Supermarine Spitfire

The Supermarine Spitfire is a British single-seat fighter aircraft that was used by the Royal Air Force and other Allied countries before, during, and after World War II. It was the only British fighter produced continuously throughout the war. The Spitfire was a short-range, high-performance interceptor aircraft designed by R. J. Mitchell, chief designer at Supermarine Aviation Works, which operated as a subsidiary of Vickers-Armstrong from 1928. Mitchell modified the Spitfire's distinctive elliptical wing (designed by Beverley Shenstone) with innovative sunken rivets to have the thinnest possible cross-section, achieving a potential top speed greater than that of several contemporary fighter aircraft, including the Hawker Hurricane. Mitchell continued to refine the design until his death from cancer in 1937, whereupon his colleague Joseph Smith took over as chief designer.

Smith oversaw the Spitfire's development through many variants, from the Mk 1 to the Rolls-Royce Griffon-engined Mk 24, using several wing configurations and guns. The original airframe was designed to be powered by a Rolls-Royce Merlin engine producing 1,030 hp (768 kW). It was strong enough and adaptable enough to use increasingly powerful Merlins, and in later marks, Rolls-Royce Griffon engines producing up to 2,340 hp (1,745 kW). As a result, the Spitfire's performance and capabilities improved over the course of its service life.

During the Battle of Britain (July–October 1940), the more numerous Hurricane flew more sorties resisting the Luftwaffe, but the Spitfire captured the public's imagination, in part because the Spitfire was generally a better fighter aircraft than the Hurricane. Spitfire units had a lower attrition rate and a higher victory-to-loss ratio than Hurricanes, most likely due to the Spitfire's higher performance. During the battle, Spitfires generally engaged Luftwaffe fighters—mainly Messerschmitt Bf 109E-series aircraft—which were a close match for them.

After the Battle of Britain, the Spitfire superseded the Hurricane as the principal aircraft of RAF Fighter Command, and it was used in the European, Mediterranean, Pacific, and South-East Asian theatres.

Much loved by its pilots, the Spitfire operated in several roles, including interceptor, photo-reconnaissance, fighter-bomber, and trainer, and it continued to do so until the 1950s. The Seafire was an aircraft carrier-based adaptation of the Spitfire, used in the Fleet Air Arm from 1942 until the mid-1950s. The Spitfire remains popular among enthusiasts. Approximately 60 remain airworthy as of 2025, and many more are static exhibits in aviation museums throughout the world. Five airworthy aircraft are also part of the Battle of Britain Memorial Flight, which is a squadron in the RAF. The BBMF is used at air shows.

In 1931, the Air Ministry released specification F7/30, calling for a modern fighter capable of a flying speed of 250 mph (400 km/h) to replace the Gloster Gauntlet biplane. R. J. Mitchell designed the Supermarine Type 224 to fill this role in competition with the Blackburn F.3 and Westland F.7/30 and privately funded designs from Gloster. The 224 was an open-cockpit monoplane with bulky gull wings and a large, fixed, spatted undercarriage powered by the 600-horsepower (450 kW), evaporatively cooled Rolls-Royce Goshawk engine. It made its first flight in February 1934. Of the seven designs tendered to F7/30, the Gloster Gladiator biplane was accepted for service.

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. This led to the Type 300, with retractable undercarriage and a wingspan reduced by 6 ft (1.8 m). This design was submitted to the Air Ministry in July 1934, but was not accepted. It then went through a series of changes, including the incorporation of an enclosed cockpit, oxygen-breathing apparatus, smaller and thinner wings, and the newly developed, more powerful Rolls-Royce PV XII V-12 engine, which was 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.

On 1 December 1934, the Air Ministry issued contract AM 361140/34, providing £10,000 for the construction of Mitchell's improved Type 300 design. In April 1935 Ralph Sorley spoke to Mitchell about the new specification F10/35 which called for armament of at least six and preferably eight guns while at the same time removing bomb carry requirement and reducing fuel capacity. Mitchell foresaw no problem adding the guns and welcomed the reduction which would reduce weight. A specification for an eight-gun fighter, F5/34 had come from a recommendation by Squadron Leader Ralph Sorley of the Operational Requirements section at the Air Ministry. In the redesign the change was made from Vickers machine guns to .303 in (7.7 mm) Brownings), and the fuel tankage dropped to 75 gallons from 94.