The height of your PVC pipe won’t effect how far it launches into the air. Adjust the height based on what is comfortable for you.
We chose a 3-inch pipe for our bottle. Whatever size you choose, make sure it's wide enough to hold your bottle in place, but not so wide that the bottle falls in.
Cut out notch in PVC Pipe for Bike Pump Nozzle with a Dremel Tool.
The water from the bottle will collect in the PVC pipe when launched.
Drill Drain Hole in Plywood Round with a regular cordless drill with a paddle bit.
From Here, You'll Also Need:
Plastic soda bottle (any size)
Use any size soda bottle you like. Ridges are fine, but the smoother the plastic, the more aerodynamic.
Have fun with your water bottle. You can add fins or a nose hose for added aerodynamics.
Hot Glue Gun PVC pipe to Plywood Round.
Make hole in Rubber Stopper with nail for Bike Needle.
Insert Bike Needle in Rubber Stopper.
Fill Water Bottle ¼ way with water. This seems to be the best ration to launch the highest.
Attach Bike Pump Nozzle to Bike Needle on Rubber Stopper.
You can add a longer hose to the bike pump to avoid getting splashed. Bike pumps can vary. Be sure to get one that has a detachable nozzle, so you can attach the longer hose. Just remember, the longer the hose, the harder and longer you have to pump the bike handle to keep the pressure building in order to launch the rocket. Isn't it fun to get splashed anyway?
Plug Water Bottle with Rubber Stopper and place upside down into PVC Pipe Stand.
Pump Bike Handle until the pressure builds and the rocket launches.
The physics of our Water Bottle Rocket are the same for that of real rockets: Pressure builds and the explosive gasses propel the rocket upward.