Westland PV.7
PV.7 | |
---|---|
Role | Military general-purpose aircraft |
National origin | United Kingdom |
Manufacturer | Westland Aircraft Co. Ltd |
Designer | Arthur Davenport |
First flight | 30 October 1933 |
Number built | 1 |
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 of promise, but was destroyed early in official tests.
Design and development
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
The fuselage was mostly constructed from square-section
The PV.7 was powered by a Bristol Pegasus IIIM3 engine within a Townend ring, 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.[5]
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 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,[6] at the request of the Air Ministry 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.[7] 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.[5]
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.[8]
Specifications
Data from James 1991, pp. 215–6
General characteristics
- Crew: 2
- Length: 38 ft 8 in (11.79 m)
- Wingspan: 60 ft 3 in (18.36 m)
- Height: 12 ft 0 in (3.66 m)
- Wing area: 537 sq ft (49.9 m2) including lift struts
- Airfoil: RAF34
- Empty weight: 4,515 lb (2,048 kg)
- Gross weight: 7,172 lb (3,253 kg)
- Powerplant: 1 × Bristol Pegasus IIIM3 9-cylinder radial, geared, unsupercharged
- Propellers: 2-bladed, 12 ft 4 in (3.76 m) diameter
Performance
- Maximum speed: 173 mph (278 km/h, 150 kn) at 5,000 ft (1,525 m)
- Service ceiling: 22,700 ft (6,900 m) absolute
- Rate of climb: 1,250 ft/min (6.4 m/s) to 10,000 ft (3,050 m)
Armament
- Guns: 1×0.303 in (7.7 mm) fixed forward firing Vickers machine gun plus 1×0.303 in (7.7 mm) Lewis gun on Scarff ring in rear cockpit
- Bombs: 1×1,100 lb (500 kg) torpedo or 2×500 lb (228 kg) bombs
References
Citations
- ^ Taylor 1974, pp. 227
- ^ James 1991, pp. 209
- ^ Wixey 1990, p. 195
- ^ Andrews & Morgan 1988, pp. 295
- ^ a b c d James 1991, pp. 209–16
- ^ James 1991, pp. 214
- ^ Obituary Independent 11 September 1996
- ^ Andrews & Morgan 1988, pp. 298–9
Cited sources
- Taylor, H.O. (1974). Fairey Aircraft since 1915. London: Putnam Publishing. ISBN 0-370-00065-X.
- Wixey, Kenneth (1990). Parnall Aircraft since 1914. Annopolis: Naval Institute Press. ISBN 1-55750-930-1.
- Andrews, CF; Morgan, E.B. (1988). Vickers Aircraft since 1908 (2nd ed.). London: Putnam. ISBN 0-85177-815-1.
- James, Derek N (1991). Westland Aircraft since 1915 (2nd ed.). London: Putnam. ISBN 0-85177-847-X.