These guys in Qatar are playing in the wind, so the airflow is going up through the rotor... they are effectively flying with the main wheels just touching the ground.

This is not a takeoff, 'by the book' ... takeoffs not allowed by the manual. From what I have read/heard, the only acceptable way to take off in most tubs is to line up into the wind with the rotor stopped... stick forward, prerotate to X amount on the rotor tach, then stick fully back and full throttle.

There have been accidents over here with tubs and cavalon like things where people have tried to do a touch and go... so, wheels on, power up and stick back (and off comes the tail and the machine rolls over)... All takeoffs should be done 'by the manual'

This is why I don't like tubs

100% ok .. imagine the engine stops ... the gyro would land going backward ... a gyro is not an heli ...

Hi Bensen in the old days used various chain saw motors as pre-rotators, not an elegant solution but he did extensive testing with them. Generally he only had a little fuel in them started them up and after pre-rotation just let them run dry. But he experimented adding 8 or 9 hp continuous to see what would happen in flight. That was the maximum hp he found he could add without it impacting on torque too much. However by leaving them running in flight he used significantly less hp in fact he was able to get similar perfomance to his 70hp Mac with a 40 Nelson engine. I have thought that when battery technology gets good enough (and apparently there's a factor being built to make 500w/h/kg batteries now so hopefully latter this year but will wait until they are available before I get too excited this may be a way of making electric gyros more viable, basically a beefed up pre-rotator on continuously reducing total kw's required to fly. I think he discussed it in the Bensen design manual. I've also wondered if you could add a tiny (and I mean tiny) amount of re-gen into such a pre-rotator It'd be risky but people often use vertical descent for getting into a runway when too high if you could add 100ft/min to your rate of descent (obviously without drawing too much down and risking stopping auto-rotation) there's a fair bit of gravitation potential energy in dropping 500ft that could be tapped into there. Given a heavily thermic day you could actually extend your time in the air. I've certainly flown in thermals ascending at 1500ft/min on idle. An electric gyro such a thermal with motor regen I wonder how long you could stay in such a thermal and how long you could stay in the air on a charge. Flying in Australia in summer it gets bloody hot and we get some massive thermals from time to time. Anyway pure speculation but as the batteries get more advanced something like this could be possible. The other guy that has engaged pre-rotator in flight is the dude that runs sports copter. He claims to have engaged in flight to slow his descent rate. about 5:20 on the time line.

https://www.youtube.com/watch?v=oaqyFRABdKA&t=318s

I have 22ft Goodwin blades they are about 22kg? I pulling that from memory much lighter than the Composite blades I've hefted up onto an aircommand but not as light as my old wood blades (18.5kg).

Gerry is a master blade builder. Each extrusion leading edge comes out with warps from the extrusion process not much but there, Gerry doesn't just match sets like some manufactures but would actually straighten the buggers out. They are beautiful blades to fly, very smooth. Wind up very nicely.

The rotor is flying at any given rpm (above zero) I suppose its just a matter of how much of the machine is lifted off. One of the things we'd nail into students in the glider is that the stick not the nosewheel is to be used to steer as soon as the blades have begun to wind up. We did this to keep them on track with the take off or they'd suddenly as the blades came up to speed and the friction of the wheels on the ground was gone would suddenly veer off one way or the other. So we'd have them steering behind the car with the rotors. As the blades came up to speed they naturally would adjust so when they came off even in strong crosswinds they'd come off behind the car. This translates into powered where you are using the rudder to point the nose but the stick to track over the runway. So even though at these speeds the blades would have been producing some lift they were no where near enough to lift off the ground. So I suppose the answer is it flies but not with enough lift to overcome gravity. Depends on your definition of flying though. Is descending flying? If flying without enough lift to maintain level flight is not flying?...Be nice to have some form of scale to measure force of lift of each wheel on the ground during a takeoff and see just how much and when its all happening.

Gerry is still about he doesn't make gyro rotors anymore and they were very smooth IMO the best of the metal blades you could get in Australia at the time. I chatted to Gerry about 6months ago he's working on some sort of jump take off head I chatted to him about Greg's system. Gerry's is different I think. It'd be nice if he was back in the game they were nice blades.