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stupid 2 Stage rocket prototype design...

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Lift off?

Poll ended at Wed Oct 15, 2008 4:27 pm

Yes!
3
20%
Noo!
5
33%
It will lift off only because it will explode!
7
47%
 
Total votes : 15
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Unread postAuthor: Demon » Thu Oct 09, 2008 3:26 pm

Will compressed aluminium foils work ?
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Unread postAuthor: Lentamentalisk » Thu Oct 09, 2008 3:35 pm

Not in the least. Think about it like this: if you can so much as put a dent in it, then a rocket engine, at insane temperatures, ridiculous velocities, and high pressures, will utterly destroy it. You would be better off with a washer (which is not a good choice btw, cuz it gets eroded too fast.)

Remember, this is a rocket, not a paper airplane. Its called rocket science for a reason. There is science behind it. You need something a little stronger than your average 3rd grader's paper mache (sp?) art project...
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Unread postAuthor: rp181 » Thu Oct 09, 2008 4:29 pm

at home depot has 500 degree F epoxy putty, and it last awhile, wont be reusable though.
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Unread postAuthor: covey12 » Thu Oct 09, 2008 5:26 pm

ok, that second comment is a bunch of crap, its not rocket science at the least, go to youtube and search how to amke a 2stage rocket motor, the fuel mixture (bcuz i dont think it tells you) is 3parts kno3 (stump remover) to 2 parts powdered sugar, mix it to gether well in a coffee grinder or pestle and mortar
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Unread postAuthor: Demon » Thu Oct 09, 2008 6:54 pm

Not in the least. Think about it like this: if you can so much as put a dent in it, then a rocket engine, at insane temperatures, ridiculous velocities, and high pressures, will utterly destroy it. You would be better off with a washer (which is not a good choice btw, cuz it gets eroded too fast.)



http://www.youtube.com/watch?v=O8kG2g8BMJs

Well, he used cat litter and it works great...

I was thinking of clay.
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Unread postAuthor: devilman » Thu Oct 09, 2008 7:26 pm

haha that guy on youtube lives here in aus. I also use kitty litter for all my nozzles and plugs, then drill a hole thru them and the fuel till i reach my desired core length. I have had nozzles and plugs fail, ejecting fuel everywhere, but most cases that was my fault, either not compressing it enough, not having a thick enough plug, or deciding it would be a good idea to cook and cast the fuel straight into the pvc casing.

ive found kno3, sugar and sulfur work well together in the right ratios. the sulfur give the rocket extra power aswell as a neat spark trail when lit. Down side is it stinks to the high heavens :P
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Unread postAuthor: Hotwired » Thu Oct 09, 2008 7:43 pm

Demon wrote:Well, he used cat litter and it works great...

I was thinking of clay.

Cat litter is normally clay anyway but getting some moist clay and waiting for it to dry out will take considerably longer than compacting the pre dried grains of cat litter.
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Unread postAuthor: Lentamentalisk » Thu Oct 09, 2008 10:26 pm

exactly my point. I never said that you had to use expensive aerograde materials, and ceramic nozzles are ideal. I am just saying that Al foil is not exactly rocket engine material. Have you ever tossed Al foil into a fire? It melts. It melts really fast. You really don't want your nozzle to melt away in the first 1/8th of a second. In October Sky they used steel washers, and even those eroded too quickly (granted they had much larger rockets)
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Unread postAuthor: Demon » Fri Oct 10, 2008 6:32 am

I already stuffed down a 30 cm x 30 cm aluminium foil in the rocket catridge and it became as hard and big as an monney piece.a nail was not able to go trough.

Why do we have to make a hole trough the rocket motor?
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Unread postAuthor: mrbadexample » Fri Oct 10, 2008 2:02 pm

to make a controlled "burn", once it ignites, it'll work it's way up through the hole (i imagine the hole is part of the combustion chamber), otherwise it may self extinguish or explode. i never made a rocket. and i'm sure if the hole isn't centered, it'll fly funny, nobody has mentioned this so far. the hole should be perfectly straight down the tube, any deviance from dead center will result in skewed flight, no matter how many fins, the thrust will direct it in the direction of the hole.

the aussie kid with the sandals making the kitty litter rocket is funny, could be a new "saying"... "go pound kitty litter!" LOL
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Unread postAuthor: TurboSuper » Fri Oct 10, 2008 2:13 pm

Have you considered a hybrid rocket motor? They seem safer since there isn't anything inheriently explosive about 'em.
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Unread postAuthor: Demon » Fri Oct 10, 2008 3:01 pm

Have you considered a hybrid rocket motor? They seem safer since there isn't anything inheriently explosive about 'em.


You are right! I Just have to spend 300$, buy dangerous, very dangerous propellants,machine titanium or tungsten and convince my dad to make it!

(my Dad is an engineer and is not stupid)
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Unread postAuthor: rp181 » Fri Oct 10, 2008 4:51 pm

hybrid rockets are NOT safer.
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Unread postAuthor: TurboSuper » Fri Oct 10, 2008 5:45 pm

Hur? Where do you get $300 and titanium and dangerous propellants? The one I saw used some PVC, some N20, and some ABS shavings.
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Unread postAuthor: Fnord » Fri Oct 10, 2008 5:47 pm

I think the hole through the center has more to do with increasing the surface area of the propellant than controlling the burn. It will also keep the heat off of the pipe walls more than an engine without a hole.
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