See [Source ~ PHA p.139]

The UniCopter, with its rigid rotors, does not [may not?] have flap back and its ability to assist with static stability. However, should not the coning angle provide this or will this coning angle cause the rotor to want to roll to the advancing side? ~ perhaps see Robinson's Wee Wa. Look into the possibility of a larger than normal precone.

"In addition to the natural tendency for the disk to tilt back with a change in forward flight speed, the disk also has a tendency to tilt laterally to the right. This effect arises because of the blade flapping displacement (coning). For the coned rotor, the blade angle of attack is decreased when the blade is at ψ = 0Ί [rear] and increased when ψ = 180Ί. Again, another source of periodic force is produced, but now this is phased 90º out of phase compared to the effect discussed previously [longitudinal flapping]. Because of the 90º force/displacement lag of the blade, this results in a lateral tilt of the rotor disk to the right when view from the behind.

Note that in the hypothetical case with no coning, the blade sees the same increase in angle of attack at ψ = 0Ί and 180Ί and there will be no lateral tilt."

Vortex Ring State