Home made water rocket and launcher system

[c_dug]

Thought some of you might be interested in my current little project.

About a month back a friend asked whether I may be able to make a sort of water rocket launcher, for use at a nights camping this coming Friday.

I didn't realise there was such a massive thing for this in general, and that plans for these things might exist. I didn't even think to google it

Still, I had an idea, and started on prototyping.

This is what I wanted to make:
https://i.imgur.com/a77k4ZG.jpg


I wanted to hold a bottle down with some sort of mechanism, with a gasket at the bottom on the flange, then release it when I decide rather than when the pressure becomes too great. The idea of the thin piece was to install a one way valve to hold water in. The thread was for some sort of adjustment.

I began turning down a bit of Delrin
https://i.imgur.com/hNNTe25.jpg

Until this happened:
https://i.imgur.com/YWnYsmU.jpg

Then I dug out the biggest die I could find, M22, and finished up the other end to make this:
https://i.imgur.com/5FwxCRK.jpg

Next I roughly hacked up a bit of ally flat bar to make a holding mechanism, it has a U shaped slot that goes over the flange on the bottle, you can also see the one way valve installed on the end here, it's a 12mm push fit:
https://i.imgur.com/CZ0Bwqv.jpg

Next I found a large piece of ally U channel and machined a piece of Nylon to fit in the gap, then attached my flat bar to the top, and drilled and tapped an M22 hole in the end, to create this:
https://i.imgur.com/AR90DZ9.jpg

https://i.imgur.com/ijpwTU8g.jpg

The thread means I could adjust the height of the bottle to match the height of the flat bar, since bottles aren't the most accurately made things.

I wanted to get a spanner onto the plastic section (I cant exactly remember why initially), so next I milled off a section of the U channel ally to allow access:

https://i.imgur.com/fzDmgr9.jpg

I repeated the same on both sides, and machined four square sides onto the black plastic piece. I don't have any pictures of it in this state, but I learned that the theory worked in general, but that I'd either have to be much more accurate, or much less accurate in my final piece.

Not sure my pictures are going to show up, so I'll end this here for now and continue in a second post!
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[FretGrinder]

Unfortunately, the pics aren't showing.
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Yamaha MT-09

ಠ_ಠ

[smegballs]

OP is v& from attempting to make hydro-powered, renewable-energy jihading tools.

[c_dug]

So fucked off at photobucket, this was simple before they made a mess of their bloody sharing stuff.

Google don't make it easy either!

Will edit with new pics soon!
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[duhawkz]

use imgur

its free
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"The guy is a worthless cunt and I honestly believe I would be a slightly happier person if he died." - Chris-Red

[kippyzona]

Add ~original after jpg to make it work.
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Zip

[c_dug]

Uploading to imgur now, annoying since they're all on google already!

[c_dug]

Fuck this shit. No idea why all of my imgur images wont show up either?

https://i.imgur.com/leFIfxU.jpg

???
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[c_dug]

Tantrum at photo-hosting over - mostly me being tech-spaz.

Too late to finish the thread this evening, so to be continued tomorrow!
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[fatjames]

+1 glass bottle = bomb

I wonder.. would the 1 way valve give up before a plastic bottle? I feel you're going to need to launch remotely.

[Polarbear]

If that's you workshop, I am as green as a green thing suffering from jealousy.
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Triumph Trophy Launch Edition

[Tracer1234]

[c_dug]

Not my personal workshop, it belongs to the employer, but I do have free reign when I'm off shift.
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[c_dug]

So where I'd left off last night I had finished what I'd consider to be Mk1, but it didn't work too well.

My black plastic piece wasn't too accurate, but my white nylon slide had no leeway for misalignment, this was a bad combination. I was happy with the theory mind, so decided to work with what I'd made as much as possible.

I decided to remake my plastic piece using hex brass:
https://i.imgur.com/lsdJzkS.jpg
https://i.imgur.com/AVw1fUw.jpg

I also made two brass nuts, so as I could do this:
https://i.imgur.com/greqz43.jpg

I popped it all together and started to have a think about how my final launch system would work. I initially planned on using a rope to pull back the prongs and release the bottle, but I figured a pull might be a little slow, and cause the bottle to fire at an angle.

I decided a spring release would be better, so I ran a bolt through the ally, and planned for a release pin, like so:
https://i.imgur.com/mlDIUYB.jpg
https://i.imgur.com/CN6nyJk.jpg
Obviously just a mock up there.

I also realised I'd need to reduce the size of my upper hex, to allow the bottle to sit lower:
https://i.imgur.com/Cl2kXdV.jpg

I have some videos to upload which fit the story right about here, so I'll update a little more after they've uploaded to Youtube!
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[c_dug]

So I turned down the shaft much further, then added an O ring to seal the bottles. Getting the O ring fit spot on is essential to this working, a fraction of a millimeter is the difference between the bottle leaking air, or not launching when expected.

This is the test fire: https://youtu.be/HG9OTTKr2D4

Wahey!

Next I tried fitting the whole lot together and doing a test fire using the spring release, unfortunately the nylon block didn't slide within my ally U channel as expected. I tried PTFE lube, and PTFE spacers between all of the metal parts, but it just wouldn't slide properly.

I decided a proper ball race of some sort would be better, given the whole project is on the cheap, I dug around and pulled pit a spare drawer runner, you can see it installed here:
https://i.imgur.com/ZQSCZ3A.jpg

This provided a good amount of slide, but introduced another thing to try and get square with the bottle.

I did another test run at this point, 25psi with no water, getting closer but a two new issues:
https://youtu.be/NSDHulB4iAk

Firstly, as you can see at around 7 seconds the entire slide mech lifts up when the pin is released, this is caused by the drawer roller flexing up by nearly an inch!
Secondly, everything being off square means the slide prongs snag on the bottle, stopping it in its tracks.

Given I'm planning on running 100+psi in the end I needed to change a few things, but I was getting much closer.

My next plan was to make a much more accurate prong to hold the bottle in place, I found a suitable piece of steel flat bar, being a bit stronger it should resist flexing so much too.

To remove the issues with alignment I got rid of the nylon block, and replaced it with a small piece of wood, then I secured the prong in place with a single screw, this allowed plenty of movement to get everything aligned nicely.
https://i.imgur.com/ZO3xX4O.jpg

Finally I installed a roller bearing to hold the prong level under pressure.

The next test fire was a far more successful run, 25psi again with no water: https://youtu.be/ZzfPd3tJvFI

This is much more promising now, but still at very low pressure. I had the genius idea next to properly plum it into the workshop air supply about 120psi.

Woops
https://i.imgur.com/PIdfUcy.jpg

It made a very loud bang too, ringing ears for all! Not one of my smarter moments!

So, mains air is bad, gradual build up of pressure necessary. A pump was on my to make list. I didn't have a suitable tyre pump but I did have a pneumatic ram and some one way valves
https://i.imgur.com/WLyLOAt.jpg

Time for another test fire, this time 40psi, no water:
https://youtu.be/GOMWY18KaTk

60psi, no water, slowmo: https://youtu.be/52qpFB9pNUA

Next I added some legs, and did an 80psi vertical launch: https://youtu.be/zsaI28G6IrQ
https://i.imgur.com/BaJ8zMS.jpg
https://i.imgur.com/zSxxu42.jpg

One dead bottle. Next post, out door testing and parachute.[/img]
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[c_dug]

At this stage I realised there was quite a big following for this sort of thing online, and loads of hobby forums dedicates to hints and tips.

Obviously I'd done most of the hard work by this point, compared to some of the launcher designs I found online it seems I'd made a pretty damn good system. But, I was still stumped by parachute designs, I only really had half an afternoon left to faff with this too. Obviously a parachute isn't a necessity, but it increases the cool factor tenfold.

A look through the dedicated forums showed three main types of parachute mechanism, air flaps, mechanical (tomy) timers, and electronic systems. I didn't have any timers (mechanical or electronic) nor suitable servo controllers. Air flaps looked confusing and over complicated.

Sod it, I figured I could do better myself!

I had an abundance of plastic bottles about, and I managed to score a toy parachute freebie, all I needed was a hinge mech of some sort, and something to spring it open. I tried a few designs and this seemed to work best:
https://i.imgur.com/PYu2Qf0.jpg
https://i.imgur.com/JuavkQk.jpg

The parachute simply strings through the bottle lid, it's hinged with some card and gaffa tape, and sprung by a loop of plastic bottle. It's held in place on the launcher by a tiny piece of tape, the tape is tied to the launcher base. When the bottle launches the string pulls the tape off, the lid is then held down by air pressure, until the loop of bottle overpowers the wind speed, at which point the loop both flips the lid and launches the parachute at the same time.

Genius I'd say!

Time for some outdoor testing, low pressure as I didn't want to hit a building or lose the bottle and chute. All around 60-80psi dry.

https://youtu.be/SZEbaCCS1gA
https://youtu.be/GvOg2j1PVR0

I'll be using it properly on Friday so I'll have some more videos of full on water launches sometime over the weekend!
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Polarbear]

Why is it called a water rocket when you only use air?
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Triumph Trophy Launch Edition

[c_dug]

It'll be a water rocket in the end, but squirting 500ml of pressurised water across a workshop is a surefire way to piss everybody off!

I didn't use water outside since it'll seriously increase the height it'll fire to, didn't want to go losing the parachute!

On Friday it'll be in a big field so all good for full on 100+psi water launches.
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[recman]

[Im-a-Ridah]

[haroman666]

This is BCF BBQ material.
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The mistresses: 2000 Honda CBR600f, 2000 Honda VTR1000

[Polarbear]

Dumb question time.

Water is incompressible and non flammable so how does it increase the effectiveness of the rocket?
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Triumph Trophy Launch Edition

[angryjonny]

[kippyzona]

If it helps fizzy drink bottles can go up to 200psi.
Edit , looks like the second bottle was.
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Zip

[haroman666]

Brain fart: Could you somehow release a powdered Mentos through the air line and prime the bottle with coke?

Even if the pressure build from that reaction isn't quick enough to be effective, it's still a good excuse to make a fucking mess.
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The mistresses: 2000 Honda CBR600f, 2000 Honda VTR1000