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Bottle Rocket School Project! Answered

I managed to snap a picture with the camera on teh Macbooks we use, and upload it here, We launched it yesterday, although the payload didn't deploy, our rocket still went the highest. Approx. 100-200m. We're working on the exact height at the moment. I'll update this as the week progresses. :D BTW, FCREM stands for Freeking Coolest Rocket Ever Made.

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user
westfw (author)2008-11-05

Looks neat. Is your pressure chamber more than one bottle, or is the extra length just "payload"? If the former, I'd like to see an instructable on how to join more than one bottle into a pressure-worthy container!

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bumpus (author)westfw2008-11-05

Nope, its only a single stage. The other bottle on the top is for the payload. And the force of the rocket going upwards, is enough to keep both ends together. :D

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user

So is the end so loose that once the rocket decelerates the nose cone falls off?

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user

Yep, there is clay in the tip of the rocket, so the weight will have it fall off at apogee.

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westfw (author)bumpus2008-11-06

This is a commonly believed fallacy in rocketry, BTW. At apogee, the rocket is in "free fall", without even drag forces acting on it (since velocity is zero.) So the heavy parts and the light parts fall at the same speed (gravity 101), and a weight in the nose will not cause it to separate (nor will a carefully positioned mercury or other "tilt" switch sense ANYTHING, which is how this usually shows up in the model rocketry communities.) What this sort of scheme DOES tend to cause is separation at the end of motor thrust, when the acceleration goes from heavy Gs (caused by thrust) to somewhat less negative Gs (caused by drag.) This is NOT when you WANT your recovery system to separate (max velocity, not max altitude.) You want your rocket to COAST to apogee, which happens some time after end-of-thrust. Detecting apogee is a rather difficult task (thus, timers.) So you probably owe your record altitude to the fact that your payload DIDN'Y deploy...

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bumpus (author)westfw2008-11-06

When we achieved our top altitude, when the payload was not on board. :D Oh well, it was still fun!

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Lftndbt (author)2008-11-05

What type of release mech did you use? As in what do you use to launch it?

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KentsOkay (author)2008-11-05

Nice! Now try with acetylene..

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