Lycoming
American aircraft-engine manufacturer known for piston engines used in general aviation and turbine engines for helicopters and other aircraft.
Last updated August 31, 2026
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Overview
Lycoming is an American aircraft-engine brand and manufacturer based in Williamsport, Pennsylvania. It is an operating division of Avco Corporation, which is owned by Textron. The company is best known for horizontally opposed, air-cooled piston engines used in light aircraft, including four-, six- and eight-cylinder models. Its products are installed in a substantial share of the worldwide general-aviation fleet and are also widely used in experimental and amateur-built aircraft. The business has industrial roots that predate aviation. Its early manufacturing history is associated with the Demorest sewing-machine and fashion business, which established a factory in Williamsport during the late nineteenth century. The factory subsequently diversified into bicycles, typewriters, opera chairs and other products. In the early twentieth century it was reorganized as the Lycoming Foundry and Machine Company and moved into automobile-engine production. Lycoming supplied engines to automobile manufacturers including Velie, Auburn, Cord and Duesenberg. Its engines powered notable vehicles such as the Cord L-29 and Duesenberg J, including high-output versions for the supercharged Duesenberg SJ and SSJ. Lycoming entered aviation-engine production in 1929 with the nine-cylinder R-680 radial engine. During the 1930s it pursued several ambitious high-power piston designs, including the O-1230, the H-2470 and the enormous 36-cylinder XR-7755. These programs were technically significant but did not become successful production powerplants, partly because competing designs and the transition toward turbojet and turboprop propulsion changed the market. After its remaining automotive customers disappeared in the late 1930s, Lycoming concentrated on aviation. During the Second World War and the postwar period, the company expanded into turbine engines. Its T53 turboshaft became associated with the Bell UH-1 Iroquois helicopter, while the larger T55 powered the Boeing CH-47 Chinook and related aircraft. Lycoming turbine derivatives also supported military aircraft, regional jets and business aircraft. In 1994, Textron sold the Stratford, Connecticut turbine-engine business to AlliedSignal; that activity subsequently became part of Honeywell Aerospace. Textron retained the Williamsport piston-engine operation. The modern Lycoming portfolio centers on general-aviation piston engines, including the O-235, O-320, O-360, O-540, O-580 and O-720 families and related fuel-injected, turbocharged and higher-output variants. These engines continue to equip aircraft from manufacturers such as Cessna, Piper, Cirrus and Diamond, as well as experimental aircraft. Lycoming therefore occupies a distinctive position: it is a legacy industrial brand with roots in sewing machines and automobiles, but its enduring commercial identity is tied to certified and experimental aircraft propulsion.
History
Lycoming's origins are linked to the Demorest manufacturing enterprise. The early claim that the company was founded in 1845 is difficult to verify, and the pre-1860 history is uncertain. During the nineteenth century, the Demorest businesses produced sewing machines, fashion accessories and paper dressmaking patterns. In the early 1880s, Gerrit S. Scofield and Frank M. Scofield acquired the sewing-machine operation and established a factory in Williamsport, Pennsylvania, with local financial support. The plant later diversified into bicycles, typewriters, opera chairs and other manufactured goods. By the beginning of the twentieth century, sewing-machine production had become unprofitable. In 1907 the business was reorganized as the Lycoming Foundry and Machine Company and shifted toward automobile engines. Lycoming supplied its first automobile engine to Velie in 1910 and became a major supplier during the following decade. By 1920 it was producing approximately 60,000 engines annually and employed around 2,000 people. Errett Lobban Cord acquired the company in 1927 and placed it within his Auburn Manufacturing interests. Lycoming subsequently supplied engines for Auburn, Cord and Duesenberg automobiles, including straight-eight engines used in the Cord L-29 and Duesenberg J, SJ and SSJ lines. The company entered aviation in 1929 with the R-680 nine-cylinder radial engine. Its interwar development work included the O-1230 high-output engine, the H-2470 formed by combining two O-1230 configurations, and the XR-7755, a 36-cylinder piston engine that was among the largest aircraft piston engines ever built. These projects did not achieve sustained production success. By the late 1930s, Lycoming's automotive customers had disappeared or changed suppliers, and the company focused exclusively on aircraft engines. In 1939, Cord reorganized his aviation holdings into AVCO, and the engine business became known as AVCO Lycoming. The company leased the government-owned Stratford Army Engine Plant in Connecticut and produced Wright radial engines under license. After the war, the Stratford operation developed the T53 turboshaft engine. The T53 became an important helicopter engine and powered the Bell UH-1. Lycoming later developed the much larger T55, which became the principal powerplant for the Boeing CH-47 Chinook and related twin-rotor aircraft. Turbine derivatives also found applications in military aircraft, turboprops, regional jetliners and business aircraft. Lycoming's postwar piston business became centered on air-cooled, horizontally opposed engines for general aviation. The O-235, O-320, O-360, O-540, O-580 and O-720 families covered a broad range of power requirements, with carbureted, fuel-injected, turbocharged and specialized variants. The general-aviation downturn of the early 1980s severely affected piston-engine demand. Attempts to relocate turbine production to Williamsport created quality-control difficulties, while a proposed SCORE rotary engine program was cancelled after Cessna suspended its small-aircraft business. Textron acquired Lycoming in 1985. In 1994, it sold the Stratford turbine-engine operation to AlliedSignal, which later integrated the business into Honeywell Aerospace. Textron retained the Williamsport piston-engine operation through Avco. Lycoming piston engines remain installed in many new and legacy light aircraft and are particularly prominent in the experimental and amateur-built sector. The brand's present identity is consequently anchored in the installed base, service support and continued production of general-aviation piston engines.
- 1994
Stratford turbine division sold
[1]Textron sold the Connecticut turbine-engine division to AlliedSignal, which later became part of Honeywell Aerospace.
- 1985
Acquired by Textron
[1]Textron purchased Lycoming and retained the Williamsport piston-engine business.
- 1940
Expanded into turbine-engine development
[1]The Stratford operation became the base for Lycoming's postwar turboshaft-engine activities, including the T53 and T55 programs.
- 1939
Became AVCO Lycoming
[1]Cord reorganized his aviation holdings into AVCO, bringing the engine business into the AVCO group.
- 1929
First aircraft engine
[1]Lycoming produced the R-680, a nine-cylinder radial aircraft engine.
- 1927
Acquired by Errett Lobban Cord
[1]Cord placed Lycoming under his Auburn Manufacturing interests, strengthening its role as a supplier to Auburn, Cord and Duesenberg.
- 1910
First automobile engine supplied to Velie
[1]Lycoming entered automobile propulsion by supplying an engine to the Velie automobile company.
- 1907
Reorganized as Lycoming Foundry and Machine Company
[1]The business moved away from declining sewing-machine production and began concentrating on foundry work and automobile engines.
- 1883
Williamsport manufacturing plant established
[1]The Scofield interests established a manufacturing facility in Williamsport, Pennsylvania, associated with the Demorest sewing-machine business.
Products and positioning
A long-established aircraft-propulsion brand emphasizing durable, widely supported piston engines for general aviation, alongside historically important turbine engines for helicopters and other aircraft.
Piston aircraft engine
O-235
A four-cylinder, air-cooled, horizontally opposed piston-engine family for light aircraft. It occupies the lower-power portion of Lycoming's general-aviation range and has been used in training, recreational and utility aircraft.
Piston aircraft engine
O-320
A widely used four-cylinder general-aviation engine family. O-320 variants have powered numerous training, utility and privately operated aircraft and are known for broad fleet support and long service history.
Piston aircraft engine
O-360
A four-cylinder engine family offered in multiple configurations, including carbureted, fuel-injected and turbocharged forms. It is used across a broad range of light aircraft and is one of Lycoming's best-known product lines.
Piston aircraft engine
O-540
A six-cylinder, air-cooled engine family providing higher power for larger general-aviation aircraft. Variants have been used in utility aircraft, high-performance singles and other light-aircraft applications.
Piston aircraft engine
O-580 and O-720
Larger-displacement piston-engine families extending Lycoming's horizontally opposed range. They serve aircraft requiring greater power than the common four- and six-cylinder product families.
Turboshaft engine
T53
A free-turbine turboshaft engine developed after the Second World War. It became strongly associated with the Bell UH-1 helicopter and was also adapted for other rotary-wing and turboprop applications.
Turboshaft engine
T55
A large turboshaft engine developed for heavy-lift helicopter applications. It is best known as the powerplant family used by the Boeing CH-47 Chinook and related twin-rotor aircraft.
Brand decisions
1994
Sale of turbine-engine divisionM&ABackground
Textron separated the Stratford turbine-engine activity from the Williamsport piston business.
Action taken
The turbine division was sold to AlliedSignal, while Textron retained piston-engine production.
Aftermath
The turbine business later became part of Honeywell Aerospace, leaving Lycoming primarily identified with piston engines.
1985
Textron acquisitionM&ABackground
Lycoming operated as part of the AVCO group before its acquisition by Textron.
Action taken
Textron acquired the company and retained its Williamsport piston-engine operations.
Aftermath
Lycoming became part of Textron's aerospace portfolio through Avco Corporation.
1937
Exited automobile-engine supplyStrategyBackground
Lycoming's remaining automobile customers, Auburn, Cord and Duesenberg, ceased operations in the late 1930s.
Action taken
The company concentrated its design and manufacturing activities on aviation engines.
Aftermath
This established aviation propulsion as Lycoming's lasting core business.
Recent events
Van’s Aircraft updates RV-14 engine options[3]
Reported:
Van’s Aircraft updated the RV-14 kitbuilt’s engine configuration with a new Lycoming IO-390-EXP119 engine rated at 215 HP, along with related cooling and firewall-forward hardware changes.
Sources3 sources
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