Water Rockets

Intro

One day in the church parking lot, while waiting for an activity to begin, my step-brothers pulled out a bike pump and a soda bottle half filled with water. The lid of the soda bottle had a hole drilled inside with a bike tire stem poking out. They attached the pump to the bottle and pressurized the contents. Finally, one of them pointed the bottle up in the air and removed the cap. It rocketed out of his hands spewing water everywhere. That was my first introduction to water bottle rockets.

As kids we never took that principle any further. It wasn't until college when I learned that some people get very serious about building complex launchers and rockets. For me it has become a fun summer pastime, but not a serious hobby. I mostly enjoy launching rockets as a way to spend fun time with my children.

My Rockets

My first rocket no longer exists. I shot it so many times that the plastic got weak from landing and it exploded during pressurization. So unless you have a soft recovery system, I recommend retiring your pressure vessel after about 20 launches.

"Red Rocket", my second rocket, is a two-liter bottle with fins stolen from a firework. The nosecone is a Nerf football cut in half and hollowed to the correct weight. The fins and nosecone are attached by duct tape to allow fast repairs and relaunches. I've found duct tape to be very reliable and convenient in withstanding launch forces. These fins are too small to be really effective, so I'll probably replace them soon.

My family at the engineering competition, me holding "Red Rocket."

"One Night Wonder", my third rocket, was designed for an engineering competition at work. I procrastinated the build until the night before the competition. The nose cone was 3D printed, and I invented a circular fin that extends on launch. This system allowed the rocket to be fired from virtually any launcher design. With only a single good launch my rocket won second place for height, and first place for closest to target. The fin extension system used short sections of drinking-straw as linear bearings. The straws were cheap and thin and failed on the second launch. The design is sound and one I will duplicate with stronger materials.

"One Night Wonder" Maiden Flight

"One Night Wonder" Catastrophic Second Flight

My Launcher

I'll add a picture soon. You can find instructions on how to build a similar launcher from The King of Random. Or you can buy a kit from the Taylors. My current release mechanism uses a Clark Cable-Tie Launcher.

Useful Links

• Dean's Benchtop - Dr. Wheeler was one of my professors and bosses in college. He is the one who re-introduced me to the world of water rockets.
• Air Command Water Rockets - Lots of resources and tutorials.
• Clifford Heath's Simulator - I don't know Clifford, but he wrote a nice simulator for modeling different rocket design parameters. I've found it to be reliable for making design choices. It also allows you to change launcher and nozzle parameters.
• It's a Blast! - The Taylors were our neighbors while I was in college. They introduced me to the world of paper rockets. The pneumatic system I use for launching my water rockets is based on their launcher design.
• 3D Printable Rocket Parts - Here are some water rocket parts that you can print with a 3D printer. I used a nosecone in the engineering challenge.