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 2008-12-19.
  2. Federal Aviation Administration (February 1988). "TYPE CERTIFICATE DATA SHEET NO. 1E15, Revision 6". Retrieved 2008-12-13.
  3. Lycoming Engines (2004). "Specialty datasheet" (PDF). Retrieved 2008-12-20.
  4. Lycoming Engines (2009). "2009 Lycoming Service Engine Price List" (PDF). Archived from the original (PDF) on June 12, 2009. Retrieved 2009-06-21.
  5. Lycoming Engines (n.d.). "Engine Finder". Retrieved 2008-12-19.
  6. Demand Media (2008). "The Piper PA-24 Comanche". Retrieved 2008-12-20.
  7. Morrison, Steve (8 August 2008). "Morrison 6 Specifications". Retrieved 11 October 2012.


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