Sounds plausible. Also, the clockwise-spinning blades will be imparting rotational momentum to the air and thus the opposite to the aircraft. Recall that the P-51 with that big Merlin engine could flip over if you went to full throttle at low speed, or so goes the story. My dad said that when he flew one, he would lift one main off the ground.
I did post on the multi-rotor forum but no response yet.