the Indian Air Force used British Canberras. So did the Argentine Air Force in 1982 in its conflict with Britain over the Falklands/Malvinas.

Besides bombing and tactical reconnaissance, the B-57 was also modified for pure intelligence missions at high altitude. Twenty RB-57D's in four versions were ordered in 1955 from the second Air Force contract. With 106-foot wings and specially modified Pratt and Whitney J57 engines, they were capable of flying well above 50,000 feet. Invulnerable to the interceptors and missiles of the day, they preceded the Lockheed U-2 in overflying the USSR and China, taking optical and radar photographs and air samples over nuclear test sites. Two were loaned to the Nationalist Chinese Air Force.

Recurring structural problems with the extra-long wings caused the grounding of all RB-57D's in 1963. The year before, General Dynamics received a contract to modify 21 retired A, B, and D models as RB-57F's. With even longer 122-foot wings and new turbofan engines, these could fly above 60,000 feet. Barred from crossing the Soviet border after 1960, RB-57F's lurked just outside, gathering data with new "side-looking" radars and cameras. In 1965 one was brought down by a Soviet surface-to-air missile over Southern Europe. Two others loaned to Pakistan were destroyed in the 1965 war with India.

In 1966, Martin was commissioned to provide new wings for the remaining nine RB-57D's, modifying them once again as EB-57D electronic countermeasures planes. Along with 59 EB-57A's, B's, and E's equipped with similar electronic gear, they were assigned to Defense Systems Evaluations Squadrons that tested American air defenses by posing as enemy intruders. B-57's served in this role with the Air Force until 1979 and with the Vermont Air National Guard until 1982. Meanwhile NB-57's tested missile guidance systems for the Army and Air Force, and other Canberras had civilian jobs. Two flew high-altitude airway surveys for the Federal Aviation Administration. The Weather Service used two more to track hurricanes. High altitude WB-57F's tested space-satellite sensors for the National Aeronautics and Space Administration.

An EB-57B belongs to the Smithsonian's National Air and Space Museum, where plans are to restore it to its original configuration as a B-57B. Two partially restored RB-57A's are on display at the Glenn L. Martin Maryland Aviation Museum at Martin State Airport, Middle River, Maryland.



RAF Canberra


RB-57A


© 2006 The Glenn L. Martin Maryland Aviation Museum
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