The Allison Engineering Company was a large and well-established precision engineering shop, formed basically to build and support racing cars competing on the Indianapolis speedway. It had little in the way of regular production sales, although it did produce a range of precision steel-backed lead-bronze bearings and a range of gears for high-power engines. Experience of marine engine building and conversion of the Liberty engine to designs from the Army and Navy had given Allison a background for it to be awarded a Navy contract for a two-stroke diesel airship engine, trials of which were successful although the engine was not subsequently used.
Other contracts were pursued, but the position of Curtiss as the Army and Navy preferred engine builder prevented Allison from getting further work. After the death of James Allison in 1929, the company was bought by the Fisher Brothers Investment Corporation, and on the instructions of Lawrence P. Fisher, Allison's then general manager N.H. Gilman designed a small six-cylinder liquid cooled engine using a cylinder design that the company had worked on the previous year while pursuing Army contracts. The engine was continued with later in the year when Fisher Brothers sold Allison to General Motors. The depression of 1929-1933 forced the project to be dropped, but Gilman had also sketched out a larger 12-cylinder engine which was aimed at a far higher output of 750hp, quite high for that period.
Gilman wanted to use turbo-supercharging in this engine, which lent itself well to this form of output boosting as it was liquid-cooled. GM were sceptical about the whole project, as both Wright and P&W were in full production of air-cooled radials which were the current preferred engine of both the Army and Navy. Gilman persisted, and GM allowed him to proceed with what was to become the V-1710 engine, the only engine that Allison were to be associated with.
Allison V1710-F Type Aero Engine
Allison were asked to contact the Navy, who were working with the Hall Aluminium Aircraft Co on a flying boat, the XP2H-1. The Navy did talk with Allison on this project, but another angle was to emerge during these talks, that of the power units for airships. The Navy wanted an all-american engine available to replace the German Maybach power plants being used at the time. It gave Allison a contract for a single V1710-A engine, to develop 650hp at sea level. Ultimately, the airship engine supply position was not to materialise as the Macon was lost on the 12th February 1935, and with it went the Navy's airship programme.
Allison V1710-C15 Type Aero Engine
Allison V1710-C 15 Type Aero Engine Rear View
Allison V1710 Aero Engine Crankshaft & Pistons
Following successful trials in the Curtiss P-36 Hawk fighter, the Allison was also fitted to the XP-38 Lockheed Lightning and the Bell XP-39 Airacobra. Orders from the Government in 1939 for over 1000 engines made the V1710 the largest-selling engine of that period, and the largest engine order placed by the Govt to date. Over 6000 engines were delivered by the end of 1941, with larger quantities to come in the later war years.
Allison V1710 Aero Engine Sectional Views