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The Bristol Type 123 was a single-seat, single-engine biplane fighter built to a United Kingdom
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 ...
specification for a four-gun fighter in the early 1930s. Only one was built.


Development

In late 1931 the
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 ...
released
Air Ministry specification This is a partial list of the British Air Ministry (AM) specifications for aircraft. A specification stemmed from an Operational Requirement, abbreviated "OR", describing what the aircraft would be used for. This in turn led to the specification ...
F.7/30. This was for a four-gun fighter with better high-altitude performance and endurance than current fighters, outstanding climb rate, manoeuvrability and all-round vision combined with a low landing speed. It was made clear that the evaporatively-cooled
Rolls-Royce Goshawk The Rolls-Royce Goshawk was a development of the Rolls-Royce Kestrel that used evaporative or steam cooling. In line with Rolls-Royce convention of naming piston engines after birds of prey, it was named after the goshawk. The engine first ...
was the preferred engine. The best-known outcome of this specification was the crank-winged Supermarine Type 224
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 con ...
with an open cockpit and fixed undercarriage designed by
R.J. Mitchell Reginald Joseph Mitchell (20 May 189511 June 1937) was a British aeronautical engineering, aircraft designer who worked for the Southampton aviation company Supermarine from 1916 until 1936. He is best remembered for designing racing seaplan ...
. Bristol submitted several biplane designs, none of which brought an order for a prototype, but they were invited to offer a private-venture aircraft. The Bristol Type 123 was the result. Bristol's last biplane, it was of compact, striking appearance and had innovative control features. It was a single-bay biplane with wings of constant chord almost to the tips and heavy stagger. The upper wings were swept and without dihedral, the
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 cant ...
lower wings unswept with 6° of dihedral. Both wings carried full-span ailerons. The upper wing also carried full-span slots on the leading edge, arranged in inner and outer groups. The ailerons were linked to
interceptors An interceptor aircraft, or simply interceptor, is a type of fighter aircraft designed specifically for the defensive interception role against an attacking enemy aircraft, particularly bombers and reconnaissance aircraft. Aircraft that are ca ...
behind the outer slots which rose when the inner slots opened at high angles of attack. As this happened, the ailerons drooped symmetrically. The slot-plus-interceptor combination was intended to prevent a stall turning into a spin and had been tested by Handley Page on a
de Havilland Moth The de Havilland Moths were a series of light aircraft, sports planes, and military trainers designed by Geoffrey de Havilland. In the late 1920s and 1930s, they were the most common civilian aircraft flying in Britain, and during that time ever ...
and later by Bristol on a
Bulldog The Bulldog is a British breed of dog of mastiff type. It may also be known as the English Bulldog or British Bulldog. It is of medium size, a muscular, hefty dog with a wrinkled face and a distinctive pushed-in nose.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 ...
and
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 were horn balanced, the latter carrying
trim tab Trim tabs are small surfaces connected to the trailing edge of a larger control surface on a boat or aircraft, used to control the trim of the controls, i.e. to counteract hydro- or aerodynamic forces and stabilise the boat or aircraft in a pa ...
s. The wings,
empennage The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third e ...
and
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 ...
behind the cockpit were all fabric covered over a metal structure. The combination of heavy stagger and a slender nose gave the Type 123 a slightly humpbacked appearance, with the pilot's open cockpit at the top above the centre of the lower wing and well behind the trailing edge of the upper wing. There were pairs of machine guns on either side of the engine. The undercarriage was fixed and almost completely enclosed in forward-thrusting fairings with a cross-axle between the wheels. The aircraft was powered by a Goshawk III loaned by the
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 ...
, which used condensers in the lower wing leading edge for cooling, coupled to a forward-mounted ventral condenser. Engine cooling problems delayed the first flight, made 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 climbin ...
on 12 June 1934. Testing revealed serious lateral instability that a series of modifications to fin, rudder and the inner slots failed to cure, and which may have been structural. Development was therefore abandoned.


Specifications


References


Notes


Bibliography

* * * * {{Bristol aircraft 1930s British fighter aircraft Type 123 Cancelled military aircraft projects of the United Kingdom Single-engined tractor aircraft Biplanes