Lycoming Engines

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Lycoming Engines
IndustryAerospace industry
Founded1845; 176 years ago (1845)
FounderMadame Ellen Curtis Demorest
HeadquartersWilliamsport, Pennsylvania
ProductsAircraft engines

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 including the only FAA-certified aerobatic and helicopter piston engines on the market.

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 is an operating division of Avco Corporation, itself a subsidiary of Textron.[1]


Sewing machines, bicycles and fashion[edit]

Demorest Manufacturing Company Machine

Lycoming dates its founding to 1845 by "Madame Ellen Curtis Demorest".[2] However, the early history of the company (especially prior to 1860) is unclear;[3] 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.[3] 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.[3] During this period, Ellen Demorest patented several fashion accessories,[4][5] while her husband patented improvements to sewing machines[3] and an apparatus for the vulcanization of rubber.[6][7]

A Demorest print advertisement

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).[3][8] 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.[3] The factory produced 50 to 60 sewing machines per day.[9] With the development of the "New York Bicycle" in 1891 (designed by employee S. H. Ellis), the company diversified its product offerings.[3][9] Until the early 1900s, the factory produced sewing machines, bicycles, typewriters, opera chairs and other products.[2][3][9]

Engine manufacture[edit]

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.[2][3] In 1910, the company supplied its first automobile engine to Velie,[10] 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.[11] Eventually Lycoming became Auburn's principal supplier, and in 1927 Errett Lobban Cord bought the company,[10] 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.[2] 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.[12] 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.[13] These companies closed their doors in 1937,[14] after which Lycoming switched to exclusively designing and producing engines for aviation.[13]

In 1939 Cord re-organized all of his aviation holdings into the AVCO group, at which point the engine manufacturing company became "AVCO Lycoming". it also leased the government-owned Stratford Army Engine Plant in Stratford, Connecticut and produced Wright radials under license. After the war, this plant was converted to produce the T53 turboshaft engine, one of its more successful designs. From this point on the piston and turbine engine lines remained separate, with the piston lines being built in the original Williamsport factories, and turbines in Stratford.

By 1961, Lycoming produced 600 to 700 engines per month.[12] Its most successful post-war products were a series of air-cooled flat-4 and flat-6 general aviation engines. Most famous among these are the O-235 and O-360 four-cylinder engines, and the O-540 six-cylinder engine. Many light aircraft are powered by versions of these engines, with power ratings in the 100–360 hp (75–270 kW) range. Engines in this series also include the O-320 four-, O-580 six- and O-720 eight-cylinder engines, and the advanced turbocharged and fuel-injected 450 hp (340 kW) TIGO-541 variant of the venerable (carbureted) O-540.

In the early 1980s, the general aviation market suddenly diminished and Lycoming's piston engine business was significantly impacted. Attempts were made to move some of the turbine production to Williamsport, but this led to a series of quality control problems and eventually it was abandoned.

Another attempt to rescue Williamsport was made in introducing the "radical" SCORE engine, a Wankel engine originally developed through a joint venture between Curtiss-Wright and John Deere. Curtiss-Wright lost interest in the design just as it was maturing and sold its interests in the project to Deere, which brought in Lycoming to sell the developed engine into the aviation markets. It was guaranteed a startup run by Cessna, also owned by Textron. Just as production was ready to start, Cessna announced it was halting its small-aircraft business for an indefinite period, and SCORE was cancelled. The remains of the Deere licenses were later purchased by Rotary Power International, which briefly produced a 340 hp (254 kW) version.

Textron purchased the company in 1985.[15] In 1994, Textron sold the Lycoming Turbine Engine Division, located in Stratford, Connecticut to AlliedSignal, who merged it with the Garrett Engine Division of AlliedSignal as part of AlliedSignal Aerospace, later becoming part of Honeywell Aerospace in 1999.[16] Textron retained piston engine production in Williamsport.


The aircraft piston engine prefixes are:[17]

  • A—Aerobatic (dry sump)
  • AE—Aerobatic (wet sump)[18]
  • E—Electronic
  • G—Geared (reduction gear)
  • H—Helicopter
  • I—Fuel injected
  • L—Left hand rotation crankshaft
  • M—Designed for unmanned drone
  • O—Opposed cylinders
  • R—Radial cylinders
  • S—Supercharged
  • T—Turbocharged
  • V—Vertical installation (usually for helicopters)
  • X—X-type engine
  • Y—Experimental

Piston engines[edit]

  • Lycoming DEL-120, 4-cylinder, non-certified military turbodiesel, 205 hp[19][20] in production.
  • Lycoming O-145, 4-cylinder, 1938, 75hp, out of production.
  • Lycoming IO-233-LSA, 4-cylinder, 100–116 hp (75–87 kW) non-certified, introduced 2008 in production.
  • Lycoming O-235, 4-cylinder, 108–118 hp (81–88 kW), introduced in 1940 and still produced, widely used on the Cessna 152 and similar GA designs, still in production.
  • Lycoming O-290, 4-cylinder, 125 hp (93 kW), downsized version of the 435 introduced in 1942 and largely ignored for aviation use, but widely used in ground-power carts sold to the US military, out of production.
  • Lycoming O-320, 4-cylinder, 150–160 hp (112–119 kW), widely used on old Cessna 172.
  • Lycoming O-340, 4-cylinder, 170 hp, out of production.
  • Lycoming O-360, 4-cylinder, 145-225 hp, introduced in 1955 and widely used ever since on new Cessna 172 , formed the basis for the 540 and 720, in production.
  • Lycoming IO-390, 4-cylinder, 210 hp (157 kW), announced 2008, used in Cirrus SR20 and Tecnam P2010 in production.
  • Lycoming O-435, 6-cylinder, 185–260 hp (137–194 kW), also developed as a tank engine, out of production.
  • Lycoming O-480, 6-cylinder, 340 hp, out of production.
  • Lycoming O-540, 6-cylinder, 230–350 hp (172–261 kW), widely used on the Piper Navajo, Comanche, Cessna 206 in production.
  • Lycoming TEO-540, 6-cylinder electronic controlled, 2500-2575RPM, 350-400HP used by the Tecnam P2012 Traveller
  • Lycoming TIO-541, 6-cylinder, 310-450 hp, improved 540, featuring turbocharging on all models, in production.
  • Lycoming IO-580, 6-cylinder, 300 hp (223 kW), introduced in 1997 in production,
  • Lycoming GSO-580, 8-cylinder, 375-400 hp, original "580", produced from 1948 to 1961, out of production.
  • Lycoming R-680, 9-cylinder radial, 1929, 220–295 hp (164–220 kW), Lycoming's first engine, out of production.
  • Lycoming IO-720, 8-cylinder, 400 hp (298 kW) engine introduced in 1961, still produced.
  • Lycoming O-1230, 12-cylinder flat, 1275 hp, prototype engine, out of production.
  • Lycoming H-2470, 24-cylinder H-configuration, 2300 hp, prototype hyper engine, out of production.
  • Lycoming XR-7755, 36-cylinder radial multibank liquid-cooled engine, 5000 hp, largest aircraft piston engine ever built, out of production.

Turbine engines[edit]

See also[edit]



  1. ^ Textron Legal Entitie
  2. ^ a b c d "History". Lycoming Engines. 2017. Retrieved 2017-08-16.
  3. ^ a b c d e f g h i Kelly (November 2006). "Demorest Sewing Machine Company History". Archived from the original on 2009-06-14. Retrieved 2008-12-30.
  4. ^ US 87648, Demorest, E. L. & W. G. Cook, "Brace and Suspender Combined", published 1869-03-05 
  5. ^ US 264935, Demorest, E. L., "Puff for Head-Dresses", published 1882-03-09 
  6. ^ US 23948, Roberts, Edward A. L. & William J. Demorest, "Apparatus for Vulcanizing Rubber" 
  7. ^ US RE 1444, Roberts, Edward A. L. & William J. Demorest, "Improvement in Apparatus for Vulcanizing Rubber, &c." 
  8. ^ "Names Obtained by Fraud". New York Times. 1888-11-04. p. 9. ISSN 0362-4331. Retrieved 2008-12-30.
  9. ^ a b c Kevin McQuown. "Lycoming County's Old Days". Williamsport Area High School Website. Williamsport Area School District. Archived from the original on 2015-07-09. Retrieved 2008-12-30.
  10. ^ a b "The Lycoming Museum" (PDF). Lycoming. Archived from the original (PDF) on 13 February 2012. Retrieved 25 October 2020.
  11. ^ "Sewing Machines to Straight-Eights | Hemmings Motor News". Retrieved 2016-08-12.
  12. ^ a b Richard Bach (December 1961). "Lycomings Piston Engines". Flying Magazine.
  13. ^ a b "Sewing Machines to Straight-Eights | Hemmings Motor News". Retrieved 2016-08-12.
  14. ^ "ACD Co. Story". AUBURN-CORD-DUESENBERG CO. Archived from the original on 2016-08-17. Retrieved 2016-08-12.
  15. ^ "History | Textron". Retrieved 2016-08-12.
  16. ^ Leyes, p. 725
  17. ^ Lycoming (2004). "360 Series" (PDF). Archived from the original (PDF) on 2010-11-26. Retrieved 2008-09-16.
  18. ^ "Aerobatic engines" (PDF). Retrieved 2011-03-19.
  19. ^ "Diesels on the Cusp". AOPA Pilot: 88. March 2015.
  20. ^ Video: A Look at Lycoming's Diesel Engine


  • Gunston, Bill (2006). World Encyclopedia of Aero Engines, 5th Edition. Phoenix Mill, Gloucestershire, England, UK: Sutton Publishing Limited. ISBN 0-7509-4479-X.
  • Leyes II, Richard A.; William A. Fleming (1999). "10". The History of North American Small Gas Turbine Aircraft Engines. Washington, DC: Smithsonian Institution. p. 725. ISBN 1-56347-332-1.

External links[edit]