Supermarine Spitfire

Supermarine Spitfire — The Supermarine Spitfire is a British single-seat fighter aircraft that was used by the Royal Air Force and many other Allied countries throughout the Second World War. The Spitfire continued to be used as a front line fighter and in secondary roles into the 1950s. It was produced in greater numbers than any other British aircraft and was the only British fighter in production throughout the war.

The Spitfire was designed as a short-range, high-performance interceptor aircraft by R. J. Mitchell, chief designer at Supermarine Aviation Works (since 1928 a subsidiary of Vickers-Armstrong). Mitchell continued to refine the design until his death from cancer in 1937, whereupon his colleague Joseph Smith became chief designer. The Spitfire’s elliptical wing had a thin cross-section, allowing a higher top speed than several contemporary fighters, including the Hawker Hurricane. Speed was seen as essential to carry out the mission of home defence against enemy bombers.

During the Battle of Britain, the Spitfire was perceived by the public as the RAF fighter of the battle, whereas in fact, the more numerous Hurricane actually shouldered a greater proportion of the burden against the Luftwaffe. The Spitfire units did, however, have a lower attrition rate and a higher victory to loss ratio than those flying Hurricanes.

After the Battle of Britain, the Spitfire became the backbone of RAF Fighter Command, and saw action in the European, Mediterranean, Pacific and the South-East Asian theatres. Much loved by its pilots, the Spitfire served in several roles, including interceptor, photo-reconnaissance, fighter-bomber, carrier-based fighter, and trainer. It was built in many variants, using several wing configurations. Although the original airframe was designed to be powered by a Rolls-Royce Merlin engine producing 1,030 hp (768 kW), it was adaptable enough to use increasingly more powerful Merlin and the later Rolls-Royce Griffon engines; the latter was eventually able to produce 2,035 hp (1,520 kW).

Design & Development

R. J. Mitchell’s 1931 design to meet Air Ministry specification F7/30 for a new and modern fighter capable of 251 mph (404 km/h), the Supermarine Type 224, resulted in an open-cockpit monoplane with bulky gull-wings and a large fixed, spatted undercarriage powered by the 600 horsepower (450 kW) evaporative-cooled Rolls-Royce Goshawk engine. This made its first flight in February 1934. The Type 224 was a big disappointment to Mitchell and his design team, who immediately embarked on a series of “cleaned-up” designs, using their experience with the Schneider Trophy seaplanes as a starting point. Of the seven designs tendered to F/30, the Gloster Gladiator biplane was accepted for service.

Mitchell had already begun working on a new aircraft, designated Type 300, based on the Type 224, but with a retractable undercarriage and the wingspan reduced by 6 ft (1.8 m). The Type 300 was submitted to the Air Ministry in July 1934, but again was not accepted. The design then evolved through a number of changes, including incorporating a faired, enclosed cockpit, oxygen-breathing apparatus, smaller and thinner wings, and the newly-developed, more powerful Rolls-Royce PV-XII V-12 engine, later named the “Merlin”. In November 1934, Mitchell, with the backing of Supermarine’s owner, Vickers-Armstrong, started detailed design work on this refined version of the Type 300 and, on 1 December 1934, the Air Ministry issued a contract AM 361140/34, providing £10,000 for the construction of Mitchell’s improved F7/30 design. On 3 January 1935, the Air Ministry formalised the contract and a new Specification F10/35 was written around the aircraft.

In April 1935, the armament was changed from two. 303 in (7.7 mm) Vickers machine guns in each wing to four. 303 in (7.7 mm) Brownings, following a recommendation by Squadron Leader Ralph Sorley of the Operational Requirements section at the Air Ministry.

On 5 March 1936, the prototype (K5054) took off on its first flight from Eastleigh Aerodrome (later Southampton Airport). At the controls was Captain Joseph “Mutt” Summers, chief test pilot for Vickers (Aviation) Ltd., who was reported in the press as saying “Don’t touch anything” on landing. This eight minute flight came four months after the maiden flight of the contemporary Hurricane.

K5054 was fitted with a new propeller, and Summers flew the aircraft on 10 March 1936; during this flight the undercarriage was retracted for the first time. After the fourth flight, a new engine was fitted, and Summers left the test-flying to his assistants, Jeffrey Quill and George Pickering. They soon discovered that the Spitfire was a very good aircraft, but not perfect. The rudder was over-sensitive and the top speed was just 330 mph (528 km/h), little faster than Sydney Camm’s new Merlin-powered Hurricane. A new and better-shaped wooden propeller meant the Spitfire reached 348 mph (557 km/h) in level flight in mid-May, when Summers flew K5054 to RAF Martlesham Heath and handed the aircraft over to Squadron Leader Anderson of the Aeroplane & Armament Experimental Establishment (A&AEE). Here, Flight Lieutenant Humphrey Edwardes-Jones took over the prototype for the RAF. He had been given orders to fly the aircraft and then to make his report to the Air Ministry as soon as he landed. Edwardes-Jones made a positive report; his only request was that the Spitfire be equipped with an undercarriage position indicator. A week later, on 3 June 1936, the Air Ministry placed an order for 310 Spitfires, before any formal report had been issued by the A&AEE; interim reports were later issued on a piecemeal basis.

The British public first saw the Spitfire at the RAF Hendon air-display on Saturday 27 June 1936. Although full-scale production was supposed to begin immediately, there were numerous problems which could not be overcome for some time and the first production Spitfire, K9787, did not roll off the Woolston, Southampton assembly line until mid-1938. The first and most immediate problem was that the main Supermarine factory at Woolston was already working at full capacity fulfilling orders for Walrus and Stranraer flying boats. Although outside contractors were supposed to be involved in manufacturing many important Spitfire components, especially the wings, Vickers-Armstrong (the parent company) were reluctant to see the Spitfire being manufactured by outside concerns and were slow to release the necessary blueprints and subcomponents. As a result of the delays in getting the Spitfire into full production, the Air Ministry put forward a plan that production of the Spitfire be stopped after the initial order for 310, after which Supermarine would build Bristol Beaufighters. The managements of Supermarine and Vickers were able to persuade the Air Ministry that the problems could be overcome and further orders were placed for 200 Spitfires on 24 March 1938, the two orders covering the K, L and N prefix serial numbers.