The Prop-Fan is introduced as a new propulsor type, intermediate between ducted propellers and low bypass fans. Compared to today's fan engines, it offers approximately twice the takeoff thrust/hp at half the tip speed and consequently much reduced noise level. Furthermore, its controllable pitch feature provides more effective reverse thrust at about one-fourth the weight of current flow reversers. Prop-Fan characteristics are particularly well matched to the propulsion requirements of advanced STOL transport aircraft. Highlighted is the uniquely low noise signature of the Prop-Fan. This now permits the design of medium-to-long range STOL transports of high-productivity which will meet the stringent noise level limits for STOL-ports. The paper describes the development status of the Prop-Fan, examines potential aircraft installation arrangements, and presents some representative STOL transport effectiveness comparisons.