Lycoming O-360

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The Lycoming O-360 is an air-cooled, carbureted, four-cylinder, horizontally opposed piston aircraft engine.

Displacement is 361 cubic inches (5.9 liters). Bore and stroke are 5.125 and 4.375 inches (130 and 111 mm) respectively. Many minor variations exist, but perhaps the most common is the "high-compression" versions O-360-A series. They have an 8.5:1 compression ratio and are nominally rated at 180 horsepower at 2700 rpm at sea-level. They were originally type certificated on a short-lived 91/96 octane aviation fuel, but now are generally required to burn 100LL aviation fuel. Some installations allow for the substitution of automotive gasoline of 91 or higher anti-knock-index (R+M)/2 rating.

A low-compression (7:1) version exists that nominally produces 168 horsepower at sea-level, but was installed in very few production aircraft. The O-360 is the slightly larger (identical bore, slightly stroked) version of the Lycoming O-320.

Nominal maximum continuous cruising power for the 180 hp version is 75%, which consumes approximately 9.5-10 gallons of fuel per hour, or approximately 34 to 36 Litres, depending on a number of circumstances.

The O-360 is generally considered to be quite reliable, with a typical TBO (Time Between Overhaul) of 2000 hours, though many have safely exceeded this number. They have been installed in thousands of aircraft including Cessna 172s, Piper Cherokees/Archers, Grumman Tigers, and many home-built aircraft.

A fuel injected version known as IO-360 which produces 160 hp/180 hp is currently used in the Cessna 172R/172S. The fuel injection system eliminates the risk of carburetor ice, and requires a slightly different starting procedure than the carbureted version. The fuel injected starting procedure requires turning on an electric fuel pump prior to start in order to pressurize the fuel injection system. The mixture contol is left in the idle-cutoff position (pulled all the way out) until the engine fires, which is opposite to the normal carbureted starting procedure.

[edit] Variants

All engines will have an additional number following the 360 to indicate the specific configuration, based on the aircraft the engine is used on.

• O-360 - standard, direct-drive, normally aspirated engine, equipped with a carburetor
• IO-360 - Fuel injected version
• TIO-360 - Turbocharged, fuel injected version
• AEIO-360 - Injected version with an inverted oil system for use in aerobatic aircraft

[edit] Applications

• 8GCBC Scout
• 8KCAB Decathlon
• Aer Lualdi L.55
• Aero Commander 100
• Aerocomp Comp Air 4
• Aeronca Sedan
• Aerotécnica AC-12
• American Aviation AA-2 Patriot
• Aviat Husky
• Beechcraft Musketeer
• Beechcraft Travel Air
• Berkut 360
• Cessna 172
• Cessna 177
• Grumman American AA-5
• McCulloch J-2
• Mooney M20
• Partenavia P.68
• Piper Cherokee
• Piper PA-24 Comanche
• Piper PA-34 Seneca
• Piper PA-44 Seminole
• Rutan Defiant
• Saab 91 Safir
• Thorp T-18
• Van's Aircraft RV-4
• Van's Aircraft RV-6
• Van's Aircraft RV-7
• Van's Aircraft RV-8

[edit] Specifications (O-360-A)

General characteristics

• Type: 4-cylinder air-cooled horizontally opposed aircraft piston engine
• Bore: 5.125 in (130 mm)
• Stroke: 4.375 in (111 mm)
• Displacement: 361 in³ (5.9 L)
• Dry weight:

Components

• Fuel type: 100LL avgas
• Cooling system: Air-cooled

Performance

• Power output: 180 hp (135 kW) at 2,700 rpm at sea level
• Specific power: 0.50 hp/in³ (22.9 kW/L)
• Compression ratio: 8.5:1
• Fuel consumption: 10 US gal (36.5 L/h) at 65% power, 10.5 USG (40L/h) at 75% power
• Power-to-weight ratio: