Historic Aircraft Story: The P-51 Mustang

The P-51’s origin can be traced right back to the rejection of one idea that was replaced with another. The British Aircraft Purchasing Commission had established talks with North American in 1940 to ask them if they could build P40s under licence from Curtiss. In response, North America proposed something different: they wanted to produce an entirely new aircraft — The P-51 (nicknamed the Mustang!) Here's the story...

North America set about its task in swift time and, using experimental data obtained from the US National Advisory Committee on Aeronautics or ‘NACA’ (which in 1958 became NASA), the yachieved a giant leap in performance from the P40 by using a newly designed laminar wing profile. This moved the maximum thickness of the wing further aft from the leading edge and used nearly as much camber on the bottom of the wing as on the top. This feature reduced turbulent air flow across the wing, resulting in reduced drag thereby increasing speed and range. 

The Mustang’s aft-mounted radiator design was also something to behold for not only did it decrease fuselage drag, it also utilised the heated air exiting the radiator as a form of jet propulsion to give it an extra bit of thrust called the ‘Meredith Effect’ (named after British engineer F.W. Meredith, who worked at the Defence Research Establishment at Farnborough, during the 1930s). 

Less than 120 days after the British accepted North American’s proposal, North American flew the Mustang prototype. This was on the 26th of October 1940. The P-51 (‘P’ for Pursuit) entered service in Britain in early 1942, but reports were raised about the declining performance above 15,000 ft. The aircraft was initially powered by the same Alison single stage supercharged engine found in the P40. So the British, never being shy of putting their own mark on things, experimented with fitting their powerful Rolls-Royce Merlin 61 engine (the same as found in the Mk. IX Spitfire). To their delight, they discovered that the Merlin’s two-stage supercharger gave the Mustang outstanding high-altitude performance. 

North American quickly followed the Brits’ lead and by the summer of 1943, the Packard Merlin (licence-built Merlins) powered all P-51s coming off North American’s assembly line. 

The best known and undoubtedly the most successful variant was the P-51D. This was powered by the Packard V-1650-7 engine, a licence-built version of the highly respected two-speed, two-stage-supercharged Merlin 66. The ‘D’ included several design changes but visibly the most notable was probably the installation of a new Plexiglas ‘bubble’ canopy for improved all-around vision (the early canopies suffered with limited rear visibility). This most celebrated version flew at a maximum speed of 440 miles per hour and if left climbing could reach a ceiling of almost 42,000 feet (that’s above the service ceiling limits of most commercial jets!). 

These aircraft proved a game-changer as the P-51’s performance, and therefore combat superiority, increased significantly. That, combined with the aircraft’s amazing range, meant the German Luftwaffe took a huge, unexpected knock as their recorded losses of Me109s and Fw 190s increased dramatically. 

“This most celebrated version flew at a maximum speed of 440 miles per hour and if left climbing could reach a ceiling of almost 42,000 feet (that’s above the service ceiling limits of most commercial jets!)”

A Plane of Firsts

The Mustang was the first US-built fighter to press into the European theatre after the fall of France. And it was the first single-engine aircraft based in Britain to reach Berlin. 

In his comments about using the Mustang to escort bomber raids over Germany, Mustang ace Brig. Gen. Thomas ‘Tommy’ Hayes said that the Merlin-powered P-51 “had the three qualities you need most if you were going to escort bombers to Berlin – range, range and range!” Add to that Mustang ace Col. Clarence E. “Bud” Anderson’s comments about performance, when he said that the Mustang “went like hell!” It’s fair to say it was a very well-liked aircraft and it was nothing short of formidable in its military role. But one of the highest accolades formally recorded was following its review in 1944 by the Truman Senate War Investigating Committee who said [at the time] that it was “the most aerodynamically perfect pursuit plane in existence.” 

The Mustang served the allied forces proudly right through to the end of the war. Not only was it capable of escorting bombers all the way to Germany (and able to return) but it’s all-round performance gave it superb qualities in a number of combat applications — it had speed, superb high-altitude performance, excellent low-altitude handling performance, and of course it had the range to get to Berlin and back. And, towards the end of the war, it could go head-to-head with Germany’s incredible jet fighter; the Me262. 

But the story doesn’t end there as the Mustang continued its active service following WWII in multiple theatres, including notably as a ground-attack fighter in the Korean War (1950–53). During this time the ‘P’ was changed to an ‘F’ for Fighter. 

When the North American assembly line in Dallas, Texas finally closed its doors on Mustang production, more than 15,000 Mustangs had been built. In the European theatre the Mustang destroyed nearly 5,000 enemy aircraft and destroyed more than 4,000 targets on the ground, having flown very close to 214,000 missions. 

Contrary Mary

Our stunning picture aircraft was built in 1944 as a P-51D and was one of the last Mustangs built by North American. Just before the Korean War it was converted to an F-51D and was shipped to South Korea where it served with the 45th Tactical Reconnaissance Squadron at Kimpo. But Mustangs were phased out in favour of jet technology, which in Korea took the shape of the Lockheed P-80 Shooting Star jet fighter. So the Mustangs were retired back to the USA. 

You will have likely noticed already that the canopy on this one is elongated to accommodate a second pilot. During its restoration, between 2005 to 2007, it was converted to a training variant, so this is called a TF-51D (‘T’ for Training). There are two main conversions possible to add a back seat in a Mustang — one is a ‘jump seat’ and aimed to give people the ‘Mustang experience’; and the other is a full second cockpit and can be used for training pilots converting on to the type. Either way, getting airborne in a Mustang is something very special indeed. 

The livery is that of ‘Contrary Mary’ - USAAF 84th Fighter Squadron, 78th Fighter Group USAAF (Duxford, UK) as flown by pilot Lt Col Roy B Caviness. 

Lt. Col. Roy Caviness was a highly decorated USAAF pilot. The Squadron was stationed at Duxford with its primary mission being to escort heavy bombers to Berlin. But they also took part in fighter sweeps and ground-attack missions. 

Can I have a go?

Yes! If you fancy getting your hands on Mary please contact www.warbirdflights.co.uk for the ultimate warbird experience. If there’s two of you, you could even go for a tail-chase with a two-seat Me109 or fly wingman with a two-seat Mk. IX Spitfire!