"Mark J. Andy" <marka@telerama.com> wrote:
>
>Even a telescoping bar would provide some support if you wanna
>take it far enough.
This is one area where I'm familiar with the rule from it's
inception in 1997 through today. The harness bar, as originally
described by Per Schroeder, was constructed of two pieces of
different-sized tubing, one inside the other. When mounted,
they could freely slide in and out of each other. That's the
telescope part. This made them useless as a stress member,
unless you drilled through and put a bolt in to fasten the two
pieces together. (We'll ignore the miniscule possibility that
the two pieces might be constructed with such close tolerances
that they would lock together by friction under a twisting
motion.)
My interpretation of the rule change is that the SEB wants
to allow alternate means of constructing a harness bar that
doesn't make it a stress member. For example, maybe a ball
joint or hinges on the ends might accomplish the same thing
while utilizing one piece of continuous tubing instead of
two shorter pieces stuck together. They don't want to stifle
creativity, while at the same time leaving in the gospel
words "...as long as it serves no other purpose....."
-Arthur ("Can't make a Schroeder bar work in the submarine" edition.)
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