Effective mission capability of future V/STOL aircraft demands significant propulsion system advancements in lower specific weight, higher specific performance, improved operational reliability, and improved structural integrity.
A five year development program conducted by the propeller industry has resulted in several major design innovations: lightweight blades, integrated propeller and gearbox, variable camber, shrouded propellers, and redundant control systems, of which all are flight qualified and used in two major VTOL aircraft programs, XC-142 and X-22A. This paper reviews these developments, defines their performance, weight, and functional potentials, and describes their current hardware status.