Ranger V-770 Explained

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.^[1] 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,^[2] 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.^[3]

SV-770: Supercharged direct-drive variants.^[3]

SGV-770: Supercharged and geared variants.^[3]

SGV-770C-1: Tested in the Curtiss XF6C-7 Hawk fighter-bomber at .

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, at 3,600 RPM, weight, height, length, width

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^[4]
• The Yankee Air Museum has a V-770 on display.
• One restored engine at the Vintage Flying Museum in Fort Worth.

Notes and References

1. Book: Adcock . Al . OS2U Kingfisher in action . Aircraft In Action . 119 . 44 . 1991 . Squadron/Signal Publications . Carrollton, TX . 0-89747-270-5.
2. Web site: Ranger V-770 Inverted. National Museum of the USAF. 7 November 2008. dead. https://web.archive.org/web/20081230004530/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=853. 30 December 2008.
3. Book: Bridgman, Leonard. Grey, C.G.. Jane's all the World's Aircraft 1937. 1937. Sampson Low, Marston & Co. Ltd.. London.
4. http://blastoland.com/blastoland/BLOWN_RANGER_BUILD.html Blown Ranger