But... there would be no ion flows near the rotor if the pingpong balls were truely insulating. A cloud of opposite ions would just gather around the pingpong balls, then all air flows (ion flows) would stop. So I bet the pingpong balls are terrible insulators, and electrons are going through them fast enough to give ion currents and air flows.
If you haven't yet dissassembled your device, try REALLY insulating the tips of the rotor wires: snip off the sharp parts and cover them with big blobs of silicone caulk. Don't use pingpong balls at all. If that greatly slows things down, then ion-flows were almost certainly the cause of the thrust. Note well that where kilovolts and microamps are involved, rubber and plastic are NOT INSULATORS. They are resistors. A large area of thin plastic (as in a pingpong ball) is a poor insulator. Better that you should fill each pingpong ball with oil! :) Or, just get rid of the pingpong balls entirely, and cast the wire tips into thick spheres of solid plastic or silicone. (((((((((((((((((( ( ( ( ( (O) ) ) ) ) ))))))))))))))))))) William J. Beaty SCIENCE HOBBYIST website billb at amasci com http://amasci.com EE/programmer/sci-exhibits amateur science, hobby projects, sci fair Seattle, WA 425-222-5066 unusual phenomena, tesla coils, weird sci
