June 23, 2012

Homemade rocket launcher


Pressurized PVC pipe soda bottle launcher.
Yesterday my nieces and nephews took turns aiming a stomp rocket at me. My big brother did the stomping. Every time I caught one, I got a point (which happened about four times in the hour or so of launching). All the other times it didn’t hurt too badly and the kids loved it. But if you ever plan on subjecting yourself to a similar firing squad, put on a pair of sunglasses and batting gloves first.

Keeping with the spirit of rockets, today we built a couple of bike pump bottle blasters. It took only fifteen minutes to cement ten feet of PVC pipe into a pair of t-shaped launchers. I wouldn’t recommend aiming these guys at anybody…

The duo.
The duo cost $12.93. Most of that was the primer and cement (so if you need some, you know who to ask). The half inch PVC pipe was dirt cheap. If you’re looking to try this out, you’ll also need two slip caps, one tee, one elbow, and one male adapter per launcher. Assembly is straightforward, but there are some detailed blueprints online if you’re interested. A 5/16” drill bit punched a perfect-sized hole for the recycled inner tube bike valve. We used one liter soda bottles for rockets (two liter bottles would fit the adapter too). The most magic seemed to happen with one part water and three parts air. A couple rounds of electrical tape on the adapter helped give the bottle a good seal. Some duct tape around the final product increased power, but decreased predictability (one side would inevitably break first, aiming the rocket anywhere). I would not recommend using duct tape around the connectors for that reason! Be safe, people!

Next time, we are going to compare water levels with greater granularity, and see how two liter bottles stack up against the one liter guys.

My niece's hieroglyphics documenting the day.

1 comment:

  1. I don't know why, but the slow motion (slow audio) laugh in that video just cracks me up :)

    There was a group in one of my ChemE classes at school that made a really simple launch mechanism so that you could apply pressure and then launch at your leisure... maybe you could include that on your next model.

    ReplyDelete