The Bristol Type 148 was a two-seat, single-engine low-wing

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 ...

built in 1937 to an

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 an army cooperation aircraft. It lost in the competition to the

Westland Lysander The Westland Lysander is a British army co-operation and liaison aircraft produced by Westland Aircraft that was used immediately before and during the Second World War. After becoming obsolete in the army co-operation role, the aircraft's ...

and did not progress past the two prototypes that were built.

Development

The Bristol 148 was built by

Bristol Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city in ...

to an

order for two prototypes of an army cooperation aircraft meeting

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 ...

A.39/34. The successful aircraft was to replace the

Hawker Audax The Hawker Hart is a British two-seater biplane light bomber aircraft that saw service with the Royal Air Force (RAF). It was designed during the 1920s by Sydney Camm and manufactured by Hawker Aircraft. The Hart was a prominent British aircra ...

and

Hector In Greek mythology, Hector (; grc, Ἕκτωρ, Hektōr, label=none, ) is a character in Homer's Iliad. He was a Trojan prince and the greatest warrior for Troy during the Trojan War. Hector led the Trojans and their allies in the defense o ...

in a wide range of tasks. By 1935 Bristol had gained experience in the design of

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 ...

low-wing monoplanes powered by

radial engine The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ca ...

s with the Types

133 133 may refer to: *133 (number) * AD 133 *133 BC *133 (song) *133 (New Jersey bus) 133 may refer to: *133 (number) * AD 133 *133 BC *133 (song) 133 may refer to: *133 (number) *AD 133 *133 BC *133 (song) *133 (New Jersey bus) 133 may refer to: * ...

and 146, and the Type 148 followed this layout, but had seating for two. The stressed-skin wings were of constant chord with rounded tips, and 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 aircraft t ...

was entirely of

monocoque Monocoque ( ), also called structural skin, is a structural system in which loads are supported by an object's external skin, in a manner similar to an egg shell. The word ''monocoque'' is a French term for "single shell". First used for boats, ...

construction. The horizontal tail was set at the top of the fuselage and carried horn-balanced

elevator An elevator or lift is a wire rope, cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or deck (building), decks of a building, watercraft, ...

s; 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 aircraft, air or watercraft, water). On an aircraft the rudder is used primarily to ...

was large and pointed. All flying surfaces were fabric-covered. The wing also carried split flaps and connected wingtip

slot Slot, the slot or Slots may refer to: People * Arne Slot (born 1978), Dutch footballer * Gerrie Slot (born 1954), Dutch cyclist * Hanke Bruins Slot (born 1977), Dutch politician * Tonny Bruins Slot (born 1947), Dutch association football coach wh ...

s to improve handling at the low speeds required by the specification. The wide-track main

undercarriage Undercarriage is the part of a moving vehicle that is underneath the main body of the vehicle. The term originally applied to this part of a horse-drawn carriage, and usage has since broadened to include: *The landing gear of an aircraft. *The ch ...

retracted inwards into the centre-section but the tailwheel was fixed and spatted. The pilot and observer/gunner/bomb aimer sat in tandem cockpits under a continuous

canopy Canopy may refer to: Plants * Canopy (biology), aboveground portion of plant community or crop (including forests) * Canopy (grape), aboveground portion of grapes Religion and ceremonies * Baldachin or canopy of state, typically placed over an a ...

, the rear part of which was modified when the .303 in (7.7 mm) Lewis Gun mounting was changed from

Scarff ring The Scarff ring was a type of machine gun mounting developed during the First World War by Warrant Officer (Gunner) F. W. Scarff of the Admiralty Air Department for use on two-seater aircraft. The mount incorporated bungee cord suspension in eleva ...

to a pillar type. The observer could also access a prone aiming position on the floor to drop bombs from the external racks. Two .303 in (7.7 mm)

machine gun A machine gun is a fully automatic, rifled autoloading firearm designed for sustained direct fire with rifle cartridges. Other automatic firearms such as automatic shotguns and automatic rifles (including assault rifles and battle rifles) a ...

s were mounted in the port wing. The intended engine for the Type 148 was the

Bristol Perseus The Bristol Perseus was a British nine-cylinder, single-row, air-cooled radial aircraft engine produced by the Bristol Engine Company starting in 1932. It was the first production sleeve valve aero engine. Design and development In late 192 ...

, but the aircraft made its first flight on 15 October 1937 with a Mercury IX. It was re-engined with a Perseus XII after a landing accident during comparative trials with the

. Both aircraft met the specification, including the demanding low-speed requirements but the visibility offered by the Lysander's high wing and the security of its fixed undercarriage made it the competition winner. The second prototype, labelled the Type 148B flew in May 1938, powered by a

Bristol Taurus The Taurus is a British 14-cylinder two-row radial aircraft engine, produced by the Bristol Engine Company starting in 1936. The Taurus was developed by adding cylinders to the existing single-row Aquila design and transforming it into a twin ...

II engine and the two machines were used to compare and evaluate the two engine types.

Development

Specifications (Type 148B)

References

Notes

Bibliography