In 1930 the Air Ministry issued Specification F.7/30 in which they asked for a day and night fighter to replace existing outdated fighters then in service with the RAF. The essential requirements were a low landing speed and short landing run, a maximum speed of 250mph, a steep initial climb rate for interception, high manoeuvrability and good all-round view.
Sir Robert McLean, chairman of Vickers Aviation Ltd. and The Supermarine Aviation Works (Vickers) Ltd., decided to give RJ Mitchell the opportunity to start creating the fighter he had had in his mind for some time.
The Supermarine Type 224 emerged in February 1934 ready for its first flight. Drawing on his experience with the Schneider Trophy winning S.6B seaplane Mitchell's design was for a narrow, streamlined fuselage monoplane with open cockpit and to be powered by a 600hp Roll-Royce Goshawk II engine. The aircraft was unofficially christened Spitfire by Sir Robert McLean. Mitchell was never really happy with the Type 224 and before it was ready for testing he was back at the drawing board working on something that he felt would be better.
Official testing of all the F.7/30 entries took place at Martlesham Heath in early 1934. Neither the Supermarine Type 224, or any of the other submissions were accepted and the contract was awarded for a Gloster Gladiator biplane under a different specification.
Birth of the legend
Sir Robert McLean felt that his design team would be better served using their qualities to develop a "real killer fighter" rather than devoting their time to the official experimental fighter (F.7/30). After unfruitful discussions with the Air Ministry, McLean and his opposite number in Rolls-Royce, AF Sidgreaves, decided that their two companies should finance the building of such an aircraft. Although the development of the Supermarine Type 300 started as a private venture, it soon become an official Air Ministry project. This strong action by Sir Robert led the Ministry to issue a contract, on 1st December 1934, of £10,000 for the new fighter and the covering Specification F.37/34 was received by Supermarine by the end of the month. The specification basically agreed with and approved the Supermarine Type 300 proposals.
Design and development
Throughout 1935 Mitchell and his team worked on the Type 300 fighter. Mitchell made many revolutionary changes to the F.7/30 design. After detailed discussions with his aerodynamist, Beverley Shenstone, the wing shape was changed to the famous elliptical configuration. It was also designed to be thin toward the tip but thick enough at the root to accommodate the retracted undercarriage and machine guns. The wing had an induced twist built into it which proved to be invaluable in giving excellent warning of a potential stall and was much appreciated by the pilots.
This new aircraft was to be powered by a new Rolls-Royce engine, the PV.12 (PV standing for private venture). Through development in cooling the PV.12 eventually emerged as the famous Merlin engine. It was destined to play a prominent role in the Second World War powering Spitfires, Hurricanes, Lancasters and many other aircraft, and its deep-throated roar became a familiar sound.
By the beginning of 1936 the prototype Type 300, bearing the serial number K5054, was ready for its first test flight. Once again Sir Robert insisted it should be called the Spitfire, a name that did not meet with general approval at Supermarine. Mitchell is said to have said that it was, "Bloody silly to call it by the same name as a previous failure".
First flight and RAF tests
In February 1936, K5054 had its first engine runs at the Woolston factory before the prototype was dismantled and transported to Eastleigh airfield, where its was reassembled. Then on the afternoon of 5th March 1936 it flew for the first time piloted by Vickers chief test pilot, Capt. J. 'Mutt' Summers. Upon landing 'Mutt' is famously quoted as saying "I don't want anything touched". No major snags were identified and, although many months of testing and alterations lay ahead, the Spitfire had made a successful first flight.
In order to achieve RAF acceptance the prototype Spitfire had to undergo tests at the Aeroplane and Armament Experimental Establishment at Martlesham Heath. On the 26th May, K5054 was delivered to Martlesham and, amazingly, on 3rd June 1936 Supermarine received their first order from the Air Ministry for 310 Spitfires to the value of £1.25million.
The prototype Spitfire achieved a maximum speed of 349mph (increased to 364mph in the first production Mk Is), had excellent manoeuvrability, rate of climb and turning circle. Pilots were to describe the ease of its control in the air as almost flying itself.
On 4th September 1939, the day after war broke out, the original prototype crash landed due to a misjudgment on the part of the pilot, Flt Lt 'Spinner' White. Sadly he was killed and K5054 never flew again.
On 15th May 1938 Jeffrey Quill, the then chief test pilot, flew the first production Spitfire, K9787, from Eastleigh and then, on 4th August 1938, he delivered the first RAF Spitfire, K9789, to No.19 Fighter Squadron at Duxford.
The Government felt that the Supermarine works at Woolston would not be able to cope with the expected volume of demand for the new aircraft and they decided to set up a "Shadow Factory" for Spitfire production at Castle Bromwich near Birmingham, initially under the control of the Nuffield organisation and later transferred to the management of Vickers-Armstrong Ltd. In 1940, the Woolston works was bombed and production of the Spitfire in the south was spread over a large number of locations, including bus depots, laundries and garages, in order to avoid such a large scale loss in the future.
From 1938 until manufacture ceased in 1947, over 22000 Spitfires were built. Unfortunately, due to his untimely death on 11th June 1937, Mitchell never saw his greatest design legacy into production. The Spitfire was developed into 24 different marks and, in addition to being an RAF fighter, fulfilled roles as a folding-wing aircraft carrier plane and photographic reconnaissance aircraft.
By 1945 the aircraft had significantly increased its fire power, nearly doubled its rate of climb and achieved a speed of 450mph, almost exactly 100mph faster than the K5054 prototype. These achievements are testament to RJ Mitchell, and his team's, brilliant original design.