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.

Design and development

The R-755 was first run in 1933 and was still in production in the 1970s. With a

bore Bore or Bores often refer to: *Boredom * Drill Relating to holes * Boring (manufacturing), a machining process that enlarges a hole ** Bore (engine), the diameter of a cylinder in a piston engine or a steam locomotive ** Bore (wind instruments), ...

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 A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infini ...

with aluminum-alloy

cylinder head In an internal combustion engine, the cylinder head (often abbreviated to simply "head") sits above the cylinder (engine), cylinders and forms the roof of the combustion chamber. In sidevalve engines, the head is a simple sheet of metal; whereas ...

s. An R-755E variant was developed for use in helicopters.

Variants

;R-755A1:The base-line direct drive production version. ;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. ;R-755B2:De-rated version of the R-755A to drive a variable or controllable pitch airscrew. ;R-755E:Up-rated engine with reduction gearing. ;R-755EH:Developed to power the Jacobs Type 104 Gyrodyne.

Applications

Anahuac Tauro __NOTOC__ The Anahuac Tauro is a Mexican agricultural aircraft built in small numbers in the late 1960s and 1970s. The first prototype flew on 3 December 1968, with Mexican Type certification (the first type approved by Mexico's DGAC) following on ...

* Beechcraft Model 17 Staggerwing (B17L, C17L, E17L) * Boeing-Stearman PT-18 Kaydet *

Cessna AT-17 Bobcat The Cessna AT-17 Bobcat or Cessna Crane is a twin-engine advanced trainer aircraft designed and made in the United States, and used during World War II to bridge the gap between single-engine trainers and larger multi-engine combat aircraft. Th ...

* Cessna 195 * Funk F-23 *

Grumman G-164 Ag Cat The Grumman G-164 Ag Cat is a single-engined biplane agricultural aircraft, developed by Grumman in the 1950s. Development In 1955, Grumman preliminary design engineers Joe Lippert and Arthur Koch proposed the design for a "purpose-built" ...

* Kellett KD-1 * Lascurain Aura *

Morane-Saulnier MS.505 Criquet The Fieseler Fi 156 ''Storch'' (, "stork") was a German liaison aircraft built by Fieseler before and during World War II. Production continued in other countries into the 1950s for the private market. It was notable for its excellent short fiel ...

* Waco F series (YMF, YPF) * Waco Custom Cabin series (YOC, YQC) * Waco Standard Cabin series (YKC, YKC-S, YKS-6) *

Waco PG-3 The Waco CG-15 was an American military glider, which was developed from the CG-4. Although outwardly similar to its predecessor and carrying the same number of passengers, a number of changes in the design, including shortened wings and a more ...

(twin-engined powered version of Waco CG-15 glider, prototype only)

Engines on display

* A preserved Jacobs R-755 is on display at the Arkansas Air Museum. * A Jacobs R-755 is on public display at the Aerospace Museum of California *A preserved Jacobs R-755 is on display a
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)

References

External links

The Jacobs Engine - Nanton Lancaster Society

FAA Type Data Certificate Sheet - R-755

Jacobs Engine Powered Plymouth Truck
{{US military piston aeroengines 1930s aircraft piston engines Aircraft air-cooled radial piston engines Jacobs aircraft engines