.

Oh, then I can't help you, sorry@thomasjaf

@ElijtheGeat Nice try but in the case I've tried to explain both runners go around the lake (same radius but one linked to the shaft and one to the blade). When you attach the nozzle to the shaft the rotor goes very slow but when you attach it to the blade the rotor spins like hell! And keep in mind that it's the same radius, it just should be the same...

Nice illustration

Generally the same speed*

(Simple English[if I understand your question correctly]) I can't download this so im just guessing that the props spin faster as the nozzles move closer to the center(plz correct me if I am wrong). The load of the prop should be so small that the nozzels are travelling at the same speed, no matter how far away from the center they are, so the ones closer to the center don't have to travel as far as the nozzels further out, so they make it around the center much faster. Analogy: there are two guys running, one is running around a pond and one is running around a lake, both running at the same speed, who will make it all the way around first?

@Nassassin Everything is attached together so it shouldn't make any difference... more than that, inertia does not set max speed but just acceleration!

It's due to the moment. The propellers have a lot of mass concentrated at the center so it requires less force to rotate.