RE: Length of controlled sparks vs air streamers, was THOR: First observations

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

Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com> 

 >I wonder if many folks have compared the ratios of controlled sparks
 >to free-air sparks for their coils?  Although I have not compared
 >the two, I would think that the controlled sparks would not be
 >tremendously shorter than the longest sparks on my TT-42
 >coil.

I have done it for my OLTC mini coil. The controlled spark was not much
shorter than the furthest distance it could hit. i.e. if I put a target 12"
away, I would get an occasional hit, but at 10" it was a continuous solid
arc. The longest streamers to air seemed to be about 10" too.

I also did it with my spark-gap coil, back when I was running a 9nF tank
cap. The result was 31" for occasional hits and about 24" for a solid
continuous arc. All the air streamers I observed fell within these limits. I
did once get a freak strike that must have gone 4 feet, but it has never
happened again.

I think my coils show these consistent results because they all run off DC,
so the bang size varies very little. OTOH, an AC charging coil with an ASRG
would have a constantly changing bang size and much more "interesting"
behavour ;)

Steve C.
http://www.scopeboy-dot-com/tesla/