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.[1]

V-770
Preserved Ranger V-770
Type Piston aero-engine
Manufacturer Ranger Aircraft Engine Division
First run 1931
Major applications Curtiss SO3C Seamew

Design and development

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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.[2][3] Its competitor Vought XSO2U also suffered from overheating problems that were never satisfactorily solved.[4] 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.[5]

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,[6] and in the two Bell XP-77 light-weight fighter prototypes.

Variants

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V-770-7 in Bell XP-77 mockup
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.[3]
V-770-9
Installed in the North American XAT-6E Texan prototype.[5]
V-770-11
Installed in the Fairchild AT-21 Gunner.[5]
V-770-15
Installed in the Fairchild AT-21 Gunner.[5]
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.[7]
SV-770
Supercharged direct-drive variants.[7]
SGV-770
Supercharged and geared variants.[7]
SGV-770C-1
Tested in the Curtiss XF6C-7 Hawk fighter-bomber at 350 hp (260 kW).[3]
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,[1] 700 hp (520 kW) at 3,600 RPM, weight 870 lb (390 kg), height 31.11 in (790 mm), length 74.92 in (1,903 mm), width 33.28 in (845 mm)

Applications

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Engines on display

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Specifications (SGV-770C-1)

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The Ranger V-770 engine as viewed along the cylinders.

Data from Janes Fighting Aircraft of World War II (1989).[1]

General characteristics

  • Type: 12-cylinder inverted Vee piston engine
  • Bore: 4 in (102 mm)
  • Stroke: 5.125 in (130 mm)
  • Displacement: 773 cu in (12.7 L)
  • Length: 62 in (1,575 mm)
  • Width: 28 in (711 mm)
  • Height: 32.2 in (818 mm)
  • Dry weight: 730 lb (330 kg)

Components

  • Valvetrain: Single overhead camshaft (SOHC) (1 shaft per bank), gear driven
  • Supercharger: Single-speed, single-stage, produced 45 inches of mercury (1.5 bar, 22 psi) at take-off
  • Fuel system: Holley non-icing carburetor
  • Fuel type: 87 octane gasoline
  • Oil system: Full pressure type
  • Cooling system: Air-cooled

Performance

See also

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Comparable engines

Related lists

References

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  1. ^ a b c Jane, Frederick Thomas; Bridgman, Leonard; Gunston, Bill (1989), Jane's Fighting Aircraft of World War II, London: Random House, ISBN 1-85170-493-0
  2. ^ Smith, Herschel H. (1986), Aircraft Piston Engines: From the Manly Balzer to the Continental Tiara, SunflowerUniversity Press, p. 255, ISBN 978-0-89745-079-9, OCLC 14253144
  3. ^ a b c Eden, Paul; Moeng, Soph (2002), The Complete Encyclopedia of World Aircraft, London: Amber Books, ISBN 978-0-7607-3432-2
  4. ^ Adcock, Al (1991). OS2U Kingfisher in action. Aircraft In Action. Vol. 119. Carrollton, TX: Squadron/Signal Publications. p. 44. ISBN 0-89747-270-5.
  5. ^ a b c d Swanborough, F. G.; Bowers, Peter M. (1964), United States Military Aircraft Since 1909, New York: Putnam, ISBN 0-85177-816-X
  6. ^ "Ranger V-770 Inverted". National Museum of the USAF. Archived from the original on 30 December 2008. Retrieved 7 November 2008.
  7. ^ a b c Bridgman, Leonard (1937). Grey, C.G. (ed.). Jane's all the World's Aircraft 1937. London: Sampson Low, Marston & Co. Ltd.
  8. ^ Blown Ranger