Jerry Hey wrote:

Paul,   I cut one inch out of the center of the 180 degree bend.  The
result is a less than perfect radius but not  bad.   The runner now
has
one half inch clearance over the engine.  And,  the option to lean
the
runners toward the firewall still exists.     This move also gets me
back to a 12 inch spinner and the stock Tailwind cowl.     A four inch
dia round plenum might work better.       Jerry

p.s.  I recently got a scroll saw.  It is very useful for this kind of
stuff.   I don't know how I ever got along with out one.

I would not do that Jerry. The air will see that discontinuity and
bounce.

Better to put a little hump on the cowling. AKA Power Bulge in the
automotive
world:)  Glue on some foam to the top of the stock cowling shape
it with a long rasp. Sand and lay-up a little gup on top. Finish off.
and then rout it out from underneath.

Come to think of it that might
be easier to do if you just went to a 16 inch spinner and then just
filled
in around the spinner on the stock cowl. Both top and and bottom.
Looks like it might cut the drag a bit. The cheek inlets
would get smaller but they are probably too big for the oil coolers as
they
are. You will have to build a scoop near the lower front anyway for the
rad. Looks like it is time to do another cowl.

I'll see if I can come up
with something better and still keep the cheek inlets for your oil
coolers.

The four inch round makes it hard to seat the injectors.

Paul Lamar

  Once the runner  halves are cut apart, I think I can add material to
the inside by welding in aluminum that could be blended, faired and
polished to make a smooth  path  for the air.

I plan to supply both oil coolers, intake air, cool tube and radiator
from the belly scoop and the two cheeks.  There will be no more holes
in the cowl.  I am willing to modify the cheek openings if I have to
(or it might be possible to syphon air off the rad plenum for the
intake.   Come to think of it, that is what I should do.  Remember, my
rad is only 13 inches wide. I can easily make a larger  scoop and
section part of it off for the intake.   Now we are talking.

  Also,  I am not willing to give up the air filter.  Just think what
one grain of blowing sand could do to your engine.  The air filter is
far more important than  ram air to me.   I like PowerSport's air
cleaner arrangement.  They seem to be developing plenty of hp without
ram air.

  Are ram air and an air filter mutually exclusive?   If I bring air in
through the belly scoop and just dump it inside the cowl,   creating
higher pressure inside the cowl, would not the engine easily  be able
to draw all it wants?

Here is a drawing of the round plenum with a flat for injector
mounting.       Jerry

Here is the latest cowl iteration. Check the length of the Schertz beam again for
me. I think a flatter rad air intake would look a bit better.

The spinner is 16" which buys you plenty of room for the intake.
Also helps clear the motor mount beam. 

Needs a bit more work here and there.

Paul Lamar
 
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