Today, we look back at World War II with a sense of pride and nostalgia.
Ask anyone that lived through those dark days and they’ll all say the same thing: fear ruled the day. This universal conflict stretched from the shores of North America to the deepest and widest oceans of the Pacific theatre and the distant forests of Europe. The allies (Great Britain, the United States, and the Soviet Union) knew war was coming to Europe’s doorstep and the need for a proper squadron of fighters could soon become a matter of life or death.
The story of the P-51 Mustang began as a partnership with the Royal Air Force and ends with one of the legendarily brilliant aircraft to ever be piloted by American airmen. So, how did the venerable Mustang end up the legend that it became?
This is a story you have to read to believe.
Early Development
In 1938, the British arranged a purchasing commission with the United States that was led by Sir Henry Self, and one of the Self’s main tasks was to organize and build a supply chain for American fighter aircraft. At the time, the only aircraft manufactured by the American’s that met the stringent European standard was the Curtiss P-40. Since Curtiss production was at an absolute peak, the British needed to find another way to boost fighter production.
North American Aviation, who was already supplying the legendary T-6 Texan trainer to the RAF (known as the Harvard), was approached by Self to produce copies of the Curtiss P-40. The ever enterprising NAA President "Dutch" Kindelberger approached Self to sell the North American B-25 Mitchell bomber but instead, Self flipped the script and asked Kindleberger to produce copies of the P-40, under license from Curtiss. The ever crafty Kindleberger instead promised that NAA could instead produce an entirely new aircraft that could compete and beat the P-40.
Intrigued, Self agreed under a strict set of conditions.
NA-73X
Self insisted that NAA utilize a design that had already been started by Curtiss for an aircraft known as the XP-46 to serve as the foundation for the Mustang project. Part of the initial development included a purchase of wind tunnel data and flight test reports directly from Curtiss, which was used in the new design. After a series of back and forth disputes, the final design was approved in May of 1940, and production of the Mustang project began in earnest with an initial order of 320 aircraft. The initial prototype was known throughout NAA as the NA-73X and it was in fact, the first Mustang; the MK1
In a staggering feat of engineering, the MK1 prototype rolled off the assembly line in only 102 days. Each MK1 Mustang utilized several technologies that were considered revolutionary at the time in order to boost not only performance but combat ability and range as well. Developed at the University of Washington Kirsten Wind Tunnel, the MK1 utilized NAA/NACA 45–100 laminar airfoils which reduced drag at high speed, allowing for higher top speed in a variety of conditions.
Other technologies included a fuselage lofted mathematically using conic sections that dramatically reduced drag, a construction built in a modular fashion of weight-saving aluminum semi-monocoque sections, and a full armament of four .30 caliber (7.62 mm) AN/M2 Browning machine guns in the wings and two .50 caliber (12.7 mm) AN/M2 Browning machine guns mounted under the engine.
The Merlin
Originally, the MK1 utilized a Supercharged V-1710-45 Allison engine that produced a total of 1,150 horsepower at altitudes of up to 22,400 feet. For combat conditions against advanced German aircraft, this left the Mk1 at a huge disadvantage. The Allison engine program was extremely underfunded but a wry British test pilot named Ronald Harker suggested that the Merlin 61 engine could be a viable swap in. This legendary engine was also found in the equally legendary RAF Spitfire Mk IX. Due to the dual-stage supercharger design of the Merlin 61, the Merlin was able to make more power at altitude and thus attain a higher top speed. This incredible engine produced anywhere from 1400 to over 1650 horsepower and was a staggering 27.04 L in displacement!
To increase production capability, United States vehicle manufacturer Packard was commissioned to produce the U.S. Built Merlin 61 in 1942. These units produced more power than the British-built units and offered a top of 445 MPH to the Mustang. These Merlin prototypes were known as the XP-51B and the United States was so interested in the design that they put an order in for 400 P-51B aircraft a full three months before the XP-51B even took to the skies.
Multi-Role Fighter
Did you know: P-51 Mustangs utilized paper mache fuel tanks that were dropped underway for ultra-long-range missions?
The Packard Merlin-powered P-51 Mustangs were originally designed to be a multi-role aircraft that could do everything from performing reconnaissance to dogfighting and bomber escorts. P-51’s played a central role in offenses like the Combined Bomber Offensive, which was designed to consistently and mercilessly bomb German industrial centers that produced aircraft, firearms, and other weapons of war. Here, the P-51 Mustang provided a critical, long-range escort to the bombers and they were applauded for their ability to take on heavy Luftwaffe planes with stunning efficacy.
P-51 Mustang aircraft would go on to achieve air superiority at the European front due to superior numbers, pilot training, and stunningly great Mustang airframe. In the Pacific theatre, the Mustang was a relative latecomer due to the need for planes in Europe but was used in 1944 and 1945 as a multi-role aircraft to great effect.
How good was the P-51 Mustang? So good that it went on to fly in the Korean War (as the F-51) and it was ordered by over 55 countries after the completion of the war.
An American Icon
What made the P-51 Mustang so successful in its day was a combination of clever engineering, a stonking power plant, and the grit of American servicemen like the Tuskeegee Airmen. Its superior design and construction were due to a combination of allied technologies and cooperation that spanned several continents and several years. Of all the planes of WWII, the P-51 is among the most beloved, and its legendary status as a multi-role fighter spawned the aircraft that our military utilizes today.
Chief Naval Test Pilot and C.O. Captured Enemy Aircraft Flight Capt. Eric Brown:
“The Mustang was a good fighter and the best escort due to its incredible range, make no mistake about it. It was also the best American dogfighter. But the laminar-flow wing fitted to the Mustang could be a little tricky. It could not by any means out-turn a Spitfire. No way. It had a good rate-of-roll, better than the Spitfire, so I would say the plusses to the Spitfire and the Mustang just about equate. If I were in a dogfight, I'd prefer to be flying the Spitfire. The problem was I wouldn't like to be in a dogfight near Berlin, because I could never get home to Britain in a Spitfire!”
