George hit the nail right on the head.  The issue isn't will the insert move
or how strong the holding force of the epoxy is. The issue is  will the
epoxy adhere to all surfaces well enough to make a waterproof sealing that
will last under the rigors an aircraft endures.

A press fit makes sense and if done like Cary suggested will seal.  A flange
welded onto the outer part of the insert held down to the housing with a
several  screws ala Everett Hatch makes sense as well. I wonder if he had
any O rings or gasket material under the plate as well.

A screw in fitting should be easy to thread seal as well. Does Mazdatrix tap
the inner liner only?  If the inner and outer part of the pipe had proper
seals then JB Weld would not be an issue or even be needed.

I see the light on the hole shape as Aubrey rightly pointed out, aviation
needs would dictate a shape that is easiest on the seals.  Thanks for
pointing that out.

More importantly concerning all the  recent discussion is unless we know and
use the R26B's port timing, port shape,  manifold ID sizes, and lengths,
slide throttle hole shape, third plug etc. then  the quest "to copy the
Lemans engine exactly" is counter productive and their data is only ballpark
for us.   Or we try to find our own way that fits aviation needs.  In that
case Everett Hatch or Mistral Corp. is the role model we need to be
emulating not a Lemans engine.

Perhaps it finally dawned on me that the Lemans winning car didn't need to
fly more than a few inches AGL:)


Respectively yours

DougFir

You are now talking big bucks for a mill that can thread internal
holes. Not something you can do on a lathe. The simple system
will work fine if you pressure test the p-port tube before
you assemble the engine. However this is a free country
spend as much money as you like :)

"In that case Everett Hatch or Mistral Corp. is the role model
we need to be emulating not a Lemans engine."

Fine if you want to limit the HP to 200 HP in the case of Mistral
and 215 HP in the case of Power Sport. With slightly worse BSFC
I might add.

Intake systems are high speed aerodynamic devices. Why add drag?
Would you purposely add drag to your airplane for no reason?
Would you get lower MPG on your airplane if you added drag?

Paul Lamar ...No rotor no motor.

Doug,
I don't wish to put anyone off-side here, so please consider these as
suggestions only.
Considering your need for perfection I would suggest you follow Cary's
method - he quite obviously has skills in this area and you have the
resources to copy his methods.

O rings are out as far as I'm concerned as they are prone to fail, although
would be easy to replace.

Advice to me is that threaded intakes will eventually leak as well.

The areas of concern are the inside of the water jacket and how to best seal
that area. As recent events have proven - it doesn't take much to have a
small leak.

Cary's method is optimum - it does take more effort, maybe much more effort,
but worth the piece of mind IMHO.

Doug I would like you to follow Cary's method for your own piece of mind.

On the threaded housing my machinist buddy suggested to me that their
probably using a large tap to cut the thread into the housing and probably
cutting the tube thread on a lathe. I initially thought this was the best
way to go but was advised otherwise.
George ( down under)


---------------------------

Gee Doug you are going to fly an epoxy composite airplane.
Are you sure the wings won't fall off eventually? :)

You could always make that coupon sample I was describing.
Put it in the freezer for 24 hours. Take it out of the freezer
and bake it in the oven for 2 hours at 200 F and then repeat
500 times. Get back to me with the actual count :)

The fact is NOBODY knows how many cycles ANY particular configuration
is going to last. There is zero tensile load on the tube. If it fails
it will not be a catastrophic failure anyway. The first thing that
will happen... you will notice your antifreeze level going down slowly.
The next thing will happen the engine will over heat. Perry flew his
Long EZ several times with an internal leak after we thought we had
it fixed. You might also notice a difference in EGT.

Most cars today have a coolant level sensor. I suggest
everybody use one.

Paul Lamar

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