Building A Better Water Rocket Launchpad

School will be starting again in a few weeks but it’s not too late to enjoy a little time with your kids. This water rocket launcher lets you do just that. Built using the frame from an old grill, a soda bottle takes its place on the upturned PVC pipe. There’s a connection for your garden hose that allows you to inject water into the bottle. From there, a compressor connection pressurizes the bottle in preparation for launch. Watch it happen in the video after the break. That bottle could use some fins and a nose cone but there’s no denying the delight the kids are enjoying when they chase after the downed craft.

If you’ve already got a compressor and some empty 2-liter bottles you might also pick up some extra PVC to make this pressurized water cannon.

13 thoughts on “Building A Better Water Rocket Launchpad

  1. There is such a thing as too much safety. I would prefer the kids learn the hard way cause they learn it faster. Kids now don’t have any sense and I think that’s part of the problem. Eventually all playgrounds will be covered in fluffy white pillows.

  2. WE MUST NOT ALLOW THIS TECHNOLOGY INTO THE HANDS OF TERRORISTS!!!! Nah, but really its nice but he should have put up some launch rails to help control the rockets trajectory.

  3. I seem to recall something about not using PVC with compressed air… something about shards of sharp PVC if it bursts or has any kind of impact (which causes it to burst)?

    Not really much PVC in this build though.

  4. I just cut a hole in the 2 liter lid and cut the valve out of a bike tube and poked it through, went down to the co-op and filled it with water/air and twisted the cap off and watched it take off! I suffered no injuries as a result of a hot summers day of fun!

  5. System seems pretty good. Thing is, it gets kinda hard to do if you don’t have an air compressor and have to pressurize it by hand.

    Actually, the best (simplest and effective) fin system i’ve found is cutting the flat circular middle section out of another bottle, using straws/skewers/coat-hanger wire to attach it below the bottle, in line with it. I found about 30cm good. Duct tape it all up (pro tip: Don’t use masking tape). It goes up straight, comes down fairly straight. Recovers fairly well from bad launching angles as well.

    Pity his system can’t accommodate this, but still a good job.

  6. Like thomas316, I drilled a hole in the cap of ‘pop’ bottles, and used a bicycle/car tyre pump which had a pressure guage built in.

    The interesting point I found was that at 120 psi, the rocket expelled all the water too quickly and didn’t go as far as when the pressure was 40 psi.

    Unfortunately, I couldn’t control the release pressure as the bottles would release themselves due to the pressure.

    Lots of fun though!

  7. A couple things. Make sure you only use carbonated water bottles. Regular bottled water bottles will explode under very little pressure. They do send shrapnel and are vey loud.
    The internal seal design launchers work better as the length of the neck of the bottle varies from bottle type to bottle type which requires frequent adjustment if you are using a bottom seal like the launcher here uses.

  8. Sorry,(to your intended YOUNG audience for this hack), but REAL MEN MAKE FIRE!Applause to your well thought out design work,but Looks Like A REAL Rocket Extinguisher To Me.’Cmon folks,if you want to get to the planets, you gotta BURN Stuff. Hey, sofar, Issac reigns supreme. HEY,You, AMAZE ME!

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