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

  • From: Jack Garibaldi <jackgaribaldi@xxxxxxx>
  • To: <roc-chat@xxxxxxxxxxxxx>
  • Date: Sun, 24 Jun 2012 10:43:29 -0700

Hey Richard

 

               As long as you stay under the waiver for BALLS and under an O
impulse you do not have to do anything but let AHPRA know of your project
but if you go over the O impulse then you have to file a Class 3 waiver on
your own and if you haven't even started it then it won't happen this year
unless you know a Congressman or woman.

 

Jack

 

From: roc-chat-bounce@xxxxxxxxxxxxx [mailto:roc-chat-bounce@xxxxxxxxxxxxx]
On Behalf Of Richard Dierking
Sent: Sunday, June 24, 2012 10:23 AM
To: roc-chat@xxxxxxxxxxxxx
Subject: [roc-chat] High Alt, Multi-staging, and Balloon Structure

 

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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