| B-57 Canberra | |
|---|---|
| B-57A in flight over Chesapeake Bay, Maryland | |
| Role | Bomber |
| Manufacturer | Martin |
| First flight | 20 July 1953 |
| Introduction | 1954 |
| Status | Retired (2 still used by NASA[1]) |
| Primary users | United States Air Force Pakistan Air Force Republic of China Air Force |
| Number built | 403 |
| Unit cost | US$1.26 million (B-57B)[2] |
| Developed from | English Electric Canberra |
| Variants | Martin RB-57F Canberra |
The Martin B-57 Canberra was a United States-built, twin jet engine tactical 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 retirement in 1983 of the B-57 ended the era of the tactical bomber that had its beginning with the World War I De Havilland DH-4. The Fairchild-Republic A-10 Thunderbolt II close air support (CAS) attack aircraft is the modern USAF equivalent. 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.[1]
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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 The AJ and B-45 were quickly dismissed because their outdated designs had limited growth potential.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.
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.
While the USAF found the B-57A lacking, the photo reconnaissance 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 a tendency for engine oil to enter the bleed air system, filling the cockpit with smoke. The problems were ameliorated when Wright took over engine production in 1954. RB-57As also suffered from a high accident rate caused in part by poor single-engine handling. This resulted in the entire fleet spending much of 1955 on the ground. By 1958, all RB-57A craft were replaced in active service by the Douglas RB-66B and McDonnell RF-101A. Air National Guard units extensively used the RB-57A for photographic surveys of the United States until 1971.
A number of modified RB-57As were used by the 7499th Support Group at Wiesbaden AB, West Germany in Operation "Heart Throb" reconnaissance missions over Europe.[3] Ten aircraft were pulled off Martin's production line and modifications were performed in August1955 by the Wright Air Development Center and by Martin. All equipment not absolutely essential for the daytime photography role was eliminated. The bomb bay door was removed and the area was skinned over. The seat for the system operator/navigator was removed, and an optical viewfinder was installed in the nose so that the pilot could perform all the reconnaissance duties without the assistance of the navigator. The clear plexiglass nose cone was replaced by an opaque fiberglass cone, but with a small optical glass window cut for the viewfinder. The plane's J65-BW-5s were replaced by higher-thrust J65-W-7s. The aircraft was referred to as RB-57A-1. The weight reduction program shaved 5665 pounds off the weight of the RB-57A, and the ceiling was increased by 5000 feet.[4]
Two RB-57A-1s were used by the Republic of China Air Force for reconnaissance missions over China; one was shot down by a Chinese Mikoyan-Gurevich MiG-17 on 18 February 1958 and the pilot killed. In 1959, two RB-57Ds were delivered to replace the A-types; one of them was shot down over China by a SA-2 Guideline missile, 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.
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. Although initially conducted by active duty Air Force units, the EB-57 mission eventually migrated to selected units of the Air National Guard.[5] [6][7]
Strategic Air Command employed 20 RB-57D aircraft from 1956 until 1964. Little is known about their use. The aircraft were retired due to structural fatigue and the advent of the U-2 and SR-71.[8]
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 15 April 1963. Under project Patricia Lynn these aircraft provided infrared coverage using their Reconofax VI cameras.[9] 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.[10]
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. 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 effect. As a result the first combat mission was only flown on 19 February 1965.[11] The first excursion into North Vietnam took 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 Fairchild C-123 Provider or Lockheed 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 10 other Canberras, 11 Douglas A-1 Skyraiders, and one Vought 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 seven other Canberras were lost to other causes. Only nine were still flying by 1969.
B-57s returned to Southeast Asia in the form of the Tropic Moon III B-57G, deployed to Thailand during the fall of 1970.[12] 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.[13] 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.[14] 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. After delays in testing at Eglin AFB, Florida, due to competition for mission time from the Tropic Moon III B-57Gs, Pave Gat tests proved "that the B-57G could hit stationary or moving targets with its 20mm gun, day or night. Loaded with 4,000 rounds of ammunition, the Pave Gat B-57G could hit as many as 20 targets, three times as many as the bomb-carrying B-57G. The Pave Gat aircraft could avoid antiaircraft fire by firing from offset positions, while the bomb carrier had to pass directly over the target." Deployment to SEA was resisted, however, by the Seventh and Thirteenth Air Forces and others as the decision had been made in August 1971 to return the B-57G squadron to the U.S. in early 1972, leaving insufficient evaluation time. Project Pave Gat was terminated 21 December 1971.[15] 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.[16]
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.[17]
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 electronic intelligence aircraft.[18] However, only one of those three was lost as a result of enemy action.[19] 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 15 minutes, which Pakistani authors believe, led to achieving a major disruption of the overall IAF effort.[19]
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 five B-57s being put out of service by the end of the war.[18][20] They were retired from service in the PAF in 1985.
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Data from Quest for Performance[36]
General characteristics
Performance
Armament
Avionics
NASA / JSC High Altitude Research Program
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