Jacobs R-755
| R-755 / L-4 | |
|---|---|
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| Jacobs R-755 on display at the Evergreen Aviation & Space Museum |
The Jacobs R-755 (company designation L-4) is a seven-cylinder, air-cooled, radial engine for aircraft manufactured in the United States by the Jacobs Aircraft Engine Company.[1]
Design and development
The R-755 was first run in 1933 and was still in production in the 1970s. With a bore and stroke of 5.25 in × 5 in (133 mm × 127 mm) the displacement was 757 cu in (12.4 L), power ranged from 200 hp to 350 hp (150 kW - 260 kW). The engine features steel cylinders with aluminum-alloy cylinder heads. An R-755E variant was developed for use in helicopters.
Variants
- R-755A1
- The base-line direct drive production version.[2]
- R-755A2
- 300 hp variant.
- R-755A3
- Similar to A1 but with Scintilla magnetoes.
- R-755B1
- De-rated version of the R-755A to drive a fixed pitch airscrew.[2]
- R-755B2
- De-rated version of the R-755A to drive a variable or controllable pitch airscrew.[2]
- R-755E
- Up-rated engine with reduction gearing.[2]
- R-755EH
- Developed to power the Jacobs Type 104 Gyrodyne.[2]
Applications
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Engines on display
- A preserved Jacobs R-755 is on display at the Arkansas Air Museum.[3]
- A Jacobs R-755 is on public display at the Aerospace Museum of California
- A preserved Jacobs R-755 is on display at Super T Aviation Academy in Medicine Hat, Canada.
- A restored Jacobs R-755A is on display at the House of Whitley.
Specifications (R-755-A1)
Data from Jane's fighting aircraft of World War II,[4] Jane's all the World's Aircraft 1938[5]
General characteristics
- Type: 7-cylinder air-cooled radial piston engine
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- Displacement: 757 cu in (12.4 L)
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Components
- Valvetrain: 2 valves per cylinder, pushrod-actuated, sodium-cooled exhaust valves
- Fuel system: Single Stromberg NA-R7A carburetor
- Fuel type: 73 octane
- Oil system: One pressure pump, two scavenge pumps
- Cooling system: Air-cooled
- Reduction gear: Direct drive, right hand tractor
Performance
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- Specific power: 0.32 hp/cu-in (14.8 kW/L)
- Power-to-weight ratio: 0.48 hp/lb (0.8 kW/kg)
See also
Comparable engines
Related lists
References
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- ↑ Arkansas Air Museum - Jacobs R-755 Script error: No such module "webarchive". Retrieved: 31 January 2009
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External links
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- The Jacobs Engine - Nanton Lancaster Society
- FAA Type Data Certificate Sheet - R-755 Script error: No such module "webarchive".
- Jacobs Engine Powered Plymouth Truck
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