The Wright R-540 Whirlwind was a series of five-cylinder air-cooled

radial Radial is a geometric term of location which may refer to: Mathematics and Direction * Vector (geometric), a line * Radius, adjective form of * Radial distance, a directional coordinate in a polar coordinate system * Radial set * A bearing f ...

aircraft engine An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Most aircraft engines are either piston engines or gas turbines, although a few have been rocket powered and in recent years many ...

s built by the

Wright Aeronautical Wright Aeronautical (1919–1929) was an American aircraft manufacturer headquartered in Paterson, New Jersey. It was the successor corporation to Wright-Martin. It built aircraft and was a supplier of aircraft engines to other builders in the ...

division of

Curtiss-Wright The Curtiss-Wright Corporation is a manufacturer and services provider headquartered in Davidson, North Carolina, with factories and operations in and outside the United States. Created in 1929 from the consolidation of Curtiss, Wright, and v ...

. These engines had a

displacement Displacement may refer to: Physical sciences Mathematics and Physics *Displacement (geometry), is the difference between the final and initial position of a point trajectory (for instance, the center of mass of a moving object). The actual path ...

of 540 in³ (8.85 L) and power ratings of around 165-175 hp (123-130 kW). They were the smallest members of the

Wright Whirlwind The Wright Whirlwind was a family of air-cooled radial aircraft engines built by Wright Aeronautical (originally an independent company, later a division of Curtiss-Wright). The family began with nine-cylinder engines, and later expanded to incl ...

engine family.

Design and development

Wright introduced the J-6 Whirlwind family in 1928 to replace the nine-cylinder R-790 series. The J-6 family included varieties with five, seven, and nine cylinders. The five-cylinder version was originally known as the J-6 Whirlwind Five, or J-6-5 for short. The U.S. government designated it as the R-540; Wright later adopted this and dropped the J-6 nomenclature. Like all the members of the J-6 Whirlwind family, the R-540 had larger cylinders than the R-790. The piston

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of 5.5 in (14.0 cm) was unchanged, but the cylinder bore was expanded to 5.0 in (12.7 cm) from the R-790's bore of 4.5 in (11.4 cm). While the R-790 was

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, the R-540, like the other J-6 engines, had a gear-driven

supercharger In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement. The current categorisation is that a supercharger is a form of forced induct ...

to boost its power output. Wright gradually refined the R-540, using suffix letters to indicate successive versions. For example, the R-540A had 165 hp (123 kW), while the R-540E of 1931 had power boosted to 175 hp (130 kW) thanks to an improved

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

design. Wright sometimes named these versions according to their power, e.g. "Whirlwind 165" or "Whirlwind 175". The engine was built in

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as the Hispano-Suiza 5Q or Hispano-Wright 5Q without modification apart from the use of Hispano's patented nitriding finishing process.

Operational history

The R-540 was the smallest, least powerful member of the Whirlwind family and was designed for light aircraft. One of the more popular types to use it was the

Curtiss Robin The Curtiss Robin, introduced in 1928, was a high-wing monoplane built by the Curtiss-Robertson Airplane Manufacturing Company. The J-1 version was flown by Wrongway Corrigan who crossed the Atlantic after being refused permission. Design The ...

, a light civil utility aircraft. A few were also used in prototype military 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.. Transcribed from Wright Aeronautical documents by Robert J. Neal T; available from the Aircraft Engine Historical Society'
reference page
. However, with the impact of the

Great Depression The Great Depression (19291939) was an economic shock that impacted most countries across the world. It was a period of economic depression that became evident after a major fall in stock prices in the United States. The economic contagio ...

, 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 Kinner Airplane & Motor Corp was an airplane and engine manufacturer, founded, in the mid-1920s, in Glendale, California, United States, by Bert Kinner, the manager of Kinner Field. Kinner's chief engineer was Max B. Harlow who later founded the ...

and

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. Since R-540 engines were found solely in light aircraft, they weren't often 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 Meridian is the List of municipalities in Mississippi, seventh largest city in the U.S. state of Mississippi, with a population of 41,148 at the 2010 United States Census, 2010 census and an estimated population in 2018 of 36,347. It is the count ...

, 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 New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...

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on July 17–18, 1938, used a Curtiss Robin with an R-540 built from the parts of two used engines.

Applications

* Curtiss Robin J-1 * Curtiss-Wright CW-16 * Detroit-Parks P-2A *

Emsco B-7 The Emsco B-4 Cirrus was a mid-wing, two-seat trainer built in the US in the late 1920s. Six were built and three variants with more powerful engines flown. Design The two-seat B-4 trainer was a mid-wing monoplane with wings of rectangular pl ...

* Kreider-Reisner Challenger C-4C (Fairchild KR-34C) * General Aristocrat * Saro Cloud * 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 The Strategic Air Command & Aerospace Museum is a museum focusing on aircraft and nuclear missiles of the United States Air Force during the Cold War. It is located near Ashland, Nebraska, along Interstate 80 southwest of Omaha. The objective of t ...

(formerly the Strategic Air Command Museum) near

Ashland, Nebraska Ashland is a city in Saunders County, Nebraska, United States. The population was 2,453 at the 2010 census. History Ashland is located at the site of a low-water limestone ledge along the bottom of Salt Creek, an otherwise mud-bottomed stream ...

.. 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 five-cylinder version of the J-5.) Another is on display at the Shannon Air Museum in

Fredericksburg, Virginia Fredericksburg is an independent city located in the Commonwealth of Virginia. As of the 2020 census, the population was 27,982. The Bureau of Economic Analysis of the United States Department of Commerce combines the city of Fredericksburg wi ...

Specifications (R-540E)

References

Notes

Bibliography

*. Available from the Aircraft Engine Historical Society'
reference page
. * * *. Available from the Aircraft Engine Historical Society'

. *. Available from the FAA'
Regulatory and Guidance Library
*. Available from the Aircraft Engine Historical Society'

. {{US military piston aeroengines 1920s aircraft piston engines Aircraft air-cooled radial piston engines R-540