When a down load is applied to the mount the ends of the tubes
tend to move in the direction shown because of the rubber
bushings causing high bending stresses on the other end of
the tubes. There are also high local bending and twisting
loads on the ends where the bolt goes through the
rubber bushings. That is easy to fix by beefing up the
area with plates and gussets.

When a prop torque load is applied the same thing happens.
The ends with the bolts through them move around.

If there were no rubber bushings in the firewall this
mount would work fine. As I mentioned before a composite
firewall is like several steel tubes and therefore it is a
good place to bolt something too you would like to stabilize
in the plane of the firewall.

When the rubber bushing get worn or sloppy the bending
stress on the tubes increases.

It is necessary to install tubes in the positions of the
yellow lines to stabilize this mount.

I caught hell from the owner of this mount because he said
I was suppressing Cozy motor mount opinions that differed from my own.

This is not an opinion! This is fact. Mechanical engineering
is not an opinion such as found in politics or religion. It is based
on the laws of physics. These laws were not written by a politician.
They are the immutable laws of nature and will not be violated
with out penalty.

Check with any mechanical engineer and he will tell you the
same thing. If you find a mechanical engineer that disagrees
with this PLEASE, by all means, let me know. I could be wrong.

Paul Lamar

"Webre, Steven P." wrote:

Paul,

I'm an ME and agree with your evaluation.

Steve Webre
Broussard, LA

Thanks Steve. I am gald you are checking my work.

Paul Lamar
 
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