2] provides a compilation of computational studies of coaxial rotors in hover and forward flight; references for the data used to validate the current studies are also cited.
335 is an extreme case where modern day coaxial rotors do not operate.
The Kamov Design Bureau (design office prefix Ka) has more recently specialized in compact helicopters with coaxial rotors
, suitable for naval service and high-speed operations.
AVX and the Boeing-Sikorsky team are offering compound helicopters with coaxial rotors
As a tail rotor typically wastes some of the power, otherwise it can be devoted to lift and thrust, however, in coaxial rotors
all of the available engine power is devoted to lift and thrust.
are also used on China's Haiou (Seagull) drone developed by the Beijing University of Aeronautics and Astronautics.
The X2--a compound helicopter with coaxial rotors
and a pusher-propeller at the rear--has flown at speeds of up to 250 knots in level flight.
Interestingly, the runner-up for the Mavdem was a conventional helicopter configuration with a low-drag fuselage and a sensor pod mounted between two coaxial rotors
Its S-97 Raider, developed from the X-2 technology demonstrator, is a new design that incorporates coaxial rotors
and a push propeller.
The S-97 will have coaxial rotors
and a pusher propeller, as tested with the two-seat 3600-kg X2 demonstrator.
Sikorsky's S-97 Raider scout and attack helicopter will be based on a prototype that has flown with coaxial rotors
The aircraft will feature a General Electric turbo shaft engine, coaxial rotors
and a six-bladed push propeller at the tail.