Sikorsky S-75

Sikorsky Aircraft · United States · first flew 1984 · helicopter

The Sikorsky S-75 was an Advanced Composite Airframe Program (ACAP) demonstrator built for the US Army in the early 1980s to prove that composite materials could substantially reduce helicopter weight and radar signature.

Recognition (WEFT)

W — Wings	High-mounted, rotary
E — Engines	2 × turboshaft, fuselage-mounted
F — Fuselage	all-composite fuselage and rotor blades
T — Tail	Conventional

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Spot it by:

composite-airframe demonstrator based on S-76 dynamics
all-composite fuselage and rotor blades
two turboshaft engines in side sponsons

Closely resembles the S-76 in overall layout — twin turboshaft engines in side-mounted fairings, retractable undercarriage, and a four-blade main rotor — but the fuselage is slightly more angular, reflecting the all-composite construction.

Specifications

The Sikorsky S-75 has a length of 13.3 m (44 ft).
It has a wingspan of 13.4 m (44 ft).
Its maximum speed is 287 km/h (178 mph).
Typical crew: 2.

Figures are for the representative variant described above; marks differ. See how AircraftIQ sources figures.

History

Contracted under the US Army ACAP programme alongside a competing Bell design, the S-75 used the dynamic system of the S-76 paired with an entirely new composite fuselage. First flown in 1984, it demonstrated significant weight savings and validated manufacturing techniques that later influenced production programmes such as the RAH-66 Comanche.

Variants

A single prototype was built; the ACAP programme did not lead directly to a production type.

Where you'll see it

Operated solely as a research and technology demonstrator for the US Army; never entered operational service.

Related aircraft

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