Lycoming Engines

Lycoming Engines
Company type	Division
Industry	Aerospace, Aircraft engines
Founded	1845
Headquarters	Williamsport, Pennsylvania, United States
Area served	Worldwide
Products	Horizontally opposed air-cooled piston engines; turbine engines for helicopters and small jets
Owner	Textron (via Avco Corporation)
Parent	Avco Corporation (Textron subsidiary)

Lycoming Engines stands as a prominent American producer of aircraft engines, with its headquarters situated in Williamsport, Pennsylvania. The firm specializes in manufacturing horizontally opposed, air-cooled piston engines featuring four, six, and eight cylinders.

Having manufactured over 325,000 piston engines, Lycoming supplies power to more than half of the worldwide general aviation fleet, encompassing both rotary-wing and fixed wing aircraft. The company has also played a significant role in pioneering turbine engines for medium and large helicopters and has provided propulsion systems for small jetliners and business jets.

Functioning as a division within Avco Corporation—a subsidiary of Textron—Lycoming forms part of a major aerospace conglomerate's corporate framework.

From Sewing Machines to Bicycles and Fashion

The origins of Lycoming date back to 1845 with Madame Ellen Curtis Demorest. However, details of the company’s early years prior to 1860 remain somewhat ambiguous; Ellen wed William Jennings Demorest in 1858. Between approximately 1860 and 1887 in New York, the Demorests managed the Demorest Fashion and Sewing-Machine Company (also referred to as the Demorest Manufacturing Company), which published fashion periodicals and produced "Madame Demorest" and "Bartlett & Demorest" sewing machines. Additionally, they marketed Ellen’s patented paper dressmaking patterns. Ellen secured patents for various fashion accessories, while William obtained patents related to sewing machine enhancements and a vulcanizing rubber device.

Around 1883, advertising entrepreneurs Gerrit S. Scofield and Frank M. Scofield acquired the Demorest sewing machine business and brand name (the Demorests retained control over the magazine segment), establishing a manufacturing plant in Williamsport, Pennsylvania. Local financiers invested US$100,000 to construct this facility, which employed approximately 250 workers producing between 50 and 60 sewing machines daily.

The company's product line broadened with the 1891 launch of the "New York Bicycle," designed by employee S. H. Ellis. Up until the early twentieth century, the Williamsport factory manufactured not only sewing machines but also bicycles, typewriters, opera chairs, among other items.

Transition to Engine Production

By 1907, declining profitability in sewing machine manufacturing led Demorest to sell the business and reorganize as the Lycoming Foundry and Machine Company, redirecting efforts toward automobile engine production. In 1910, Lycoming delivered its first engine to Velie and became a principal supplier for Auburn automobiles, which produced Auburn, Cord, and Duesenberg vehicles. By 1920, Lycoming employed around 2,000 people and produced approximately 60,000 engines annually; a new foundry was also established in Williamsport. In 1927, Errett Lobban Cord acquired Lycoming, incorporating it into his Auburn Manufacturing enterprise.

Lycoming crafted notable engines for Cord vehicles including a 298.5 cu. in. L-head straight-eight engine generating 125 hp for the Cord L-29 model and a double overhead cam straight-eight engine producing 265 hp for the Duesenberg J series; a supercharged variant powered the Duesenberg SJ and SSJ models with an output of 325 hp.

In 1929, Lycoming ventured into aircraft engine production with its nine-cylinder R-680 radial engine, extensively utilized in light aircraft such as Cord's Travel Air. During the 1930s, the company pursued high-powered aircraft engines: the O-1230 delivering 1,200 hp based on the US Army Air Corps hyper engine concept failed commercially despite innovative design elements; its successor—the H-2470 H engine producing 2,300 hp—was used solely in prototypes like the Vultee XP-54. Lycoming’s largest piston engine—the XR-7755 with 36 cylinders—was completed near World War II’s conclusion but was eclipsed by emerging turbojet technology and never achieved widespread adoption.

Throughout the 1920s and ’30s, Lycoming continued providing automotive engines but lost most customers except Auburn, Cord, and Duesenberg—all under Cord’s ownership—until their closure in 1937. Subsequently, Lycoming concentrated exclusively on aircraft engine production. Concurrently, Cord acquired Smith Engineering Corporation (a propeller manufacturer) relocating it to Williamsport.

In 1939, Cord consolidated its aviation-related assets into AVCO; Lycoming was rebranded as "AVCO Lycoming," leasing the Stratford Army Engine Plant in Connecticut to manufacture Wright radial engines under license. After World War II, Stratford transitioned to producing successful turbine engines such as the T53 turboshaft. Piston engine manufacturing remained centered in Williamsport.

By 1961, monthly production ranged from 600 to 700 engines. Postwar success was primarily based on air-cooled flat-four and flat-six general aviation engines like the O-320 and O-360 four-cylinder models along with the O-540 six-cylinder engine. These powered numerous light aircraft with outputs spanning from 100 to 360 hp. The product range expanded to include O-235 four-cylinder engines, IO-580 six-cylinder models, O-720 eight-cylinder variants, plus turbocharged fuel-injected models such as the TIGO-541 delivering up to 450 hp.

The early 1980s downturn in general aviation severely affected Lycoming’s piston engine segment. Efforts to relocate turbine production to Williamsport led to quality challenges and were ultimately discontinued. Another initiative focused on developing the SCORE Wankel rotary engine—initially created by Curtiss-Wright and John Deere—with plans for integration into Cessna aircraft under Textron ownership. However, Cessna’s halt of small-aircraft manufacturing delayed SCORE’s introduction; Rotary Power International later produced a limited version.

Textron acquired Lycoming in 1985. In 1994, Textron divested Lycoming’s Turbine Engine Division located in Stratford to AlliedSignal (which later became Honeywell Aerospace), while retaining piston engine operations at Williamsport.

Currently, Lycoming engines equip new light aircraft from Textron’s Cessna division as well as Piper, Cirrus, Diamond Aircraft among others. They dominate the U.S. Experimental/Amateur-Built aircraft market segment by outselling the next five leading brands combined.

Products

The prefixes used in the company's aircraft piston engines denote particular characteristics and intended uses:

A—Aerobatic with dry sump lubrication
AE—Aerobatic with wet sump lubrication
E—Equipped with electronic controls
G—Incorporates reduction gearing
H—Designed for helicopter use
I—Fuel injection system
L—Crankshaft rotates counterclockwise (left-hand rotation)
M—Built for unmanned aerial vehicles
O—Opposed cylinder arrangement
R—Radial cylinder configuration
S—Supercharged engine
T—Turbocharged engine
V—Vertical mounting, commonly in helicopters
X—X-type engine configuration
Y—Experimental model

Piston engines

Opposed 8-cylinder, geared and supercharged| Template:Cvt 578 cuin L| 400 hp| 1948| Radial 9-cylinder| Template:Cvt 680 cuin L 2| 330 hp| 1930| Opposed 8-cylinder, fuel injected| Template:Cvt 721 cuin L 2| 400 hp| 1961| Opposed 12-cylinder| Template:Cvt 1233.9 cuin L 2| 1000 hp| –| Helicopter H24 configuration| Template:Cvt 2467.8 cuin L 2| 2300 hp| –| Inline radial 36-cylinder (IR36)| Template:Cvt 7756.3 cuin L 2| 5000 hp| –|

Model designation	Cylinder layout	Displacement	Horsepower output	Year introduced
Lycoming DEL-120	Inline 4-cylinder	117 cu in (1.92 L)	205 hp	2013
Lycoming O-145	Opposed 4-cylinder	144.5 cu in (2.37 L)	55 hp	1938
Lycoming IO-233	Opposed 4-cylinder	233.3 cu in (3.82 L)	100 hp	2008
Lycoming O-235	Opposed 4-cylinder	233.3 cu in (3.82 L)	100 hp	1942
Lycoming O-290	Opposed 4-cylinder	289 cu in (4.74 L)	140 hp	1942
Lycoming O-320	Opposed 4-cylinder	319.8 cu in (5.24 L)	150 hp	1953
Lycoming O-340	Opposed 4-cylinder	340.4 cu in (5.58 L)	170 hp	1954
Lycoming O-360	Opposed 4-cylinder	361 cu in (5.92 L)	180 hp	1955
Lycoming IO-360	Opposed 4-cylinder, fuel injected	361 cu in (5.92 L)	200 hp	1963
Lycoming IO-390	Opposed 4-cylinder, fuel injected	389 cu in (6.37 L)	210 hp	2009
Lycoming O-435	Opposed 6-cylinder	424 cu in (6.95 L)	212 hp	1942
Lycoming O-480	Opposed 6-cylinder	479.6 cu in (7.86 L)	340 hp	1954
Lycoming O-540	Opposed 6-cylinder	541.5 cu in (8.87 L)	300 hp	1957
Lycoming TIO-541	Opposed 6-cylinder, turbocharged and fuel injected	541.5 cu in (8.87 L)	310 hp	1965
Lycoming IO-580	Opposed 6-cylinder, fuel injected	583 cu in (9.55 L)	300 hp	1997

This comprehensive range highlights the company’s commitment to varied piston engine architectures, catering to a wide spectrum of aviation sectors including general aviation, aerobatics, rotorcraft, and unmanned platforms. This diverse engine portfolio reinforces Lycoming’s strong position within the aerospace propulsion market, facilitating continued growth and increased market penetration.

Turbine engines

Lycoming has been a trailblazer in developing turbine powerplants, especially turboshaft engines tailored for medium to heavy-lift helicopters. The T53 model notably powered the Bell UH-1 "Huey," while the T55 engine is utilized in the twin-turbine Boeing CH-47 Chinook helicopter. Beyond rotary-wing applications, these turbine engines have been adapted for turboprop and turbofan aircraft such as the OV-1 Mohawk military reconnaissance plane, BAe 146 regional jet, and Canadair Challenger business jet.

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