P-51: Several of the most widely held and patently false myths of WWII involve the P-51 Mustang.
Everyone knows that the British approached North American Aviation about building the Curtiss P-40 on license in January of 1940. The story goes that NAA told the British they'd produce a better fighter using the same engine within 120 days. Unfortunately, there's no confirmation of the "120 days" claim anywhere. It's certainly not in the contract for the prototype.
Even more misunderstood is the performance expectations & development of the Mustang, particularly with the US military. Supposedly the 51 was a dog and uninspiring to everyone until some British wizard stuck a Merlin engine in it.
Facts don't support this. First off, the US military was interested in the Mustang from the start. So much so that the production contract stipulated that 2 of the early aircraft would be held back from Britian and sent to Wright Field for testing. At the time, the Pursuit division of the US Army simply didn't have the money to purchase the airplanes themselves. So, in effect, Britain bought the Army 2 planes which they hoped to use to convince the government to finance more.
The AAC was, in fact, so interested in the Mustang that they ordered all that the Pursuit Office could afford (150) even before the first text aircraft arrived at Wright Field. Tests eventually justified the expenditure, when it was shown that the 51 was a superior plane to the current best the AAF had to offer, the P-40.
The AAC wanted P-51's so badly that despite not having any more money in the budget for fighters, they found a way to get more Mustangs. The AAC never saw much use in dive bombing but they asked NAA to design a dive bomber version, which became the A-36.
(Yet another myth about the P-51 is ties up in the name of the A-36. The US Army orginally wanted to name the P-51 the "Apache." Britain had already named their version of the plane "Mustang" and that stuck with Americans who were woking on the plane. The A-36 was commonly called the "Apache", but it never had any offical nickname. "Invader" had been proposed by the Army, but it didn't take and that name was eventually applied to another aircraft.)
To return to the performance topic...both the designers & the military were very familair with the Allison engine that was to be used in the P-51. To claim that they were suprised by its lackluster high altitude performance is foolish. They
knew that the Allison's performance dropped off over 15K in the configuration that the 51 would use. Which is why 2 of the original US order were slated for testing with the Merlin. This was ordered before the US had even begun testing on the planes they received from the British order. Original plans were for the Allison engined versions to be lower altitude fighters (where they outperformed the Merlins) while the Merlin powered planes would be used for high altitude missions.
People cry, "the Mustang sucked at high alt until the Merlin was installed." Which is true. What you don't hear from them is," the
Mustang sucked at low alt when the Allison was taken out." Which is relatively true. The Allison Mustang simply performed better at low alts than the Merlin. (Can you imagine an early US P-51 in AH MA where most combat takes place at less than 15K alts? The original US order of 150 P-51's were equipped with 4 20mm cannon. Perked for sure.
)
And finally, there's the myth that the 51 won the war in the West by allowing bombers to fly escorted to Berlin. As has been brought up here recently in another thread, it's simply not true. P-38's had the range to escort bombers deep into Germany from the outset. Ira Eaker, who was in command of the 8th AF at the time, didn't believe the bombers needed escort though. He thought that the bomber's gunset was enough defense. P-38's sat around in England for a while with nothing to do, watching their bomber brethern get shot up day after day. Most of them were eventually reassigned to Africa. It wasn't until Jimmy Doolittle replaced Eaker that the bombers got the escorts that they so sorely needed.
D
