Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!ucsd!ucsdhub!hp-sdd!ncr-sd!ncrlnk!ncrcce!c10sd3!c10sd1!johnson
From: johnson@c10sd1.StPaul.NCR.COM (Wayne D. T. Johnson)
Newsgroups: sci.space.shuttle
Subject: Re: Rockets Pulling (was Re: Challenger tragedy)
Message-ID: <481@c10sd1.StPaul.NCR.COM>
Date: 29 Aug 88 16:39:20 GMT
References: <1001@scicom.alphacdc.com> <44700006@pyr1.cs.ucl.ac.uk> <6204@ihlpl.ATT.COM> <1988Aug15.162352.22902@utzoo.uucp> <3058@ttidca.TTI.COM>
Reply-To: johnson@c10sd1.StPaul.NCR.COM (Wayne D. T. Johnson)
Organization: NCR Comten, St Paul
Lines: 22

In article <3058@ttidca.TTI.COM> jackson@ttidcc.tti.com (Dick Jackson) writes:
>I agree with this BUT -- how about firework rockets, which gain their
>stability from the long stick hanging down? Is the function of the stick
>just to increase the moment of intertia so that any pitching motion takes
>longer? Come to think of it, at school we used to take the sticks off the
>rockets and glue fins on (a la V2) and they went quite well. But intuitively
>it seems that a stickless rocket would just tumble.
>
>Dick Jackson

If I remember right (Its been a few years since I designed any model rockets),
The stability of the rocket depends on the center of gravity being ahead of the
center or pressure.  The center of pressure can be moved tward the rear of the
rocket by adding (or making larger) fins.  The center of gravity can be moved
forward by adding weight to the nose.  In the case of a bottle rocket, the 
majority of the weight is at the top and the stick acts to move the center
of pressure back.
-- 
Wayne Johnson                 (Voice) 612-638-7665
NCR Comten, Inc.             (E-MAIL) W.Johnson@StPaul.NCR.COM or
Roseville MN 55113                    johnson@c10sd1.StPaul.NCR.COM
These opinions (or spelling) do not necessarily reflect those of NCR Comten.