Jacobs R-915

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Type Radial engine
Manufacturer Jacobs Aircraft Engine Company
Developed from Jacobs R-755

The Jacobs R-915 or L-6 is a seven-cylinder, air-cooled, radial engine for aircraft manufactured in the United States, production started in 1936.[1]

Design and development[edit]

The R-915 was effectively an enlargement of the R-755 with strengthened stressed parts. With a bore and stroke of 5.5 in × 5.5 in (140 mm × 140 mm), for a displacement of 915 cu in (15 L). Takeoff power was around 330 hp (250 kW). The engine features steel cylinders with aluminum-alloy cylinder heads.


Baseline variant; an enlarged R-755
Similar to the A1 but with Scintilla magnetoes
With a power take-off for autogyros


Engines on display[edit]

Specifications (R-915A1)[edit]

Data from Jane's[4]

General characteristics

  • Type: 7-cylinder air-cooled radial piston engine
  • Bore: 5.5 in (140 mm)
  • Stroke: 5.5 in (140 mm)
  • Displacement: 915 cu in (15 L)
  • Length: 40 in (1,030 mm)
  • Diameter: 45.5 in (1,160 mm)
  • Dry weight: 555 lb (252 kg)


  • Valvetrain: 2 valves per cylinder (pushrod-actuated); sodium cooled exhaust valves
  • Fuel system: Single Stromberg[disambiguation needed] 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


See also[edit]

Related development

Comparable engines

Related lists



  1. ^ Gunston 1989, p.85.
  2. ^ Nanton Lancaster Society: Jacobs L-6 MB Retrieved: 23 July 2015
  3. ^ The Canadian Museum of Flight - L-6 Retrieved: 31 January 2009
  4. ^ Janes 1989, p.305.


  • Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9
  • Jane's Fighting Aircraft of World War II. London. Studio Editions Ltd, 1989. ISBN 0-517-67964-7

External links[edit]