Flutterby™! : Vinegar and Baking Soda Bottle launcher 2010-05-30 21:57:45.215335+00

Vinegar and Baking Soda Bottle launcher

2010-05-30 21:57:45.215335+00 by Dan Lyke 6 comments

Sage, the third grader from across the street, and his mom came across to ask some questions, and one digression led to another and he learned how to use a Dozuki and a drill press and a file and we ended up with a vinegar and baking soda soda bottle rocket launcher.

Direct link to the YouTube video.

I think I've heard someone say that just putting a valve stem through a rubber stopper and using friction as the release mechanism gets some altitude. I've done the hole drilled into the 2 liter bottle top thing, usually with a washer for strength (not necessary under 100PSI, or if you only care about a few pumps out of the bottle cap), sometimes trimming off a few threads so I can unscrew it fast. I've thought that a couple of verticals to keep the bottle upright and a rope wrapped around the bottle to spin it out of the cap might work, I'll have to try that...

It was actually pretty nice, hard to explain though I guess. If you've ever taken the valve stem out of a tire and you see the rounded end on the bottom, that's basically what was on the platform. The clamp held the hard plastic of the bottle tightly against that little black piece of rubber. You'd have to put the launch pad on the bottle with it upside down, then clamp it down, then flip it over, and then use the attached bike pump to pressurize the whole thing until the clamp gave way. The little odd cone that screwed onto the top of the bottle would probably be the hardest to reproduce, however with a few brass fittings and a nice hole drilled into a regular plastic 2 liter bottle top, it could probably be remade. That's what made the tight seal over the rubber piece that the hose attached to.

I'd love to do it here and take pictures, but I'm sure the base would have an issue with gas pressure rocketry on a restricted training base. :)

The release mechanism we're using would probably also work if we could get a valve stem through the cork and out the bottom. Didn't cut the cork down (it's just a wine cork), so it's pretty long, I don't think I've got anything with a valve stem that long, and I don't know how I'd join the valve stem to tubing.

I really wish I could remember the place where I got the soda bottle rocket kit, I keep thinking it was Edmund Scientific but I don't see anything in their catalog that is the same. It was a neat little cone that you screwed onto the top of the bottle and was held on the "launcher" but some little clamp. When the pressure got high enough in the bottle, the clamp would give way and the bottle would launch off. It came with something like a 5 foot rubber hose, so you were sure to get sprayed in the process, but that was half the fun anyway.

We started with the bike pump thing, but the launch involves manually unscrewing the cap, and kids usually aren't strong enough to do that themselves, so it ends up being "watch Dan launch". Which I think is less fun for them (I'm still good with it).

We haven't edited the video from it together yet, Charlene was running the camera while we were playing in the shop, and I have some weird limits about what and how I'll put stuff on the web that shows other people's kids, but I think the real triumph of that wasn't the rocket, it was watching him figure out how to use a pull saw (with its floppy blade and need to be pulled really straight), and telling him to have the confidence to keep pulling on the drill press handle, he'd feel it when he was through the piece we were drilling.

His mom came over for dinner last night while the kids were watching Bob the Builder and asked if he could set up a little workbench in our back yard so he had a place that was his own where he could lock stuff away from his sister (they're in the two bedroom house across the street, the back yard of which is shared with the daycare around the corner). So when I make my hardware store run in a moment I'm going to pick up a hasp and a lock and we'll put a box on legs together that's his, where he can store his disassembled radios and build his spaceship cockpits.

Of course I'm pretty sure that means that at some point we'll be using the angle grinder to take the hasp off of it when he loses the keys to the lock, but that'll be cool 'cause the solution to the problem will involve be sparks and noise and destruction.

I used to love making these when I was a kid. There was also a kit you could buy that would make the same out of water and a bicycle pump. It was always fun trying to figure out the best ratio of water to air in order to get the best launch.