[Fot] Roll Bar/Cage History

[Norlin Engineering]

I think I've mentioned before that my wife is Historian for Oregon Region
SCCA.  Anyway, after reading some of the list messages this morning, I went
downstairs and grabbed the 1967 and 1971 GCR's.

The 1967 Appendix Z just covers roll bars and is only 3 1/2 pages long.  It
allows the roll bar to be as much as 1 inch below the top of the drivers
helmet.  It covers minimum bracing, but I cannot find where it precludes
stiffening the frame.  In fact, it states "The roll bar must be designed in
such a way as to be an extension of the frame itself in such a way as to
properly distribute the loads."

In 1971, there was a major change in Appendix Z.  The appendix grew to 5 1/2
pages and now included several drawings.  One change was that the top of the
bar now had to be at least 2 inches above the drivers head.  I remember
having to install a new roll bar in the Spitfire I now own as a result of
this rule change.  Appendix Z states "It is recommended, but not mandatory,
except in Trans-Am competition, that all cars utilize a roll cage type of
construction."  Again, I see nothing that limits stiffening the frame, quite
the opposite as it now includes "Considerable care must be used to add as
necessary to the frame structure itself in such a way as to properly
distribute the loads."

BTW in response to an earlier question about spoilers, it appears that this
is the first time that a front spoiler is allowed.

Jim Norlin