Ken Powell wrote:
 >
 > Dave and Paul,
 > I agree with Paul on this one but for different reasons.  Of
 > primary importance here is that the main tuning effect comes from
 > the length of the tubes and the main timing of the pressure waves
 > is dependent on this length.  What is called the dynamic tuning
 > effect is not nearly as strong (or as important).  Daves
 > discussion of this dynamic timing is correct for a 2 rotor but is
 > in conflict with the length of the intake tubes when they are 18"
 > to 24" long.  Due to the event timing worked out by Dave I do not
 > see how dynamic tuning can work in a 3 rotor.  It looks like the
 > pulses will arrive at the wrong time, giving no benefit (or maybe
 > even having a negative effect).  Dave, it appears to me that your
 > logic supports this argument.  Did I miss anything or do you guys
 > agree.
 >
 > Ken Powell

Thanks Ken, that actually clears it up for me.  I was beginning to suspect
that what I thought was the major effect in tuning (what you call dynamic
tuning) was really just a minor effect.  I guess the more important effect is
due to some sort of harmonics within each individual runner.  Given that this
is the more important effect, then I agree that the tuned length for a 20B
would be the same as on a 13B.  What do you call this effect, static tuning?
How is it calculated?  My guess is that it would be based on standing wave
equations.  Unfortunately, I threw away all my college physics books when I
went to medical school (and had to move every 6 months).  I suspect, though,
that for a standing wave both the length and diameter of the runner are
important.

Dave Leonard

True Dave. Keep the diameter up to reduce the skin friction in the pipe.

Paul Lamar

 
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