Subject: Lancair 360 motor mount new hard points
From: Rotary Engine
Date: 1/19/2008, 9:07 AM
To: AARotary Engine

Make a new folder Jerry.

Here is what we decided on the lower firewall connection.

The angle of the lower tubes is almost straight in.


Old messages.


     > That would be great. If you moved the upper ones up 5 inches higher
     > and
     > the lower ones out 5 inches and up one inch that would make it a
     > near normal
     > airplane :) It would look like the Lagacy.
     >
     > Beef it up with a couple of layers of carbon.
     >
     > --
     > Paul Lamar ...No rotor no motor.





    Paul,

    OK, that settles it.  These are changes I know I can make and I'm
    sure it will be a much better mount - like the Legacy.  Seems like I
    remember reading about 360 guys starting to see engine mount cracks.
    They were thinking it was being caused by nose wheel shimmy.  Perhaps
    not. Please revise the mount drawings and let me take a peak.

    Thanks for all the work,


    Steve

    OK Steve will do. I hope to do the same on mind if I get one.
    --
    ------------------------------------------------------

    Steve,

    We need to depart slightly from the traditional firewall hard
    point details due to the shallow angle of the lower one inch OD tubes.
    Here is the problem and the solution. Use four 1/4 inch bolts rather
    than
    one 7/16 bolt. The four bolts have a tensile capacity of roughly
    19,600 pounds at 100,000 psi stress level while the 7/16th bolt
    would be about 15,000 pounds at the same stress level. In other words
    way over kill in either case.

    The round part (washer) is 2 1/8 OD. Use allen head bolts for
    clearance reasons around the tubes.



Paul Lamar ...No rotor no motor.

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