Ultra light coaxials
In between realsize helicopters and RC models the following Ultralights have apeared :
* Gen H-4 ( J )
( man carrying machine, piston engine powered, yaw trough differential rpm control of rotors, stability : natural gyroscopic rotor stability thanks to size )
http://www.engineeringsystem.co.jp/genh4_en/
* Eagle Perch ( US )
( man carrying machine, piston engine powered, yaw trough orientation of down swash, stability : natural gyroscopic rotor stability thanks to size )
http://www.eagleaviationtech.com/epi%20brochure.htm
* Airscooter ( US )
( man carrying machine, piston engine powered, yaw trough orientation of down swash, stability : natural gyroscopic rotor stability thanks to size )
* Flying platform ( US )
( man carrying machine, piston engine powered, yaw : 2 small lateral rotors, stability : human sense of balance )
http://www.flying-platform.com