Flying the helicopters with the new flight model enabled (auto trim off, and all other options also off), I noticed that at medium to high speeds, the antitorque is too powerful as the slipstream effect does not seem to be taken into consideration. When flying up to about 160kmh full 360° turns are possible in flight by just applying full left or right rudder.

I would expect this to be prohibited by the slipstream effect at these high speeds.