Armstrong Whitworth Atlas
The Armstrong Whitworth Atlas was a British single-engine biplane designed and built by Armstrong Whitworth Aircraft. It served as an army co-operation aircraft for the Royal Air Force (RAF) in the 1920s and 1930s. It was the first purpose-designed aircraft of the type to serve with the RAF.
|Role||Army cooperation aircraft|
|First flight||10 May 1925|
|Primary users||Royal Air Force|
Royal Canadian Air Force
|Produced||1927 - 1933|
The Armstrong Whitworth Atlas was designed by a team led by John Lloyd, chief designer of Armstrong Whitworth Aircraft, as a replacement for the DH.9A and Bristol Fighter as an army co-operation aircraft for the RAF, in parallel with the related aircraft, the Ajax and Aries. The Atlas was intended to meet the requirements of Specification 20/25.
The prototype Atlas (G-EBLK) was built as a private venture, first flying on 10 May 1925. It was delivered to the Aeroplane and Armament Experimental Establishment (A & AEE), Martlesham Heath, where it was evaluated against the Bristol Boarhound, de Havilland Hyena, Vickers Vespa, and Short Chamois. It proved superior in performance and handling and was recommended for production.
While the performance was generally good, the prototype could not be sideslipped steeply, and this resulted in a redesign where sweptback metal wings, with differing wing section, were fitted. When tested again, the Atlas was found to have lost its good handling, having dangerous stall characteristics. The Atlas had already been ordered for service, however, and suffered a number of accidents during takeoff and landing in the first few months of operation until modified with automatic slats and increased sweepback. This cured the poor handling.
The production Atlas had a steel tube fuselage with fabric covering with single-bay swept metal wings. It could be fitted with a hook under the fuselage to pick up messages and could carry a 460 lb (210 kg) bombload under the wings.
The first batch of 37 aircraft were ordered in 1927, entering service with 13 Squadron RAF and 26 Squadron in that year. Once the initial handling problems had been solved by the fitting of slats, the Atlas proved well suited to the army co-operation role, serving both at home and overseas, with 208 squadron, being the first squadron to operate Atlases outside Britain, replacing Bristol fighters at Heliopolis, Egypt in 1930.
The Atlas continued in service in the army co-operations role until replaced with the Hawker Audax, a variant of the Hawker Hart, with the last operational squadron, 208, re-equipping in 1935. It was also replaced in the advanced trainer role in 1935 by the Hawker Hart Trainer.
- Atlas I Army co-operation aircraft - 271 built for the RAF.
- Atlas Trainer Dual-control trainer version of Atlas I - 175 built.
- Atlas II Cleaned up, more powerful version, powered by 525 hp (391 kW) Armstrong Siddeley Panther. Rejected in favour of Audax by RAF. 15 built for Kwangsi Air Force, China.
- Ajax minor differences from Atlas I - 4 built for RAF.
- Aries improved Atlas I with easier access for maintenance and increased dimensions - one built
- EAF Atlas Greek lower-cost version (main differences in wing structure, engine and propeller) - 10 built by EAF (KEA) after 1931.
- Kwangsi Air Force
- Air Service Training Ltd.
Specifications (Atlas I)
- Crew: 2
- Length: 28 ft 6 1⁄2 in (8.700 m)
- Wingspan: 39 ft 6 1⁄2 in (12.052 m)
- Height: 10 ft 6 in (3.20 m)
- Wing area: 391 sq ft (36.3 m2)
- Airfoil: RAF 28
- Empty weight: 2,550 lb (1,157 kg)
- Max takeoff weight: 4,020 lb (1,823 kg)
- Powerplant: 1 × Armstrong Siddeley Jaguar IVC 14-cylinder two-row air-cooled radial engine, 450 hp (340 kW)
- Maximum speed: 142 mph (229 km/h, 123 kn) at sea level, 134 mph (216 km/h; 116 kn) at 10,000 ft (3,000 m)
- Range: 400 mi (640 km, 350 nmi)
- Endurance: 3 hr 25 min
- Service ceiling: 16,800 ft (5,100 m)
- Time to altitude: 5 min 30 to 5,000 ft (1,500 m)
- Mason 1994, p. 170.
- Mason 1994, pp. 170–171.
- Thetford 1957, p. 24.
- Mason 1994, p. 171.
- Jackson 1974, p. 321.
- Jackson 1974, p. 322.
- "Armstrong - Whitworth "Atlas"". Hellenic Air Force. Retrieved 6 March 2016.
- Kostenuk and Griffin 1977, p. 23
- Thetford 1957, p. 25.
- Jackson, A.J. (1974). British Civil Aircraft since 1919 Volume 1. London: Putnam. ISBN 0-370-10006-9.
- Kostenuk, Samuel; Griffin, John (1977). RCAF: Squadron Histories and Aircraft, 1924–1968. Canadian War Museum Historical Publication No. 14. Sarasota/Toronto: Samuel Stevens/Hakkert & Company. ISBN 0-88866-577-6.
- Mason, Francis K (1994). The British Bomber since 1914. Putnam Aeronautical Books. ISBN 0-85177-861-5.
- Thetford, Owen (1957). Aircraft of the Royal Air Force 1918-57 (1st ed.). London: Putnam.
- The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985). Orbis Publishing.
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