Tuning, toploads and tank caps

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "jpeakall by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jpeakall-at-mcn-dot-org>

Howdy all,

Before I ask my questions, let's make sure I have this right:

More caps in tank circuit = lower tuning on primary
Less caps in circuit = higher tuning on primary
Larger topload = lower tuning on primary
Smaller topload = higher tuning on primary
Increasing gap = lowering frequency
Reducing gap = raising frequency

And here are basic coil specs:

Secondary: 14" of 22ga wire, close wound, on a 3.25 form
Primary : Have several, one I am trying now is helical, 10 wraps 10 ga on a
9.5" form
PSU: 15/120 Franceformer, have tried a 12/120 and 2*15/60
Tank caps: see below
SG: Single vacuum gap ala Lau
Topload: 3" duct / 9" pie pan torrid or a copper toilet float

I normally run this TC with about 7.4nf SW caps. This tunes at around four
turns. I have two caps that connected in series give 14.3nf. I have tried
and tried, but I can't get the coil to break out with these caps. When using
the toilet float, best output is on one turn, judging by drawing arcs to a
ground rod. With the torrid, best tuning is at 3 turns. At most, with the
torrid, I can draw about 8" sparks, but no break out. I have raised and
lowered both the secondary and topload, and am not undercoupled, even with
the large primary (I have to keep the secondary raised to avoid racing
sparks). SG action is hot and heavy, and has been with all the PSUs I have
tried, so I think the caps and trannys are ok.

My questions:

Why the heck won't it break out?
Is it possible to have a tank cap too big for a coil, regardless of PSU
current? Inductance?
Shouldn't closing the gap allow for higher tuning on the primary?
Is it possible that the primary  "sweet spot" is so small that I am missing
it? I only have taps every turn.
Would using a smaller topload help?
Isn't a 15/120 more than adequate for the 14.3nf caps?

Any ideas or advice would be most welcome. This is like a loose tooth when
you're a kid, I just can't leave it alone, and it's bugging the !#%^&* out
of me!!

Thanks all,

Jonathan Peakall