The Bristol Berkeley was built to a British government specification for a single-engine day or night bomber. Three of these two-seat
biplanes were built, but no contract for further production was awarded.
Development
In August 1923, British aircraft manufacturers were invited to submit designs to
Air Ministry Specification 26/23, which called for a single
Rolls-Royce Condor
The Rolls-Royce Condor aircraft piston engine was a larger version of the Rolls-Royce Eagle developing up to 675 horsepower (500 kW). The engine first ran in 1918 and a total of 327 engines were recorded as being built.
Variants
''Note:'' ...
-engined two-seat day or night bomber. The Berkeley was Bristol's response, designed largely by W.T. Reid with finishing touches from Bristol's longtime chief designer,
Frank Barnwell. It was a fabric-covered all-metal structured three-bay biplane, with equal span, unswept and
unstaggered wings with
Frise-type ailerons on the upper and lower planes. Structurally, the wings were of rolled steel and
duralumin.
The
fuselage
The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraf ...
was built from steel tubes and had a rectangular cross section. The pilot sat forward of the leading edge of the wing in an open cockpit and the gunner/observer in a cockpit well aft, fitted with a
ring-mounted .303 in (7.7 mm)
Lewis Gun. He could also access a bomb aimer's position, when he lay prone on the aircraft floor. The horizontal tail was positioned at the top of the fuselage and braced below, carrying
elevator
An elevator or lift is a cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or decks of a building, vessel, or other structure. They a ...
s whose balances protruded beyond the fixed surfaces. The
rudder
A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally air or water). On an aircraft the rudder is used primarily to counter adve ...
was tall and also horn-balanced, but more elegantly than the elevators with the edge running smoothly into the fin. The
undercarriage was of wide track, mounted to the wings below the centre section
interplane strut
In aeronautics, bracing comprises additional structural members which stiffen the functional airframe to give it rigidity and strength under load. Bracing may be applied both internally and externally, and may take the form of strut, which act in ...
s and braced to the fuselage.
The 650 hp (490 kW) Condor engine drove a two-blade propeller and had, after some
Air Ministry
The Air Ministry was a department of the Government of the United Kingdom with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964. It was under the political authority of the Secretary of State ...
input, a nose-mounted radiator under the propeller shaft. The Ministry advised that the wings of the first two Berkeleys of the three specified in the contract should have wooden wings for speed of completion, with the third to be all metal.
Leitner-Watts
The Metal Airscrew Company was formed in 1919 by Dr. Henry Charles Watts and Henry Leitner to produce hollow metal aircraft propellers with a method set out their joint patent. By 1928 the company name had changed to Metal Propellers Ltd. It re ...
Metal airscrews were required for the second and third machine. The first Berkeley flew on 5 March 1925.
The Type 90 Berkeley was the first Bristol aircraft to receive a type number at the start of its design rather than retrospectively.
Operational history
The first Berkeley was accepted for trials at
RAF Martlesham Heath in May 1925 and remained there until November. Other aircraft competing for production contracts were the
Handley Page Handcross
The Handley Page Handcross was a single-engined biplane day bomber built to an Air Ministry specification. It was not put into production and only the three prototypes were built.
Development
In August 1923 the Air Ministry issued specificatio ...
, the
Hawker Horsley
The Hawker Horsley was a British single-engined biplane bomber of the 1920s. It was the last all-wooden aircraft built by Hawker Aircraft, and served as a medium day bomber and torpedo bomber with Britain's Royal Air Force between 1926 and 1935 ...
and the
Westland Yeovil
The Westland Yeovil was a British biplane bomber designed and built by Westland Aircraft in 1923 to meet an Air Ministry Specification for a single-engined day bomber.
Development
The Yeovil was designed to meet Air Ministry Specification 26/ ...
. The Handcross and the Berkeley were the two larger machines and for that reason judged more suitable for the night bombing role; unfortunately for Handley-Page and Bristol, the Air Ministry had already decided, on the basis of experience with the
Avro Aldershot that single-engine aircraft were not suitable for night-bombing. In the end, therefore the only successful contender was the Horsley, chosen for the day-bomber role.
The second Berkeley was accepted by the Air Ministry in December 1925 and the all-metal third one in the following June. All three went to the
Royal Aircraft Establishment (RAE) for experimental flight. The second aircraft undertook comparative trials of a four-blade wooden airscrew against its original two-blade steel one. One of the three Berkeleys was still flying with the RAE at the end of 1930.
Specifications
References
Citations
Bibliography
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{{Bristol aircraft
1920s British bomber aircraft
Berkeley
Single-engined tractor aircraft
Biplanes