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Re: CFM and RQ Gaps

Hi Gary and All,

There's something strange about this air flow thing. I have worked with two
coils in the last month. When I was optimizing a small coil (The Radical
Radio) I tried airflow Vs no airflow and found that turning on the fan
degraded the performance slightly. I have described this coil to you, but
for the sake of the rest of the list I will describe the setups. I was using
a gap assembly consisting of 4 copper pipe sections. I was only using one of
the three gaps. The power supply is a 5/60 NST, the secondary is the size of
a paper towel roll wound with 34 AWG wire. The primary is a helical cylinder
type. The output is 1 foot streamers.

I used the same gap assembly to fire up a 5.5 by 22" secondary wound with 20
AWG litz wire. (I know, too little inductance, but I am determined to get it
working anyway!)  The primary is a flat spiral. I used a 12/60 NST, and all
three of the gap sections. I adjusted the width of the gaps the same way I
always do-by Hi Potting it with the NST that I will be using in the circuit.
I adjust for the maximum width that will permit breakdown with the NST
alone. For this setup I noticed that using the fan made a big improvement in
the output! I need a bigger room with less clutter before I can accurately
determine maximum streamer length of this thing. I can't move the desk any
further back than 36" so that is the reported length for now.

I don't know if it is the differences in coupling or the difference in power
levels that makes the difference, but I thought this would make an
interesting post because I got different results with the same gap in
different coil set ups. It does prove to me that each coil has a different
set of requirements for getting the most efficiency. Perhaps someone else
can shed more light on this subject?

S. Gaeta (Pvt. Sparky!)
----- Original Message -----
From: Tesla List <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, June 05, 2000 7:13 PM
Subject: RE: CFM and RQ Gaps

> Original Poster: "Lau, Gary" <Gary.Lau-at-compaq-dot-com>
> When I was using an RQ/TCBOR cylinder gap, I tried both a 4.5"
> computer-grade fan and a vacuum cleaner motor, both drawing air through
> gaps between the cylinders.  Photos of the gap may be seen on my web site
> at: http://people.ne.mediaone-dot-net/lau/tesla/RQGap.htm
> I noted no performance difference between the fan and the vacuum cleaner
> motor, but performance plummets if the airflow is turned off completely.
> The 4.5" fans are typically rated in the 60-100 CFM range, although the
> actual number is highly dependent upon the back pressure.  The
> of the fan is also probably dependent upon whether the air passes through
> the gaps or just blows through the pipes.  The CFM of the vacuum cleaner
> motor is unknown but many times greater than the 4.5" fan.
> It is also interesting to note that several well-respected coilers have
> reported that their gaps appear to work just fine with NO airflow.  It's
> unclear if they tried it with airflow for a true with/without comparison.
> Regards, Gary Lau
> Waltham, MA USA
> >Many discuss the electronics of the coil in detailed numbers. But I
> >recall anyone throwing a CFM figure around.