P-51 Mustang

History: One of the most effective, famous and beautiful fighter aircraft of WWII, the P-51 was designed to fulfill a British requirement dated April 1940. Because of the rapidly-mounting clouds of war in Europe, the UK asked North American Aircraft to design and build a new fighter in only 120 days. The NA-73X prototype was produced in record time, but did not fly until 26 October 1940. The first RAF production models, designated Mustang Mk Is, underwent rigorous testing and evaluation, and it was found that the 1,100-hp Allison engine was well suited for low-altitude tactical reconnaissance, but the engine's power decreased dramatically above an altitude of 12,000 feet, making it a poor choice for air-to-air combat or interception roles. Because of this, the RAF left its eight machine guns intact, but also fitted the Mustang with cameras. In this configuration, it served in at least 23 RAF squadrons, beginning in April 1942.