[roc-chat] High Alt, Multi-staging, and Balloon Structure

  • From: Richard Dierking <richard.dierking@xxxxxxxxx>
  • To: roc-chat@xxxxxxxxxxxxx
  • Date: Sun, 24 Jun 2012 10:22:52 -0700

I got the high-alt bug at BALLS last year.  I saw some multi-stage projects
attempt to reach high-alt, and they all didn't seem to do too well.  For
one thing, I think it's difficult to design/build a stable N to M to M kind
of rocket.  So, many people just build the P, Q, whatever large single
stage rocket or reduce the number of stages to two.  I have ideas about a 3
stage rocket with strap-ons for the initial boost, and even have done some
experimenting, but need some advice.

*First, are there specific FAA restrictions on launching high altitude
multistage rockets?*

Again, I'm not planning minimum diameter, which I understand has some great
advantages.  But, the method for the strap-ons requires some attachment
depth.  Additionally, I like the idea of having some through-the-wall fin
attachment.  So, I plan on using 6" tube with 98 mm mount, and 4" strap-ons
with 75 mm mount.

To reduce weight on the first stage, I'm thinking about thin
fiberglass over paper tube (I would like to use carbon fiber, but honestly,
have no experience with this).  Then, stripping the layers of paper out
from the inside of the tube, adding the motor mount, and being able to
pressurize the inside to 5 to 10 psi (over ambient of course) for a strong
balloon structure.  *Has anyone ever done this for a amateur-type rocket?
Is there even such a thing as thin carbon fiber cloth?*
**
*I would like to try the 1st stage core with balloon structure for my
L3 project.  Is this too weird?  *

I've messed around with modifying aquarium check valves and I think I can
build a very simple and light pressure regulator to prevent over-pressure
of the airframe.  Strength must be maintained, and it must be very robust
during launch, because I'm also planning on using 3 or 4 strap-ons attached
to the centering rings of the airframe..

Richard Dierking
Level 2
TRA 11366
NAR 84983

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