Ranger V-770

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

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]

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.^[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

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

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^[8]
The Yankee Air Museum has a V-770 on display.
One restored engine at the Vintage Flying Museum in Fort Worth.

Specifications (SGV-770C-1)

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

Power output: 520 hp (390 kW) at 3,150 rpm
Specific power: 0.68 hp/in³
Compression ratio: 6.5:1
Power-to-weight ratio: 0.71 hp/lb

References

^ ^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
^ 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
^ ^a ^b ^c Eden, Paul; Moeng, Soph (2002), The Complete Encyclopedia of World Aircraft, London: Amber Books, ISBN 978-0-7607-3432-2
^ Adcock, Al (1991). OS2U Kingfisher in action. Aircraft In Action. Vol. 119. Carrollton, TX: Squadron/Signal Publications. p. 44. ISBN 0-89747-270-5.
^ ^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
^ "Ranger V-770 Inverted". National Museum of the USAF. Archived from the original on 30 December 2008. Retrieved 7 November 2008.
^ ^a ^b ^c Bridgman, Leonard (1937). Grey, C.G. (ed.). Jane's all the World's Aircraft 1937. London: Sampson Low, Marston & Co. Ltd.
^ Blown Ranger

[Janes-1] 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

[EdenMoeng-3] 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.

[Swanborough-5] Swanborough, F. G.; Bowers, Peter M. (1964), United States Military Aircraft Since 1909, New York: Putnam, ISBN 0-85177-816-X

[Museum-6] "Ranger V-770 Inverted". National Museum of the USAF. Archived from the original on 30 December 2008. Retrieved 7 November 2008.

[JAWA1937-7] Bridgman, Leonard (1937). Grey, C.G. (ed.). Jane's all the World's Aircraft 1937. London: Sampson Low, Marston & Co. Ltd.

[8] Blown Ranger

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