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

[1]

v t e Lycoming aircraft engines
Opposed piston engines	O-145 O-233 IO-233 O-235 O-290 O-320 O-340 O-360 (O-360 variants) IO-390 O-435 O-480 O-540 TIO-541 GSO-580 IO-580 IO-720 O-1230
Radial engines and H engines	R-680 XR-7755 XH-2470
Aircraft diesel engines	DEL-120
Turbofans	PLF1 ALF 502/YF102 LF 507
Turboprops/Turboshafts	AGT1500 LTS101/LTP101 T53 T55
Aero-derivative marine gas turbines	TF-40
Joint development	Avco (Lycoming)/Pratt & Whitney: T800-APW (Turboshaft)
See also	AlliedSignal Aerospace/Honeywell Aerospace

v t e United States military piston aircraft engine designation system
H (four-bank H-configuration inline)	H-1640 XH-2240 XH-2470 XH-2600 XH-3130 XH-3730 H-4070
IV (inverted-V inline)	IV-1430 IV-2040 IV-2220
L (single-bank inline)	L-330 L-365 L-375 L-390 L-410 L-440 L-510 L-825
O (opposed)	O-15 O-40 O-45 O-90 O-100 O-145 O-150 O-170 O-175 O-180 O-190 O-200 (C) O-200 (F) O-205 O-235 O-290 O-300 O-335 O-360 (C) O-360 (L) O-405 O-425 O-435 O-470 O-480 O-520 O-540 (F) O-540 (L) O-550 O-580 O-805 O-1230
R (radial)	R-250 R-265 R-270 R-370 (LB) R-370 (K) R-420 R-440 R-500 R-540 (W) R-540 (K) R-545 R-550 R-600 R-670 R-680 R-720 R-755 R-760 R-790 R-830 R-915 R-975 DR-980 R-985 R-1044 R-1300 R-1340 R-1454 R-1510 R-1535 R-1640 R-1670 R-1690 R-1750 R-1820 R-1830 R-1860 R-2000 R-2060 R-2160 R-2180 R-2600 R-2800 R-3350 R-4090 R-4360 XR-7755
V (upright-V inline)	V-720 V-1150 V-1237 V-1400 V-1440 V-1460 V-1510 V-1560 V-1570 V-1650 (P) V-1710 V-1950 V-3420
V (inverted-V inline)	V-770 V-1650 (L)
VG (inverted-V inline)	VG-1410
W (three-bank W-configuration inline)	W-2779
See also: X-1800 US military gas turbine aeroengines Piston engine configurations