New Ultra Light helicopter being developed in Australia
 

I built one of these in 1996, with chainsaw engines running wide open and opposing flaps beneath each motor to kill lift and provide yaw control. Kind of like a opposing thrust reverser on a fixed wing jet. Plan was to use it to use it as a portable ski lift in the back country. It worked, but wife decided it or she was leaving me. So now it hangs in the garage, a mute testimony to what could have been.

Awesome, I was unaware that chainsaws generated so much lift. And another thing.... how in the world did you manage to get not just one but two chain saws to start sucessfully. They must have been brand new. :)

Cash flow analysis indicated keeping the wife was the correct choice. It was a quad copter, 4 big chainsaws were enough to pull me up the hill. A $20 model heli gyro on each axis, and some rather elegant mechanical mixing of lift-kill and yaw control under each saw motor. The gyros would drift pretty bad, so it was a challenge to control, what with the rpms of the saws being independent. Next step was going to be a VW motor with belt drive to four props to cure the assymetric lift caused by rpm fluctuation. The saws were brand new! Getting all 4 to run was never the problem.