North American F-51D N3451D
In 1939, with the shadows of World War II covering Europe, the British Royal Air Force began looking for a new plane to increase its fighter strength. The R.A.F. approached North American Aviation with a request to build Curtiss P-40s. North American responded with an offer to build a completely new fighter incorporating the latest aerodynamic refinements and using the same Allison engine as the P-40. This marked the birth of the North American Mustang.
Ironically, one of the key North American designers was a German named Edgar Schmued. It has been mistakenly reported that Schmued had been part of Willy Messerschmitt’s design group, but he never worked for any German aircraft company.
The prototype NA-73 was assembled in a remarkable 102 days. However, the engine was not ready until several weeks later. The new plane’s first flight took place on October 26, 1940.
During the design of the NA-73, the U.S. Army requested that two planes be delivered for evaluation. When these aircraft were received, the NA-73 name was changed to XP-51. For a brief period, the Army called this aircraft the “Apache”, but then changed the name to “Mustang”.
The P-51 was immediately recognized for superb performance at low altitudes. Tests at Boscombe Down in Britain, however, revealed it quickly ran out of power above 10,000 feet. This lack of performance at high altitudes severely restricted the plane’s use for escort and interception work. A Rolls-Royce test pilot, Ronald Harker, was among the first to conclude that what the Mustang needed to realize its full potential was the “Merlin” engine. Calculations by engineers at R-R suggested that speeds over 440 mph at 25,000 feet could be achieved using the Merlin 61 (high altitude version). Some reports of the history of this incident argue that it was known from the start the Allison engine would only provide good performance below 15,000 feet and the R-R Merlin engine would be eventually needed.
During the winter of 1942-43, R-R pilots test flew the Mustang “X” and sent their data back to North American, which became the basis for production of Merlin Mustangs, designated P-51B. Packard was licensed to build the Merlin engine in the United States.
The P-51B and the P-51C are identical. The “C” designation was for aircraft built at the Dallas plant. A major re-design, which included the teardrop canopy and other improvements, led to the P-51D.
The final production type, the P-51H, incorporated changes that made it the fastest production version with a maximum speed of 487 mph at 25,000 feet.
The P-51 was one of the first fighters to use a laminar-flow airfoil, which became standard on most later, high performance fighters. This wing design, along with the low drag airframe, resulted in very high speeds. In addition, a large fuel capacity, coupled with external (drop) fuel tanks, allowed the Mustang a range of almost 2,000 miles, making it possible to escort bombers all the way from England to Germany.
A total of 14,855 Mustangs were delivered to the U.S. Army. Mustangs powered by the “Merlin” engine are often said to be one of the best propeller driven fighters ever built. Although originally designed as a fighter, Mustangs were also used as dive-bombers, bomber escorts, ground attackers, interceptors, trainers and for photo-recon. Some planes became high performance racers after World War II.
On June 11, 1948, the U.S. Army Air Force introduced a new designation system that resulted in the P-51D becoming the F-51D.
Initially designed in 1939, Mustangs continued in military service long after World War II and Korea. The official end of military service came in May, 1984 when Dominica sold its last nine Mustangs and spare parts to a civilian in Florida.
The F-51D in the EAA collection was manufactured in 1944. Its original designation was P-51D-30NA, its serial number is 44-75007N and its registration number is N3451D. It was acquired by the EAA in 1977 and flew until it was retired to the museum’s Eagle Hangar in 2003.
This aircraft researched by EAA volunteer George Arnold