The Parnall Pipit was a single-engined, single-seat naval fighter

Fighter aircraft

A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...

 designed to an Air Ministry

Air Ministry

The Air Ministry was a department of the British Government with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964...

 specification in 1927. Two prototypes were built but both destroyed by tail flutter.

Design and development

The Pipit was Parnall's submission to Air Ministry specification 21/26, which called for a single seat ship-borne fighter. The same specification attracted a version of the Vickers 141, modified from the original landplane fighter and the private venture Hawker Hoopoe

Hawker Hoopoe

-See also:-Bibliography:* Mason, Francis K. Hawker Aircraft since 1920. London: Putnam, 1991. ISBN 0-85177-839-9-External links:*...

  The specification required operation off deck or water.

The Pipit was a single-bay biplane with staggered, equal-span wings, unswept and of constant chord. The upper wing only carried dihedral; the ailerons were on the lower plane, extending over most of the span. The was a large rounded cut-out in the upper wing over the cockpit for visibility, since the pilot's head was immediately below the trailing edge. Because of the stagger, he sat ahead of the lower trailing edge and so there were a pair of cut-outs in the lower wings, a little way out from the roots, to assist downward vision. Apart from the stainless-steel N-shaped interplane struts, the wings were duralumin structures, fabric covered. The lower wing was fixed near the bottom of the fuselage and the upper one supported above it by four outward-leaning centre-section struts.

The Pipit's fuselage was constructed from stainless-steel tubes braced with duralumin struts. The 495 hp (370 kW) Rolls-Royce F.XI

Rolls-Royce Kestrel

|-See also:-Bibliography:* Erfurth, Helmut. Junkers Ju 87 . Bonn, Germany: Bernard & Graefe Verlag, 2004. ISBN 1-85780-186-5....

 water cooled V-12 was housed in a refined, streamlined aluminium cowling. Behind the cockpit the fuselage was fabric covered, as was the empennage, which had a stainless-steel structure. The fin was tall and rounded, carrying a rudder which was neither aerodynamically nor dynamically balanced. The tailplane was attached at mid-fuselage and was rather rectangular, carrying split elevators which were horn balanced.

A retractable radiator, deployed via a handwheel in the cockpit, was mounted under the nose. When retracted this radiator warmed the cockpit and it was claimed that there would be no need for electrically heated clothing in the open cockpit, even at 20,000 ft (6,100 m) in winter. There were air vents for cooling the cockpit in summer and also a skin type ancillary radiator built into the upper wing centre section surface. The land undercarriage was of the single-axle type, with forward-leaning oleo

Oleo

Oleo is a term for oils. It is commonly used to refer to a variety of things:* Margarine* Oleic acid* Oleo , A type of shock absorbers on airplane landing gear* Oleo , a bebop composition by Sonny Rollins...

 legs to the lower fuselage ahead of the leading edge and rearward struts. The wheels incorporated servo-assisted brakes operated from the rudder bar. The land- and seaplane undercarriages were designed to be rapidly interchangeable and shared the same attachment points, though the oleo legs were moved aft for the floats and there were additional bracing struts forward from their feet to the fuselage. The floats, linked by a pair of horizontal struts, were duralumin with a single step and water rudder.

The pilot's view was good, particularly that over the nose, important for deck landings. The Pipit was armed with a pair of Vickers machine guns, mounted at seat level and firing via troughs in the fuselage sides.

The Pipit prototype, N232, first flew sometime in the summer of 1928. In October it flew to the A&AAE

Aeroplane and Armament Experimental Establishment

The Aeroplane and Armament Experimental Establishment was a research facility for British military aviation from 1918 to 1992.-History:...

 at RAF Martlesham Heath

RAF Martlesham Heath

RAF Martlesham Heath is a former Royal Air Force airfield in England. The field is located 1½ miles SW of Woodbridge, Suffolk.- RFC/RAF prewar use:Martlesham Heath was first used as a Royal Flying Corps airfield during World War I...

 for official trials. During that month, the Pipit was put into a terminal-velocity dive during which tail flutter set in and became so violent that the tailplane spar fractured. The aircraft was a complete write-off, but happily the pilot survived, despite a broken neck, to fly again. The loss was a severe blow to Parnall's, who had staked a lot on the hope of getting a production order for the promising Pipit. A second prototype was built, as the first but with distinguishing modifications. It was allocated the serial N233 but, confusingly, was painted with the same serial as the first prototype. The tailplane was now braced on each underside with a pair of struts, the fin and rudder had a less smoothly-rounded shape largely because of the addition of a large horn balance and there were now ailerons on all wings, linked between upper and lower planes by an external rod. This aircraft began testing at the Parnall factory field at Yate

Yate

Yate is a town in South Gloucestershire, England, at the southwest extremity of the Cotswold Hills, 12 miles northeast of the city of Bristol. At the 2001 census the population was 21,789. The town of Chipping Sodbury is continuous with Yate to the east...

 early in 1929, but on 24 February the Pipit encountered flutter strong enough to break the fin and rudder from the fuselage. The aircraft was lost, but the pilot escaped by parachute.

After the failure of the Pipit, Parnall never got a production order for a military aircraft and never submitted a front-line prototype again, though they did compete for the trainer specification Air Ministry specification T.1/37 with the Parnall Heck III. The Pipit crashes did contribute to a better understand of flutter and how to prevent it, with wind-tunnel models and a detailed study of the two cases published in 1930. A subsequent and more general report came out of a research program which reported in 1931 with an emphasis on structural stiffness and above all careful mass (dynamic) balancing.

Specifications