Yvon Cournoyer wrote:

Good morning Paul
Thank you for posting the photos
My message was intended for Ed and also for whoever else would care to
comment
By "observations" I meant: that now that Ed has used the exhaust for a
number of hours and on cross-country flights, he might wish to comment

on

sound levels, apparent back pressure, etc...
Is Tracy Crook  using a similar design exhaust?
My Zenith is slowly coming out from under the snow where it was buried

all

winter and spring fever is welling up in me!.

Tracy has a similar set up but both exhaust pipes converge into one larger
diameter pipe with a similar number of holes.

Paul Lamar

Hi Yvon,
    My observations are mainly subjective - no hard data measurements for
the most part.  I can tell you that the exhaust does not appear to detract
from performance.  This trip I flew my fastest speed to date (192 MPH TAS).

   Subjectively, the cockpit is less noisy, I believe primarily because the
exhaust pulse is dumped by the 4 foot pipes behind the cockpit.  It is also
quieter on the ground, perhaps for the same reason.

   The "Fishtail" tips make a noticeable difference in sound level, however,
I have not been able to get them to survive longer than a few minutes at
high power.  Perhaps thicker, braced parts are the answer, although I
suspect that the high impulse of the exhaust pulse might just take longer to
destroy heavier fishtail exhaust.  But, I intend to keep working on it as it
does make a light weight exhaust and does not seem to kill power.

Ed Anderson

 
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