The North American P-51 Mustang was one of the truly great fighters of the war, it was originally designed in 1940 to a British requirement. In spite of being superseded by jet fighters, the Mustang remained in service with some air forces until the early 1980s. After World War II and the Korean War, many Mustangs were converted for civilian use, especially air racing.
The prototype NA-73 was first flown in October that year with a 820-kW (1,100-hp) Allison V-1710-F3F but, although two early aircraft were evaluated by the USAAF as XP-51 aircraft, the type was not adopted by that air force. Most of the early aircraft were supplied to the RAF (620 aircraft as Mustang Mk IA and Mustang Mk II).
Their outstanding low-level speed and range resulted in their assignment to the ground support (army co-operation) role. After the USA’s entry into the war the USAAF adopted the aircraft, ordering 148 P-51s which had four 20-mm cannon (instead of four 0.5-in and four 0.3-in) wing bomb shackles in the attack category as the A-36A, The British in the meantime had re-engmed four Mustangs with Rolls-Royce Merlins, and this expedient transformed the aircraft.
In America the armament was reduced to four 12.7-mm (0.5-in) guns, all in the wings, and an 895-kW (1,200-hp) Allison V-1710-81 was used in the P-51 A, 310 being ordered in 1942. So spectacular were the benefits of the Merlin that a Packard-built Merlin (as the V-1650) was used in the P-51B, of which 1,988 were produced at Inglewood; 1,750 of the similar P-51C were built at Dallas, Texas. Later aircraft had the armament restored to six guns, while increased fuel capacity extended the range to a maximum of 3347 km (2,080 miles), enabling Mustangs to escort American bombers to Berlin
The P5ID featured a cut-down rear fuselage and ‘tear-drop’ canopy. The Merlin P51 joined the RAF as the Mustang Mk HI (P-5 IB and P-51C) and Mustang Mk IV (P-5ID). Fastest of all versions was the lightened P-5 IH with a top speed of 784 km/h (487 mph), 555 being built during the war. Total production of the P-51 was 15,586, including 7,956 P5IDs and 1,337 generally similar P-51K fighters with an Aeroproducts propeller .
The most prominent firm to convert Mustangs to civilian use was Trans-Florida Aviation, later renamed Cavalier Aircraft Corporation, which produced the Cavalier Mustang. Modifications included a taller tailfin and wingtip tanks. A number of conversions included a Cavalier Mustang specialty: a “tight” second seat added in the space formerly occupied by the military radio and fuselage fuel tank.
In the 21st century a P-51 can command a price of more than one million dollars. According to the FAA there are 204 privately owned P-51 Mustangs in the U.S. Most of which are still flying, often associated with organizations such as the Commemorative Air Force.