I've been working on several rockets that I've never flown, for various
reasons, in anticipation of flying them at NYPOWER2002. One of those
rockets was a LOC Vulcanite H76. I built it mostly stock (years ago, I
still followed directions) with the exception of using the, then touted,
anti-zipper technique. What a mistake that was. I lost over 2' of
usable space doing that...but I digress.
The rocket has no positive motor retention. At the time that I built it,
I wasn't as gung-ho on it as I am now, but now I wanted to add positive
retention. Looking at my options, T-nuts were out; not enough room in
between the 38 mm motor tube and 2" body tube. Being a sensible person,
I can't see paying $30 for "slimline" motor retention on a rocket that
didn't cost much more than that when I bought it, so that was out.
I got a bright idea of using 3' sections of allthread and running them
the full length of the body tube from anti-zipper to past the rear
centering ring. No go. Besides the fact that the allthread rods were a
few inches short, I failed to remember that I'd also have to go through
the centering ring at the front of the motor; a ring that would be
difficult to drill holes in.
So, I was standing there holding my 3' section of 10-24 while sweat
rolled off my nose when it came to me. Put a hook in the end of a piece
of the allthread rod and feed it into the centering ring. As you
tighten it, the hook part grabs the inside of the centering ring and
voila!, positive retention.
Now, I'm sure that I wasn't the first to use that technique, but I had
to share my epiphany with all of you while I enjoyed a little air
conditioning in between trips to the very hot garage.
NAR 71503 Level II