Airspeed Fleet Shadower
|A.S.39 Fleet Shadower|
|Role||Special observation monoplane|
|First flight||17 October 1940|
The Airspeed A.S.39 Fleet Shadower was a British long-range patrol aircraft design that did not go beyond the prototype stage. While the concept of a fleet shadower had some promise, the resulting prototypes were soon overtaken by wartime developments in airborne radar.
Design and development
The Royal Navy envisaged a need (Operational Requirement OR.52) 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 1500 ft for not less than six hours.
General Aircraft submitted the G.A.L.38, of very similar general design to the A.S.39. General Aircraft and Airspeed were selected to build two prototypes each and Airspeed received awarded a contract on 10 August 1938.
The A.S.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 tailwheel. The observation aircraft had a crew of three: pilot, observer and radio operator. The A.S.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 130hp Pobjoy Niagara V seven-cylinder radial air-cooled engines were mounted on the wings. Each wing and an engine could be folded for storage when used on an aircraft carrier.
Of two prototypes started, only one was completed, flying on 17 October 1940, the first flight was delayed due to problems with the Niagara V engines which had a vibration problem. The prototype had stability problems and poor stall handling not helped by the under-powered engines. Airspeed were asked to respond to a proposal to re-engine the aircraft with two Armstrong Whitworth Cheetah XI radial engines and add rear-facing machine guns. Only a preliminary proposal had been made and the second aircraft was not complete when on 17 February 1941 the Navy cancelled the fleet shadower program along with the AS.39, the company were requested to scrap both aircraft. The competing G.A.L.38 flew for a few months before it was cancelled and scrapped in March 1942. The requirement for such aircraft had been made obsolete due to the introduction of radar on long-range patrol aircraft such as the Liberator I.
Data from Nothing ventured...Airspeed AS.39 Night Shadower
- Crew: 3 (Pilot, observer, radio operator)
- 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 ft² (43.6 m²)
- Empty weight: 4,592 lb (2087 kg)
- Loaded weight: 6,935 lb (3,152 kg)
- Powerplant: 4 × Pobjoy Niagara V seven-cylinder air-cooled radial engines, 140 hp (104 kW) each
- Maximum speed: 126 mph (110 knots, 203 km/h) at 5,000 ft (1,500 m)
- Cruise speed: 113 mph (98 knots , 182 km/h) at 5,000 ft (1,500 m)
- Stall speed: 33 mph (29 knots, 53 km/h) at sea level
- Endurance: 6 hours
- Service ceiling: 14,700 ft  (4,480 m)
- Rate of climb: 865 ft/min (4.40 m/s)
- Climb to 10,000 ft (3,050 m): 18 min
- Aircraft of comparable role, configuration and era
- "Airspeed Types." Flight, 1951
- Bridgman, Leonard, ed. Jane’s All The World’s Aircraft 1945-1946. London: Samson Low, Marston & Company, Ltd, 1946.
- Butler, Phil. "The Night Shawdowers." Air-Britain Aeromilitaria Vol. 32, Issue 125, Spring 2006, pp. 19–22. ISSB 0262-8791.
- "Fleet Shadower." Fleet Air Arm archive. Retrieved: 2 February 2007.
- Jarrett, Phil. "Nothing ventured...", Part 24. Aeroplane Monthly, April 1992, Vol 20 No 4. London: IPC. ISSN 0143-7240. pp. 16–19.
- Jarrett, Phil. "Nothing ventured... General Aircraft GAL 38 Night Shadower". Aeroplane Monthly, May 1992, Vol 20 No 5. London: IPC. ISSN 0143-7240. pp. 18–23.
- Jarrett, Phil. "Nothing ventured... Airspeed AS.39 Night Shadower". Aeroplane Monthly, June 1992, Vol 20 No 6. London: IPC. ISSN 0143-7240. pp. 52–57.
- Winchester, Jim, ed. "General Aircraft Fleet Shadower (1940)". The World's Worst Aircraft: From Pioneering Failures to Multimillion Dollar Disasters. London: Amber Books Ltd., 2005. ISBN 1-904687-34-2.