Sikorsky Cypher
The Sikorsky Cypher and Cypher II are types of unmanned aerial vehicles developed by Sikorsky Aircraft. They are vertical takeoff and landing aircraft which use two opposing rotors enclosed in a circular shroud for propulsion.
Design and development
Cypher
Sikorsky began work on the Cypher in the late 1980s as a small unmanned aerial vehicle with coaxial rotors enclosed within a torus-shaped shroud. The circular duct improved handling safety and added lift. The first proof-of-concept aircraft measured in diameter and in height, weighed, and flew in the summer of 1988 powered by a four-stroke engine. For early trials it was mounted on a truck to conduct forward-flight tests.A larger prototype followed, with a diameter of, weight of, and a Wankel engine. It achieved its first flight in April 1992 and its first free flight in 1993. Over the remainder of the decade the vehicle accumulated more than 550 demonstration flights for U.S. government agencies.
The Cypher could carry a sensor payload mounted above the fuselage or transport external loads of up to. The program provided the basis for the follow-on Cypher II, which was submitted to the United States Navy’s VT-UAV competition.