How about an RC Sikorsky S-97?

[Gryf]

Rigid co-ax rotor system with a pusher prop for thrust... sounds intriguing!

http://www.military.com/video/aircraft/helicopters/sikorsky-s-97-raider-at-ausa/4556052749001/

Gryf

 

[Crazy Goats]

wow. looks cool anyway.