The Bristol Type 167 Brabazon was a large British piston-engined propeller-driven airliner designed by the Bristol Aeroplane Company to fly transatlantic routes between the UK and the United States. The type was named Brabazon after the Brabazon Committee and its chairman, Lord Brabazon of Tara, which had developed the specification to which the airliner was designed.
While Bristol had studied the prospects of developing very large aircraft as bombers prior to and during the Second World War, it was the release of a report compiled by the Brabazon Committee which led the company to adapt its proposed bomber into a large civil airliner to meet the Type I specification for the long-distance transatlantic route. Initially designated the Type 167, the proposed aircraft had a -diameter fuselage, containing full upper and lower decks on which passengers would be seated in luxurious conditions. It was powered by an arrangement of eight Bristol Centaurus radial engines which drove eight paired contra-rotating propellers set on four forward-facing nacelles.
Bristol decided to submit the Type 167 proposal to meet Air Ministry Specification 2/44. Following a brief evaluation period, a contract to build a pair of prototypes was awarded. At the time of its construction, the Brabazon was one of the largest aeroplanes ever built, being sized roughly between the much later Airbus A300 and Boeing 767 airliners. Despite its vast size, the Brabazon was designed to carry only 100 passengers, each one allowed an area about the size of the interior of a small car. On 4 September 1949 the first prototype made its maiden flight. In addition to participating in a flight test programme in support of the intended production aircraft, the prototype made high-profile public appearances at the 1950 Farnborough Airshow, Heathrow Airport, and the 1951 Paris Air Show.
However, due to the high cost per seat mile compared to the alternatives, the Brabazon did not attract any firm orders, so the aircraft was a commercial failure. On 17 July 1953 Duncan Sandys, the Minister of Supply, announced that the Brabazon had been cancelled due to a lack of military or civil orders. In the end, only the single prototype was flown, and it was broken up in 1953 for scrap, along with the incomplete, turboprop-powered Brabazon I Mk.II.
Design and development Background
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 the majority of its transport aircraft from manufacturers in the United States. Having foreseen that the effective abandonment of any development in terms of civil aviation would put Britain's aviation industry at a substantial disadvantage once the conflict had come to an end, during 1943 a British government committee began meeting under the leadership of Lord Brabazon of Tara with the aim of investigating and forecasting the post-war civil aviation requirements of Britain and the Commonwealth of Nations.Kaplan 2005, p. 115.
The committee, which had become known simply as the Brabazon Committee, delivered its report, which was likewise known as the Brabazon Report. The report called for the construction of a total of four of five designs they had studied. Of those designs, the Type I was a very large transatlantic airliner, the Type II was a short-haul airliner, the Type III was a medium-range airliner for the multiple-hop "Empire" air routes, and the Type IV was an innovative jet-powered 500 mph (800 km/h) airliner. In particular, the Type I and Type IV were regarded as being of very high importance to the industry, particularly the jet-powered Type IV, which would give Britain a commanding lead in the field of jet transport. An outline of the specifications for the various envisioned aircraft, including the gigantic Type I, was issued by the Committee.
As early as 1937, the Bristol Aeroplane Company had conducted studies into very large bomber designs, one of which received the internal company designation of Type 159, and another, undesignated design that broadly resembled the eventual configuration of the Brabazon.Kaplan 2005, pp. 115–116. Additionally, Bristol's design team had already been considering the requirements of an aircraft capable of conducting routine transatlantic flights, which had led to projections of the necessary size, weight and range of such an airliner. Amongst those, it was determined that, in order to be profitable, a minimum payload of 100 passengers should be carried by the type.Kaplan 2005, pp. 116.
In 1942, the Air Ministry issued a draft operational requirement from the Air Staff, which sought a heavy bomber design that would be capable of carrying a payload of at least 15 tons of bombs. In response, Bristol dusted off their original work and updated it to incorporate their newer and substantially more powerful Bristol Centaurus engines. The Bristol design team, led by L. G. Frise and Archibald Russell,Jackson 1973, p. 311. worked with several key performance parameters. Those 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 that projected "100-ton bomber". In addition to Bristol, many leading British manufacturers had provided several preliminary studies in response to the Air Ministry's operational requirement. However, in expectation of long development times, and the difficulties associated with balancing the aircraft's range, load and defensive armament, the Ministry never took up any of the British manufacturer's designs. Instead, it was decided to continue development of the existing Avro Lancaster, which led to the production of the improved Avro Lincoln.Buttler 2004, p. 128.
In 1942, the Brabazon Report was published and Bristol chose to respond, submitting a slightly modified version of their bomber to fulfil the Type I requirement. Bristol's earlier work had demonstrated the sort of performance that the Brabazon Committee had been looking for, and so the Committee authorised the firm to begin preliminary design of such an aircraft that year, with the proviso that work on wartime aircraft should not be disrupted by the project. Bristol was soon issued with a contract to produce a pair of prototype aircraft.
Bristol 167 In November 1944, after further work on the design, a final concept for the Type 167 was published. The final design featured a large 177 ft (54 m) fuselage, paired with a sizable wing. The wing, which had a 230 ft (70.1 m) wingspan, possessed an enormous internal volume, to house sufficient fuel for the transatlantic flights envisioned for the type. It was powered by eight Bristol Centaurus 18-cylinder radial engines, which were the most powerful British-built piston engines available at the time, each being capable of generating . These were set in pairs in the wing, and instead of using a common crankshaft, the paired engines each had their driveshafts angled towards an enormous central gearbox. They drove a series of eight paired contra-rotating propellers, which were set on four forward-facing nacelles.Kaplan 2005, p. 117.
The Brabazon Report had assumed that the wealthy people flying in the aircraft would consider a long trip by air to be uncomfortable, and so designed the Type I for luxury, demanding 200 ft3 (6 m3) of space for every passenger, which was expanded to 270 ft3 (8 m3) for luxury class. If outfitted with conventionally spaced seating, the dimensions of the Type 167 could have accommodated up to 300 passengers, instead of the 60 seats opted for. Other high-comfort measures were proposed, such as an onboard cinema, a cocktail bar, and lounge area. According to author Stephan Wilkinson, the decision to focus on comfort over other qualities such as speed and payload had been a historic preoccupation of Britain operators to specifically tailor their services towards wealthy travellers, and noted that as having been a key pre-war ethos of the British airline Imperial Airways. Meanwhile, some figures within the aircraft industry were forecasting heavy demand from passengers then relying on ocean liners.Kaplan 2005, pp. 116–117.
To meet these varied requirements, the Type 167 specified a huge -diameter fuselage, which was about 5 ft (1.5 m) greater than the 1970 Boeing 747 "jumbo jet", with full-length upper and lower decks. That enclosed sleeping berths for 80 passengers, a dining room, 37-seat cinema, promenade and bar or, alternatively, day seats for 150 people. At one point, the Committee recommended the adoption of a narrower fuselage to house a total of 50 passengers. The British Overseas Airways Corporation (BOAC) agreed with that recommendation, and also expressed its preference for a design accommodating only 25 passengers. In August 1943,Barnes p. 325. an agreement with the airline led to the selection of an interior layout which contained a forward area housing six compartments, each one for six passengers, along with a seventh compartment for just three passengers, a midsection above the wing – the wing was deep at that point – which accommodated 38 seats arranged around tables in groups of four along with a pantry and galley, and a rear area with 23 seats in an aft-facing cinema, complete with a cocktail bar and lounge. Similar to 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 relevant in the postwar world.Winchester 2005, p. 18.
The Brabazon was the first aircraft to be outfitted with 100 per cent powered flying controls; it was also the first with electric engine controls, and the first equipped with high-pressure hydraulics.Kaplan 2005, p. 119. 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. One of the innovative features of the Brabazon was a purpose-developed gust-alleviation system, which used an assortment of servos that were triggered from a gust-sensing probe installed on the exterior of the aircraft's nose; an improved version of this system, along with fully automated trimming, was to have been deployed on the Brabazon Mark II."Airborne in the “Brab”." Flight, 3 August 1951, p. 149. Hydraulic power units were also designed to operate the aircraft's giant control surfaces.
A tremendous effort was put into saving weight across the aircraft. 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. Bristol employed revolutionary new machining and construction methods for drilling, milling, folding, and rolling many of the airframe's components. Rivets were sealed in aircraft dope to greatly reduce the number required for airframe assembly. Significant emphasis had been placed upon simplifying the construction process and incorporating several manufacturing efficiencies.Kaplan 2005, pp. 118–119. Some of the design and construction work for the aircraft was shared out to other British companies, such as Folland Aircraft.