Airspeed AS.39 Fleet Shadower

The Royal Navy envisaged a need for an aircraft that could shadow enemy fleets at night and the resulting Specification S.23/37 called for a slow-flying low-noise aircraft with a long range, capable of operating from an aircraft carrier’s flight deck.

The specified performance was to be a speed of 38 knots at 1,500 ft (460 m) for not less than six hours.

Five companies showed interest: Percival, Short Brothers, Fairey Aviation, General Aircraft Ltd and Airspeed.

General Aircraft submitted the G.A.L.38, of very similar general design to the AS.39.

General Aircraft and Airspeed were selected to build two prototypes each and Airspeed received a contract on 10 August 1938.

The AS.39 was a high-wing, semi-cantilever, strut-braced (on the outer panels) monoplane with wooden wings and tail unit and an all-metal monocoque fuselage.

It had a fixed, divided type landing gear and tail wheel.

The observation aircraft had a crew of three: pilot, observer and radio operator.

The AS.39 had a unique crew configuration with the observer accommodated in the nose with clear-vision windows on three sides and the pilot’s compartment raised to allow passage to the radio operator’s compartment.

Four small 130 hp Pobjoy Niagara V seven-cylinder air-cooled radial engines were mounted on the wings.

This maximized propwash over the wing giving extra lift at low speed.

The wings could be folded for storage when used on an aircraft carrier.

Specifications

Crew

Length

39 ft 10 in (12.14 m)

Wingspan

55 ft 4 in (16.87 m)

Height

10 ft 5 in (3.18 m)

Wing area

469 sq ft (43.6 m2)

Empty weight

4,592 lb (2,083 kg)

Gross weight

6,935 lb (3,146 kg)

Powerplant

4 × Pobjoy Niagara V 7-cylinder air-cooled radial piston engines, 140 hp (100 kW) each

Performance

Maximum speed

126 mph (203 km/h, 109 kn) at 5,000 ft (1,524 m)

Cruise speed

113 mph (182 km/h, 98 kn) at 5,000 ft (1,524 m)

Stall speed

33 mph (53 km/h, 29 kn)

Endurance

6 hours

Service ceiling

14,700 ft (4,500 m)

Absolute ceiling

16,700 ft (5,090 m)

Rate of climb

865 ft/min (4.39 m/s)

Time to altitude

10,000 ft (3,048 m) in 18 minutes.

 

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