Lycoming R-680

R-680
	Lycoming R-680
Type	Piston aero-engine
National origin	United States
Manufacturer	Lycoming Engines
First run	1929
Major applications	Beechcraft AT-10 Wichita ; Stinson Reliant; Curtiss-Wright AT-9 ; Stinson Airliner
Produced	1930-1945 out of production
Number built	over 26.000

The Lycoming R-680 is a nine-cylinder air-cooled radial engine, the first aero engine produced by Lycoming. The engine was produced in two types, the E and B series; both are essentially the same. The B4E was available in a trainer version with a front exhaust collector "ring" for use without cylinder air baffles. R-680 received Approved Type Certificate No. 42 on 4 Feb 1930.

Variants

R-680: Rated at 210 hp (160 kW) at 2,000 rpm.
R-680B4Erpm: Rated at 225 hp (168 kW) at 2,100 rpm.^[1]
R-680BA: Rated at 240 hp (180 kW)
R-680E3A: Rated at 285 hp (213 kW) at 2,200 rpm.^[1]
R-680-6: Rated at 245 hp (183 kW)
R-680-9: Rated at 300 hp (220 kW) at 2,200 rpm.
R-680-13: Rated at 300 hp (220 kW) at 2,200 rpm.^[1]

Applications

Specifications (R-680-E3A)

Data from Jane's Fighting Aircraft of World War II.^[1]

General characteristics

Type: Nine cylinder air-cooled radial
Bore: 4 5⁄8 in (117 mm)
Stroke: 4 1⁄2 in (114 mm)
Displacement: 680 in³ (11.15 litres)
Length: 37.5 in (953.1 mm)
Diameter: 43.5 in (1104 mm)
Dry weight: 515.46 lb (233.9 kg)

Components

Valvetrain: One inlet and one exhaust valve per cylinder at 30 degrees.
Fuel system: single-barrel carburetor
Fuel type: 87 octane rating gasoline
Oil system: Full pressure type
Cooling system: Air-cooled

Performance

Power output: 330 hp (246 kW) at 2,300 rpm at sea level
Compression ratio: 7:1
Power-to-weight ratio: 0.64 hp/lb (1.05 kW/kg)

References

Notes

^ ^a ^b ^c ^d Bridgman 1988

Bibliography

Bridgman, Leonard (1988). Jane's Fighting Aircraft of World War II. New York: Crescent Books. ISBN 0-517-67964-7.

[janes-1] Bridgman 1988

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