WikiPortallus: Martin B-57

At the outbreak of the Korean War in 1950, the United States Air Force 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. Thus, 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 AJ Savage. In an extremely rare move, foreign aircraft including the Canadian Avro Canada CF-100 Canuck and the British English Electric Canberra were also given consideration. The AJ and B-45 were quickly dismissed because their outdated designs had limited growth potential. The CF-100 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 became the first-ever jet to make a non-stop unrefuelled flight across the Atlantic Ocean, arriving in the United States for USAF evaluation. The Canberra emerged a clear winner of the 26 February flyoff against the XB-51. Since English Electric was unable to produce enough aircraft for both the RAF and the USAF, on 3 April 1951 Martin was granted the license to build Canberras, designated B-57 (Martin Model 272) in the US. To expedite production, the first B-57As were largely identical to the Canberra B.2s with the exception of more powerful Armstrong Siddeley Sapphire engines of 7,200 lbf (32 kN) of thrust, also license-built in the US 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. During the production run from 1953 to 1957, a total of 403 B-57s were built.

Operational history

The B-57A was not considered combat-ready by the USAF and the aircraft were used solely for testing and development. One of the aircraft was given to the National Oceanic and Atmospheric Administration (NOAA) which fitted it with a new nose radome and used it to track hurricanes. The reason for such limited production was that the distinctly British B-57A was considered unfit for USAF service. Particularly contentious were the odd cockpit arrangement and the lack of guns, the British Canberra having been designed as a high-speed, high altitude bomber rather than for close air support. The definitive B-57B introduced a new tandem cockpit with a bubble canopy, the engines were now started with a pyrotechnic cartridge, the airbrakes were moved from the wings to the sides of the fuselage for increased effectiveness, the controls were now boosted, four hardpoints were fitted under the wings, and the aircraft was given gun armament in the form of 8 x 0.50 in (12.7 mm) Browning machine guns in the wings, later replaced by 4 x 20 mm M39 cannons. The first B-57B flew on 18 June 1954. The aircraft initially suffered from the same engine malfunctions as the RB-57As and several were lost in high-speed low-level operations due to a faulty tailplane actuator which caused the aircraft to dive into the ground. The USAF considered the B-57B inadequate for the night intruder role and Martin put all aircraft through an extensive avionics upgrade. Regardless, by the end of 1957 the USAF tactical squadrons were being re-equipped with supersonic F-100 Super Sabres. The complete retirement was delayed, however, by the start of the Vietnam War.

Reconnaissance B-57s

While the USAF found the B-57A lacking, the photoreconnaissance RB-57A saw some operational use. First flying in October 1953, RB-57As fully equipped the 363rd Tactical Reconnaissance Wing at Shaw Air Force Base by July 1954. The aircraft were also deployed with USAF squadrons in Germany, France, and Japan. However, operational readiness was poor and the aircraft suffered from significant production delays because of engine problems. Wright had subcontracted production of J65 engines to Buick which resulted in slow deliveries and tendency to burn oil which filled the cockpit with smoke. The problems were ameliorated when Wright took over the production in 1954. RB-57As also suffered from a high accident rate caused in part by very poor single-engine handling, which resulted in the entire fleet spending much of 1955 on the ground. By 1958, all RB-57As were replaced in active service by Douglas RB-66Bs and RF-101As.

Air National Guard units extensively used RB-57As for photographic surveys of the United States and traded in their last aircraft in 1971. Two RB-57As were used by the Republic of China Air Force for reconnaissance missions over People's Republic of China. One of these was shot down by a Chinese Mikoyan-Gurevich MiG-17 on 18 February 1958. In 1959, a RB-57A flown by a ROCAF captain was shot down over the PRC by SA-2 SAM, marking the very first successful operational engagement of surface-to-air missiles. Two other RB-57As were used by the Federal Aviation Administration to plan high-altitude airways for the upcoming jet passenger aircraft.

A number of RB-57s were used by the 7499th Support Group at Wiesbaden in 'Heart Throb' reconnaissance missions over Europe.^[2]

Starting in 1959, Martin began to modify retired RB-57As with electronic countermeasures (ECM) equipment in the bomb bay. Redesignated EB-57A, these aircraft were deployed with Defense Systems Evaluation Squadrons which played the role of aggressors to train the friendly air defense units in the art of electronic warfare. Subsequent bomber variants were also modified to fulfill this role.

Vietnam

Though intended as a bomber and never before deployed by the USAF to a combat zone, the first B-57s to be deployed to South Vietnam were not operated in an offensive role. The need for additional reconnaissance assets, especially those capable of operating at night, led to the deployment of two RB-57E aircraft on April 15, 1963. Under project Patricia Lynn these aircraft provided infrared coverage using their Reconofax VI cameras.^[3] Later in August 1965, a single RB-57F would be deployed to Udon, RTAB in an attempt to gather information about North Vietnamese SAM sites, first under project Greek God and then under project Mad King. In December another RB-57F would be deployed for this purpose, under project Sky Wave. Neither project garnered useful results and they were terminated in October 1965 and February 1966 respectively.^[4]

The deployment of actual combat capable B-57Bs from 8th and 13th Bomb Squadrons to Bien Hoa in August 1964 began with three aircraft lost in collisions on arrival.^{citation needed} An additional five aircraft were destroyed with another 15 damaged by a Viet Cong mortar attack in November of the same year. Low level sorties designated as training flights were conducted with the hope of it having a psychological affect. As a result the first combat mission was only flown on 19 February 1965.^[5] The first excursion into North Vietnam taking place on 2 March as part of Operation Rolling Thunder. The aircraft typically carried 9 x 500 lb (227 kg) bombs in the bomb bay and 4 x 750 lb (340 kg) bombs under the wings. In April, Canberras began flying night intruder missions supported by C-123 Provider or C-130 Hercules flare ships and EF-10B Skyknight electronic warfare aircraft.

On 16 May 1965, an armed B-57B exploded on the runway at Bien Hoa setting off a chain reaction that destroyed ten other Canberras, eleven A-1 Skyraiders, and one F-8 Crusader. Due to combat attrition, in October 1966 B-57Bs were transferred to Phan Rang where they supported operations in the Iron Triangle along with Australian Canberra B.20s. The aircraft also continued to fly night interdiction missions against the Ho Chi Minh trail. Of the 94 B-57Bs deployed to Southeast Asia, 51 were lost in combat and 7 other Canberra's were lost to other causes. Only 9 were still flying by 1969.^{citation needed}

B-57s returned to Southeast Asia in the form of the Tropic Moon III B-57G, deployed to Thailand during the fall of 1970.^[6] Intended as a night intruder to help combat movement along the Ho Chi Minh trail, these aircraft were equipped with a variety of new sensors and other equipment, and were capable of dropping laser guided munitions.^[7] The relative kill rates per sortie during Operation Commando Hunt V between the B-57G and the AC-130A/E showed that the former was not as suited to the role of trucker hunter.^[8] An attempt to combine both led to one B-57G being modified to house a special bomb bay installation of one Emerson TAT-161 turret with a single M61 20mm cannon as a gunship under project Pave Gat. Poor results led to this system not being produced and the prototype was not deployed to the theatre.^[9] The B-57G was removed from Thailand in May 1972. Plans remained for the continuation of the B-57G program but post-conflict spending cuts forced the abandonment of these plans.^[10]

For a short period South Vietnamese Air Force personnel operated four B-57B aircraft. The VNAF never officially took control of the aircraft, and, after accidents and other problems, including apparent claims by VNAF pilots that the B-57 was beyond their physical capabilities, the program was terminated in April 1966, and the aircraft were returned to their original USAF units.^[11]

Pakistan

The Pakistan Air Force was one of the main users of the B-57 and made use of it in two wars with India. In the Second Kashmir War of 1965 B-57s flew 167 sorties, dropping over 600 tons of bombs. Three B-57s were lost in action, along with one RB-57F electronics intelligence aircraft.^[12] However, only one of those three was lost as a result of enemy action.^[13] During the war, the bomber wing of the PAF was attacking the concentration of airfields in north India. In order to avoid enemy fighter-bombers, the B-57s operated from several different airbases. The B-57 bombers would arrive over their targets in a stream at intervals of about fifteen minutes, which Pakistani authors believe, led to achieving a major disruption of the overall IAF effort.^[14]

During the Indo-Pakistani War of 1971, the PAF again made use of the B-57. On the very first night, 12 IAF runways were targeted and a total of 183 bombs were dropped. As the war progressed, PAF B-57s carried out many night missions. There was a higher attrition rate than in 1965, with at least 5 B-57s being put out of service by the end of the war.^[15]^[16] They were retired from service in the PAF in 1985.

Variants