Bristol Brabazon

Brabazon
Brabazon in 1950
Role Airliner
Manufacturer Bristol Aeroplane Company
First flight 4 September 1949
Retired 1953
Status Only example scrapped in 1953
Number built 1


The Bristol Type 167 Brabazon was a large propeller-driven airliner which was designed by the Bristol Aeroplane Company to fly transatlantic routes between the United Kingdom and the United States. Despite its size, roughly between an Airbus A300 and a Boeing 767, it was designed to carry only 100 passengers, each one allocated a space about the size of the entire interior of a small car.

The prototype was completed and flown in 1949, only to prove a commercial failure because airlines felt the airliner was too large and expensive to be useful. In the end, only the single prototype was flown; it was broken up in 1953 for scrap, along with the uncompleted turboprop-powered Brabazon I Mk.II.

Design and development

Background

Main article: Brabazon Committee

During the Second World War, the British government made the decision to dedicate its aircraft industry to the production of combat aircraft and to source transport aircraft designs from the US. Knowing that abandoning development of civil aviation would put them at a disadvantage once the war was over, a British government committee began meeting in 1943 under the leadership of Lord Brabazon of Tara to investigate and forecast the post-war civil aviation needs of Britain and the Commonwealth.

The Brabazon Committee delivered a report, known as the "Brabazon Report", calling for the construction of four of five designs they had studied. Type I was a very large transatlantic airliner, Type II a short-haul, Type III a medium-range airliner for the multiple-hop Empire air routes, and Type IV a jet-powered 500 mph (800 km/h) airliner. The Type I and IV were considered to be very important to the industry, particularly the jet-powered Type IV which would give the UK a commanding lead in jet transports.

Bristol had already studied a large bomber design starting as early as 1937, but nothing had come of this. In 1942 the Air Ministry issued a draft operational requirement from the Air Staff for a heavy bomber design capable of carrying at least 15 tons of bombs, and Bristol dusted off their original work and updated it for their newer and much more powerful Bristol Centaurus engines. Led by L. G. Frise and Archibald Russell,[1] the Bristol design team worked with parameters that included a range of 5,000 mi (8,000 km), 225 ft (69 m) wingspan, eight engines buried in the wings driving four pusher propeller installations, and enough fuel for transatlantic range. The Convair B-36 was in many ways the American equivalent of this "100 ton bomber".

The leading British manufacturers provided several preliminary studies; however, in expectation of long development times, and the problems associated with balancing range, load and defensive armament, the Air Ministry never took up any of the British manufacturer's designs and decided to continue development of the Avro Lancaster, (leading to the Avro Lincoln) instead.[2]

Bristol Brabazon main undercarriage wheels with woman for scale

Bristol 167

A year later, the Brabazon Report was published and Bristol was able to respond with a slightly modified version of their bomber to fill the needs for the Type I requirement. Their earlier work was the sort of performance the Brabazon committee was looking for, and they were given a contract for two prototype aircraft. After further work on the design, a final concept was published in November 1944. It was for a 177 ft (54 m) fuselage with 230 ft (70.1 m) wingspan (35 ft/11 m greater than a Boeing 747) powered by eight Bristol Centaurus 18-cylinder radial engines nested in pairs in the wing. These drove eight paired contra-rotating propellers on four forward-facing nacelles.

The Brabazon Report assumed that the wealthy people flying in the aircraft would consider a long trip by air to be uncomfortable, and they designed the Type I for luxury, demanding 200 ft³ (6 m³) of space for every passenger, and 270 ft³ (8 m³) for luxury class.

To meet these requirements the Type 167 specified a huge 25 ft (8 m)-diameter fuselage, which is about 5 ft (1.5 m) greater than a 747, with full-length upper and lower decks. This enclosed sleeping berths for 80 passengers, a dining room, 37-seat cinema, promenade and bar; or day seats for 150 people. The Committee recommended a narrower fuselage designed for 50 passengers. BOAC agreed, but preferred a design for only 25 passengers. In August 1943 [3] an agreement with the airline led to an interior layout housing a forward area with six compartments, each for six passengers and a seventh for just three; a midsection above the wing - the wing was 6 feet deep at that point - with 38 seats arranged around tables in groups of four with a pantry and galley; and a rear area with 23 seats in an aft-facing cinema with a cocktail bar and lounge. Like the Saunders-Roe Princess, the Brabazon concept was a fusion of prewar and postwar thinking, using highly advanced design and engineering to build an aircraft that was no longer required in the postwar world.[4]

A tremendous effort was put into saving weight. The Type 167 used a number of non-standard gauges of skinning in order to tailor every panel to the strength required, thereby saving several tons of metal. The large span and mounting of the engines close inboard, together with structural weight economies, demanded some new measure to prevent bending of wing surfaces in turbulence. A system of gust-alleviation was developed for the Brabazon, using servos triggered from a probe in the aircraft's nose.[5] Hydraulic power units were also designed to operate the giant control surfaces. The Brabazon was the first aircraft with 100% powered flying controls, the first with electric engine controls, and the first with high-pressure hydraulics.

Building the aircraft was a challenge. Bristol's existing factory at Bristol Filton Airport was too small to handle what was one of the largest aircraft in the world, and the 2,000 ft (610 m) runway was too short to launch it. Construction of the first prototype's fuselage started in October 1945 in an existing hangar while a gigantic hall for final assembly was built, whose designer, T. P. O'Sullivan, was awarded the Telford Premium for the work. The runway was lengthened to 8,000 ft (2,440 m), which required moving elsewhere the inhabitants of the village of Charlton.

Some design and construction work was shared out to other British companies such as Folland Aircraft.

Mark II

In 1946 it was decided to build the second prototype using eight Bristol Coupled Proteus turboprop engines - paired turboprops driving 4-bladed screws through a common gearbox.[6] This would increase cruising speed, from 260 to 330 mph (420–530 km/h), and ceiling, while reducing the empty weight by about 10,000 lb (4,540 kg). This Brabazon Mark II would have been able to cross the Atlantic (London-New York) in a reduced time of 12 hours.

Although the Proteus was slimmer than the Centaurus, the wing thickness was not to be reduced in the Mark II but the leading edge would be extended around the engines.

Changes to the wheel arrangement planned for the Mark II would have allowed it to use most runways on both the North Atlantic and Empire routes.[7]

Testing

Bristol Brabazon G-AGPW takes off on its maiden flight on 4 September 1949 at Filton Aerodrome

The Mk.I aircraft, registration G-AGPW, rolled out for engine runs in December 1948, and flew for the first time, over the Bristol area for 25 minutes, on 4 September 1949 captained by Bristol Chief Test Pilot Bill Pegg. It flew to about 3,000 ft (910 m) at 160 mph (257 km/h) and landed at 115 mph (185 km/h), throttling back at 50 ft (15 m). Four days later, it was presented at Society of British Aircraft Constructors' Airshow at Farnborough before starting testing in earnest. It was demonstrated at the 1950 Farnborough Airshow with a takeoff, clean configuration flypast and a landing. The Brabazon visited London's Heathrow Airport in June 1950 making a number of successful takeoffs and landings, and was demonstrated at the 1951 Paris Air Show. By this time, BOAC had lost interest in the design and although some interest was shown by BEA on flying the prototype, various problems that would be expected of a prototype meant it was never given an airworthiness certificate.

Cancellation

By 1952, about £3.4 million had been spent on development and there were no signs of purchase by any airline. In March, the British government announced that work on the second prototype had been postponed. The cancellation of the project was announced by the Minister for Supply (Duncan Sandys) on 17 July 1953 in the Commons saying it had given all the useful technical knowledge it could but with no interest from civil or military users, they had no justification for continuing to spend money on it. About £6 million had been spent and a further £2 million would be required to complete the Mark II.[8] In October 1953, after 164 flights totalling 382 hours’ flying time, the first prototype was broken up, sold for £10,000 in scrap value, along with the uncompleted Mk.II prototype. All that remains are a few parts at the M Shed museum in Bristol and the National Museum of Flight in Scotland.

Brabazon model

Although considered a failure and a white elephant, the record of the Brabazon is not entirely unfavourable. At least half of the large sums spent on the project were put into infrastructure, including £6 million for large hangars and runway at Filton.[9] This meant Bristol was now in an excellent position to continue production of other designs and the hall was used for building the Britannia. In addition, many of the techniques developed as a part of the Brabazon project were applicable to any aircraft, not just airliners.

Bristol had also won the contract for the Type III aircraft, which they delivered as the Britannia. Using all of the advances of the Brabazon meant the Britannia had the best payload fraction of any aircraft up to that time, and it kept that record for a number of years. Although the Britannia was delayed after problems with the Type IV, the de Havilland Comet, it went on to be a workhorse for many airlines into the 1970s.

Specifications (Mark I)

Data from Flight

General characteristics

Performance

See also


Related lists

References

Notes

  1. ↑ Jackson 1973, p. 311.
  2. ↑ Buttler Secret Projects 1935-1950 Fighters and Bombers Midland Publishing p128
  3. ↑ Barnes p.325
  4. ↑ Winchester 2005, p. 18.
  5. ↑ "Airborne in the “Brab”" Flight, 3 August 1951, p. 149.
  6. ↑ King, H.F. "Brabazon Mark II." Flight, 29 September 1949, p. 416.
  7. ↑ King, H.F. "The Story of the Brabazon: A Comprehensive Appraisal of Britain's Greatest Airliner: Vicissitudes/ Development: Prototype and Operational Versions Studied." Flight, 29 September 1949.
  8. ↑ King, H.F. "End of the Brabazons." Flight, 29 September 1949.
  9. ↑ King, H.F. "End of the Brabazons." Flight, 29 September 1949.
  10. ↑ "Brabazon brochure". Bristol Aeroplane Company, 1949.
  11. ↑ Flight 29 Sept 1949 p419,p430

Bibliography

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