General Electric GE36

The General Electric GE36 was an experimental aircraft engine, a hybrid between a turbofan and a turboprop known as an unducted fan or propfan. It was developed by General Electric Aircraft Engines, with CFM International partner Snecma taking a 35 percent share of development, and development was cancelled in 1989. GE began studies and component tests of the concept in 1981, building on early NASA propfan studies, and moved to full-scale development testing in 1982. The demonstrator was to be a 25,000 pounds-force engine on an F404 core with a pair of six-stage contra-rotating free turbines driving two eight-blade, 12-foot unducted fans, for an effective bypass ratio of about 30 to 1, and it was to be flight tested on a Boeing 727 testbed from late 1986.