Avro 549 Aldershot

The Avro 549 Aldershot was a British single-engined heavy bomber aircraft built by Avro.

Development and design

The Aldershot was designed to meet the 1920 British Specification 2/20 for a heavy long-range day and night bomber to be powered by a Rolls-Royce Condor engine.Jarrett 1993, p.9. The specification required a range of 500 miles (800 km) and a bombload of 2,000 lb (900 kg), originally comprising a single World War I vintage 1,800 lb (820 kg) SN bomb, but then changed to four 500 lb (230 kg) bombs carried externally or eight 250 lb (114 kg) bombs internally.Mason 1994, p.136.Sharpe, Michael. ''Biplanes, Triplanes, and Seaplanes''. London, England: Friedman/Fairfax Books , 2000. . The Air Ministry gave Avro a contract for two prototypes, designated Aldershot I, on 2 December 1920, in competition with the de Havilland Derby.

The first prototype flew at Hamble Aerodrome near Southampton in October 1921.Mason 1994, p.137. As a result of test flying, the fuselage was lengthened by 6 ft (2 m) in order to improve directional control, being displayed in this form at the RAF Display at Hendon on 24 June, the second prototype flying in July with the lengthened fuselage and a modified undercarriage.Jarrett 1993, p.11.

The first prototype was modified as a testbed for the water-cooled Napier Cub engine, in this form becoming the Aldershot II, flying on 15 December 1922.Jackson 1990, p.195. It was later used to test the slow-revving 850 hp (630 kW) Beardmore Typhoon I inline engine, flying in this form on 10 January 1927.Jackson 1990, p.197.

The Aldershot was a three-bay biplane, with a steel-framed fuselage structure with plywood and fabric covering, and wooden wings. The pilot and navigator were seated side by side in a cockpit behind the upper wing trailing edge, with additional accommodation for the navigator who was also the bomb-aimer, in a cabin inside the fuselage, which was provided with four circular windows on each side. A gunner sat in a separate cockpit behind the pilot, and was armed with a Lewis gun on a Scarff ring. Another Lewis gun could be fitted to a ventral mounting in the cabin, while there was provision for a fixed, forward-firing Vickers machine gun operated by the pilot, although this was rarely fitted. A bomb bay forward of the cabin could hold eight 250 lb (114 kg) bombs, with larger bombs being carried externally under the fuselage.Jarrett 1993, pp.9–10.

The Aldershot also formed the basis for the Avro Andover transport, which used the same wings, tail and powerplant but had a new fuselage.

Operational history

When it was evaluated against the de Havilland Derby, the Aldershot proved to be the superior aircraft,Thetford 1993, p.7. with the mixed-construction Aldershot being about 800 lb (360 kg) lighter than the all-wooden Derby, which had no provision for carrying its bombload internally, or for any ventral armament.Mason 1994, pp.138–139.

On 26 January 1923, the Air Ministry ordered 15 aircraft under the designation Aldershot III.Thetford 1993, p.8. The only operator of the aircraft was No. 99 Squadron RAF which reformed on 1 April 1924,Lewis 1959, p.49. receiving its Aldershots from July that year.Thetford 1993, p.10. The Aldershot was mainly used for night flying, but occasionally flew day bombing exercises. Unlike the other members of the RAF's heavy bomber force, it was operated in an all-silver colour scheme, rather than the dark-green NIVO scheme usually used for night operations.Thetford 1993, p.8–9. By 1925, the Air Ministry had decided that heavy bombers should have multiple engines, and 99 Squadron started to receive the twin-engined Handley Page Hyderabad in January 1926, with the Aldershots being completely replaced in Squadron service by March that year.

Variants

;Avro 549 Aldershot I
:Prototype. Two built.
;Avro 549A Aldershot II
:First prototype modified with 1,000 hp (746 kW) Napier Cub engine.
;Avro 549B Aldershot III
:Production version. 15 built. One modified with metal wings as Avro 549M.Mason 1994, p.138.
;Avro 549C Aldershot IV
:First prototype modified with Beardmore Typhoon engine.

Operators

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* Royal Air Force
** No. 99 Squadron RAF

Specifications (Aldershot III)

See also

Notes

References

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External links

Avro Aldershot
– British Aircraft Directory

{{Avro aircraft

1920s British bomber aircraft
549
Single-engined tractor aircraft
Biplanes
Aircraft first flown in 1921