Russell Kent wrote:

Paul,
The bottom braces (there are two) seem to be positioned to restrain
lateral movement of the motor mount.  Do you think the bottom cross
member you suggest is really needed?

Paul Lamar responded:

You are probably right on the diagonal brace. As it is now
the lateral rectangular tube that the horizontals butt up against
back near the firewall have some strength in bending that might take
care of lateral forces. I would put in the diagonal tube to be on
the safe side.

Paul,
I think I may have been misunderstood.  Yes, the rectangular main
support will resist (slightly) lateral movement because of the weld at
the firewall member, but I meant that the existing *round* bracing
tubes, because of their offset placement at the firewall (slightly
outside and lower than the main rectangular tubes), would provide some
margin of resistance to lateral movement of the motor mount (at the
connection to the motor, obviously).  Since there are two such round
tube braces (one on each side), I was thinking we could forgo the
underside cross brace.  That space could then be used for the radiator.

By the way, this same existing round brace tube is the one that I
believe will crumple in a hard landing or extreme G turn. The former
would be unfortunate; the latter disastrous!


Russell Kent