"C. Newport" wrote in message
. ..
I know that this is off topic but where else can you find such a group of
individuals interested in space and rocketry?

As some of you may or may not know, in addition to the underwater stuff, I
also dabble in amateur rocketry. I am well past the Estes stage, you could
say. My last design was about 12 feet long with a launch weight of 130
lbs. and should have reached about 30,000 feet and close to Mach 2 (it was
launched at LDRS 2006). There were, shall we say, some stability issues,
and the rocket came apart at about 5 seconds into the flight. This
particular design was a modification of an existing rocket.

I am now working on a new design and have been trying to find some
simulation software that can do a decent dynamic stability analysis
through Mach 3 but have so far been unsuccessful. While I am shooting for
about one caliber of stability at launch (one caliber between the static
CG and Center of Pressure), I know this is going to change as the vehicle
accelerates. Consequently, I need the right software (or someone who can
do this kind of analysis) to ensure that this next design is stable
through it expected burn-out velocity.

I think what you want to do is determine the CG and CP at both launch and at
burn out. You ought to be able to find the CG with an empty/spent engine,
right? I don't think any software is needed, unless you already have
software that you're using to estimate the CG of a design.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)