-Joseph M Berki wrote:

Paul,
         We are thinking about an annular discharge muffler / augmenter
that has the prop shaft going through it.  It looks like a big

doughnut fed

from the headers.  Louvers on the outside surface discharge exhaust

to the

space between the cowl and the muffler (venturi).  The whole cowl is
pressurized via the rads.  This eliminates the lower augmenter tube and a
better lower cowl shape.  Exhaust is discharged around the prop.  What
about the shape of the wedge duct floor?  Is there an equation for

the curve?

Joe

Not that I know of. Are you going to use a prop extension?

Paul Lamar

Joe I'll ask a question that any engineering manager should ask.

What are the advantages and disadvantages of your proposed arrangement?

Paul Lamar

The Limo EZ, although slightly bigger than the Long, presents a challenge
in integrating all of the various systems so that they function
properly.  A side by side configuration would be easier to do.

I do not want to use a prop extension.  It depends on the proximity of the
PSRU and how big the muffler gets, I may need one.  As far as advantages
and disadvantages, I see this type of muffler cleaning up the lower cowl
which is critical for canard pushers, easier to build than other exhaust
systems, one scoop feeds the whole airplane, simplifies ducting under the
cowl as there isn't any.  Disadvantages heat in front of the prop, close to
PSRU, Part of the cowl may be metal as well as the spinner and flow guide,
has not been tried before? Warm air under the cowl kind of like an auto
engine compartment.  As far as stuff going through the prop all pushers are
face with that challenge.

On another topic, I was searching the web for radiator candidates and found
that a fabricator that makes go kart radiators makes one that is curved.  I
wonder how it would work in a wedge duct that had no curve?  Instead of
curving the aft end of the wedge duct leave it straight and curve the
rad.  It might have some application in a tight space if the size was correct.

Joe Berki
Limo EZ

I am not following you on your configuration Joe. Got any sketches?

No scoops on the bottom? How are you going to get air in for cooling?

Got any pictures of that curved rad or the URL for the web site?

Be careful of sloping up the bottom back of the cowl too severely as that is
probably more drag than an ejector exit.

Paul Lamar
 
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