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 con ...

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 Stat ...

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' ...

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

Development

The Bristol 148 was built by

Bristol Bristol () is a City status in the United Kingdom, city, Ceremonial counties of England, ceremonial county and unitary authority in England. Situated on the River Avon, Bristol, River Avon, it is bordered by the ceremonial counties of Glouces ...

to an

order for two prototypes of an army cooperation aircraft meeting Air Ministry specification A.39/34. The successful aircraft was to replace the Hawker Audax and Hector 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 cant ...

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 ...

s with the Types

133 133 may refer to: *133 (number) *AD 133 *133 BC *133 (song) 133 may refer to: *133 (number) *AD 133 *133 BC __NOTOC__ Year 133 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Scaevola ...

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 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 ...

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 air or water). On an aircraft the rudder is used primarily to counter adve ...

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 ...

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

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 ...

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

Development

Specifications (Type 148B)

References

Notes

Bibliography