Propfan
| Part of a series on | 
| Aircraft propulsion | 
|---|
| Shaft engines: driving propellers, rotors, ducted fans or propfans | 
| Reaction engines | 
A propfan, also called an open rotor engine, open fan engine is an aircraft engine combining features of turbofans and turboprops. It uses advanced, curved propeller blades without a duct. Propfans aim to combine the speed capability of turbofans with the fuel efficiency of turboprops, especially at high subsonic speeds. It is sometimes called a "ultra-high-bypass (UHB) turbofan".