Lycoming IO-720

The Lycoming IO-720 engine is a large displacement, horizontally opposed, eight-cylinder aircraft engine featuring four cylinders per side, manufactured by Lycoming Engines.[1]

IO-720
Type Piston aero-engine
National origin United States
Manufacturer Lycoming Engines
First run 1961
Major applications PAC Fletcher
Piper Comanche 400
Helio Courier
Produced 1961–present
Developed from Lycoming O-360

There is no carburated version of the engine, which would have been designated O-720 and therefore the base model is the IO-720. The IO-720 and the Jabiru 5100 are the only flat-eight configuration aircraft engines currently in production.[2]

Design and development

The engine has a fuel injection system which schedules fuel flow proportionally to the airflow, with fuel vaporization occurring at the intake ports. The engine has a displacement of 722 cubic inches (11.8 litres) and produces 400 hp (298 kW). The cylinders have air-cooled heads cast from aluminum alloy with a fully machined combustion chamber.[1][3]

The first IO-720 was type certified on 25 October 1961 to the CAR 13 standard as amended to 15 June 1956 including 13-1, 13-2, 13-3, 13-4.[2]

In 2009 a new IO-720-A1B cost US$113,621, with a rebuilt engine retailing for US$75,435 and a factory overhaul priced at US$66,289.[4]

Variants
IO-720-A1A
Eight-cylinder, horizontally opposed, air-cooled direct drive, fuel injection, internal oil jet piston cooling, 722 cubic inches (11.8 litres), 400 hp (298 kW), certified 25 October 1961[2]
IO-720-A1B
fuel-injected, 722 cubic inches (11.8 litres), 400 hp (298 kW), same as -A1A except equipped with Bendix S8LN-1208 and S8LN-1209 magnetos, certified 22 February 1971[2][5]
IO-720-A1BD
fuel-injected, 722 cubic inches (11.8 litres), 400 hp (298 kW), same as -A1B except has a dual magneto, certified 30 December 1976[2]
IO-720-B1A
fuel-injected, 722 cubic inches (11.8 litres), 400 hp (298 kW), same as -A1A except for top exhaust cylinders and offset exhaust valve shroud tubes, certified 4 November 1965[2]
IO-720-B1B
fuel-injected, 722 cubic inches (11.8 litres), 400 hp (298 kW), same as -B1A except equipped with Bendix S8LN-1208 and S8LN-1209 magnetos and Bendix RSA-10ED1 fuel injection, certified 22 February 1971[2][5]
IO-720-B1BD
fuel-injected, 722 cubic inches (11.8 litres), 400 hp (298 kW), same as -B1B except has a dual magneto, certified 30 December 1976[2][5]
IO-720-C1B
fuel-injected, 722 cubic inches (11.8 litres), 400 hp (298 kW), same as -A1B except that it has up-exhaust cylinder heads, certified 22 December 1971[2]
IO-720-C1BD
fuel-injected, 722 cubic inches (11.8 litres), 400 hp (298 kW), same as -C1B except has a dual magneto, certified 28 January 1977[2]
IO-720-D1B
fuel-injected, 722 cubic inches (11.8 litres), 400 hp (298 kW), same as -A1B except has a rear type air inlet housing instead of a front inlet, certified 29 October 1973[2][5]
IO-720-D1BD
fuel-injected, 722 cubic inches (11.8 litres), 400 hp (298 kW), same as -D1B except has a dual magneto, certified 28 January 1977[2]
IO-720-D1C
fuel-injected, 722 cubic inches (11.8 litres), 400 hp (298 kW), same as -D1B except equipped with an angled fuel injector adapter, certified 15 April 1982[2][5]
IO-720-D1CD
fuel-injected, 722 cubic inches (11.8 litres), 400 hp (298 kW), same as -D1C except has a dual magneto, certified 10 June 1977[2][5]

Applications
IO-720-A1A
IO-720-A1B
IO-720-A1BD
IO-720-B1A
IO-720-B1B
IO-720-B1BD
IO-720-D1B
IO-720-D1C
IO-720-D1CD

Specifications (IO-720A)

Data from Lycoming Specialty Datasheet[3] and TYPE CERTIFICATE DATA SHEET NO. 1E15, Revision 6[2]

General characteristics
  • Type: 8-cylinder fuel-injected horizontally opposed aircraft engine
  • Bore: 5.125 in (130.18 mm)
  • Stroke: 4.375 (111.12 mm)
  • Displacement: 722 in³ (11.8 litres)
  • Length: 46.41 In (117.88 cm)
  • Width: 34.25 in (87.00 cm)
  • Height: 22.53 in (57.23 cm)
  • Dry weight: 597 lb (271 kg) dry

Components
  • Fuel system: Bendix RSA-10AD1 fuel-injection
  • Fuel type: 100LL avgas
  • Cooling system: air-cooled

Performance

See also

References
  1. Lycoming Engines (n.d.). "Lycoming IO-720". Retrieved December 19, 2008.
  2. Federal Aviation Administration (February 1988). "TYPE CERTIFICATE DATA SHEET NO. 1E15, Revision 6". Retrieved December 13, 2008.
  3. Lycoming Engines (2004). "Specialty datasheet" (PDF). Retrieved December 20, 2008.
  4. Lycoming Engines (2009). "2009 Lycoming Service Engine Price List" (PDF). Archived from the original (PDF) on June 12, 2009. Retrieved June 21, 2009.
  5. Lycoming Engines (n.d.). "Engine Finder". Retrieved December 19, 2008.
  6. Demand Media (2008). "The Piper PA-24 Comanche". Retrieved December 20, 2008.
  7. Morrison, Steve (August 8, 2008). "Morrison 6 Specifications". Retrieved October 11, 2012.


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