The Westland PV.7 was a private venture submission to a 1930s British specification for a general purpose military aircraft with two crew. It was a single-engined, high-wing monoplane

Monoplane

A monoplane is a fixed-wing aircraft with one main set of wing surfaces, in contrast to a biplane or triplane. Since the late 1930s it has been the most common form for a fixed wing aircraft.-Types of monoplane:...

 of promise, but was destroyed early in official tests.

Design and development

The Air Ministry specification G.4/31 called for a Westland Wapiti

Westland Wapiti

The Westland Wapiti was a British two-seat general purpose military single-engined biplane of the 1920s. It was designed and built by Westland Aircraft Works to replace the Airco DH.9A in Royal Air Force service....

 replacement, a multi role aircraft capable of carrying out level bombing, army co-operation, dive bombing

Dive bomber

A dive bomber is a bomber aircraft that dives directly at its targets in order to provide greater accuracy for the bomb it drops. Diving towards the target reduces the distance the bomb has to fall, which is the primary factor in determining the accuracy of the drop...

, reconnaissance

Reconnaissance

Reconnaissance is the military term for exploring beyond the area occupied by friendly forces to gain information about enemy forces or features of the environment....

, casualty evacuation and torpedo bombing

Torpedo bomber

A torpedo bomber is a bomber aircraft designed primarily to attack ships with aerial torpedoes which could also carry out conventional bombings. Torpedo bombers existed almost exclusively prior to and during World War II when they were an important element in many famous battles, notably the...

. Nine manufacturers responded with designs and while some gained contracts for single prototypes, such were the potential rewards that others, like Westland, built aircraft as private ventures. Contenders were the Armstrong Whitworth A.W.19, Blackburn B-7, Bristol 120, Fairey G.4/31

Fairey G.4/31

The Fairey G.4/31 was a British single-engined, two-seat biplane contender for an Air Ministry specification for a multi-role or general purpose aircraft. Unsuccessful, only one was built.-Development:...

, Handley Page HP.47, Hawker P.V.4

Hawker P.V.4

-See also:-Bibliography:* Hannah, Donald. Hawker FlyPast Reference Library. Stamford, Lincolnshire, UK: Key Publishing Ltd., 1982. ISBN 0-946219-01-X....

, Parnall G.4/31

Parnall G.4/31

-References:NotesBibliography* Lewis, Peter. "Parnall G.4/31." Air Pictorial, Volume 25, No. 9, September 1963.* Mason, Francis K. The British Bomber since 1914. London:Putnam, 1994. ISBN 0-85177-861-5....

, Vickers Type 253 and the Westland PV.7. Only Westland and Handley Page submitted monoplane designs. The Ministry expressed a preference for an air cooled engine and all manufacturers apart from Armstrong-Whitworth and Blackburn chose the nine cylinder Bristol Pegasus radial.

The Westland PV.7 was a large, tall single-engined high-wing monoplane with separate cockpits for two crew. The constant chord wings were all metal, built around two spars with ribs and inter-spar rods for stiffening. Leading edge Handley Page slats

Leading edge slats

Slats are aerodynamic surfaces on the leading edge of the wings of fixed-wing aircraft which, when deployed, allow the wing to operate at a higher angle of attack. A higher coefficient of lift is produced as a result of angle of attack and speed, so by deploying slats an aircraft can fly at slower...

 were fitted outboard and the inboard trailing edges carried 4 ft 9 in (1.45 m) span split flaps that opened symmetrically above and below the wing to act as dive brakes. Ailerons extended Immediately outboard of the flaps, almost to the wing tips. The wings met the top of the fuselage, with the pilot's head between them and behind the line of the outer leading edge, so at the centre the wings were thinned and tapered on the leading edge to improve his view. Originally his cockpit was open, but as it was only 6 ft (1.83 m) behind the propeller it was very draughty and was eventually glazed in, with entry via an opening upper panel and extending rearwards above the wing. On each side a pair of parallel, cranked lift struts joined the lower fuselage to about mid span, reinforced by struts from the crank-point to the upper fuselage. The main lift struts had a wide chord airfoil section and themselves contributed to lift. The main undercarriage legs were fitted to these struts at the crank-point, each axle supported by a pair of V-struts to the lower fuselage. There was a castoring tailwheel under the tailplane.

The fuselage was mostly constructed from square section duralumin

Duralumin

Duralumin is the trade name of one of the earliest types of age-hardenable aluminium alloys. The main alloying constituents are copper, manganese, and magnesium. A commonly used modern equivalent of this alloy type is AA2024, which contains 4.4% copper, 1.5% magnesium, 0.6% manganese and 93.5%...

 tube with some steel at critical points and alloys formers and stringer to shape it. It was mostly fabric covered, though there was some metal sheet in the forward part and a plywood decking around the rear cockpit. The tail unit was metal framed and fabric covered, with a narrow parallel chord braced tailplane and elevators. The fin and rudder were broad, the latter extending to the base of the fuselage. Initially both elevators and rudder were horn balanced. The second crew member's large cockpit was just behind the trailing edge, enclosed in a multi-piece, segmented glazed cover that could be folded away forward when gunnery using the Scarff ring

Scarff ring

The Scarff ring was a type of machine gun mounting developed during the First World War by Warrant Officer F. W. Scarff of the Admiralty Air Department for use on two-seater aircraft...

 mounted Lewis machine gun was necessary. From there he could access the bomb aimer's position, lit by two small underwing windows on each side, lying prone on the fuselage floor. Part of the reason for the tall, split axle undercarriage was to allow a torpedo of up to 1,100 lb (500 kg) to be held in crutches between the legs; alternatively two 500 lb (227 kg) bombs could be carried in under-fuselage racks.The pilot had control of a port side, forward firing Vickers machine gun

Vickers machine gun

Not to be confused with the Vickers light machine gunThe Vickers machine gun or Vickers gun is a name primarily used to refer to the water-cooled .303 inch machine gun produced by Vickers Limited, originally for the British Army...

.

The PV.7 was powered by a Bristol Pegasus IIIM3 engine within a Townend ring

Townend ring

A Townend Ring is a narrow-chord cowling ring fitted around the cylinders of an aircraft radial engine to reduce drag and improve cooling.-Development:...

, which produced 722 hp (538 kW) and drove a two bladed wooden propeller. It flew for the first time on 30 October 1933, with Harald Penrose, Westland's regular test pilot at the controls. Early flights showed the need to glaze the cockpit and lighten the ailerons, and later tests at higher speed revealed that the wing twisted under aileron loads. This latter problem required significant re-working of the wing structure, specifically the replacement of the inter-spar rods with torsionally stiffer tubes. Flight testing also showed that the rudder was aerodynamically over-balanced, causing oscillations cured by removal of the horn balance entirely.

The PV.7 featured in the New Types Park at the 1934 Hendon RAF Display at the end of June, then went to the 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 testing. Since this was to be done by Service pilots, Westland cancelled their insurance cover as any damage would be paid for by the government. The initial reaction of the RAF pilots was encouraging. On 25 August, at the request of the 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...

 Penrose flew the aircraft again, making tests of its behaviour with the centre of gravity far aft. After he had taken off, a telegram arrived at Martlesham saying that this test should not proceed as the airframe would be over-stressed, but Penrose was not in radio contact and went ahead. In a high speed dive the Westland calculations were confirmed by the collapse of the port wing. Penrose was lucky to escape by parachute, as the upper hatch had jammed and he had to squeeze out of a small side window, becoming the first British pilot to bale out of an aircraft with an enclosed cockpit. It was the end of Westland's G.4/31 hopes, though; the Air Ministry would not pay for the loss of an aircraft flown by a civilian, and the company could not afford to build a replacement.

In the end, none of the aircraft originally submitted to the specification was built in quantity, for although the Vickers 253 was declared winner and ordered, it was replaced by the slightly later and much superior Vickers Wellesley

Vickers Wellesley

The Vickers Wellesley was a British 1930s light bomber built by Vickers-Armstrongs at Brooklands near Weybridge, Surrey, for the Royal Air Force...

.

Specifications