. The runner length
should be 22 inches for the 6000 rpm and somewhat shorter for 7500 rpm.
  Maybe someone can suggest a compromise length that will work well
enough throughout that rpm range.  

david mccandless wrote:

Hi Paul, surely somewhere in your vast database you have a graph or table that
shows tuned runner length plotted against rpm?
I cannot see why we want a tuned length for any rpm other than max T/O and
Climb power. Surely when we throttle back for cruise , we deliberately reduce
V/E, ie reduce the amount of combustible gas flow through the engine? Why
would you tune runner length for cruise rpm and then restrict the flow with a
with a partially closed butterfly?  This seems to me to be a conflict of aims;
the only time tuned length has relevance is with wide open throttle. This is a
silly as reducing the top end  performace by incorporating a dynamic chamber
to run boost torque at 3000 rpm. Who needs high torque at 3000 in a rotary
airplane engine? Comments please;    Dave McC

It is somewhat a function of runner diameter but yes I have it for the Leman
engine with what ever intake runner they used. My guess is two inches. 
Don't forget to add the fixed length to these numbers.

At 8000 feet and above the throttle is wide open so a tuned length 
for max torque gives best BSFC.

Paul Lamar
 
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