The beginning of the Korean conflict on 25 June 1950 and the shortcomings of the weary Douglas B-26, a World War II production originally known as the A-26, accounted for the urgent procurement of a light tactical bomber. The new bomber became the Martin B-57, a by product of the English Electric Canberra, the first British built jet bomber, initially flown in 1949.
Adaptation of a foreign made aircraft to American mass production methods, as well as the use of different materials and tools, could present many difficulties. Another problem, perhaps more critical, centered on the Wright J65 turbojets, due to replace the Canberra's 2 Rolls Royce Avon turbojet engines. The J65 was the US version of the Sapphire, a British hand tooled production currently scheduled for manufacturing by the US. Curtiss Wright Corporation. The Air Force was fully aware of these potential pitfalls, but had no better option. It had an immediate requirement for a light jet bomber, with a 40,000 foot service ceiling, a 1,000 nautical mile range, and a maximum speed of 550 knots. The new bomber had to be capable of operating from unimproved airfields, at night and in every kind of weather, with conventional or atomic weapons. High altitude reconnaissance was another must. For such purposes, the B-45 was too heavy; the Navy AJ-1, too slow; and the Martin experimental B-51's range too short.
As a result of the outbreak in Korea, the Air Force reached a final decision. The desire for a night intruder was so strong that it took just a few days to set in motion the informal production endorsement of February 1951. Because of its experience.with the XB-51, the Glenn L. Martin Company was recognized as the most qualified contractor to assume the domestic production of the British aircraft and to deal with the likely engineering difficulties involved in manufacturing a high performance tactical bomber.
While the Air Force did not expect the B-57 venture to be free of problems, it did not foresee their magnitude. Testing of the 2 imported Canberras revealed design faults that could affect the safety, utility, and maintenance of the future B-57. Then, one of the British planes crashed; Martin's subcontractors could not meet their commitments; and the J65 prototype engines consistently failed to satisfy USAF requirements. In June 1952, further test flights had to be postponed for a year because of continuing engine and cockpit troubles. As a result, the Korea bound B-57 did not fly before 20 July 1953, just 7 days before the conflict ended. Production of the crucial RB-57 was also delayed. The reconnaissance version entered service in mid 1954, after testing again confirmed that the more powerful J65 engines, added equipment, and other improvements had increased the aircraft's weight, in turn reducing the speed, distance, and altitude of both the B-57 and the RB-57.
Even though the Douglas B/RB-66s, on order since 1952, were expected to satisfy the tactical bombardment and reconnaissance requirements of the near future, the Air Force handled the disappointing B/RB-57 program with caution. The program was reduced, but there was no talk of cancellation. In keeping with procedures that unfortunately appeared to have become almost customary, steps were taken to ensure that the deficient B/RB-57s would be operational. This turned out to be expensive; later and considerably improved models still carried flaws, but in the long run the program's retention proved sound. In 1955, the B/RB-57s justified their costs when they served overseas pending the B/RB-66 deliveries which, as predicted, had fallen behind schedule. In 1956, much needed RB-57Ds joined the Strategic Air Command, and various configurations of this model satisfied important special purposes.
Delivered too late for combat in Korea, the RB-57 in May 1963 and the B-57 in February 1965 began to demonstrate under fire in Southeast Asia the basic qualities justifying the Canberra's original selection. In 1970, other reactivated and newly equipped B-57s, known as Tropic Moon III B-57Gs, were deployed to Southeast Asia, where they made valuable contributions until April 1972. Finally, WB-57Fs, either modified RB-57Fs or former B-57Bs, were still flying high altitude radiation sampling missions in 1973. Concurrently, EB-57Es, and related adaptations of the versatile B-57, continued to play significant roles, with no immediate phaseout in sight.
The B-57 is usually considered to be a light bomber; however, this classification must be related to the time frame under discussion. With a gross weight of 53,721 pounds, the B-57B was only 2,000 pounds lighter than the Boeing B-17G, one of the standard heavy bombers of World War II. Mission radius of the B-57B was 948 miles with a payload of 5240 pounds, and ferry range was 2722 miles. Maximum speed was 598 miles per hour (Mach 0.79) at 2500 feet and cruising speed was 476 miles per hour. The performance characteristics of the B-57B and the B-45C have many similarities. Being about twice as heavy as the B-57B, the B-45C carried nearly twice the payload for approximately the same mission distance.
The Canberra class of aircraft has seen action in many wars, including service with the USAF in Vietnam. More recently, it was used by the Argentine Air Force in the undeclared war with Britain in the Falkland Islands. Although the B-57 was originally procured by the USAF as a night intruder, it has been successfully used in many other roles, including photoreconnaissance and strategic bombing. No distinctive design innovations were incorporated in the purely subsonic B-57; however, its pertinent design parameters were chosen in such a way that the aircraft was readily adaptable to a variety of roles calling for diverse characteristics.
The Air Force accepted a grand total of 403 B-57s, all of which were produced in Baltimore, Maryland, by the Glenn L. Martin Co. Specifically, the B-57 program comprised 8 B-57As, 202 B-57Bs, 38 B-57Cs, 68 B-57Es, 67 RB-57As, and 20 RB-57Ds. Other B-57s, such as the B-57Gs, RB-57Fs and WB-57Fs, were the result of extensive post production modifications. Production ended in early 1957, but at the close of the year USAF records showed that 47 of the 403 aircraft had been destroyed in major accidents. This came as no great surprise. Overall, the B-57 was not easy to fly. Moreover, prior to modification of its longitudinal control and stabilizer systems, the B-57 was uncontrollable if 1 of its 2 engines failed during takeoff or landing. In 1958, after completion of all possible modifications, the Air Force ascertained that 50 percent of the major accidents resulted from pilot errors, with 38 percent of the accidents occurring upon landing. Yet, while the number of B-57 accidents was high 129 major and minor accidents as of 1958, the rate compared favorably with that of the B-47 and some other aircraft.
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