Gyrocopter Blues
I'm seeking a good technical answer for a question that came up over a pint awhile back {There's bottle of scotch at stake on this one}.
What makes the boody blades keep spinning on a Gyrocopter?
Now, I know about the principles of autorotation to some degree {I'm a fixed winger, take pity on me!}.
But I've yet to find a detailed explanation about autogyros. Obviously the forward momentum of the machine is provided by the pusher engine, and the blades are pre-spun to start the blades up, but I would like to know more about the rotor disc;
1. Assuming the machine is in normal flight, at which direction is the airflow striking the blade? [eg. underside, topside]
2. What is the relative blade angle in normal flight and what if any is the range of travel? [0' being flat pitch]
Now my probem stems a massive mental block based on windmilling props, if the rotor disc is tilted aft, [as it appears] and the blades are advancing, [as the normal chord design would indicate] and there's any kind of positive pitch, the bloody things stop! even back up if it where possible.
Help me please, I'm losing valuable couch potato time thinking about this.
Cheers, Hiker..........