I think the problem relies in the fact that the speed is gathered at center of mass, so when that spins it doesn't actually register any speed, if you start moving forward then it gets speed and it acts somewhat accordingly, but it doesn't need the spin to work in the first place which is not a helicopter.

To solve this I changed the speed to be gathered at the wing position in my local dev version but I never got around to figuring the rest of the things out and it's still WIP xD

I could update the mod with that slight change, it shouldn't affect planes at all but would drastically affect how helicopters work :-? unless you see any issue with that change.

Oh, yes, that explains why. Thanks ! Update this mod when you have time and you think the change is good.
In the meantime the heli will stay grounded ;-)
I just can imagine that the wings used in rotor configuration develope a pretty strong thrust at a very low energy consumption.

Updated with just that thing for now, let me know how it works :P

Oh, thanks !
The performance is not as good as I expected but at least it's flying now.
Climb rate empty is 4.5 m/s @ 10° AOA
Falls with (only) 4.0 m/s @ 1° AOA. Despite the low drop rate, one gear is breaking most of the times on touchdown.
I could lift 27 tons payload, a little bit more is possible.
Maximum horizontal speed with support of 2 small atmo thrusters: 50 m/s
Currently the heli is not balanced well (tail heavy) so I constantly had to fight with the gyros against pitch and also a bit roll. So the flight behaviour is currently mediocre.
The Kamov design proved to be the right choice. With one rotor the heli is not yawing much but the flight behaviour is (much) worse.

Btw. the maximum horizontal speed fits to the calculation:
The radius of the rotors is 9.5 m.
I.e. at 60 rpm the wingtip is moving with 59,7 m/s.
59,7 m/s wingtip speed + 50 m/s forward speed = 109.7 m/s
I observerved that with 10° or 15° AOA the rotors are rotating a bit slower => the wingtip moves with around 100 m/s

Vice versa this means:
With a higher RPM or a larger diameter of the rotor more lift can be created but this will reduce the top speed accordingly !
Or with strong thrusters you can go up to 100 m/s but the rotation of the rotors will slow down until being totally locked at 100 m/s, effectively converting the heli into a plane.

Ok, here it is: the "20+ hours-endurance-using just one battery-without thrusters" flying object unless an engineer is sitting in the cockpit (bug will make him/her suck 1MWh).
http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=623509041

Btw. I think a little convenient bug with the "aerodynamic" rotors is enabling the Tigershark to some kind of "supercruise": flying and even climbing at 104.4 m/s without thruster. The thrusters are just needed to enter the "supercruise".