Bristol Bullfinch

Bullfinch
	Bullfinch as single-seat monoplane (top) and as two-seat biplane
Role	Fighter/Reconnaissance
Manufacturer	Bristol Aeroplane Company
Designer	Frank Barnwell
First flight	6 November 1922
Number built	3

TheBristol Bullfinchwas an experimentalBritishmilitary aircraft first flown in 1922. Variants were built as bothparasol wing monoplanesandbiplanes,but both versions proved unsuccessful, and only the threeprototypeswere built.

Development

TheBullfinchwas designed byFrank Barnwell,chief designer of theBristol Aeroplane Company,as a parasol-wing monoplane single-seatfighter,which was convertible to a two-seatbiplane,thus meeting the requirements of theRoyal Air Forcefor both a single-seatinterceptorfighter and a two-seatreconnaissance-fighter. The potential cost savings associated with this concept, which was planned to be powered by theJupiterengine, the rights to which Bristol had just acquired from the bankruptCosmos Engineering,interested theAir Ministry,who wrote a specification (Specification 2/21) around Barnwell's proposed design, and ordered three prototypes in June 1921.^[1]

The Bullfinch monoplane, orType 52 Bullfinch Mk I,was acantileverparasol monoplane with a welded steel tubefuselage.The wing was in two halves, joined at the aircraft centreline, with each half tapering from maximum thickness at half span to both the wing root and tips.^[2]The wing was wooden on theprototypes,but was planned to be of metal construction for any subsequent production aircraft. To produce the two-seat fighter-reconnaissance version, theType 53 Bullfinch Mk II,an extra fuselagebaywas added aft of the pilot containing acockpitfor the observer, and a cantilever bottom wing attached which compensated for the shift incentre of gravityresulting from the weight of the observer and the lengthened fuselage.

The first prototype, a Type 52 monoplane, flew on 6 November 1922, with the second prototype, also a monoplane, flying in May 1923.^[1]After first flying as a monoplane, the third prototype was converted to the biplane configuration, flying in that configuration on 17 March 1924. While the single-seater demonstrated reasonable performance, the two-seater was overweight, and proved incapable of carrying the required military load.^[2]No further production occurred.

Variants

Type 52 Bullfinch Mk I: Single-seat parasol monoplane. Two built.

Type 53 Bullfinch Mk II: Two-seat biplane derivative. One built

Operators

United Kingdom

Royal Air Force

Specifications (Bullfinch I)

Data fromBristol Aircraft Since 1910^[2]

General characteristics

Crew:one(Bullfinch II):two
Length:24 ft 5 in (7.44 m)(Bullfinch II):27 ft 6 in (8.38 m)
Wingspan:38 ft 5 in (11.71 m)
Height:10 ft 9 in (3.28 m)
Wing area:267 sq ft (24.8 m²)(Bullfinch II):391 sq ft (36.33 m²)
Empty weight:2,175 lb (987 kg)(Bullfinch II):2,495 lb (1,131.7 kg)
Gross weight:3,205 lb (1,454 kg)(Bullfinch II):4,088 lb (1,854.3 kg)
Powerplant:1 ×Bristol Jupiter IIIorIV9-cyl. air-cooled radial piston engine, 425 hp (317 kW)

Performance

Maximum speed:135 mph (217 km/h, 117 kn) at 15,000 ft (4,600 m)
(Bullfinch II):120 mph (100 kn; 190 km/h) at 15,000 ft (4,600 m)
Endurance:4 hours
Service ceiling:22,000 ft (6,700 m)(Bullfinch II):18,000 ft (5,500 m)
Wing loading:12 lb/sq ft (59 kg/m²)(Bullfinch II):10.5 lb/sqft (51.27 kg/m²)

Armament

2 × fixed, forward-firing.303 in (7.7 mm)Vickers machine guns.
(Bullfinch II):1 ×.303 in (7.7 mm)Lewis Gunon aScarff ringin the rear cockpit.

References

^^a ^bMason, Francis K (1992).The British Fighter since 1912.Naval Institute Press.ISBN 1-55750-082-7.
^^a ^b ^cBarnes, C.H. (1964).Bristol Aircraft Since 1910(1st ed.). London: Putnam.

External links

[mason_fighter-1] Mason, Francis K (1992).The British Fighter since 1912.Naval Institute Press.ISBN 1-55750-082-7.

[bristol_1910-2] Barnes, C.H. (1964).Bristol Aircraft Since 1910(1st ed.). London: Putnam.

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