F-5 Mustang

P-51 Mustang
P-51D of 374th Fighter Squadron, with underwing drop tanks.
Role	Fighter
National origin	United States
Manufacturer	North American Aviation
First flight	26 October 1940
Introduction	January 1942 (RAF)
Status	Retired from military service 1984 (Dominican Air Force)
Primary users	United States Army Air Forces Royal Air Force Chinese Nationalist Air Force numerous others (see below)
Number built	More than 15,000
Unit cost	US$50,985 in 1945
Variants	North American A-36 Apache Rolls-Royce Mustang Mk.X Cavalier Mustang
Developed into	North American F-82 Twin Mustang Piper PA-48 Enforcer

The North American Aviation P-51 Mustang is an American long-range, single-seat fighter and fighter-bomber used during World War II and the Korean War, among other conflicts. The Mustang was designed in 1940 by North American Aviation (NAA) in response to a requirement of the British Purchasing Commission. The Purchasing Commission approached North American Aviation to build Curtiss P-40 fighters under license for the Royal Air Force (RAF). Rather than build an old design from another company, North American Aviation proposed the design and production of a more modern fighter. The prototype NA-73X airframe was rolled out on 9 September 1940, 102 days after the contract was signed, and first flew on 26 October.

The Mustang was originally designed to use the Allison V-1710 engine, which, in its earlier variants, had limited high-altitude performance. It was first flown operationally by the RAF as a tactical-reconnaissance aircraft and fighter-bomber (Mustang Mk I). The addition of the Rolls-Royce Merlin to the P-51B/C model transformed the Mustang's performance at altitudes above 15,000 ft, allowing the aircraft to compete with the Luftwaffe's fighters. The definitive version, the P-51D, was powered by the Packard V-1650-7, a license-built version of the Rolls-Royce Merlin 66 two-stage two-speed supercharged engine and was armed with six .50 caliber (12.7 mm) M2/AN Browning machine guns.