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Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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Unread postAuthor: Counterstriker » Thu Mar 13, 2008 4:18 pm

D_Hall wrote:Jello in a cup would likely make one hell of a padding. After all, it's molded to the shape of the egg!

(Or is there a requirement for an egg to "fly free"?)


True,True. But if you want to keep it clean go get some Knox brand gelatin and make some ballistics gel.
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Unread postAuthor: Fnord » Thu Mar 13, 2008 4:39 pm

True,True. But if you want to keep it clean go get some Knox brand gelatin and make some ballistics gel.


Just something I noticed a while ago...
Why is knox jello ridiculously expensive?!
It would cost me probably over $100 to make a cubic foot of gel if I got it from walmart.

I don't have a need for it right now, just wondering if anyone else has this problem.
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Unread postAuthor: psycix » Thu Mar 13, 2008 4:48 pm

BC Pneumatics wrote:Psycix, I am not sure what you are trying to say, but I do want to clarify that we are worried about the g-forces experienced by the egg at launch destroying the egg. Since g-force is in fact acceleration (with one G ~ 9.8m/s^2) the slower we accelerate the egg to its final velocity, the less Gs it will experience.


What I was trying to make clear is that the acceleration matters (thus G-forces) and not the "speed of G-force increase"

bigbob12345 wrote:i actually think you should use a ball valve as it has a slower opening rate which would be less likely to damage the egg.


He stated that the egg might break if the G-forces increased too fast.
With what I am not agreeing.
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Unread postAuthor: jimmy101 » Fri Mar 14, 2008 12:37 pm

psycix wrote:What I was trying to make clear is that the acceleration matters (thus G-forces) and not the "speed of G-force increase".

I believe "speed of G-force increase" does matter. It is called "jerk". High jerk will smash the egg just as effectively as high G-force.

Jerk is d<sup>3</sup>x/dt<sup>3</sup>, or d<sup>2</sup>v/dt<sup>2</sup>, or d(acceleration)/dt.
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Unread postAuthor: BC Pneumatics » Fri Mar 14, 2008 12:49 pm

Third derivs make me cry.
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Unread postAuthor: Jared Haehnel » Fri Mar 14, 2008 12:49 pm

I think the egg would survive if it has a sabot around it...as long as the egg fit tightly in the sabot there shouldn't be any problem... I think you guys are making to much of the G force thing. If he uses a high volume chamber and a low pressure the acceleration won't generate enough stress on the egg shell to break it. The worry would be a too loosely of a fitting sabot.

Of course if it came down to it he could always hard boil it...

The real challenge comes when it must go up 100 and down with out breaking 8)
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