On Jun 2, 2007, at 3:15 AM, Michel Jullian wrote:
4. Put "corona wires" fanning out from the axis of rotation of the
pinwheel, about 3 inches below it, and pointed so that they emit
radially, and not tangentially (so they contribute little to any
wind-caused thrust) and the thing begins spinning in the opposite
direction as before, towards the charged face of the plastic
"covers".
Ah yes I had forgotten about those stator bound emitters in the
Borbas device!
As did I! I did not even see the (stator) corona wires in the photos
of the (small white) replication device at first. I found them only
after going back to look at the photos specifically to look for
corona wires. In the replication, they are located (taped) down at
the base instead of on the shaft.
Indeed, to develop what you say in point 8 below, those become the
strongest (the only basically) ion emitters when the pinwheel's
tips are covered, so that counteremission (a well known effect in
lifters with not well smoothed skirts which lowers the net thrust
by inducing a small reverse thrust) now dominates the emission (now
basically zero, as correctly pointed out by Horace). If the covers
were conductive instead of high resistivity plastic the thing would
rotate backwards too, only faster because they would enable a
stronger ionic current and therefore a stronger thrust.
The chasing effect you and GOB describe is to be expected, it's due
to opposite sign image charge induced at the surface of the
approaching object (effect discussed with Fred Sparber many times).
I suspect the asymmetry in the the shape of the field in front of the
ping pong balls is important. I expect the field attracts ions
towards the balls and actually makes a wind around the balls. A
surface charge builds up on exterior the balls reducing the effect,
but the ion wind probably carries away enough of it to maintain
itself. However, the smoke test didn't show any of this happening?
It should show up in a smoke test. I suppose the much larger radial
wind might cover that up somewhat.
Regards,
Horace Heffner
