Re: FEA of new rotary spark gap

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Hi Ed,

Early on, I did just this. I had a 9" aluminum flywheel. I tapped 
1/4-20 holes around the outer edge and screwed in 1/4" x 1.5" copper 
electrodes. This gizmo was belt driven. It sucked! I could probably 
write a book on how "not" to build a gap. I've built some real losers 
before I broke down and decided to take the advice of the list.

In retrospect, I suspect the problem was reignition due to the 
metallic outer flywheel. I'm not sure of the reason as I had about 1" 
from mount to electrode end. Maybe it was the use of copper.

The very next gap was my G10/tungsten assembly. It made a world of 
difference (I would guesstimate 40% sparklength increase just on the 
gap itself). Maybe others have had better luck than I did. But, I 
never went backwards. That was just my personal experience.

Take care,
Bart

Tesla list wrote:

> Original poster: Ed Phillips <evp@xxxxxxxxxxx>
>
>    I can't see any reason why a good RSG couldn't be made using a 
> metal disk to hold the electrodes; it would be fitted with an 
> insulating hub which wouldn't have very much stress in it 
> (particularly if the disk were made of steel) and there should be 
> some significant heat sinking to the disk.  There were certainly 
> gaps made that day in "the good old days of wireless" and they 
> would certainly get around the problems of expensive materials.  Any thoughts?
>
> Ed