X-Mozilla-Keys:                                                                                 
V. E. Welch wrote:

Paul,

Most of your motor mount designs seem to be sized for 6G,  what changes are
required for a 10G rated mount?  The RV-8 is designed to pull 6Gs at
aerobatic weight with a destruction loading of 9Gs.  It has been stated
that a hard landing can easily produce 6Gs.  I'd just feel a little better
if the mount was designed for 10Gs.  Would the weight penalty for the
additional strength be that great?

Vince

The lower fore and aft motor mount tube might have to go to 7/8 and the
tube
bracing the 3 X 1.5 X 1/8 aluminum channel might have to go up to 5/8th
from
9/16th. Still using .049 wall. The weight increase will be minimal.
Add 50% to all the loads and check the buckling chart on the web site.

BTW If you check the drawing there was a mistake. The small tube
call out should have been 9/16th and not 5/16th. I will fix that before
I up load it to the web site.


10 G's is a lot most people will black out.
If you land with 10 G's something else might break somewhere else like
the
fusleage. :-)

I saw a Bonaza dead stick land one time at Santa Paula without
flaring or benefit of flaps. The airplane looked OK but the main 
spar was buckled and the motor mounts broken.

Also with a sustained 9 G's the oil pump might cavitate and your engine
will probably lose oil pressure.

Of course sustained inverted flight with out a dry sump system is a no
no as well.


Paul Lamar
 
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