some pictures/questions

["David Dean" <deano-at-corridor-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi all
A friend came by and took some video of my coil running. This is at a lower
power level, and with a 16nf MMC so not very spectacular. (This was a day or
two before the caps I got from Dale Hall came in.) He posted some stills to
the web at his site.
After the new caps came in from Dale, I was able to get some very long
sparks, but have been having a lot of trouble with primary strikes. I got
one 80" arc to the grounded metal ceiling
but have not been able to get enough control over the streamers to get a
real length measurement to a grounded target. I was wondering what the
problem might be, then David (dross) sent me an email saying that the pics
were up. Now I have a clue. It seems a streamer always wants to form over
the side nearest the gap. This streamer always goes down, and the primary
strikes start there. In some of the pictures, you can see a "sheet" of faint
purple glow coming from the spark gap to the primary on that side. (this is
the side the video was shot from) It seems the hot ions from the gap are
what is screwing things up. BTW the gap is running without an explosion
shield, it wants to power arc to the shield when it is in place, the
clearance is about 1 1/2 inches from the disk all around.

http://1071737050/site/TCList/strike10.jpg

I am sending one of the pictures that shows best this sheet effect. The
white lines at the top and the vertical line behind the coil are sunlight
coming in the cracks around the back doors. A very faint streamer is visible
to the right of the toroid, not a god spark picture, but the sheet of
(plasma?) from the gap to the primary is quite visible in this shot.


Here are my questions.
1) how far from the coil do most coilers place their gaps?

2) How come the gap wants to power arc to the shield? my other gap never
did.

3) This is for those using a metal shield- How much clearance do you run
between the rotor and the shield?

4) How much difference in e-field control would using a Styrofoam "tire"
instead of a toroid make if the outer diameter of the tire is close to
semi-circular? (both are covered with aluminum foil tape and fairly smooth.)

That's all for now,
later
deano