-Joseph Berki wrote:

Perry and all,

         Once you determine what route the scat tubing  takes, you

could

hot wire straight tubing sections out of the blue foam scraps that you

used

in the wings.  Cut the sections at various angles and glue together to

get

curved bends.  Sand to get smooth contours.  You can start with a

larger

diameter.  Coat the entire core with silicon and then glass.  Use

gasoline

or other solvent to remove the foam.  Grab the silicon with pliers and

pull

it off of the tube and the inside will be smooth not rough.  I am
interested in your results with the new intake system, Perry.  I

appreciate

the discussion on the exhaust system items as this is a problem in a

pusher.

Joe Berki
Limo EZ
ailerons

Really really great idea Joe. You could also use a hole saw and cut a
bunch of round slugs the proper size. You could make your own deeper
hole saw out of steel tubing. Or just use an arbor or drill press to
cut the foam slugs with the sharpened steel tubing.

Sand the angles on them and glue them together with contact cement
or hot glue.

This sounds like a real break through in fabing composite intake

manifold

runners. About two years ago we had a bunch of ideas discussed on
fabing composite intake runners and this is head and shoulders above
anything else we could come up with.

Thanks Joe for sharing that idea.

BTW does anybody know how to dilute silicone RTV so you can paint
it on? How about a source for low viscosity silicone RTV?

I also think wrapping the cores with vinyl electrical tape
will also work but not as smooth as silicone.

Paul Lamar

Do we really want a smooth surface on the interior of the intake.  I am

of the impression that a

rough surface creates a turbulent boundary layer which in turn helps

keep the fuel in suspension.

Please correct me if I'm wrong.

Tom Webber

Noooo. Intake air velocities can approach the transonic range. Smooth
as possible is the best. That might have been a problem in the old
carb days. With EFI you have one injector per pipe so that is
no longer a problem. The fuel does not disappear. Even if it puddles
it does not go anywhere but down the pipe sooner or later.
Paul Lamar

I have another suggestion. I make my fiberglas parts by moulding over wood.
2x4s are cheap and for flat surfaces particleboard is useful. glue the
pieces toghther with bondo ,carve the wood as necessary and sand smooth.
Cover the wood with cheap polyester (boat) resin and finish with finishing
resin. mould the parts a half at time
mark the separating line with masking tape and wax the polyester surface
with mould release wax. after making the pieces bond them together with
glass tape at the joint line. peelply makes the job less messy. may sound
complex but actually goes very fast. the inner surface is as smooth as the
polyester surface. I can make a intake tube in half a day. The most time is
spent waiting for resins to harden in the final moulding. The wood form is
stiff and easy to mould over.
smale@ncinternet.net>

 
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