The Avro Anson is a British twin-engine, multi-role aircraft built by the aircraft manufacturer Avro. Large numbers served in a variety of roles with the Royal Air Force (RAF), Fleet Air Arm (FAA), Royal Canadian Air Force (RCAF), Royal Australian Air Force (RAAF), and numerous other air forces before, during, and after the Second World War.
Originally designated the Avro 652A, the Anson was developed during the mid-1930s from the earlier Avro 652 airliner in response to an Air Ministry request for tender for a coastal maritime reconnaissance aircraft. After impressing the Air Ministry during evaluation, a single prototype was ordered and made its maiden flight on 24 March 1935. Following trials in which the Type 652A outperformed the competing de Havilland DH.89, it was selected for production. This led to Air Ministry Specification G.18/35 being written around the design, and an initial order for 174 aircraft was placed in July 1935. The Type 652A was subsequently named Anson after the British Admiral George Anson.
The Anson entered service with the RAF in its intended maritime reconnaissance role, operating alongside larger flying boats. After the outbreak of the Second World War, however, it quickly became obsolete as a front-line combat aircraft. It was instead widely employed as a multi-engine aircrew trainer, proving well suited to the role and becoming one of the main training aircraft of the British Commonwealth Air Training Plan. The type remained in this role throughout and after the war, serving with the RAF as a trainer and communications aircraft until 28 June 1968.
After the war, a small number of new-build aircraft, known as the Avro 19, were produced for the civilian market. Many more surplus military aircraft were converted for civil use as light transports and executive aircraft. By the end of production in 1952, Avro had built 8,138 Ansons in nine variants, while a further 2,882 aircraft were manufactured in Canada by Federal Aircraft Ltd from 1941. By the 21st century, almost all Ansons had been retired, although three aircraft continue to appear at flying displays.
Development
In 1933, the British Air Ministry proposed acquiring a relatively inexpensive landplane for coastal maritime reconnaissance duties to supplement the more capable, but significantly more expensive, flying boats then used by the Royal Air Force (RAF). The Ministry invited proposals from British aircraft manufacturers. Avro responded with the Avro 652A, a modified version of its earlier Avro 652, a twin-engined, six-seat monoplane airliner. de Havilland submitted a design based on its D.H.89A Dragon Rapide biplane. After considering the submissions, the Air Ministry ordered one prototype each of the Type 652A and the de Havilland DH.89 for evaluation in late 1934, with a production decision scheduled for May 1935.Sturtivant Air Enthusiast Forty-two, pp. 38–39.Jackson 1990, pp. 321–322.
On 24 March 1935, the Avro 652A made its maiden flight from Woodford Aerodrome, Greater Manchester. Between 11 and 17 May 1935, the prototype underwent formal evaluation against the competing DH.89M by the RAF's Coastal Defence Development Unit at RAF Gosport, Hampshire. During the trials, the Avro design proved superior and was selected as the winner on 25 May 1935.Jackson 1990, pp. 322–323. In response, Air Ministry Specification G.18/35 was written around the Type 652A. An initial order for 174 aircraft, by then named Anson, was placed in July 1935.Middleton Aeroplane Monthly April 1980, p. 187.
The first production Anson made its maiden flight on 31 December 1935. Compared with the prototype, production aircraft featured an enlarged horizontal tailplane and a reduced elevator span to improve stability. Although the prototype had not been fitted with flaps, production aircraft were designed to accommodate them from the outset, improving the approach angle and reducing landing speed. Deliveries to the RAF began on 6 March 1936.Middleton Aeroplane Monthly April 1980, pp. 187–188.
By the end of production in 1952, a total of 11,020 Ansons had been completed, making it the second most-produced British multi-engined aircraft of the Second World War after the Vickers Wellington, of which approximately 11,500 were built.
Design
The Avro Anson was a twin-engine, low-wing cantilever monoplane. Developed as a general reconnaissance aircraft, it possessed many features that lent itself to the role, including considerable load-carrying ability, and long range. The structure of the Anson was relatively straightforward and uncomplicated, relying on proven methods and robust construction to produce an airframe that minimised maintenance requirements. Much of the internal structure retained similarities to the earlier Avro 652 airliner from which it had been developed. The Anson Mk I was furnished with a low-mounted one-piece wooden wing, composed of a combination of plywood and spruce throughout the wingbox and ribs. The fuselage was composed of a welded steel tubing framework which was principally clad in fabric; the exterior of the nose was clad in magnesium alloy.
The Anson was powered by a pair of Armstrong Siddeley Cheetah IX seven-cylinder air-cooled radial engines, which were each rated at .Mondey 1994, p. 26. Each engine was provided with its own duplicated fuel pumps and separate fuel and oil tanks; the tanks were composed of welded aluminium and mounted in cradles housed within the wing. The engine cowlings were intentionally designed to have a reduced diameter in order to reduce their negative impact on external visibility, which was considered to be valuable to the type's reconnaissance function. These engines drove two-bladed Fairey-built metal propellers.Flight 30 January 1936, p. d.
The Anson was the first aircraft equipped with retractable landing gear to enter service with the RAF.Flight 30 January 1936, p. c.Jackson 1990, p. 323. While the main undercarriage was retracted into recesses set into the bottom of the engine nacelles, the tail wheel was fixed in position. Commonly, the undercarriage was fitted with Dunlop-built wheels, tyres and pneumatic brakes and Turner legs. The retractable undercarriage was mechanically operated by hand; 144 turns of a crank handle, situated beside the pilot's seat, were needed.Sturtivant Air Enthusiast Forty-two, p. 40.Flight 30 January 1936, pp. c–d. To avoid this laborious process, early aircraft would often perform short flights with the landing gear remaining extended throughout, which would reduce the aircraft's cruising speed by 30 mph (50 km/h).Gunston 1995,
Initially, the Anson was flown by a crew of three, which comprised a pilot, a navigator/bomb-aimer and a radio operator/gunner, when it was used in the maritime reconnaissance role;Flight 30 January 1936, p. 117. from 1938 onwards, it was typically operated by a four-man crew.Jackson 1990, p. 326. The bomb-aimer would perform his function from a prone position in the forward section of the nose, which was provisioned with a bombsight, driftsight, and other appropriate instrumentation, including a landing light. The pilot was located in a cockpit behind the bomb aimer's position and was provided with a variety of contemporary instrumentation, including those to enable flight under instrument flight rules (IFR) and indirect instrument lighting for night flying purposes.Flight 30 January 1936, pp. 117–119.
Immediately behind the pilot's position is a small folding seat fixed to the starboard side of the fuselage for an additional crew member or passenger, along with racks that would contain a pair of parachute packs that would be clipped onto the harnesses worn by both the pilot and the navigator. Behind these is the navigator's station, a chair and table provisioned with navigational aids such as compasses, Bigsworth chart boards, sea markers, slide rules for course, wind and speed, a signalling lamp and float flares. Aft of the rear spar is the wireless operator's station – a table with contemporary wireless equipment, including a winch for the trailing aerial, which was attached to the upper fuselage immediately behind the aircraft's cockpit.
The armaments of the Anson consisted of a single .303 in (7.7 mm) Vickers machine gun which was fixed within the forward fuselage and aimed by the pilot, while an Armstrong Whitworth-built manually operated gun turret located on the Anson's dorsal section was fitted with a single Lewis gun. Additionally, up to of bombs, which could consist of a maximum of two and eight bombs, could be carried in the aircraft's wings.Sturtivant Air Enthusiast Forty-two, p. 39. Those Ansons that were used in the training role were outfitted with dual controls and usually had the gun turret removed, although specific aircraft used for gunnery training were fitted with a Bristol hydraulically operated gun turret, similar to that used in the Bristol Blenheim.Sturtivant Air Enthusiast Forty-two, pp. 43–44.Middleton Aeroplane Monthly April 1980, p. 191. The tail fairing of the starboard nacelle contains an inflatable dinghy which is provided with automatic actuators and marine distress beacons.
Operational history
On 6 March 1936, the Anson entered RAF service with No. 48 Squadron, the first RAF unit to be equipped with the type. Its introduction marked a significant advance in capability, serving not only as a general reconnaissance aircraft but also as an effective general-purpose aircraft. In July 1937, a Coastal Command Anson was fitted with an experimental airborne early warning radar capable of detecting large warships away in poor visibility. The system was successfully used during fleet exercises off the east coast of England in September.
By the outbreak of the Second World War, the RAF had received 824 Ansons. Twenty-six RAF squadrons operated the Anson I: 10 with Coastal Command and 16 with Bomber Command.March 1985, pp. 262–263. By 1939, all Bomber Command squadrons equipped with the Anson I had become operational training units responsible for preparing crews for frontline service. Twelve of these squadrons formed part of No. 6 (Operational Training) Group. Newly formed crews, having completed their individual flying and technical training, received bomber crew instruction in Ansons before converting to frontline aircraft within the same squadrons. They then progressed to operational bomber squadrons equipped with aircraft such as the Fairey Battle, Bristol Blenheim, Vickers Wellington, Armstrong Whitworth Whitley, and Handley Page Hampden.