Rear brace rule clarification


#1

My car is in the cage builders shop and he has a copy of the NASA regs. He wants to put in diagonal bars from the top of the main hoop to the strut tower wall on the opposite side of the car. He read the 15.6.11 rule on the rear brace and the angle having to be between 75 and 105 degrees as being prohibitive of any diagonals. He already has braces going straight back to the rear wheel well. I know most of the cages I have seen on this forum have rear diagonals.
Could some of you rule oriented guys (Bruce) comment on this rule and the use of rear diagonal bars.
Thanks
Paul


#2

the "between 75 and 105 degrees" criteria is for the required bars going straight back (which it sounds like you already have in place). The rear diagonals would fall into the non-required bars category and are fine. You definitely would have seen some "you can’t do that" comments posted with the cage build threads if diagonals wern’t allowed. The only gray area is when you start putting in more than one set of rear X’s as you are potentially open to a claim by a regional tech steward that it is being done for structural rigidity advantage.

just my $0.02. The most definitive answer would come from your NASA regional tech steward.
cheers,
bruce