12/31/2007. This was the Advanced Composite Aircraft Program (ACAP) all composite proof of concept vehicle. Composite materials were used to build the airframe, providing greater strength and reducing weight, and manufacturing and maintenance costs. The airframe was mated to the Sikorsky S-76 powerplant, transmission and rotor system. The aircraft was funded by the US Army Applied Technology Laboratory, the ATL logo is visible on the fuselage.
The S-75 was flown for the first time by Sidney Gurley and Richard
Mills at the Sikorsky test center at West Palm Beach, Florida, on July