Wright R-540

The Wright R-540 Whirlwind was a series of 5-cylinder air-cooled radial aircraft engines built by the Wright Aeronautical division of Curtiss-Wright. These engines had a displacement of 540 cubic inches (8.85 liters) and a power rating of 165 to 175 horsepower (123 to 130 kW). They were the smallest members of the Wright Whirlwind engine family.

The Wright R-540 should not be confused with the Kinner R-540, a generally similar engine made by Kinner Airplane & Motor Corporation.

History

Wright first introduced the J-6 Whirlwind family in 1928. This family, which had larger cylinders than the previous J-5, originally included varieties with seven and nine cylinders. In 1929, Wright introduced a five-cylinder version, the J-6 Whirlwind Five, designated as R-540 by the U.S. government.

Like all the members of the J-6 Whirlwind family, the R-540 had a piston stroke of 5.5 inches (14.0 cm), unchanged from the J-5, but a cylinder bore of 5.0 inches (12.7 cm), expanded from the J-5's bore of 4.5 inches (11.4 cm). While the J-5 was naturally aspirated, the R-540, like the other J-6 engines, had a gear-driven supercharger to boost its power output.

The R-540 was lighter and less powerful than previous examples in the Whirlwind family and was designed for small aircraft. One of the more popular types to use it was the Curtiss Robin, a light civil utility aircraft. A few were also used in trainer aircraft that were evaluated by the U.S. Army but not put into production.

The R-540 sold well at first, with over 400 engines being built in 1929.Citation|title=Summary of Wright Engine Shipments: 1920 to 1963|url=http://enginehistory.org/Wright/WrightProd.pdf|accessdate=2008-09-12. Transcribed from Wright Aeronautical documents by Robert J. Neal T; available from the [http://enginehistory.org Aircraft Engine Historical Society's] [http://enginehistory.org/reference.htm reference page] .] However, with the impact of the Great Depression, sales plummeted, and only about 100 further examples were built over the next eight years. Wright finally ceased production of five-cylinder Whirlwinds in 1937, concentrating on larger engines and leaving the market for small radials to companies like Kinner and Warner.

During Wright's production of the R-540, the engine was gradually refined, and its name also changed several times. Wright soon dropped their original "J-6" family designation and adopted the government's R-540 designation, with a suffix letter to indicate the version. The name changed from "Whirlwind Five" to Whirlwind 165, based on the engine's power rating of 165 horsepower (123 kW). In 1931, the R-540E was introduced, with an improved cylinder head boosting power to 175 horsepower (130 kW), and the name was updated to Whirlwind 175. [Citation|title=Wright Engines - Past and Present|url=http://enginehistory.org/Wright/CWthrough1940.pdf|last=Curtiss-Wright|author-link=Curtiss-Wright|year=1940|page=13|accessdate=2008-09-12. Available from the [http://enginehistory.org Aircraft Engine Historical Society's] [http://enginehistory.org/reference.htm reference page] .]

Since R-540 engines were found solely in light aircraft, they weren't normally used for groundbreaking flights. However, there were a couple of noteworthy exceptions which took advantage of the Whirlwind family's reputation for high reliability. In 1935 the brothers Al and Fred Key set a new flight endurance record of 653 hours, 34 minutes in the Curtiss Robin J-1 "Ole Miss", flying over Meridian, Mississippi, from June 4 to July 1. Their plane was refueled and resupplied in flight, and they could perform simple engine maintenance by walking out on a small catwalk extending between the cabin and the engine. Douglas "Wrong-Way" Corrigan's famous unauthorized transatlantic flight from New York City to Dublin, Ireland on July 17-18, 1938, used a Curtiss Robin with an R-540 built from the parts of two used engines.

Variants

* J-6 Whirlwind Five: Original production version, 1929.
* R-540A Whirlwind 165: Slightly later version, 165 hp (123 kW) @ 2000 RPM. U.S. Army designation R-540-1.Citation|title=Model Designations of USAF Aircraft Engines: Section I, Reciprocating Engine Characteristics|url=http://enginehistory.org/ModDesig/SecI.pdf|last=USAF Air Materiel Command|date=1949-01-01|page=8|access-date=2008-09-12. Available from the [http://enginehistory.org Aircraft Engine Historical Society's] [http://enginehistory.org/moddesig.htm page for this document] .]
* R-540E Whirlwind 175: Version with improved cylinder head, 1931, 175 hp (130 kW) @ 2000 RPM. U.S. Army designation R-540-3.
* GR-540E: R-540E with propeller reduction gearing of 1.58:1 or 2:1.Citation|title=Approved Type Certificate No. 23 (ATC 23) data sheet|url=http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgMakeModel.nsf/0/DC281F1481D67B3A8525670E006674D6?OpenDocument|last=Federal Aviation Administration|author-link=Federal Aviation Administration|accessdate=2008-09-12. Available from the FAA's [http://rgl.faa.gov Regulatory and Guidance Library] .]

Specifications (R-540E Whirlwind 175)

pistonspecs

ref=Type certificate data sheet for the R-540E; dimensions from a Curtiss-Wright reference. [Citation|title=Historical Engine Summary|url=http://enginehistory.org/Wright/CWafter1930_2.pdf|last=Curtiss-Wright|author-link=Curtiss-Wright|page=1|accessdate=2008-09-12. Available from the [http://enginehistory.org Aircraft Engine Historical Society's] [http://enginehistory.org/reference.htm reference page] .]
type=5-cylinder supercharged air-cooled radial piston engine
bore=5.0 in (127 mm)
stroke=5.5 in (140 mm)
displacement=540 cu in (8.85 L)
length=41.1 in (104.4 cm)
diameter=45.0 in (114.3 cm)
width=
height=
weight=420 lb (191 kg)
valvetrain=2 valves per cylinder, pushrod-actuated
supercharger=gear-driven, 7.05:1 impeller gear ratio
turbocharger=
fuelsystem=
fueltype=65 octane
oilsystem=
coolingsystem=
power=175 hp (130 kW) @ 2000 RPM
specpower=0.324 hp/cu-in (14.7 kW/L)
compression=5.1:1
fuelcon=
specfuelcon=
oilcon=
power/weight=0.417 hp/lb (0.685 kW/kg)

designer=
reduction_gear=

general_other=
components_other=
performance_other=

Applications

*Curtiss Robin J-1
*Kreider-Reisner Challenger C-4C (Fairchild KR-34C)
*Spartan C3-165
*Stinson Junior SM-2AA and SM-2AB
*Travel Air E-4000
*Waco BSO

Engines on display

Wright R-540 engines on display are uncommon, but there is one at the Strategic Air and Space Museum (formerly the Strategic Air Command Museum) near Ashland, Nebraska. [Citation|title=Aircraft Engines|url=http://passion-aviation.qc.ca/engines.htm|accessdate=2008-09-11. This personal collection of museum aircraft engine photos includes a photo of a Wright R-540 under the SAC Museum section. (The page mislabels it as a "Wright R-540 J-5"—there never was a 5-cylinder version of the J-5.)]

ee also

*Wright Whirlwind
*List of aircraft engines

References