The Hiller X-2-235 was an experimental American coaxial helicopter developed in the 1940s that helped pave the way for the ...
Sagita has built an RC model of its concept. A new helicopter concept with less complex mechanics aims to make aviation safer, simpler, and easier to maintain. Sagita Helicopters in Belgium is behind ...
Neither use a pusher-prop, but the Russians have been flying counter-rotating helicopters for over 50 years now so this is only new for the US. This does look an awful lot like the Comanche of the ...