stupid 2 Stage rocket prototype design...

[Demon]

Hur? Where do you get $300 and titanium and dangerous propellants? The one I saw used some PVC, some N20, and some ABS shavings.

Well, hybrid rocket produce a lot of power and pvc is not designed for that...

[TurboSuper]

Seemed to work for this dude:

http://www.intertlan.com/cohetes/hybrids/

[Demon]

I will rather make this one for a first time

[DYI]

I see a few problems here. The first is that the PVC "nozzle" will become a full-bore hole in a very short time. The second is that the hole you show is likely too small, and will result in your rocket turning into an expensive, time consuming firework. Somewhere down the list after that are the facts that your rocket design is nowhere close to aerodynamically stable, and that you are using over 3 pounds of propellant in your first attempt at a rocket.

On the subject of hybrid rockets: While the technology is perfectly accessible to the average hobbyist (and you certainly don't need titanium, tungsten, or any particulary dangerous materials), oxidisers can get expensive. For the small scales that most sane amateurs would be working with, this isn't particulary problematic. When you're using almost 10kg of fuel alone, well...

[mark.f]

What's wrong with cardboard (Kraft) tubing and bentonite clay?

[ammosmoke]

Has anyone here gone to jamesyawn.com? The guy has already solved all your problems and more. He makes nozzles from aluminum, and well... he is just brilliant.

[Demon]

you are using over 3 pounds of propellant in your first attempt at a rocket.

What????

This model just use approx 50 grams of very basic fuel...

[DYI]

What????

This model just use approx 50 grams of very basic fuel...

The diagram says, very distinctly, 550g of KNO₃ and 1kg of sugar. That's 1.55kg, or about 3.41 pounds. You might want to take a look at the plan YOU posted before making comments

[Demon]

???okay, try to put 3 lbs in a 1 inch x 6 inch pvc pipe.

I dont know exactly how i need, so i make more fuel then i need, thats seem logic for me.

[ammosmoke]

Ahem. Is anyone listening to me?

[TurboSuper]

Welp, guess you should just give it a try. Just hide behind something in case it decides to go in an odd direction.

[Lentamentalisk]

Thanks so much for the link ammo, I found that incredibly helpful.

btw, I found something that looks absolutely perfect for my nozzle. I have no clue what it was, I just found a box of them at the local junk yard type place, for next to nothing. They seem to be from plumbing of some sort, these little porcelain 3/4" doodads that look like perfect nozzles.

[SEAKING9006]

Does everyone in this thread live outside the U.S. or something? Because last I heard, Potassium Nitrate is HEAVILY regulated here in the 'States.

[Lentamentalisk]

not at all. Potassium Nitrate is a regular fertilizer. I couldn't find any at my local OSH, but then I read that stump remover is like 98% KNO3, though it is $5 a lb... Transport of Rcandy fuel is quite possibly illegal across state lines, but that is a whole nother deal.

Here are some pics of my rocket casing prototype. I used an old "nob and tube" electrical insulator for the nozzle, as it is a perfectly shaped porciline nozzle.


The hose clamps are holding the nails on, which hook around the end of the nozzle, for an attempt at a physical connection.
I know they must go before I actually get around to launching it, but they will do for now.

[Demon]

i just went to rona, based on the plans just there ^.