Jacobs R-830

R-830
R-830
Type	Radial engine
Manufacturer	Jacobs Aircraft Engine Company
First run	1935
Developed from	Jacobs R-755
Developed into	Jacobs R-915

The Jacobs R-830 or L-5 is a seven-cylinder, air-cooled, radial engine for aircraft manufactured in the United States by the Jacobs Aircraft Engine Company, beginning in 1935.

Design and development

The R-830 was effectively an enlargement of the R-755 with strengthened stressed parts. With a bore and stroke of 5.0 in × 5.5 in (140 mm × 127 mm) the displacement was 831 cu in (13.6 L), takeoff power was around 285 hp (212 kW). The engine features steel cylinders with aluminum-alloy cylinder heads.

Variants

L-5: Dual battery
L-5M: Dual magneto

Applications

Specifications (L-5)

Data from FAA TCDS

General characteristics

Type: 7-cylinder air-cooled radial piston engine
Bore: 5.5 in (140 mm)
Stroke: 5.0 in (127 mm)
Displacement: 831 cu in (13.6 L)
Dry weight: 515 lb (234 kg)

Components

Valvetrain: 2 valves per cylinder (pushrod-actuated); sodium cooled exhaust valves
Fuel system: Stromberg NA-R7A carburetor
Fuel type: 73 octane
Cooling system: Air-cooled
Reduction gear: Direct drive, right hand tractor

Performance

Power output: 285 hp (212 kW) at 2,000 rpm at sea level
Compression ratio: 6:1
Power-to-weight ratio: 0.55 hp/lb (0.9 kW/kg)

References

Notes

↑ Gunston 1989, p.85.
1 2 "The Jacobs 285 H.P. L-5 & L-5M Engines". Aero Digest. Vol. 28, no. 3. Aeronautical Digest Publishing Corporation. March 1936. p. 36. Retrieved 9 October 2026.
↑ FAA TCDS Retrieved: 31 January 2009

Bibliography

Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9

External links

The Jacobs Engine - Nanton Lancaster Society

[1] Gunston 1989, p.85.

[AeroDigest-2] 1 2 "The Jacobs 285 H.P. L-5 & L-5M Engines". Aero Digest. Vol. 28, no. 3. Aeronautical Digest Publishing Corporation. March 1936. p. 36. Retrieved 9 October 2026.

[3] FAA TCDS Retrieved: 31 January 2009

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-1740 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 R-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