The Bristol Type 91 Brownie was a light sports aircraft produced in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

by the

Bristol Aeroplane Company The Bristol Aeroplane Company, originally the British and Colonial Aeroplane Company, was both one of the first and one of the most important British aviation companies, designing and manufacturing both airframes and aircraft engines. Notable a ...

in 1924. It was a low-wing

cantilever A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a canti ...

monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...

aircraft of conventional configuration with fixed tailskid undercarriage. The pilot and passenger sat in tandem open

cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a Pilot in command, pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the ...

s. It won the £1,000 pound prize for second place at the

Lympne light aircraft trials The Lympne Light Aircraft Trials were held to encourage the development of practical light aircraft for private ownership, with a strong but not exclusive emphasis on fuel economy. They were held in 1923, 1924 and 1926. Each year saw different rest ...

in October 1924.

Design

Bristol had not built an aircraft to compete in the 1923

, which had been for aircraft with engines of 750 cc or less, making use of Bristol's

Cherub A cherub (; plural cherubim; he, כְּרוּב ''kərūḇ'', pl. ''kərūḇīm'', likely borrowed from a derived form of akk, 𒅗𒊏𒁍 ''karabu'' "to bless" such as ''karibu'', "one who blesses", a name for the lamassu) is one of the u ...

engine impossible. The rules were changed for the 1924 trials, permitting engines of up to 1,100 cc to be used, and accordingly

Frank Barnwell Captain Frank Sowter Barnwell OBE AFC FRAeS BSc (23 November 1880 – 2 August 1938) was a Scottish aeronautical engineer. With his elder brother Harold, he built the first successful powered aircraft made in Scotland and later went on to a c ...

started design work on a competitor early in 1924. He produced studies for alternative wood and metal aircraft, and after consideration of these the Board of Bristol Aircraft authorised the production of two aircraft on 4 February, adding a third on 5 May. All three aircraft had a similar fuselage, made of wire-braced high-tensile steel tubing, but for experimental purposes three different wing designs were produced: a 34 ft 7in (10.54m) span wooden wing and two different metal wings, one of 36 ft 7 in (11.15 m) span of all-steel construction, the other, intended for high-speed use, of 30 ft 7 in (9.32 m) span with combined steel and

duralumin Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age-hardenable aluminium alloys. The term is a combination of '' Dürener'' and ''aluminium''. Its use as a tra ...

construction. To satisfy the rules of the competition the wings had to be readily detachable and the aircraft fitted with dual controls. The three aircraft were registered G-EBJK, G-EBJL and G-EBJM on 14 July, and immediately named ''Jack'', ''Jill'' and ''Jim''. G-EBJK, fitted with the wooden wings, was the first flown, on 6 Aug piloted by

Cyril Uwins Cyril Frank Uwins OBE, AFC, FRAeS (1896–1972) was a British test pilot who worked for Bristol Aeroplane Company, where he made the first flight of 58 types of aircraft. On 16 September 1932 he broke the world aeroplane height record by climbi ...

. It performed and handled so well that a second flight was immediately made by Frank Barnwell, followed by a third by Uwins and Barnwell together. G-EBJL, which had the large metal wings fitted, first flew on 22 September and G-EBJM, completed as a single-seater with a long-range tank and the smaller metal wings, followed on 4 September. All took part in the trials, which took place between 27 September and 4 October. Uwins, flying 'JK, winning second prize in the main trials. 'JL, to be flown by T.W. Campbell, was withdrawn because of aileron flutter, and Campbell in 'JM won third place in the

Grosvenor Cup The Grosvenor Challenge Cup, commonly known as the Grosvenor Cup, was a trophy presented by Lord Edward Grosvenor in 1923 to the winner of a light aircraft time trial competition.Dorman 1951, p. 188. Entries were initially restricted to Britis ...

race, averaging over 70 mph.

Development

After the Lympne trials 'JK and 'JL were delivered to Martlesham Heath for evaluation as a primary trainer, but did not impress the Air Ministry enough for any development to be funded by them. G-EBJK was returned to Filton for modifications in December 1925. It was fitted with the newly developed 36 hp Cherub III mounted slightly lower in the fuselage, and the top longerons were curved down more to improve the view from the rear cockpit. The fuel tank was enlarged and it was fitted with new metal wings giving it a span of 37 ft 7 in (11.45 m). This was designated Type 91A. After further trials at Martlesham it was again returned to Filton, where the engine mounting was further lowered and a Fairey-Reed duralmin propeller fitted. Additionally, a curved decking was added to the rear fuselage, and it was fitted with an enlarged horn-balanced rudder and a new undercarriage using rubber shock absorbers. This was designated Type 91 B, or Brownie II. In this form the aircraft took place in the 1926 Lympne trials, where Uwins won the third place prize of £500.

Specifications (Brownie I, wooden wing)

References

Citations

Bibliography