"The first altitude-rated C engine with integral supercharger, the V-1710-C13, was installed in the Curtiss XP-40 in 1938 and this engine was put into production as the V-1710-C15 in 1939."

There is nothing incorrect about this statement.
It is easily miss understood as the first Allison
with a integral supercharger.

In reality it was the first Allison with an altitude rated integral supercharger
to be installed in a XP-37....

All airworthy Allison V-1710 engines were equipped with a integral engine driven supercharger.

Jane's 1945-46, of which I own an original, is not incorrect.
It is a mere miss understanding ;-)

Boris

Sorry. Myself and Jane's 1945/46 are wrong."The first practical flight installation of the C model was made in 1937 in the Curtiss XP-37. This engine was the V-1710-C10 with exhaust-driven turbo-supercharger. The first altitude-rated C engine with integral supercharger, the V-1710-C13, was installed in the Curtiss XP-40 in 1938 and this engine was put into production as the V-1710-C15 in 1939. Sir William Stephenson,"Intrepid", once said "A document is the best lie". Dr. Theodore von Karman once asked "how can there be progress without controversy?" For myself, I do not have an original thought without the germ of fact to support it.

On the versions of the V-1710 that included a turbocharger, the Turbo was the second, or, "auxillary" stage.
Leo, A Turbocharger is still a supercharger, it just isn't an "engine-driven" supercharer.

V-1710-11 (C7) Engine driven blower ratio was 7:1.
Turbocharging was also used but the results were poor.
All Allison V-1710s were equipped with a engine
driven superchager with a gear ratio of 7:1 or 8:1.
The original contract was for a airship and that version had no blower.
It was also reversable.
All aircraft versions had a supercharger driven by the engine )I am repeating myself!).

Boris

1937 allison V-1710-C10, fitted to the Curtiss XP-37?

All Allison V-1710s had a engine driven supercharger.
Turbocharged versions had the engine driven unit and a turbosupercharger as a first stage.

Myth BUSTED.

Boris

Never heard the myth but semantically speaking, turbo-charged Allisons weren't supercharged. No Allison engines were equipped with viable high-altitude-rated superchargers worthy of being in service. And without picking Stanley Hooker's brain, there never would have been a two-stage supercharger with anti-backfire screen. But, that's just semantics.

Correction, for those who still believe the myth, NO Allison V-1710
was ever built with no supercharger (except the airship version).
The Allison powering the P-40Q was a two stage supercharged engine
with intercooler.

I repeat, NO Allison V-1710 that ever got into an airplane was un supercharged.

Boris

yes Leo, the Merlin was a great engine, its h.p. rating equal or better than its total cubic inches. The Merlin was 1,650 cu.in.?

Do you know what company built critical components for Allison? If you dont know , the answer will probably surprise you.

I don't believe I ever suggested that the P-40N was the ultimate P-40 but it was the ultimate production P-40, the "Q" being a one-off. The P-40Q was much improved in performance but very short-ranged. Both the P-40Q and Fisher P-75A suffered in comparison to the Merlin Mustangs already in full production. Max Mil. hp rating for V-3420-19 was 2600hp for 15 minutes

My research shows that the Q did have six .50 calibers, and ample range, using a 1,475 h.p. Allison V1710, but still w/o supercharging. To say the P-51 was a success, would be a complete understatement, its one of aviations elite, along w/ the Vought F4U. Still, the P-40 was on hand when needed, and in the hands of a seasoned pilot, not even the Mitsubishi Zero was a match. Ask the Japanese pilots who went up against the Flying Tigers in China.

Correction on Allison V-3420, h.p. output was 2,885. Slightly under anticipated output, this was not the primary factor of the failure of the p-75 design. Mixing parts from various aircraft could and did produce some surprising results. Aileron control was extremely heavy, and engineers actually calculated the center of gravity incorrectly!

If your info. is accurate, the addition of guns and fuel tanks , weight being a factor, would have brought the Q into the 400 mph range.

So you are saying the ultimate p-40 design was the N model? Still, the Q was a design w/ many aerodynamic refinements, wasnt aware of absense of guns and fuel tank. The Allison V3420 did produce 2,800 hp, came too late.

Berlin left Curtiss because he was unhappy with corporate decisions which affected his designs. That the Eagle was unsuccessful could be predicated on the use of a double Allison engine being no better than a single engine. It didn't work in the Boeing B-29 version or the Lockheed P-58. How were they supposed to clean up the P-40? On the P-40Q, they removed fuel tanks and guns for performance. The P-51 had guns, fuel, and performance. Have you seen the movie,"1941' with John Belushi and the P-40? A classic. " Lemme hear your guns!" A great scene.

Why did Don Berlin go over to Fisher? His P-75 wasnt the work of a gifted aviation designer. Mixing parts of dif. existing aircraft proved unsucessful, perhaps practical in theory but unimaginative.

were dif. airframes.

P-46's etc. where different airframes.

P-46's etc. where different airframes.

my point was to clean up the p40 early on....

Don Berlin went to Fisher, Curtiss went to the toilet, and yes, Allison finally developed their engine in time to fight a Jet war. Curtiss built a turbo fighter, the P-37. Didn't work out. Took forever to lengthen the tail. The P-46 and P-60 was their attempt to clean up the P-40. The Mustang and it's pilots won the air war over Germany.

Don Berlin went over to North American? The Allison V-1710 was a rugged and powerful engine, in final form used in the twin mustang in the Korean war. Removal of the turbosupercharger doomed aircraft using this engine to medicocrity, unless of course one considers the p-38, with turbosuperchargers used to give maximum h.p. output at higher altitudes. Back to the p-40, much more rugged and manueverable than the p-51, it only lacked the turbosupercharger, and an early "clean-up" program. Curtiss became involved in too many projects, instead of focusing on this magnificent airplane.

The P40Q shouldn't be counted as a separate aircraft type but rather blocked with all Kittyhawk/ Hawk 87 models, as apart from Tomahawk/ Hawk 81 models. The P-40, like the Hurricane, was an effective and tractable warplane, available in quantities, thanks to an efficient production line, at a time it was sorely needed. Like the Hurricane, it was produced too long. Curtiss was a corporate entity lacking the spark of brilliance, when Don Berlin left, to create a Mustang or any other great airplane. The P40Q was , like all other Curtiss projects, almost as good, when first built, as aircraft already in service. The Allison V-1710 was nearly ready to fulfil its destiny as a Hydroplane racing engine.

Your Curtiss aircraft timeline puts the p-40q2 at 1941. Everything I have read in the past 25 years suggests this p-40 model did not appear until 1944.

Instead of wasting effort on the p-46, p-53, p-55, p-60 and p-62, Curtiss had a thorouhbred from the start with its p-40. Had it began immediately in cleaning up the high drag design, this airplane would not be a bit of an enigma, but one of aviations elite. Much more manueverable than the p-51, this would have been the star aircraft of WW2. However, often outclassed in speed during most of its service life, this rugged design certainly helped win the war.