Shortly before my return to solid-fuel rockets, I became interested in water rockets. Great Fun!
My first attempt was a 500ml sparkling water bottle with a 3/8" hole drilled in the cap and some 1/4" wood dowels duct-taped to the sides with milk jug plastic fins taped to the ends of the sticks. I used a bicycle foot pump with a conical inflator nozzel that could be held firmly into hole in the bottle cap. Fill bottle half full of water, pump to 60 psi, and let go. It went well over 100' and I was pretty excited.
Now we use a PVC tubing launcher to remotely pressurize and release the rockets. This way I don't get as wet, and I can actually see the launch.
My current water rocket project is a 4' section of flourescent light shield tubing with bottle necks glued into each end with PL Construction Adhesive (see the Water Rocket Garage link below). Styrofoam meat trays laminated with duct tape were used to build the fins. Recovery is with a 14" nylon parachute folded into a large plastic detergent jug cap which sits loosely on top of the upper bottle-neck and falls off at apogee to release the chute. This rocket makes spectacular flights to over 250' and really looks nice descending under the chute.
Always follow the Water Rocket Safety Code to reduce the risks of this activity.
Join the Water Rockets Mailing List to learn more.
At the 2004 IEAS Convention, I taught a class on making and flying water rockets.
On September 6, 2005 I made several successful launches at Farnsworth Aerospace Elementary School to help them "Launch into a new year of learning.".
Handheld PVC Water Rocket Launcher:
First, a simple hand-held launcher that works nice for 500ml bottles. It is powered by a bicycle tire pump:
This small launcher is made from standard parts purchased at Hardware Hank:
Caution: Because this launcher is hand held, please always
wear safety glasses when using it and only give about 3 pumps of
air. Do not exceed about 50 psi.
To use this launcher, first just try with an empty
bottle. Might need to trim/scrape the inner lip of the bottle so
it slides nicely on the launcher tube.
Slide the bottle onto the launcher. Connect the tire pump, and without holding the bottle down, give one slow pump. Notice how bottle rises. Now try a fast pump and see how the bottle flys off quickly. Then try with bottle 1/3 full of water. Hold the bottle neck down tightly against the o-ring with one hand while giving 3 pumps with the other. Then let go and watch the bottle fly over 50 feet into the air.
Notice that the bottle will tumble. It will fly better by adding fins.
A more complex launch system is pictured here:
This is my dual-pad "Ty-Wrap" release launcher system used at IEAS
Convention 1 in 2004. Only the first laucher is connected
here. The orange air hose leads to a valve and guage, then to a
portable air tank. The release is triggered by an orange string
barely visible. The unused launcher has it's roll of green
surveyor's line string sitting over the unused air fitting.
The launcher tube is again 1/2" Schd 40 PVC. It has a couple
of modifications though: First a groove was filed 11 inches down
from the top so the o-ring recesses almost completely so the bottle
neck can fit over the o-ring. Second, some PVC rings cut from a
coupler section were cemented about 3/4" apart beginning 2 and 3/4"
below the o-ring groove. These rings help secure the bundle of
Ty-Wrap(tm?) cable ties that circle the launch tube and hold the
bottle down by it's neck when the larger collar is slid over them.
The plumbing at the bottom is more complex than necessary because I
added a fitting to accept a water hose for remote water fill (not used
More details on this launcher to follow later ...