
Lycoming Engines is a major American manufacturer of aircraft engines. With a factory in Williamsport, Pennsylvania, Lycoming produces a line of horizontally opposed, air-cooled, four, six and eight-cylinder engines. The company has built more than 325,000 piston aircraft engines and powers more than half the world's general aviation fleet, both rotary and fixed wing. Lycoming has been a principal pioneer of turbine engines for medium and large helicopters, and has also produced engines for small jetliners and business jets. Lycoming is an operating division of Avco Corporation, itself a subsidiary of Textron.

Williamsport (Pennsylvania), United States
Component or engine plant
ALF502, IO-540
Every plant is checked against the company’s own website — or that of whoever inherited its history — and placed in its town. A green dot is a working plant; an amber one has closed.
Lycoming dates its founding to 1845 by "Madame Ellen Curtis Demorest". However, the early history of the company (especially prior to 1860) is unclear; biographer Ishbel Ross notes that the marriage of Ellen Louise Curtis to William Jennings Demorest took place in 1858, somewhat later than the purported date of establishment of the company. A few years later in New York, between c. 1860 and 1887, the Demorests published fashion magazines and operated the Demorest Fashion and Sewing-Machine Company (sometimes known as the Demorest Manufacturing Company). They produced "Madame Demorest" and "Bartlett & Demorest" sewing machines and sold Ellen Demorest's innovative paper patterns for dressmaking. During this period, Ellen Demorest patented several fashion accessories, while her husband patented improvements to sewing machines and an apparatus for the vulcanization of rubber.
Around 1883, Gerrit S. Scofield & Frank M. Scofield (advertising agents from New York) bought the Demorest brand and the sewing machine business (the Demorests retained the magazine business), and constructed a factory in Williamsport, Pennsylvania (in Lycoming County). At the urging of the newly established Williamsport Board of Trade, citizens invested US$100, 000 in the new manufacturing facility, which employed 250 people. The factory produced 50 to 60 sewing machines per day.
With the development of the "New York Bicycle" in 1891 (designed by employee S. H. Ellis), the company diversified its product offerings. Until the early 1900s, the factory produced sewing machines, bicycles, typewriters, opera chairs and other products.
By 1907, the manufacture of sewing machines had become unprofitable for Demorest, and the company was sold and restructured as the Lycoming Foundry and Machine Company, shifting its focus toward automobile engine manufacture. In 1910, the company supplied its first automobile engine to Velie, and during the early post-World-War-I era, the company was a major supplier to Auburn (which produced the Auburn, Cord, and Duesenberg lines).
By 1920, Lycoming was producing 60,000 engines a year, with a 2,000-strong workforce. To handle the capacity, a new foundry complex was built in Williamsport that year. Eventually Lycoming became Auburn's principal supplier, and in 1927 Errett Lobban Cord bought the company, placing it under his Auburn Manufacturing umbrella group.
Among the engines Lycoming produced for Cord was an L-head straight-eight engine of 298.5 cu. in. displacement that produced 125 horsepower. This was used in the Cord L-29. Lycoming also produced a double overhead cam straight 8 used in the legendary Duesenberg J series. This powerplant produced 265 horsepower, six times the power of a contemporary Model A Ford. A supercharged version, generating 325 horsepower, was installed in the Duesenberg SJ and SSJ models.
In 1929, Lycoming produced its first aviation engine, the nine-cylinder R-680 radial. This was a fairly successful design, and was used widely in light aircraft, including Cord's Travel Air.
In the 1930s, Lycoming made a number of attempts to develop successful high-power aircraft engines. The 1 200 hp (895 kW) O-1230 was Lycoming's attempt to produce an engine based on the United States Army Air Corps hyper engine concept, and used a variety of features to produce nearly 1 hp/in3 (46 kW/L) of engine displacement. However, by the O-1230's entry into service, it had been surpassed by other designs and the US$500 000 investment was not recouped.
Another attempt was made to rescue the design by stacking two O-1230s to make the 2 300 hp (1 700 kW) H engine H-2470 but the only design to use it, the Vultee XP-54, never entered production. The Curtiss XF14C was originally intended to be powered by the H-2470, but the engine's poor performance led to the adoption of an alternative radial engine on the prototype. (The XF14C did not enter production.)
Undeterred by the O-1230/H-2470's failure, Lycoming turned to an even larger design, the 36-cylinder XR-7755, the largest aviation piston engine ever built. This design also experienced problems, and was only ready for use at the very end of World War II, when the aviation world was turning to turbojets and turboprop engines to power future large aircraft. There was apparently some interest in using it on the Convair B-36 Peacemaker bomber, but the 28-cylinder Pratt & Whitney R-4360 Wasp Major four-bank radial was used instead.
Through the 1920s and -30s, Lycoming had still been supplying automotive manufacturers with engines. However, these clients each slowly went out of business or switched to Continental engines for their vehicles. By 1931, the company was supplying automotive engines to only three companies: Auburn, Cord and Duesenburg, still all under the control of Cord. These companies closed their doors in 1937, after which Lycoming switched to exclusively designing and producing engines for aviation.
The engine families of its own that power aircraft in the encyclopedia.
The aircraft families in the encyclopedia that fly on its engines.
The airlines with the most of its aircraft in our documented fleet; this is not a ranking of its order book.
Identity, founding and headquarters from Wikidata; the narrative from Wikipedia (CC BY-SA). Plants checked one by one on each company’s own website. Counts are of our documented fleet.
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This page was last updated on September 28, 2026
APA
Vuelopedia. (2026, September 28). Lycoming. Retrieved October 19, 2026, from https://vuelopedia.org/en/manufacturer/lycoming
MLA
“Lycoming.” Vuelopedia, Fundación Poderia, 28 Sept. 2026, vuelopedia.org/en/manufacturer/lycoming. Accessed 19 Oct. 2026.
Chicago
Vuelopedia. “Lycoming.” Fundación Poderia. Last modified September 28, 2026. https://vuelopedia.org/en/manufacturer/lycoming.
Harvard
Vuelopedia (2026) Lycoming. Available at: https://vuelopedia.org/en/manufacturer/lycoming (Accessed: 19 October 2026).
BibTeX
@misc{vuelopedia_en_manufacturer_lycoming,
author = {{Vuelopedia}},
title = {{Lycoming}},
publisher = {Fundación Poderia},
year = {2026},
date = {2026-09-28},
url = {https://vuelopedia.org/en/manufacturer/lycoming},
howpublished = {\url{https://vuelopedia.org/en/manufacturer/lycoming}},
urldate = {2026-10-19},
note = {Accessed 2026-10-19}
}Wikipedia
{{cite web |url=https://vuelopedia.org/en/manufacturer/lycoming |title=Lycoming |website=Vuelopedia |publisher=Fundación Poderia |date=2026-09-28 |access-date=2026-10-19 |language=en}}