>   David,
> I have done all the design with Butch, who did all the FEA on it and I
made
> the pattern.
> The big problem is getting thin enough and strong enough with sand
casting -
> mine is 5 to 6 mm.
> Then there is the problem with getting the Al to flow over distance in
such
> a thin section. Then there's the problem of porosity of such a thin
section.
> The Al has to be heated beyond recommendations for it to retain
sufficient
> flow ( read heat) over distance in thin sections - this walled casting
which
> aren't pressure cast are a nightmare!!
>
> But there's more! the real problem is the machining, I can do the casting
at
> a reasonable price, but the machining costs (especially CNC) are
outrageous.
> Then there's the postage and handling cost to USA - ever posted something
to
> the States -again outrageous.
>
> Our design ( Butch and myself) is strong, is a reasonable weight,
includes
3
> positions for starters, allows for 2 different starters, but I can't
supply
> them at a reasonable cost! It is also caters for engine mounting at the
> sides, will accommodate 2 different PSRU ( Tracy's and my own
design). has
> additional supports for Aerobatic work
>
> You will notice Tracy does his own machining in-house, I don't wonder
why!
> George ( down under)
>
> ---------------
> George,
>
> I worked on a foundry for a short while (3 months) a very long time ago,
> from memory when there was something like the size of the bell housing or
> bigger the way they used to get the alloy to flow all the way through was
> to heat up the sand casting (lost wax system) to an applicable
temperature
> you need a big cooker for that, they did of course, when the whole
cast is
> that hot the alloy will keep flowing until the entire cast is full, did
> you try it that way? Just a thought.
>
> George why don't you contact me direct on the phone at 03 95480704 ex-711
>
>
> Regards David Gaze
> Also down under but further than George :)

David,
I worked in a foundry as well - first job!
The local foundry chap has many years of experience, so I leave it up to
him. The end result is pretty good. You will notice I don't need a two piece
pattern like many foundries insist on, he will do it with a one piece and
it's much easier making the pattern and no misalignment.
George (down under)

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

George,

OK, it was just a thought, as I didn't know how it was being done
or what method was used. Of course if you do have a picture with
dimensions then I could still run it past them.

Regards David Gaze


A carbon fiber composite bell housing might be the right answer.
300 F epoxy of course.

Paul Lamar ...No rotor no motor.

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