Vickers Wellesley

The design originated from the Air Ministry Specification G.4/31 which called for a General Purpose aircraft, capable of carrying out level bombing, army co-operation, dive bombing, reconnaissance, casualty evacuation and torpedo bombing. The Vickers Type 253 (using a radical geodetic construction that was derived from that used by Barnes Wallis in the airship R100 in the fuselage structure), the Fairey G.4/31, Westland PV-7, Handley Page HP.47, Armstrong Whitworth A.W.19, Blackburn B-7, Hawker P.V.4 and the Parnall G.4/31 offerings were tested against the specification. The Type 253, was declared the winner, with 150 being ordered.
The Vickers Type 246 monoplane, which used the same geodetic design principles for both the fuselage and wings, was then built as a private venture, first flying on the 19 June 1935 and offered to the RAF. This had superior performance, but did not attempt to meet the multi-role requirements of the specification, being designed as a bomber only. An initial order for 96 Type 246s was substituted for the Type 253 order. The RAF ultimately ordered a total of 176 as the Wellesley, to a newly written specification 22/35.
The Wellesley was a single-engined monoplane with a very high aspect ratio wing, and a manually operated, retractable undercarriage. As it was not known how the geodetic structure could cope with being disrupted by a bomb bay, the Wellesley's bomb load was carried in two panniers under the wings. The Wellesley Mk I had two separate cockpits. This was changed in the Wellesley Mk II to a single-piece cockpit canopy covering both the pilot and navigator positions.

General characteristics
Crew: Two
Length: 39 ft 3 in (11.96 m)
Wingspan: 74 ft 7 in (22.73 m)
Height: 12 ft 4 in (3.75 m)
Wing area: 630 ft² (58.5 m²)
Empty weight: 6,369 lb (2,889 kg)
Loaded weight: 11,000 lb (5,035 kg)
Max takeoff weight: 12,500 lb (5,670 kg)
Powerplant: 1× Bristol Pegasus XX radial, 925 hp (690 kW)
Performance
Maximum speed: 228 mph (369 km/h)
Range: 1,110 miles (1,786 km)
Service ceiling: 33,000 ft (10,060 m)
Rate of climb: 1,200 ft/min (366 m/min)
Wing loading: 18 lb/ft² (86 kg/m²)
Power/mass: 0.08 hp/lb (0.14 kW/kg)
Armament
1 x .303 (7.7 mm) Vickers machine gun in right wing
1 x .303 (7.7 mm) Vickers K machine gun in rear cockpit
2,000 lb (908 kg) of bombs