Largest diameter is about 15 inches for the bolt flange.

Here is what I have come up with so far. The flat lower sides
can be used to bolt on your fabricated rubber bushing brackets
of choice. This give a maximum amount of flexibility as it
seems nobody can agree on just how wide they want their rubber
bushings to be. It is rather more complicate inside as various
and assorted ribs are required to provide support for Tracy's
PSRU.

What does everybody think?

Paul Lamar

Paul,
Couldn't you just incorporate the mounting brackets (for the Majority

users)

in such a way that they could be easily removed (cut back) for those
requiring closer mounting points.
I just feel a single piece unit will be stiffer and stronger.
George (down under)

I agree George but there are some other factors going on here.
Mainly pattern issues. It is tough to put efficient beams out
there and still keep the pattern and casting cost in sight.
The bolt on pieces are almost identical to what Perry is using.
These are cheap and easy to make.

Paul Lamar

Paul - I am sure that I could turn the "bowl" for the bell housing on my
lathe
using wood as the pattern material. The other parts could then be
pieced on rather easily. With a bit of draft and planning it looks like
it could be a simple cope and drag sand casting with no fancy
coring. I made aluminum cast wheels for a sports car project about
25 years ago - Vance J

That is the hard way. It only takes me a couple of hours to make
a pattern. Not only that it does it while I sleep :)

The big thing is the .010 accuracy possible with 3D. You will play
hell turning a bowl only .2 inches thick with a constant wall
thickness by hand. The entire lower half of the pattern is
a box. Mainly due to the necessity of mounting the starter.
then you have the vertical walls on each side needed for the
motor mount brackets. Not to mention all the drafts needed on
all the interior reinforcing webs and all the walls. Then you
have fillets on all the junctions between interior webs and
the outer walls. It could take a month of hard work.

Hand made casting patterns in the age of Rhino and 3D machines
are ancient history.

Paul Lamar

Here is a wire frame. None of the interior reinforcing webs
are in there yet. Looks like I will need a lot as the radius
on the upper bell is too large. That means I will have a large
flat panel with a high bending load input from Tracy's gear
box. If you go up on the wall thickness the whole thing gets
too heavy very fast.

BTW Vance thanks for the offer anyway.

Paul Lamar
 
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