Supermarine Spitfire (late Merlin-powered variants)

Spitfire
A restored Supermarine Spitfire VIII, A58-758, in the colours and markings of Wg. Cdr Bobby Gibbes of 80 Wing RAAF, based on Morotai in 1945.
Role	Fighter / Photo-reconnaissance Type of aircraft
Manufacturer	Supermarine
Designer	Joseph Smith
First flight	September 1941 (Mk III with Merlin 61)
Introduction	June 1942 (Mk IX)
Retired	1955, RAF
Primary user	Royal Air Force
Produced	1942–1945
Number built	8,996 (20,346 total)[1]
Variants	Seafire, Spiteful, Seafang

The British Supermarine Spitfire was facing several challenges by mid-1942. The debut of the formidable Focke-Wulf Fw 190 in late 1941 had caused problems for RAF fighter squadrons flying the latest Spitfire Mk Vb.^[2] Rolls-Royce engineers were already working on a new version of the Merlin incorporating a two-stage supercharger; the combination of the improved Merlin and the Spitfire Mk Vc airframe in a "stop-gap" design allowed the RAF to combat the Fw 190 on equal terms.

In a second stream of development Supermarine was working on an improved, reinforced, Spitfire airframe which incorporated several new features and was designed for the Merlin 60 and 70 series engines.^[3] This new airframe later formed the basis for the Rolls-Royce Griffon powered Spitfires. This article presents a history of the Spitfire powered by two-stage engine variants and also describes some of the "drawing board" projects and experimental Spitfires. The Griffon powered variants are described in a separate article.