Convair XP-81 Note: This aircraft is currently in storage. The Convair twin-engine XP-81, tested in 1944-1945, was powered by a conventional turbojet engine and also a turboprop engine in which most of the power was used to turn a propeller rather than being expended as jet thrust. Originally, turboprops offered greater fuel economy than turbojets, but this advantage was offset by improvements in turbojet design. Click here to return to the Featured Accessions index.