Convair XB-46

The Convair XB-46 was a single example of an experimental medium jet bomber which was developed in the mid-1940s but which never saw production or active duty. It competed with similar designs, the North American XB-45 and Martin XB-48, all of which saw little use after the successful development of the Boeing XB-47.

XB-46
Convair XB46
Role Medium bomber
Manufacturer Convair
First flight 2 April 1947
Retired 1947
Status Cancelled
Primary user United States Air Force
Number built 1
Unit cost
US$4.9 million for the program[1] (equivalent to $55 million today)

Development

In 1944, the War Department was aware of aviation advances in Germany and issued a requirement for a range of designs for medium bombers weighing from 80,000 pounds (36,000 kg) to more than 200,000 pounds (91,000 kg). Other designs resulting from this competition, sometimes named the class of '45, included the North American XB-45 and the Martin XB-48. Procurement began with a letter contract (cost-plus-fixed-fee) on 17 January 1945 with mockup inspection and approval in early February. Orders for three prototypes followed on 27 February 1945 with certain changes recommended by the board. Serials 45-59582 to 59584 were assigned. Budgetary concerns also led to the contract being changed to a fixed-price type.

In the fall of 1945, Convair found it was competing with itself when the USAAF became interested in an unorthodox forward-swept wing jet attack design, the XA-44-CO that the company had also been working on. With the end of World War II severely curtailing budgets, the company considered canceling the XB-46 in favor of the other project as there was insufficient funding for both. Company officials argued that it made more sense to allow them to complete the XB-46 prototype as a stripped-down testbed omitting armament and other equipment and for the AAF to allow them to proceed with two XA-44 airframes in lieu of the other two XB-46s on contract. In June 1946, the AAF agreed to the substitution but that project was ultimately cancelled in December 1946 before the prototypes were completed. The B-46 would be completed with only the equipment necessary to prove its airworthiness and handling characteristics.

The XB-46 had a long streamlined oval torpedo-shaped fuselage, long narrow straight shoulder-mounted wings with four Chevrolet-built J35-C3 axial-flow eleven stage turbojets of 3,820 pounds-force (17.0 kN) static thrust paired in an integral nacelle under each wing. The fuselage turned out to be a problem, as it distorted under flight loads. The pilots sat in tandem in a pressurized fighter-style cockpit under a single Plexiglas teardrop canopy with the bombardier-navigator-radio operator in a transparent Plexiglas nose section.

Convair XB-46 wing detail
XB-46 aileron and spoiler detail

The straight wing had an aspect ratio of 11.6, and was equipped with Fowler flaps which extended over 90 percent of the span, in four sections. The flaps extended via electrical actuators, and had very small ailerons. Each wing had five spoilers made of perforated magnesium alloy. The engine air intakes were flat oval inlets, with a duct curving downward in a flat “S” to the engines, which were mounted behind the leading edge of the wing. The unusual flight control system utilized a system of pneumatic piping to transmit the pilots control inputs and actuate various systems, rather than the more typical hydraulic, manual or electrical control lines and systems of most aircraft of the era.

Production versions were to be equipped with a pair of .50 caliber Browning M2 machine guns in a tail turret designed by Emerson Electric Company and provision was made for an APG-27 remote control optics and sighting system, but no weaponry was fitted into the prototype. Likewise, production aircraft were intended to be built with the General Electric J47 engines with 5,200 lbf (23 kN) static thrust rather than the J35s used on the prototype.

Testing

The XB-46's first flight occurred 2 April 1947 after a month of taxi testing, and lasted ninety minutes as the bomber departed the Convair plant in San Diego, California for Muroc Army Airfield in the high desert. The pilot praised its handling qualities. Basic flight testing took place for five months, and by September 1947 it was concluded after 127 hours aloft on 64 flights by both the Convair company and AAF test pilots. Stability and control were excellent but there were engineering problems with engine de-icing, the cabin air system, and vertical oscillations caused by harmonic resonance between the wing and spoilers. There was also concern regarding the ability of the three man crew to exit the aircraft in case of an emergency, since the exit plan relied on the pneumatic system to hold the main door open against the airstream. The aircraft was accepted on 7 November and delivered on 12 November 1947.

Cancellation

The B-46 program was cancelled in August 1947, even before flight testing had been completed, because it was already obsolete. The North American B-45 Tornado already had production orders, and even it would be eclipsed by the Boeing B-47 Stratojet's superior performance. Furthermore, the bulky radar fire-control system which was not installed in the XB-46 prototype would have undoubtedly forced an expensive redesign of the slender fuselage. Subsequent testing investigated excessive noise, tail vibration, and stability and control issues, and was conducted at Palm Beach Air Force Base, Florida between August 1948 and August 1949. After 44 additional flight hours, the XB-46 was taken out of service, since the cost of support and maintenance, coupled with a lack of spare parts, had become prohibitive. After sitting idle for a year, it was flown to Eglin Air Force Base, Florida, in July 1950, where its pneumatic system was tested under the coldest conditions in the large climatic facility there. Most jet aircraft of this period used hydraulic or electrical systems, so the pneumatic control system of this aircraft offered a unique opportunity for investigation. When this testing program was concluded in November 1950, the Air Force no longer had need for the XB-46, a fact acknowledged in the press as early as August,[2] and on 13 January 1951 the nose section was sent to the U.S. Air Force Museum at Wright-Patterson Air Force Base, Ohio, although it appears that the airframe section has not survived in the collection. The rest of the airframe was scrapped on 28 February 1952.

Specifications (XB-46)

Data from General Dynamic Aircraft and their Predecessors[3]

General characteristics

Performance

  • Maximum speed: 545 mph (474 knots, 877 km/h) at 15,000 ft (4,580 m)
  • Cruise speed: 439 mph (382 knots, 707 km/h) at 35,000 ft (10,700 m)
  • Range: 2,870 mi (2,496 nm, 4,621 km)
  • Service ceiling: 40,000 ft (12,200 m)
  • Climb to 35,000 ft (10,700 m): 19 min

Armament

See also

Aircraft of comparable role, configuration and era

Related lists

References

Notes
  1. ^ Knaack 1988, p. 526.
  2. ^ Fort Walton, Florida, "XB-46 Bomber to Undergo Tests in Climatic Hangar", Playground News, Thursday 3 August 1950, Volume 5, Number 27, page 3.
  3. ^ Wegg 1990, pp. 182–183.
  4. ^ Knaack 1988, p. 527.
Bibliography
  • Andrade, John M. (1979). U.S. Military Aircraft Designations and Serials since 1909. Earl Shilton, Leicester: Midland Counties Publications. ISBN 0-904597-22-9.
  • Gunston, Bill (1979). Jet Bombers from the Messerschmitt M2 262 to the Stealth B-2. Osprey Aerospace. ISBN 1-85532-258-7.
  • Knaack, Marcelle Size (1988). Post-World War II bombers, 1945-1973. Office of Air Force History. ISBN 0-16-002260-6.
  • Wegg, John (1990). General Dynamics Aircraft and their Predecessors. London: Putnam. ISBN 0-85177-833-X.

External links

Allison J35

The General Electric/Allison J35 was originally developed by General Electric (GE company designation TG-180) in parallel with the Whittle-based centrifugal-flow J33, and was the United States Air Force's first axial-flow (straight-through airflow) compressor engine. The J35 was fairly simple, consisting of an eleven-stage axial-flow compressor and a single-stage turbine. With the afterburner, which most models carried, it produced a thrust of 7,400 lbf (32.92 kN).

Like the J33, the design of the J35 originated at General Electric, but major production was by the Allison Engine Company.

B46

B46 may refer to:

Bundesstraße 46, a German road

B46 (New York City bus) in Brooklyn

B46 nuclear bomb

HLA-B46, a HLA-B serotype

Sicilian Defence, Taimanov Variation in the Encyclopaedia of Chess Openings

Boca Raton Army Air Field

Boca Raton Army Air Field was a World War II United States Army Air Forces airfield, located 1.7 miles (2.7 km) northwest of the 1940s borders of Boca Raton, Florida. During World War II, it operated the only training for the then new and secret technology of radar. Closed in 1946, due to annexation the former base is now within the city of Boca Raton; the land is currently occupied by the Boca Raton Airport, Florida Atlantic University and Palm Beach State College.

Boeing B-47 Stratojet

The Boeing B-47 Stratojet (company Model 450) is a retired American long-range, six-engined, turbojet-powered strategic bomber designed to fly at high subsonic speed and at high altitude to avoid enemy interceptor aircraft. The primary mission of the B-47 was as a nuclear bomber capable of striking targets within the Soviet Union.

Development of the B-47 can be traced back to a requirement expressed by the United States Army Air Forces (USAAF) in 1943 for a reconnaissance bomber that harnessed newly developed jet propulsion. Another key innovation adopted during the development process was the swept wing, drawing upon captured German research. With its engines carried in nacelles underneath the wing, the B-47 represented a major innovation in post-World War II combat jet design, and contributed to the development of modern jet airliners. Suitably impressed, in April 1946, the USAAF ordered two prototypes, designated "XB-47"; on 17 December 1947, the first prototype performed its maiden flight. Facing off competition such as the North American XB-45, Convair XB-46 and Martin XB-48, a formal contract for 10 B-47A bombers was signed on 3 September 1948. This would be soon followed by much larger contracts.

During 1951, the B-47 entered operational service with the United States Air Force's Strategic Air Command (SAC), quickly becoming a mainstay of its bomber strength by the late 1950s. Over 2,000 were manufactured to meet the Air Force's extensive demands, driven by the tensions of the Cold War. The B-47 was in service as a strategic bomber until 1965, at which point it had largely been supplanted by more capable aircraft, such as the Boeing B-52 Stratofortress. However, the B-47 was also adapted to perform a number of other roles and functions, including photographic reconnaissance, electronic intelligence, and weather reconnaissance. While never seeing combat as a bomber, reconnaissance RB-47s would occasionally come under fire near to or within Soviet air space. The type remained in service as a reconnaissance aircraft until 1969; a handful served as flying testbeds up until 1977.

Convair

Convair, previously Consolidated Vultee, was an American aircraft manufacturing company that later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Consolidated Aircraft and Vultee Aircraft. In 1953 it was purchased by General Dynamics, and operated as their Convair Division for most of its corporate history.

Convair is best known for its military aircraft; it produced aircraft such as the Convair B-36 Peacemaker, the F-102 Delta Dagger, the F-106 Delta Dart, and the B-58 Hustler bombers. It also manufactured the first Atlas rockets, including the rockets that were used for the manned orbital flights of Project Mercury. The company's subsequent Atlas-Centaur design continued this success and derivatives of the design remain in use as of 2019.

The company also entered the jet airliner business with its Convair 880 and Convair 990 designs. These were smaller than contemporary aircraft like the Boeing 707 and Douglas DC-8, but somewhat faster than either. This combination of features failed to find a profitable niche and the company exited the airliner design business. However, the manufacturing capability built up for these projects proved very profitable and the company became a major subcontractor for airliner fuselages.

In 1994 most of the company's divisions were sold by General Dynamics to McDonnell Douglas and Lockheed, with the remaining components deactivated in 1996.

Fat Man

"Fat Man" was the codename for the nuclear bomb that was detonated over the Japanese city of Nagasaki by the United States on 9 August 1945. It was the second of the only two nuclear weapons ever used in warfare, the first being Little Boy, and its detonation marked the third nuclear explosion in history. It was built by scientists and engineers at Los Alamos Laboratory using plutonium from the Hanford Site, and it was dropped from the Boeing B-29 Superfortress Bockscar piloted by Major Charles Sweeney.

The name Fat Man refers to the early design of the bomb because it had a wide, round shape; it was also known as the Mark III. Fat Man was an implosion-type nuclear weapon with a solid plutonium core. The first of that type to be detonated was the Gadget in the Trinity nuclear test less than a month earlier on 16 July at the Alamogordo Bombing and Gunnery Range in New Mexico. Two more were detonated during the Operation Crossroads nuclear tests at Bikini Atoll in 1946, and some 120 were produced between 1947 and 1949, when it was superseded by the Mark 4 nuclear bomb. The Fat Man was retired in 1950.

Glen Edwards (pilot)

Glen Walter Edwards (March 5, 1918 – June 5, 1948) was a test pilot for the United States Air Force, and is the namesake of Edwards Air Force Base.

Guy M. Townsend

Guy Mannering Townsend III (October 25, 1920 – March 28, 2011) was a retired United States Air Force brigadier general, test pilot, and combat veteran. As an Air Force officer, he served as chief of bomber test at Wright-Patterson Air Force Base, flew as co-pilot on the first flight of the B-52 Stratofortress, was test force director for the XB-70 Valkyrie, and served as program director for the C-5 Galaxy and B-1 Lancer. He was the first military pilot to fly the B-47 Stratojet, B-50 Superfortress, B-52 Stratofortress, and the prototype of the KC-135 Stratotanker. During his years at Boeing, he was the head of the Supersonic Transport operations organization.

History of Eglin Air Force Base

Eglin Air Force Base, a United States Air Force base located southwest of Valparaiso, Florida, was established in 1935 as the Valparaiso Bombing and Gunnery Base. It is named in honor of Lieutenant Colonel Frederick I. Eglin (1891–1937), who was killed in a crash of his Northrop A-17 pursuit aircraft on a flight from Langley to Maxwell Field, Alabama.

Eglin is the home of the Air Armament Center (AAC) and is one of three product centers in the Air Force Materiel Command (AFMC).

Ilyushin Il-22

For the 1970s Airborne Command Post aircraft of the same designation, see Ilyushin Il-18

The Ilyushin Il-22, USAF/DOD designation Type 10, was the first Soviet jet-engined bomber to fly. It used four Lyulka TR-1 turbojets carried on short horizontal pylons ahead and below the wing. The engines did not meet their designed thrust ratings and their fuel consumption was higher than planned. These problems meant that the aircraft could not reach its required performance and it was cancelled on 22 September 1947.

List of United States bomber aircraft

This is a list of United States bomber aircraft

List of bomber aircraft

The following is a list of bomber airplanes and does not include bomber airships, organized by era and manufacturer. A bomber is a military aircraft designed to attack ground or sea targets.

List of radars

This is a list of radars. A radar is an electronic system used to detect, range (determine the distance of), and map various types of targets.

Martin XB-48

The Martin XB-48 was an American medium jet bomber developed in the mid-1940s. It competed with the Boeing B-47 Stratojet, which proved to be a superior design, and was largely considered as a backup plan in case the B-47 ran into development problems. It never saw production or active duty, and only two prototypes, serial numbers 45-59585 and 45-59586, were built.

North American B-45 Tornado

The North American B-45 Tornado was an early American jet-powered bomber designed and manufactured by aircraft company North American Aviation. It has the distinction of being the first operational jet bomber to enter service with the United States Air Force (USAF), as well as being the first multiengine jet bomber in the world to be refueled in midair.The B-45 originated from a wartime initiative launched by the U.S. War Department, which sought a company to develop a jet-propelled bomber to equal those being fielded by Nazi Germany, such as the Arado Ar 234. Following a competitive review of the submissions, the War Department issued a contract to North American to develop its NA-130 proposal; on 8 September 1944, work commenced on the assembly of three prototypes. However, progress on the program was delayed by post-war cutbacks in defense expenditure, but soon regained importance due to growing tensions between America and the Soviet Union. On 2 January 1947, North American was issued with a production contract for the bomber by the USAF, which had been designated B-45A. On 24 February 1947, the first prototype performed its maiden flight.

Soon after its entry to service on 22 April 1948, early B-45 operations were troubled by technical problems, particularly low levels of engine reliability. The USAF found the type to be quite useful during the Korean War, it was used to perform both conventional bombing and aerial reconnaissance missions in this theatre. On 4 December 1950, the first successful interception of a jet bomber by a jet fighter occurred when a B-45 was shot down by a Soviet-built MiG-15 while inside Chinese airspace. During the early 1950s, a total of 40 B-45s were extensively modified so that they could be equipped with nuclear weapons; for this purpose, improvements were made to their defensive systems and the fuel tankage was expanded to increase the type's survivability and range.

In its heyday, the B-45 become an important element of the United States' defense strategy, performing the strategically-critical deterrence mission for several years during the early 1950s, after which time the Tornado was quickly superseded by the larger and more capable Boeing B-47 Stratojet. Both bomber-orientated B-45s and reconnaissance-orientated RB-45s served in quantity in the USAF's Strategic Air Command from 1950 until 1959. The USAF withdrew the last examples of the type in favour of the more advanced Convair B-58 Hustler, an early supersonic bomber. The Tornado was also adopted by the Royal Air Force (RAF) and operated from bases in Britain, where it was repeatedly used to overfly the Soviet Union on various intelligence-related missions. The RAF operated the type until it had introduced its own indigenously-developed jet bomber fleet, initially in the form of the English Electric Canberra.

Short Sperrin

The Short SA.4 Sperrin (named after the Sperrin Mountains) was a British jet bomber design of the early 1950s, built by Short Brothers and Harland of Belfast. It first flew in 1951. From the onset, the design had been viewed as a fall-back option in case the more advanced strategic bomber aircraft, then in development to equip the Royal Air Force's nuclear-armed V bomber force, experienced delays; the Sperrin was not put into production because these swept-wing designs, such as the Vickers Valiant, were by then available.

As their usefulness as an interim bomber aircraft did not emerge, a pair of flying prototypes were instead used to gather research data on large jet aircraft and to support the development of other technologies, such as several models of jet engines. The two aircraft completed were retired in the late 1950s and ultimately scrapped sometime thereafter.

Sukhoi Su-10

The Sukhoi Su-10 or Izdeliye Ye (Russian: Product E) was a Soviet turbojet-powered bomber aircraft built shortly after World War II.

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