A mechanical engineer friend of mine and me were discussing the
Schertz beam and she mentioned a possible failure mode.

"Looking from the top down, put a large gyroscopic twist on it from a really
abrupt pull-up. The inner 6 mm bolts take next to no load, the outer 6 mm
bolts are taking the whole load. The vertical side braces do nothing to
help there either."

Horizontal fore and aft braces from the rubber bushing area on the
Schertz beam to the engine or to the gear box nose would help.

Typically this rapid pitch at 60 degrees per second would generate
a 300 ft pound torque around a vertical axis assuming a wood prop.
Double that for a metal prop.

You could also weld on a clip on the bottom of the Schertz beam tube on
each side adjacent to the side walls of the oil pan. Weld an aluminum
angle on the corners of the oil pan in the same areas and
bolt the two together with at least two 5/16 inch bolts.
One on each side. This will distribute the gyro torque load into
all the 6 mm pan bolts.

If a 4130 steel channel and vertical braces are used you could bolt
that to the angle clips on the pan directly.

No time right now to do a 3D but will do one shortly.

I think if using the beam, then the mounts on the front of the engine 
need to do a more substantial job of bracing against such gyroscopic loads.
...Chrissi

Cozy Mk-IV 13B Turbo
www.CozyGirrrl.com
Chrissi@BlueMountainAvionics.com

I don't follow you Chrissi. Can you be a bit more specific about
"more substantial job". 

A 5/16th AN bolt with an area of .0767 has a tensile strength
of about 11,000 pounds at a stress level of 150,000 psi.
So 300 ft pounds would only stress the bolt to about 4,000 psi. 
A couple of 1/4 inch bolts per side would distribute the stress
in the sheet metal joints better. 

If the oil pan walls are made from .065 aluminum a section two 
inches wide would have an area of .13 square inches.
The concentrated load of the bolt is distributed into
the sheet metal oil pan sides by the welded on aluminum
angle clip.
 
300 pounds tensile  / .13 area is a tensile stress in the 
aluminum pan side walls of 2,300 psi. Not much. 

Paul Lamar
 
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