Sikorsky S-72 X-Wing
Sikorsky Aircraft Corporation, a helicopter manufacturer, developed the S-72 for NASA. This hybrid aircraft is half helicopter half fixed wing plane.
NASA and the United States Army’s Rotar System Research Aircraft (RSRA) project evaluated helicopter rotor attributes. NASA and the US Army desired a four-bladed rotor added to the system. The program failed.
The Naval Ship Research and Development Center engineers designed the X-wing, a concept integrating helicopter hovering and winged aircraft high speed. The Defense Advanced Research Projects Agency (DARPA) funded this vertical take-off aircraft .
Sikorsky captured a contract and customized a S-72 with the X-Wing concept. Sikorsky built the prototype in 1986.
The Sikorsky X-Wing never flew.
In 1988, DARPA officially cancelled the X-Wing project.