Lycoming IO-720

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

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

There is no carbureted version of the engine, which would have been designated O-720 and therefore the base model is the IO-720. The IO-720 is the only flat-eight configuration aircraft engine currently in production.