Allison V-1710 Supercharger Impeller

[Elvis]

Around the time the Army was washing its hands of the Curtiss Conqueror, Allison began to develop its own engine, at the request of Allison General manager Norm Gilman. The target was 1,000 hp, and Allison intended that the engine should be large enough to deliver this power easily. A successful V-1710-A was test run in 1931 and delivered 650 hp at 2,400 RPM on 80-octane fuel. Development proceeded slowly until the Navy entered the picture. The Navy, while not losing its attachment to air-cooled power plants for airplanes, it still needed liquid cooling for dirigibles...

Sorry Shortround, I had it backwards. The Navy requested the engine for dirigible use, but it was already under development at that time.
Here's a link to the full article - Allison V-1710 Engine


Elvis