General Electric CJ805

The General Electric CJ805 is a jet engine that General Electric Aircraft Engines developed in the late 1950s as a civilian version of the J79, differing only in detail. It came in two versions: the basic CJ805-3, a turbojet that powered the Convair 880 airliner, and the CJ805-23, a turbofan derivative with a military designation of TF35 that powered the Convair 990 Coronado. The CJ805-23 solved the problem of driving a fan from a fast single-spool core by adding a separate free-running turbine stage at the rear, with fan blades set on the outer rim of the turbine blades, and its transonic single-stage fan exceeded its design targets. The program was not a commercial success, with only a few hundred engines built and a loss of about 80 million dollars, but the service reputation GE earned from it lasted, and the aft-fan idea carried into the CF700.