Allison Piston Engine Images
Courtesy of John Leonard, Dan Whitney. Unless otherwise noted, Images are Courtesy of the Rolls-Royce Heritage Trust - Allison Branch
Published 8 Aug 2019; Revised 14 Aug 2019
Norman Gilman, Allison's chief engineer, began designing the GV-1710-A in May 1929. It was intended for development into an ethylene-glycol-cooled 1,000 hp aircraft engine. Both the U.S. Army Air Corps and U.S. Navy were interested. The Army version was rated at 750 hp, and the Navy version at 650 hp. Both versions were built and tested extensively by the U.S. Armed services, along with the National Advisory Committee for Aeronautics. Neither version flew.
GV-1710-A Images: F, LF, L, LA, A, RA, R, RF, T, B, T with Marvel Fuel Injection.
The V-1710-B was intended to replace German Mayback VL-2 engines that powered the airships USS Akron and Macon. No supercharger was required since the engines operated at low altitude. The V-1710-B had to be reversible and capable of going from full power forward to full power reverse in just eight seconds. This was accomplished by the introduction of 24-lobe cams that translated when engine direction was changed, magnetos capable of maintaining correct timing in either direction, and an accessory gear train that drove the accessories in one direction regardless of engine direction. A set of controls at the engine's rear controlled these reversing features. Although the V-1710-B passed a 150-hr type test, the project was cancelled after the USS Macon was lost.
V-1710-B Images: F, LF, L, LA, A, RA, R, RF, T, B
The Allison V-1710-C was the first engine to pass a 150-hr type test at 1,000 hp, which it did in April 1937. A total of 2,580 V-1710-Cs were built, with the majority being used in Curtiss P-40s. Aircraft that it powered included the Consolidated A-11A (Wiki), Curtiss (X)YP-37 (Wiki), Curtiss XP-40 (Wiki), P-40 (Wiki), P-40B, P-40C, and Lockheed XP-38 (Wiki). Allison proposed the V-1710-C power the Consolidated B-24, Douglas C-39 and Lockheed Loadstar.
V-1710-C Images: F, LF, L, LA, A, RA, R, RF, T
Allison V-1710-D models were designed for pusher propeller installations using a driveshaft. D-model design began in December 1935 and production ended October 1940. Two aircraft were slated for V-1710-D power — the Martin XB-16 and the Bell X/YFM-1. Only the X/YFM-1 flew.
V-1710-D Images: F, LA, A, RA, R, T
V-1710-E engines were designed for use with remote gearboxes. Three variants powered single-engine Bell P-39 (LF, RF, Firing), P-63 and XFL-1 fighters, all of which had the engine behind the pilot. This arrangement made room for a 37mm cannon firing through the propeller hub. A fourth variant powered the Douglas XB-42. P-39 engines used single-stage superchargers, while some P-63 engines added a variable-speed auxiliary altitude supercharger stage (LF, RA). The XB-42 employed two V-1710-E23 (L, RF) engines to drive contra-rotating pusher propellers. A turbocompound engine, the V-1710-E27 (L, A, R, T) was built and tested, as were numerous other variations on the shaft-driven remote gearbox (90°, Tandem, Tandem).
V-1710-E Images: F, LF, L, LA, A, RA, R, RF, T, B, with Driveshaft, Gearbox.
The V-1710-F featured a crankcase that was common to the -E engines, allowing the same reduction gear assemblies to be used on both engines. The V-1710-F was also capable of left-hand rotation by swapping the crankshaft end-for-end and fitting an idler gear to the accessory section so that supercharger, generator, pumps and magnetos all operated in the same direction. V-1710-F engines powered the Boeing/Lockheed/Vega XB-38, Curtiss P-40, XP-55 and P-60, Lockheed P-38, and North American P-51A and A-36. The V-1710-F32 featured an intercooled two-stage supercharger and was used in the two North American XP-51Js that were built. More V-1710-F models (about 48,700) were built than any other Allison engine.
V-1710-F Images: F, LF, L, LA, A, RA, R, RF, T, B
The Allison V-1710-G6 powered the North American F-82 (USAF Photo). Of 272 F-82s built, 250 were powered with V-1710s, the remainder by Rolls-Royce Merlins. An F-82 shot down a Yak 9 on 27 June 1950; this was the first enemy aircraft downed during the Korean conflict.
V-1710-G Images: L, R.