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Posted: Mon Dec 10, 2007 5:35 pm
by sandman
um, anyone see the mythbusters with the hot water tank?

maybe heating the "rocket" will produce a longer burst of thrust

Posted: Mon Dec 10, 2007 7:17 pm
by Eddbot
i'm surprised no one brought up the fact that he's going to be on a skateboard... with pressurized PVC underneath him... near the ground... going fast, in otherwords don't crash before you've dumped the tank
on the subject of furthering production, put it in a backpack with pressure hose going to a sprinkler on the back of the board, then you could have a little handheld blowgun that came off the sprinkler(modded), although Jack would go crazy cause the pilot volume would be huge

Posted: Mon Dec 10, 2007 7:27 pm
by schmanman
that would require throwing at the ground tank first with some force. without pulling the valve.


or pulling the valve the instant you hit a wall.


you would pretty much have to be trying. :lol:



it was a good thought though, as it is always a good idea to practice caution when doing anything like this.

Posted: Mon Dec 10, 2007 8:09 pm
by Ragnarok
@ Boilingleadbath: It may not be the right way to think about it, and if I were going into depth, I wouldn't even go near it, but it proves that even in optimal conditions, the speed is really going to leave something to be desired.

That's a jogging pace, even if the maximum amount of energy was applied perfectly.

Posted: Mon Dec 10, 2007 8:11 pm
by sandman
do i hear a cry for high power rocketry?

Posted: Mon Dec 10, 2007 8:12 pm
by schmanman
go explosives!!!!!!!!!


jk. :wink:

Posted: Mon Dec 10, 2007 8:27 pm
by Novacastrian
Ragnarok wrote:@ Boilingleadbath: It may not be the right way to think about it, and if I were going into depth, I wouldn't even go near it, but it proves that even in optimal conditions, the speed is really going to leave something to be desired.

That's a jogging pace, even if the maximum amount of energy was applied perfectly.
Way to beat down the idea Rag, i mean just let us poor simple folk have our fun! He would be the only one on his block to own such a contraption witch would be far cooler than any performance one was to expect.

Posted: Mon Dec 10, 2007 9:32 pm
by Ragnarok
Novacastrian wrote:Way to beat down the idea Rag, i mean just let us poor simple folk have our fun! He would be the only one on his block to own such a contraption witch would be far cooler than any performance one was to expect.
It's an interesting idea, but I've fired water guns at higher pressures than that with 3/4" nozzles, and although they kick quite a bit, they don't send me zooming off backwards.
I don't believe it will move at all, and in the unlikely event that it does, it would be outrun by a one legged zimmerframe user with severe arthritis in their remaining knee.
It'll be a fun watergun, but a rocket motor it isn't.

It needs more pressure, more "fuel" and more flow.
Or real power is needed - like this (Full clip here), or this.
Yes, I like Top Gear.

Posted: Mon Dec 10, 2007 10:00 pm
by Atlantis
You could always just launch the skateboard without you on it, that is if it's too heavy with you on it, a skateboard can't weigh more than 5 pounds.

Posted: Tue Dec 11, 2007 7:19 pm
by Acdcmonkey1991
good job being the party pooper ragnarok... what I ended up doing was straping it to a dolly,I'm going to test it now.

Posted: Tue Dec 11, 2007 8:39 pm
by Ragnarok
Acdcmonkey1991 wrote:good job being the party pooper ragnarok... what I ended up doing was straping it to a dolly,I'm going to test it now.
I can tell you what I honestly believe is the truth, or I can beat around the bush and lie.
If in future you want me to lie, and treat you like a baby... I can arrange that. I think you'd probably rather that I'm upfront with you.

Posted: Wed Dec 12, 2007 2:37 am
by Eddbot
i think i like the part where you baby us, it lets our imaginations run wild!
give us a few years before you tell us santa isn't real...or the tooth fairy for that matter

Posted: Wed Dec 12, 2007 2:52 am
by Ragnarok
Eddbot wrote:i think i like the part where you baby us, it lets our imaginations run wild!
give us a few years before you tell us santa isn't real...or the tooth fairy for that matter
None of it is real. This is the world that has been pulled over your eyes. There is no spud, MrCrowley is an agent, PCGUY is leader of the free humans and JSR is the one. I'm hacking in from the real world, because it's better than eating the bacteria grown behind the engines.

On a more serious note, I'm learning to be an engineer (or trying to, at least), I naturally see problems in a situation, and I'll mention them. Engineers that deliberately don't mention the errors they see won't get good employment.

Posted: Wed Dec 12, 2007 5:56 pm
by Acdcmonkey1991
Anyway... I tested it today and ragnorak you were partially right, it got about 20 feet on its own, but about three with me riding it. But, the good news is that I learned from this, and I haven't invested to much money in this idea...yet.... Anyway I've thought up some new plans as seen below. It is basicly two of those 5 gallon portable air tanks, fitted together into one 3/4" ball valve. After that the ball valve is threaded into about 4 feet of 3in pipe. Inside the pipe there is a piston and on the other side there is water. At the end of the 3in pipe there is a 1/2' in burst disk. Will it work?
(plans below, everything is a view from the outside, except for the pipe which shows the working inside)

Posted: Wed Dec 12, 2007 6:21 pm
by bigbob12345
I think it might work but I would make the three inch pipe holding the water even longer I would do 6 or 7 feet instead of four because you have such a large air supply and you will want to use all the pressure store in the tanks dont angle the pipe leadind to the burst disk and use a .25 burst disk instead of a .5 one if you do all those things it might work
but it probably wont but if it does tell me and I will make one. But I wouldnt dump 100$ on something that probably wont work make it if you want but I dont recomend it.