Original poster: Steve Conner <steve@xxxxxxxxxxxx>
Spark length (meters) = F x SQRT(bang energy x BPS)
"F" would stand for "Freau" so John will be eternally famous!! I would
suggest going to meters just to keep things "scientific".
I agree that "F" is a handy way of measuring coil performance, a bit like
the specific impulse for a rocket or such like. But I wonder if there is a
way to make it into a proper dimensionless number. Otherwise you have to
call it the "Freau coefficient" with its rather unwieldy dimensions of
"metres per root watt".
Also I remember Nick Field mentioning that the law may not be quite a
square root. Square rooting is raising to the power 0.5, and he suggested
the exponent might actually be nearer 0.6 or something.
I suggest the "Watts number" (streamer length divided by resonator length)
as another handy parameter. Some day I ought to try making a graph of F vs.
Wa for a coil and see if it throws up any interesting results.