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Pneumatic Rocket Launcher

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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Pneumatic Rocket Launcher

Unread postAuthor: no-limit » Fri Apr 11, 2008 9:04 am

So I 've built my 5th launcher and think it's pretty good, at least compared to my last one. I never could figure out the chamber size but seems to work good. I'm getting somewhere between 100 and 150 yards, my best guess. Do you see anything I can improve? All my rockets are short now because they hit so hard they crush themselves and have to cut them down. Working on some sort of parachute. That's 2" pvc sch 40 into a 1" cp-100 with a 1" barrel. Building some 3/4" rockets now to see the difference, I think they will go a little further. I'm using C02.

Link is here. Click on the eye. It says 404 but it works.Image
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Last edited by no-limit on Fri Apr 11, 2008 5:41 pm, edited 1 time in total.
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Unread postAuthor: rcman50166 » Fri Apr 11, 2008 9:20 am

There is a difference between a rcoket and a dart you know. A rocket is self propelled while a dart uses momentum. Anyway, I would say you could absorb shock by adding a foam nose. It will absorb enough energy to save the body. You will need to build a nose every time you want to shoot it so I would go with the parachute instead. It's also safer for spectators also. The only way to make a timed paracute is to add an electronic parachute ejector or add a trail wire pulling the parachute out. Other techniques are available but these two are the most reliable.
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Unread postAuthor: jimmy101 » Fri Apr 11, 2008 11:55 am

Maybe try making the body of your rockets out of foam pipe insulation? The insulation is so light it can probably be as long as your launch tube. Put on a noise with just a bit of weight in it and it'll be stable even without fins.

Another recovery system, that works well and is amazingly simple, is to use a ping-pong ball and a paper towel tube as the nose. The paper towel tube is the front of the rocket and the ball just rests on the top of the tube. The ball is attached to the rocket by several inches of string. At apogee the ping-pong ball falls off but is retained by the string. This total trashes the aerodynamics of the rocket and, if everything is sized correctly, the rocket falls back to earth horizontally and slowly.

See the bottom of page two [url="http://www.kelvin.com/zPDFs/Cat249/49-56.pdf"]here[/url]
or [url="http://catalog.pitsco.com/store/detail.aspx?CategoryID=24&pt=14&ID=2201"]here[/url]
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Unread postAuthor: no-limit » Fri Apr 11, 2008 1:21 pm

Thanks for all your replys. Just try and tell my grandson, the one pictured, it's not a "rocket".

I am using 90 psi which seems to be the best. I have pushed it up to 150 psi, but it scares me a little.

I was thinking of trying a 2" barrel but thought I would loose to much. I will have to look more into the making of one inside the barrel. Looks cool.

I will have to try the suggested parachute systems mentioned, they sound good.

I looked at foam insulation but have not found any that will work for me so far. I put a lot of weight at the nose, to get the balance point further towards the front, and to add a little more weight. Fins make ithem look awesome so I couldn't do without them. With the kids it's a lot about the looks.

When I go to the park and not see one kid around, all I have to do it launch one. I get a pretty big crowd of them then. It's like fireworks, and when I'm done I got a big moan from them.
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Unread postAuthor: THUNDERLORD » Fri Apr 11, 2008 1:42 pm

One concept for verticle launch w/ parachute recovery I haven't noticed mentioned would be to use an electrical switch similar to a mercury switch only instead of mercury, try something solid like a copper weight or ball bearing.

The G force will hold it back during launch and flight but at "Apogee" point it will drop to the front closing the switch to maybe ativate an electromagnet coil to pop the nose cone open.

Maybe even a small battery would work, for weight considerations.
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Unread postAuthor: no-limit » Fri Apr 11, 2008 5:45 pm

I'm a 5 year old genius. Thanks for noticeing.

Now I will have to try a 2" barrel. I will have to make the rockets a lot lighter though.

I think any type of battery would be to heavy. Going to try and make dewey-1s slide.
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Unread postAuthor: STHORNE » Fri Apr 11, 2008 6:00 pm

no-limit wrote:I'm a 5 year old genius. Thanks for noticeing.


being sarcastic are we?... so how old are you accually?

btw, nice job on the "rocket launcher"
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Unread postAuthor: XxtriviumxX » Fri Apr 11, 2008 7:09 pm

I never could figure out the chamber size but seems to work good.


You can simply use a ruler with mms on it, then you can use a calculator to convert it into inches :)

so how old are you accually?


Some geniuses like to start young :D
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Unread postAuthor: Spuddin » Fri Apr 11, 2008 8:58 pm

that is really clever, ive never seen a rocket launcher like this i'd love to have one. btw i found a 1" sprinkler valve at lowes for 15 bucks, is this the going price?. good job.
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Unread postAuthor: no-limit » Fri Apr 11, 2008 10:02 pm

hahahaha you guys are funny! 5 year old genius builds (air) rockets. Nice hijacking too, I see how you got your 500.

I got my valve at home depot for, I think, hard to remember now, about $12 - 15.
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Unread postAuthor: D_Hall » Sat Apr 12, 2008 12:19 am

Or for $2/each you can just buy some "air rockets."

http://scientificsonline.com/product.as ... 1207977499

They work great.
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Unread postAuthor: benstern » Sat Apr 12, 2008 1:20 am

D_Hall wrote:Or for $2/each you can just buy some "air rockets."

http://scientificsonline.com/product.as ... 1207977499

They work great.


Now I want to get one and modify it so that the burst disks on them stand up to higher pressure and thus higher altitude at apogee.
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Unread postAuthor: no-limit » Sat Apr 12, 2008 1:25 am

Can you explain how they can get those to 1000'? It has such a little chamber it doesn't seem possible. It's seems like 90 psi is 90 psi no matter the size of the chamber. Is it time to get out the hack saw?
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Unread postAuthor: no-limit » Sat Apr 12, 2008 12:29 pm

Look at the dia. of that rocket, it's about 3/4", and it's going 1000'. I think I need to learn how to make a piston valve.
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Unread postAuthor: Tooo Easssyy » Thu May 01, 2008 5:04 am

nice rocket launcher, very impressed !!!!!!

you could try making it out of foam piping or something along the lines like that ????
What do you use to set it off....
Do you have any plans for that or think of it off the top of your head.

Tooo Easssyy
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