Ok, you've inspired me to dig into my memories (and logbook) for my 3 lessons in a Bill Parsons Tandem Gyro - like the one below:
(hope that worked)
Probably the closest I have ever come to flying a broomstick.
On the subject of long take off runs, the technique in the Parsons was:
1. Use the pre-rotor which got the rotor spinning at something like 100 rpm
2. Simultaneously bring the stick fully back while advancing the throttle to full. This dangled the rotor in the prop wash and encouraged the rotor to spin up to about 200 rpm. Note that the propeller trying to move you forwards was cancelled out by the rotor wash trying to pull you backwards.
3. Slowly move the stick forward so you start to accelerate.
It was necessary to do all this slowly because while the rotor could take a certain amount of positive G, it couldn't take negative G. At all. And losing you rotor was a pretty terminal event.
It could stop on a sixpence though.
I'm sure that 20 years later, the modern autogyro has had most of its shortcomings reduced if not addressed.
I have to say, it was bloody brilliant fun. I'd recommend anyone to have a go. You will either get off at the end with a huge grin on your face, or a very urgent need to change your underwear.
G'wan. You know you want to.