Ranger V-770

The Ranger V-770 was an American air-cooled inverted V-12 aircraft engine developed by the Ranger Aircraft Engine Division of the Fairchild Engine & Aircraft Corporation in the early 1930s.

Design and development
In 1931, the V-770 design was built, derived from the Ranger 6-440 series of inverted inline air-cooled engines, and test flown in the Vought XSO2U-1 Scout. In 1938 it was tested in the Curtiss SO3C Seamew but was found to be unreliable with a tendency to overheat in low-speed flight, but would still be the most produced aircraft to have the V-770, with 795 being built. Its competitor Vought XSO2U also suffered from overheating problems that were never satisfactorily solved. By 1941 a more developed V-770 was installed in the Fairchild XAT-14 Gunner prototype gunnery school aircraft, which went into limited production as the Fairchild AT-21 Gunner, of which 174 were built, not including one radial engine prototype.

Produced from 1941 to 1945, the V-770 featured a two-piece aluminum alloy crankcase, steel cylinder barrels with integral aluminum alloy fins and aluminum alloy heads. The V-770 was the only American inverted V-12 air-cooled engine to reach production. The engine was used in very few aircraft, among them the short lived Fairchild AT-21 twin-engine bomber trainer, and in the two Bell XP-77 light-weight fighter prototypes.

Variants

 * V-770-4: Installed in the Vought XSO2U-1 scout aircraft
 * V-770-6: Installed in the Fairchild XAT-14 Gunner prototype, intended for the Ryan SOR-1 Scout
 * V-770-7: Installed in the Bell XP-77 lightweight fighter prototype
 * V-770-8: Installed in the Curtiss SO3C Seamew Scout.
 * V-770-9: Installed in the North American XAT-6E Texan prototype.
 * V-770-11: Installed in the Fairchild AT-21 Gunner.
 * V-770-15: Installed in the Fairchild AT-21 Gunner.
 * V-770-17: Similar to V-770-8 but with raised hollow propeller shaft for mounting cannon or machine gun.
 * GV-770: Geared un-supercharged variants.
 * SV-770: Supercharged direct-drive variants.
 * SGV-770: Supercharged and geared variants.
 * SGV-770C-1: Tested in the Curtiss XF6C-7 Hawk fighter-bomber at 350 hp.
 * SGV-770C-1B: (V-770-11)
 * SGV-770C-2A: (V-770-8)
 * SGV-770C-B1: Installed in the Ikarus 214 prototype
 * SGV-770D-4: (V-770-17) Similar to C-2A but with raised hollow propeller shaft for mounting cannon or machine gun.
 * SGV-770D-5: Developed for post-war commercial use, 700 hp at 3,600 RPM, weight 870 lb, height 31.11 in, length 74.92 in, width 33.28 in

Applications

 * AEKKEA-RAAB R-29
 * Bell XP-77
 * Curtiss SO3C Seamew
 * Edo OSE
 * Fairchild F-46
 * Fairchild AT-21 Gunner
 * Fairchild BQ-3
 * Ikarus 213/Utva 213 Vihor
 * Ikarus 214 (prototype)
 * Vought XSO2U
 * North American XAT-6E

Engines on display

 * One restored engine in storage at the Carolinas Aviation Museum
 * One survives at Cincinnati State Aviation school
 * One modified V-770 survives in an art car by Michael Leeds
 * The Yankee Air Museum has a V-770 on display.
 * One restored engine at the Vintage Flying Museum in Fort Worth.