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Working designs for parachute ammo (with a difference...)

Post about things you have launched or thought about launching. Also post about various materials used for building cannons. No posts about explosive projectiles!
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Unread postAuthor: BigGrib » Thu Dec 06, 2007 3:25 am

i think you would need a spring or something to pop those wings open at max height or something
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Yea, that's definitely going to get you at least a tazer.

<a href="http://www.youtube.com/watch?v=AkMkGOpAF4s">DONT TAZE ME BRO.. DONT TAZE ME... AHHHH</a>
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Unread postAuthor: Carlman » Thu Dec 06, 2007 3:30 am

rubber band worx aswell as JSR has put in one of the posts on the previous page.
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Unread postAuthor: jackssmirkingrevenge » Thu Dec 06, 2007 4:39 am

Carlman wrote:would it 'glide' and hit slow enough to preserve the camera though?


It will be a fast glide but if the camera's in a well padded housing it should survive. Of course first I would recommend a few dummy runs with a counterweight in place of the camera, and even before firing a few hand thrown launches to make sure you have the CG right would not go amiss.

what kind of lab work u in?, ive just finished skwl and am considering lab tech/analysist as a career


I work in a pharmaceutical lab, we manufacture APIs, so basically I get paid to play with expensive white powder :) I would recommend it as a career if you're technically and chemically inclined, certainly beats an office job :D
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Unread postAuthor: rna_duelers » Thu Dec 06, 2007 5:33 am

It also means that your on a list of "watch" if lots of exotic drugs become available around were you live.

Just shoot and hope for the best!
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Unread postAuthor: jackssmirkingrevenge » Thu Dec 06, 2007 5:36 am

Highly unlikely anyone would be using what we make recreationally, unless they enjoyed skin rashes and weak bones with no beneficial narcotic effects.
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Unread postAuthor: rna_duelers » Thu Dec 06, 2007 5:39 am

So very true,do you think that the ingredients and time going into making the drugs is worth the amount the companies charge?Because some of my medication is...Well expensive,very expensive.
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Unread postAuthor: jackssmirkingrevenge » Thu Dec 06, 2007 5:54 am

It's very, very expensive to manufacture, the profit margins aren't that great - aside from patents and licensing, the materials, equipment and facilities are all extremely costly, some of the instruments I use come close to $100,000 and they're just as costly to maintain. When you're talking about people's health, you can't afford to be less than 100% safe with everything you do, and that costs money.
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Unread postAuthor: Carlman » Fri Dec 07, 2007 2:26 am

yes i will definetly do a test run or 20 lol

just had a brainwave, what if the chute was ejected via the force of a mini combustion inside the projectile activated from a mercury switch?

yea ill be thinking more into that career mite hav a few Qs sumtime aswell if thts all good.
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Unread postAuthor: jackssmirkingrevenge » Fri Dec 07, 2007 2:36 am

just had a brainwave, what if the chute was ejected via the force of a mini combustion inside the projectile activated from a mercury switch?


That sounds like a plan, if you're willing to pack stungun/camera flash electronics into your projectile. Another (lighter, cheaper) idea would be to use a model rocket ingitor in the middle of your fuel/air mix.
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Unread postAuthor: Carlman » Fri Dec 07, 2007 2:53 am

how about a bit of steel wool between two screws conected to a mercury switch and a 9v battery??
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Unread postAuthor: jackssmirkingrevenge » Fri Dec 07, 2007 2:59 am

Just as good, even better if you tape a match head to it, and I'll stop there as this forum does not allow discussions about solid propellant.
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Unread postAuthor: Carlman » Fri Dec 07, 2007 3:02 am

its all good thn just gotta get the time 2 make 1 now :D
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Unread postAuthor: jimmy101 » Fri Dec 07, 2007 12:15 pm

BigGrib wrote:
Jack, you would be surprised, water rockets typically pull 100~200 G's at launch. I looked it up and Estes rockets only do 10~30 G's.

A 300 FPS spud gun with a 3' barrel has an average accelation of about 470g. A lot more than an Estes rocket but not that much more than a water rocket (only a factor of 3 or so :D ).


umm check on page 2 of this thread, because i did the math at 300 fps and a 3' barrel and it's almost twice as much coming in at 928.57 g's


ummm, I think you made an error in your math. The acceleration is gross estimate is ~470 Gs.

Accelerating from 0 to 300 FPS and assuming constant acceleration means the average velocity in the barrel is 150 FPS.

Time to travel 3' at 150 FPS is 0.02 seconds.

Acceleration = dV/dT = 300 FPS/0.02 seconds = 15,000 FPSS.

G=32 FPSS so 15,000 FPSS/32 FPSS = 470 G.
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Unread postAuthor: jimmy101 » Fri Dec 07, 2007 1:12 pm

jackssmirkingrevenge wrote::shock:

Water rockets accelerate better than their solid propellant burning cousins?!

Someone should tell NASA :D


Yep, water rockets typical outperform, in terms of maximum acceleration, solid fuel burning rockets by an order of magnitude or more. It is "all the other stuff" that makes water rockets impractical.

A very good water rocket flight simulator is
http://www.et.byu.edu/~wheeler/benchtop/sim.php
With all defaults values the acceleration peaks out at ~300G. But, the rocket only maintains that acceleration for a small fraction of a second. (This programs is to water rockets what GGDT is to pneumatic spud guns. It is generally considered to be reasonably accurate if the input parameters are correct.)

NASA already knows about water rockets.
NASA has an extensive set of pages on the design, building, testing and simulation of water rockets.

For example;
http://exploration.grc.nasa.gov/educati ... ourney.htm

Some of the NASA water rocket simulators;
http://exploration.grc.nasa.gov/educati ... ocket.html
http://exploration.grc.nasa.gov/educati ... t/RM2.html
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Unread postAuthor: BigGrib » Fri Dec 07, 2007 3:24 pm

Hey Thanks for going over and correcting everyone and I'm sure that NASA did know about water rockets and I think it was a smart ass coment that JSR wrote. And 928.57 g's sounds more impressive. oh yeah and since you can't tell a smart ass comment when you see one, THIS IS ONE OF THEM.
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Yea, that's definitely going to get you at least a tazer.

<a href="http://www.youtube.com/watch?v=AkMkGOpAF4s">DONT TAZE ME BRO.. DONT TAZE ME... AHHHH</a>
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