Dual ducted contra-rotating fan helicopter as in "Avatar"?

[HoHun]

Hi everyone,

Has anyone tried to create a dual ducted contra-rotating fan "helicopter" as featured in James Cameron's "Avatar"?

I like the looks of those things, but it was rather funny to hear them going "whop-whop-whop" in the movie ... probably because this sounds "realistic" to an audience associating the pictures with the Vietnam-era Hueys from "Apocalypse Now" :-)

I tried to convert X-Plane's Osprey to an "Avatar chopper" configuration, but the contra-rotating fans did not respond to cyclic commands too well, with both fans on one side occasionally opposing each other (which would have lead to instant self-destruction in real life).

From the way they are depicted in the movie, the Avatar choppers don't actually have cyclic controls (I suppose), as they appear to turn by vectoring the fans fore and aft. I don't think I have noticed any lateral swivelling, so I assume they'd use differential thrust to roll.

I have no idea what they might do to achieve pitch control ... maybe a puffer in the tail?

In any case, my (mostly unsuccessful) attempts to convert the Osprey seems to indicate that the Avatar chopper setup requires quite a bit more power to achive vertical take-off than the original Osprey setup :-)

Regards,

Henning (HoHun)