I was so shocked to see this on Finn's airplane I forgot
to take a picture. So I did this 3D. His rubber motor mount 
bushings had melted and allowed the engine to sag down about an 
inch or so. This means the engine is flopping
around as he is doing aerobatics. It is also twisting slightly
in an unrestrained manner as he opens and closes the throttle.

This over and under motor mount scheme has other serious problems
as well. The bolt is subjected to super high stresses and Finn's
may be cracked as we speak. I will get into those problems shortly. 
Seems like there is little understanding out there for the principles 
of space frames and structures. The Egyptians figured all this 
out 5000 years ago or they would not have been able to build the 
pyramids. I have signed up to do a forum at next years Sun & Fun 
on how to design motor mounts.  

Finn is a strange guy. He ignores peoples suggested improvements
on his engine installation until something serious happens. I warned
him about the tension bolts and he failed to take them out one
at a time and coat them with RTV. Sure enough  he had a tension bolt
fail. Ed Anderson said he would pay for the fuel lines if
Finn replaced the cheap clear plastic lines he is now using with
AN fuel lines. Finn declined.

I also warned him about having the rubber motor mounts
in an aluminum plate sandwiched between engine and pan as that
would conduct too much heat into the rubber motor mounts. Rubber
motor mounts are limited to about 180 degrees max. Sure enough
his rubber motor mounts melted.

Come on Finn. We don't want to lose you. Who would we have
to humiliate if you were gone? :-) Fix the fuel lines and the 
motor mount. You don't want to have your engine fall out of the
cowl. Use a Schertz beam motor mount and get rid of that 
silly dumb idea sandwich plate.

Paul Lamar
 
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