Still looking at the idea of the front engine mount material.

This would be using Tracy's PSRU unit. Using 15" x 30" x 0.375" 7075-T6
Plate.   Material wise 7075-T6 would be stronger than 0.500" 6061-T6 that is
normally used.

Originally thought of using a 3" x 3" x 0.125" 7075-T6 36" long tubing for
the "s-beam" function.
(Original is 4130 x 0.063" box material). My concern is fatigue and heat
from the exhaust adding to fatigue.

Just looking for guidance. Approx 12# for PSRU plate, 5# for the 3" sq.
"s-beam".

Tom Walter
Bearhawk Builder


In one direction 3/8 7075 -T6 would be but it would be less stiff in the
fore and aft direction.

The main problem with the aluminum schertz beam is heat transfer from the
end housing into the beam. I think a 3" by 3" by .125 thick might be OK but
the fatigue limit of aluminum is not near as good as 4130.
Have you located a source for this tubing?

The adapter plate is once removed from the engine and much stronger.

However you can make your own silicone rubber bushings. Barry will also sell
you silicone rubber bushings I think. Should be good to 500 F.

Check with Jeff. The NC pocketed adapter plate weighs about 5 pounds but it
does two jobs. I does both the scherts beam and the adapter plate.
You will need an adapter plate anyway.

Paul Lamar

Paul, does Jeff have the final files ready for production? If you could
forward my personal e-mail to him, I would like to move forward, if he is
ready to produce product. I have his phone number, but I think e-mail is
better, you have a record of discussion, don't have to write down things,
and an e-mail will never interrupt your dinner.

As for material, the blanks would be 15"x30"x0.500" 6061-t6? We could do it
either I have online metals ship blank directly to him, or send payment and
he can procure material through his own sources. Not sure if he is cash
only, or up for MO or check. I guess there is also the aluminum cups for the
Barry mounts too... I don't know what the blank dimensions for that would
be. I now have TIG capability in my hangar.

For now I'll hold off on modifying the PSRU housings, as that may affect any
warranty from Tracy. Then again, I won't be flying for a couple years
anyway.
C. Smith

I can send the stp files to Jeff anytime he wants them.
I have stp files on the Barry bushing cups as well.

Here are the 2D dxf's zipped Jeff.

jeff doddridge <4starr@cox.net>

Paul Lamar