Description of a new Coil

The folowing may be of interest to others like me who may never own a pig

For the past couple of years I have been trying to figure out how to 
maximize a Tesla coil for a given size neon driver xformer. I have a 
psuedo lotus program that designed this coil:

Secondary :14" diameter open acrylic frame, 30" high, wound with 240 
turns of #16 guage machine tool wire, 8 turns to the inch. 1/4 wave 
operating frequency: 279 khz.
Primary: 4 turns, 19" diameter, solenoid wound, .375" copper tubing 
spaced .25" apart. Expected  resonance using a .021 uf capacitor to be
about 275 khz. 
Actual measured secondary parameters: free air resonance 397 khz. With a 
6" x 28" toroid, resonance is 286 khz.
Actual measured primary resonant frequency with gap shorted and using a 
.021 uf cap: 272 khz
The unit is driven with a 15kv 120 ma neon. The break is a synchronous 
1800 rpm rotary with .25" electrodes. there are 4 stationary contacts and
4 rotating contacts giving 1 firing for each half cycle through 4 gaps.
The firing point is adjustable.
First firing was a lashup on the floor using #10 guage wire. As a 
starting point for all my coils I place the bottom of the secondary even 
with the top of the primary. Ground was only a water pipe (really not too 
bad since I'm 25' from the water. With this setup I'm getting 48" 
discharges and have to move outside.
This is the best I have ever done on a first pass. Obviously there is 
some tuning to be done but it appears that the program is on the money.
I would hope that this coil is capable of 72" discharges. Will make 
further reports in the future after I get outside and get a good ground.

Skip Greiner