750psi water rocket

[psycix]

Dumbest idea I've heard all year.

And we're still just in febuary, imagine of what's to come.

Making 2 identical rockets one with a restricted nozel and one with a regular nozel the restricted nozel rocket will go higher because not all the water comes out right at the start of the launch considering there is the same ammount of water to air and pressure.

Depends, there is some optimum of that for every rocket.
At a certain size of nozzle, the thrust of the rocket will have a hard time to win over the gravity. It will indeed become more efficient though.

[Lentamentalisk]

There was a website that I had bookmarked that was made by a guy who had done exactly what you are trying to do. I can't find the link at the moment...
He pressure tested various ways of preparing the bottle to make it work at higher pressures. He ended up wrapping it in carbon fiber, and pressurizing it remotely with N2. He made a special De Laval nozzle for it, and used a mixture of soap and water. The benefit of the soap is that rather than just spitting out water, you can propel a soap/water/air mix, which expands in the nozzle, giving you (I think he said) 20% more thrust.
The deal with bottle rockets is that the the neck of the bottle is FAR FAR FAR too large. You need a restriction of some sort to take advantage of all of that mass. Remember KE=1/2mv^2, so the faster you have the mass moving, the more energy you get out of it, propelling you upward (yes I know that is overly simplifying it, but it gets the idea accross).

edit: ok, I found the people who did it: http://www.antigravityresearch.com
but I can't find the site where they discribed everything they did. Check out their videos, and you can see their 1242' lanuch, at 1150psi in a single stage soda bottle.

[dudeman508]

dudeman508 wrote:
1/2in. sch120pvc is rated to 1200psi, but i might be wrong

It's still incredibly stupid.

PVC is impact intollerant.

You're using it as a rocket.

When it comes back down... Hey, that's an impact!

Unless you're planning on making them single use rockets, you're now proposing filling up a potentially damaged pressure vessel to 800 psi.

I say it again... Dumbest idea I've heard all year.

We thought about that and wereonlyplaning to use it once, but we decided to use aluminum

[POS]

I did water rockets too some while ago. I did a lot of research before i started building.

Instead of water, use water and soap mixture. When the rocket is launched, the instant difference in pressure will have the reaction that the soapy water turns into foam, not only the part of the bottle that is filled with water, also the "air"part. So the whole bottle filles with foam. So the propellant is in the WHOLE bottle, giving relatively continous trust.

When using only water and air, the water is pressed out, which results in the trust of the rocket, but once the water is out, the presurised air get out with minor trust.

Using soapy water, that becomes foam on launch, will spread the trust during the complete trust.?

Also, for comon sized rockets, i mean, the diameter of a coca cola bottle (PET) the best nozzle is about 9 mm. Use a quick connect you use to screw on a tab to connect a garden hose.

[Sticky_Tape]

I've seen that website before very nice. [youtube][/youtube]

Also, for comon sized rockets, i mean, the diameter of a coca cola bottle (PET) the best nozzle is about 9 mm. Use a quick connect you use to screw on a tab to connect a garden hose.

Garden hose connectors with 750psi hmmmm seems abbout right lol. They are no stonger than pvc!

[sniper hero]

POS you did some good research and some good thinking:D that's how we like to see it
dudeman: I guess you understand pvc is out of the question
make a diagram with some measurements

I made water rockets when I was younger they worked pretty good and I had a lot of fun. I even once thouht of making a very big one to launch myself would be fun and is far too dangerous

[Mitchza89]

I thought of this release mechanism a while back but I never used it properly. I don't know how hard it will be to use at those extreme pressures because I made this thing to work at about 150-200.

Anyway it's pretty self explanitory.

Good luck with the build.

[Sticky_Tape]

That is almost exactly what I suggested I think it could work at higher pressures too because of them being seen on shock pumps (mine included). I like your diagram

[Mitchza89]

Sorry Sticky, I only saw your post just after I posted mine. Great minds think alike .

[Sticky_Tape]

Sorry Sticky, I only saw your post just after I posted mine. Great minds think alike .

They do, two monkeys theory http://www.shepmedia.com/Paul'sCorner/Monkey.html

[inonickname]

I just thought of this, you can get to 800psi with dry ice....but i think i would make the pvc brittle

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Dumbest statement I've heard all year.

Wrong. My signature. Again.

Far out, at least use aluminium..

Consider a steam rocket..they work quite well. Personally I wouldn't use those pressure in a rocket as slamming into the ground wont make it stronger. (parachute..). For a real water rocket go FTC (flourescent tube cover) covered with a carbon braided line and epoxy.

Those pressures in PVC are ridiculous, I don't care if you think it's rated to that..

[D_Hall]

We thought about that and were onlyplaning to use it once,

Then I would be remiss if I didn't offer my appologies.