Type of Body tube vs engine size

So, I have this giant (9" in diameter) plastic pig.
I was planning on putting a body tube up his... But after running some
calculations, the finished rocket will be upwards of 10-15 oz. The pig itself is 5 oz. Add parts and clear plastic fins, and it really is... a pig.
Sounds like it will require an E+ engine to gain any sort of reasonable altitude. I was planning a standard Estes type BT-60 main tube, 24mm engine tube with rear ejection. Stop laughing.
Will a BT-60 handle an F? G? Should I go to a 29mm engine? How much power can I use and hope it won't shred? I could go to a .1" wall thickness, but that just adds more weight.
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Aerotech E30-4 or F21-4 are 24mm and will lift quite a bit.
BT-60 will do fine.
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The probelm is not the weight but the diameter. You will need more power to overcome that. When doing a sim, assume a hemispherical nose cone and a high drag coefficient, perhaps 0.85-1.
Jerry
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Jerry Irvine, Box 1242, Claremont, California 91711 USA
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I've been talked into trying my Bt60 Patriot on a H128W for a L1 flight. I'm cheating & giving it a single layer of glass.... :-)
Clint.

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Good luck with the recovery.
    Bob Kaplow    NAR # 18L    TRA # "Impeach the TRA BoD"         >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle:    http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org
Men never do evil so completely and cheerfully as when they do it with religious conviction. -- Blaise Pascal
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Just remember -- you can always adapt down to a smaller motor, but there's no easy way to use a larger motor in too-small of a motor mount tube.
With a 9" diameter plastic pig, I'd probably look at using a 54mm motor mount, so I could use a J90 for a nice long burn.... But, that's just me :-)
Realistically, I'd suggest a 29mm mount. With the whole rocket weighing just under a pound, there are lots of motors in the F and G range that will work just fine to lift your pig, and you'd be able to adapt down if you wanted to use a 24mm motor. In fact, the F39 reload for the 24/40 casing would probably work great.
- Rick "Short delay, of course" Dickinson
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