The North American P-51 Mustang was developed from the prototype, designated NA-73X, which was designed by Edgar Schmued with wings designed using laminar flow air foils, which generate low drag.
The all-aluminium fuselage was made from five main sections, forward, centre, rear and two wing halves, all were complete subassemblies before joining. The complete fuselage was lofted when designed to produce low drag surfaces.
The oil and water radiators were fed from a single duct positioned on the belly behind the cockpit reducing fuselage drag.
The engine used in NA-73X was the Allison V-1710 with a single-stage supercharger. Whereas this engine was suitable for low level flight it lost power at higher altitude above 15,000 ft. (4,600m).
The lack of power at higher altitude made the aircraft unsuitable for air combat, however, after trials by the RAF it was used as a tactical-reconnaissance aircraft and fighter-bomber, designated the Mustang Mk I.
The Allison engine was changed for the Rolls Royce Merlin engine which transformed the aircraft at higher altitudes allowing it to be used as a fighter, designated P-51B/C (Mustang Mk III).
The definitive version of the Mustang, the P-51D, was powered by the supercharged Merlin 66 licence built by Packard as the V-1650-7.
The North American P-51 Mustang was produced from 1941, with over 15,000 built.