Hi Doug: my comment was about gravity, or the weight (so the mass) of SuperTurbine if you prefer.
On the video below (at 10:52) you can see the downward curvature in the middle (but not close to the generator, and not close to the lifter balloons) while the rotors are not turning. The same but less pronounced curvature remains at 11:15, the rotors turning, despite the lifting balloons.
