The link in post #1 says that the Hybrid Tandem Rotor could achieve a forward speed of 225 kts, but the video appears to show turbo-jets.
Strange. The cruise speed and the turbo-jets are not compatible.
Lt.Fubar;
The idea seems to be coming back - first with Focke-Wulf FW61, then Fa223, and than Ka-22 and Mi-12, not very practical then, but today a FBW should eliminate some problems.
It had to happen, eventually.
Bilateral Symmetry
Dave