The assembly is
straightforward. It is after all a 3FNC, so most BARs can build one
without using the beautifully prepared instructions included in the
kit 
Being a hard head, I failed to check the directions before I attached
the fins with the result they're mounted flush aft rather than offset
forward ¼"  So, the black
ring you see that's supposed to be just aft of the fins is in fact on
the motor and not part of the rocket.
Here's a close-up of the fins. It's clear here the black ring aft is
not on the airframe.
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Despite that mistake, I'm very pleased with the outcome. For that
matter, having the fins all the way aft makes sanding and masking a
whole lot easier. Sometimes it pays to skip the instructions |
Like the Mark, the laser
cut fins make for quick work building the rocket.
The kit contains the bits shown below. One thing I particularly
liked was the inclusion of kevlar which I attached it to the motor
block. Normally, I don't use kit chutes, and instead rely on my stash
of assembled chutes, but since this has a Semroc custom chute with it,
it'd be bad ju-ju for me to fly it on anything else So I'm sure I'll find
myself building this chute and adding it to my stash.
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As with the Mark. I tied
the kevlar to the motor block. The ring fit slightly loose in the
ST-770 tube, so I added a wrap of kraft paper to snug it up. The blue
on the ring is from ink on the paper (reclaimed from a grocery sack). A
groove was cut in the outside of the ring for the kevlar to sit in
before the kraft paper was added.
Speaking of the ST-770, I'm curious why Semroc used ST-7 rather than
BT-30. I'm guessing, given the age of the kit, that they didn't have
BT-30 in their portfolio back then; they were just getting started as I
recall.
It's not a big deal. The ST-7 is an excellent substitute. (For that
matter, from this cloner's perspective, BT-20 would have been fine, too
)
According to the card shown below, this was serial number 22 in the
production run. I hope that number wasn't especially valuable - I'd
hate to think I just spent my kids' college tuition
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The kevlar from the motor
mount connects to a nomex ribbon thru the opening. From there,
kevlar connects the nosecone. The ribbon is formed by doubling
over a strip of nomex fabric, then stitching the perimeter with a
leather stitch. Next, each end of the ribbon is folded over and
thru the loop in the kevlar. The fold is then stitched all the
way around. The stitches over the kevlar wrap around it thus
leaving it free to slide back and forth to keep itself even.
I'm sure this is overkill for this rocket. Little, light rockets
are
much more tolerant of high speed deployments - they can be slowed down
in a hurry without zippering - so this much anti-zipper protection is
probably uncalled for, but this how I've been doing shock cords for a
while, so that's how I did this one
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I hope to post some flight pics soon.
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8-16-2010
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