[ExI] It's not rocket science - Well, it is actually.

spike spike66 at att.net
Tue Aug 16 05:25:54 UTC 2011

-----Original Message-----
From: extropy-chat-bounces at lists.extropy.org
[mailto:extropy-chat-bounces at lists.extropy.org] On Behalf Of Brent Allsop

...I always wondered how adding weight in the front of a rocket made it more
Brent Allsop

Brent, the center of mass of a rocket needs to be forward of the center of
pressure in order to keep it flying pointy end first.  Notice with your tail
heavy rockets, they would go unstable immediately after ignition, when the
rocket fuel is all back there and the CG is aft.  When the rocket burns off
some of the fuel the CG moves forward and you get stability.

Agreed this simulation would have been way cool in our misspent youth.  Back
in those days, we just had to try stuff until we found what works.  A good
for instance of something that didn't work right: using metal containment
vessels and loading our own rocket fuel.  The reasoning went like this: the
metal motors should be able to contain more pressure than the paper element
rocket motors, so the thrust should go up, ja?  Well, ja right, but the
metal containment also weighed a lot more, which pulled the CG of the rocket
aft, so it was far more likely to go unstable.  Also, with the higher
pressures, it was more likely to explode.  If the rockets crashed or
exploded very often, that could become an expensive hobby.


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