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Posted: Wed Oct 08, 2008 8:19 pm
by ramses
Demon wrote:Its me or now evryone is taking me for the last idiot?
:violent1:
Why?
Be safe, and be damn sure you don't have bubbles in the fuel.
I think i am really as what described Ragnarok...
(*Whispering very quietly*)what are you talking about?bubbles?
have you ever watched October sky or read Rocket Boys. They had air bubbles in their fuel. BOOM
and yeah, if your parents found out that we gave you the go-ahead to build this and you get killed, there will be repercussions for this site, it's members, and especially the staff. That's why we want you to be careful.
Besides, I don't wish PVC flack on anyone
ps. listen to Lentamentalisk he seems to know his stuff.
look into the effect specifically of center of pressure, center of mass, and center of drag, including the effect of slightly different fins, and the methods of reducing these effects.
Posted: Wed Oct 08, 2008 9:34 pm
by brogdenlaxmiddie
Posted: Wed Oct 08, 2008 9:52 pm
by Lentamentalisk
Damn right I know what I'm talking about!
I spent several years overly obsessed with rockets, and was making rockets far more complex (at age 9 or so) than many of the adults who went to the monthly launch I was a member of (LUNAR is it's name, for those of you who may have seen it at the California Maker Fair)
I would really suggest that if you plan on making anything much more advanced than a tube filled with fuel, a nozzle, and some big fins glued on the bottom (and a guide rod mount of course!!!!!) then you really need to start using
RockSim, the rocket modeling and design program.
And two stages? Forget about it before you kill your self please... That is really advanced.
Posted: Wed Oct 08, 2008 10:16 pm
by SpudUke5
Lentamentalisk wrote:Damn right I know what I'm talking about!
I spent several years overly obsessed with rockets, and was making rockets far more complex (at age 9 or so) than many of the adults who went to the monthly launch I was a member of (LUNAR is it's name, for those of you who may have seen it at the California Maker Fair)
I would really suggest that if you plan on making anything much more advanced than a tube filled with fuel, a nozzle, and some big fins glued on the bottom (and a guide rod mount of course!!!!!) then you really need to start using
RockSim, the rocket modeling and design program.
And two stages? Forget about it before you kill your self please... That is really advanced.
Im in the rocketry club at my school and we use that!
I have it on my comp right now.
Now i have you yo help me if ever needed. This is a great find for me.
P.S. Dont do it.
Posted: Wed Oct 08, 2008 10:23 pm
by rp181
lol, october sky was where i got it. If we made a rocket not store bought, extra credit =)
By all means make a two stage rocket, just make sure you know what your doing, and if your materials can withstand it.
Posted: Wed Oct 08, 2008 10:25 pm
by Lentamentalisk
ya, I am trying to convince some of my friends to help me make a rocket for our end of the year physics project. Here are some videos of my fuel testing.
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needless to say, I have some bugs to work out...
Still trying to figure out what I want to use for my casing. Copper would be nice, but I wont be able to retrieve all of my launches, as I have to launch by the bay (its the only safe place away from people) and copper prices could start really hurting my pockets. The last video I was using a home made cardboard casing. The next trick is going to be making a nozzle that doesn't erode away. I have to try that kitty litter I have been hearing so much about.
edit: also, if you are planning to go ahead and make a rocket (please make something not two staged!!!!) then I really suggest reading October Sky, not just watching it. A lot of the movie is BS or not true. The book will actually help you understand the whole design process and all.
Posted: Thu Oct 09, 2008 12:27 am
by Carlman
electrical conduit 9orange in aus) is great, its soft so doesnt explode. and so seal the ends and make the nozzle use epoxy putty
[youtube][/youtube]
this is wattos, im thr aswell
Posted: Thu Oct 09, 2008 12:40 am
by Lentamentalisk
does epoxy putty really hold up to the heat? Did you find a special high temp epoxy, or does it just work well enough? What to use for a nozzle has really been bugging me. I guess I need to shape the nozzle out of epoxy putty in a paper tube, and then once that drys, I can pack in the powder, and then glue in the nozzle. Or I could mold the nozzle in the pipe, and then just plug it while I pack the powder.
edit: why is it that nobody ever uses a guide rod? for like $5 you can get a little steel rod, and then just stick that in the ground, and glue 2 eye-bolts or a small section of straw onto the side of your rocket. It will decrease you chance of a rocket through your head (or your neighbor's roof) by a good 90%
Posted: Thu Oct 09, 2008 2:32 am
by Carlman
we did use a guide rod, it turned when airborn because of a bubble in the mix, ok! lol
make the plug out of normal epoxy putty works just fine then pack the rocket (use the mix as stated at the start of the video, melt in microwave) pour it in and then make another plug the same out of epoxy then drill out core and nozzle. or drill out core first then use putty to make and shape nozzle. for 15mm pipe use approx 6mm.
kitty litter sucks by the way.
oh and yea just norm epoxy putty
Posted: Thu Oct 09, 2008 3:43 am
by jackssmirkingrevenge
Solid propellant rules no longer apply?
Posted: Thu Oct 09, 2008 5:48 am
by Demon
Solid propellant rules no longer apply?
Well, If mod delete my topic,i think i will be happy...
You now all convinced me, i will start by a tiny tiny rocket(20grms)
And do you all meaned then this could happen?
Posted: Thu Oct 09, 2008 6:15 am
by Hotwired
A good example of why sugar rocket fuel is also a nifty homemade smoke mixture

Posted: Thu Oct 09, 2008 6:27 am
by Demon
This rocket engine is made of pvc, and it works.
I will start by that, look simple.
What could replace the cat litter powder?
did you know when pvc pipe is burnt it creates a gas that can be deadly?!
What? Is that real?
POWNED!
Posted: Thu Oct 09, 2008 2:05 pm
by ramses
possible substitutes: Bentonite clay (same thing, different name), machined ceramic, machined tungsten, and possibly steel or aluminum. you could try JB weld also.
Hotwired wrote:A good example of why sugar rocket fuel is also a nifty homemade smoke mixture

smoke mix is usually a little under-oxidized. keeps it from becoming a massive flare, blowing up, etc.
Posted: Thu Oct 09, 2008 3:16 pm
by Lentamentalisk
and where, might I ask, could anyone find tungsten bar stock? Ideally I would get someone in the ceramics class to fire a cylinder of clay that I can just dremel into shape, but I don't know anyone in it.