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compressed air "rocket"

Posted: Sat May 01, 2010 2:54 pm
by jackssmirkingrevenge
[youtube][/youtube]

This popped up on youtube, interesting project but it could be improved in oh-so-many ways :) "rocket" inside the barrel with folding fins, longer barrel, bigger chamber, modded valve...

Posted: Sat May 01, 2010 3:21 pm
by clemsonguy1125
I saw that and thought the same thing, sad thing is that they are now selling kits for that, which are totally over priced Im sure

Edit-Just checked and its 50 bucks for a sprinkler valve and 5 bucks worth of pvc

Posted: Sat May 01, 2010 3:23 pm
by john bunsenburner
For the fins you could have them fixed on the side towards the tip. You have a ball bearing inside the rocked infront of the fins. When in the barrel they will fold in, but then inertia and gravity will push them out when fired. For longer barrels add a spring behind the ball.

Posted: Sat May 01, 2010 3:24 pm
by jrrdw
clemsonguy1125 wrote:I saw that and thought the same thing, sad thing is that they are now selling kits for that, which are totally over priced Im sure
Without a dought!!!! :?

Posted: Sat May 01, 2010 3:57 pm
by jackssmirkingrevenge
There are several ways to make folding fins, using for example the body itself cut in sections and spring loaded:

Image

Some other ideas:

Re: compressed air "rocket"

Posted: Sat May 01, 2010 5:06 pm
by Hotwired
jackssmirkingrevenge wrote:interesting project but it could be improved in oh-so-many ways :) "rocket" inside the barrel with folding fins, longer barrel, bigger chamber, modded valve...
So, basically my rocket launcher then :P

Re: compressed air "rocket"

Posted: Sat May 01, 2010 5:13 pm
by jackssmirkingrevenge
Hotwired wrote:So, basically my rocket launcher then :P
... which we've never seenin action ;)

Posted: Sat May 01, 2010 5:31 pm
by Hotwired
Details, details, next thing you'll be asking for proof that my cold fusion reactor works....

The theory is sound, what more could you ask for :P

Posted: Sat May 01, 2010 8:26 pm
by Insomniac
Could be worse. There's a commercial version (can't remember it's name) which uses burst disks instead of a valve, and they retail for somthing like sixty bucks around here (for 2 cardboard rockets, a short bit of pipe and a foam framework to hold it).

Posted: Sat May 01, 2010 8:36 pm
by maverik94
Pretty cool. I like it! I wonder what the max distance you could get with one of these would be, compared to one of your standard Estes rockets with a B or C engine in it. I have a rocket that will got 1500-1800 feet up, but I know there are commercially available ones that will go up over 3000 feet. I doubt a compressed air rocket would even get close to that height because they only get a quick burst of air as propulsion and Estes rockets have engines that burn for a while, giving them more altitude. It wold be interesting to see what kind of height someone could get with a piston valve with, say, 400 psi.

Posted: Sat May 01, 2010 8:40 pm
by spudtyrrant
Hotwired wrote:The theory is sound, what more could you ask for :P
An awesome video of it in action, what else? :P

Posted: Sun May 02, 2010 5:47 pm
by Lentamentalisk
That guy, or at least the guy who actually designed it, was at the local Maker Faire last year. I tried to tell him about SpudFiles, and how a modified valve would work better, and all that mumbo jumbo, but he brushed me off, and said that he wanted to keep it simple. Never mind his terrible C:B ratio and all that...
Still a fun concept. I have been considering building a cold launch system for some estes rockets, like the SS-18 Satan: [youtube][/youtube]

Posted: Sun May 02, 2010 11:57 pm
by jackssmirkingrevenge
Lentamentalisk wrote:I tried to tell him about SpudFiles, and how a modified valve would work better, and all that mumbo jumbo, but he brushed me off, and said that he wanted to keep it simple.
Looks a bit like a nonce, to be expected :roll: