Jeff Spitzer wrote:

Two points.  

1) The actual propagation of waves is more complex than simple
speed of sound.  For instance, the speed of sound is superimposed on the
flow in the pipe.  For long pipes this is not trivial.  Don't get me wrong,
the simple calculations presented previously are a great way for a first
guess.  

2)  The physical process described by Paul Yaw is correct and
accounts for different tuning effects with pipe diameter.  The general rule
is smaller pipes will give more power (yes more) at the tuned condition but
less at detuned conditions (which is everywhere else).  So if you truly
want a peaky system keep the pipes small (up to the point where frictional
losses get extreme)  If you want a flatter torque curve then keep the pipes
bigger.

Jeff Spitzer

 
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