Spool stability question

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    John A. Wilke

    Question – why is a spool stable? does it need “nose” weight? I’d think the CP would be half way up the “rocket”. The CG would be lower than that if the spool had any length to it, as the motor is (of course) nearer the aft end.

    I’m inquiring because I have to comply with the must-build-your-own-rocket rule for the Alphabet contest, which by the way – I think is a silly rule. But that is for another thread. Actually, is an RTF (ready-to-fly) rocket eligible? I’d have to say NO – as you didn’t “build” it.

    There – I’ve started two threads at once, though I’m most interested in the CG/CP thing. I’ve got to get started on construction…



    I don’t know the reason a spool is stable, but you actually only need one of the plates, and it doesn’t matter which. I launched a few C6-5 spools, some with the front plate only, some with the back plate only, and a few with both.

    Didn’t matter 🙂


    Jeffrey Joe Hinton

    And I thought I was a semantic warrior. Mister Wilke raises an interesting aspect of Rule Making and Breaking. The process was to make the rules straight forward and simple enough that the contest was fun, regardless of personal interpretations. Obviously, I’m not a lawyer and don’t pretend to be. Please. RTF rockets still need some minor “assembly” (the motor still needs to be installed nozzle end to the open rear end) and therefore qualify/fit in the “Built” by competitor framework.

    I can’t answer the CP/CG question about spools exactly but I know that it has something to do with Newton’s Law, gravity, and “May the Force be with you.”


    Question – why is a spool stable?

    Maybe it has to do with how much air they are pushing.
    Have to look at it in a wind tunnel.
    Some one should get on that! 😉

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