On May 16, 9:40 am, "Stuart & Kathryn Fields" wrote:

Anyone have a clue as to how it controls yaw?

As a guess, differential torque. The blades are fixed pitch so differential
collective ala Kaman is not possible.

Hasn't that been done in the past? I once asked about a tandem-rotor
fixed-pitch helicopter. At the time, it seemed reasonable that such
a device could be controlled by differential torque; forward movement
would be produced by tilting the entire craft (my thought at the time
was a sliding weight).

Note that the guy says while it is
possible to fly as high as 165 yds, his demo would be at 16.5 yds altitude.

Hmmm... All I really need is a way to get to the grocery store.
Over the power lines and through the alley to the street is all I'd
need.

If the engines fail, though it would require all 4 failing, the helo quickly
converts to a lawn dart. If it was me I would demo at 1.65yds altitude and
no faster than I could run.

Any idea why there are four engines?

I saw a demo of this ship at Sun'n Fun a number
of years ago. The pilot got a bit carried away with some low altitude
swooping and tipped the ship over to far and it hit the ground shedding
rotor parts:; some of which were later found several hundred feet down the
flight line in front of an RV. No injuries though.

is this the famous "Head-o-copter"?
http://www.flurl.com/item/Head_o_Copter_u_307813


Mike