Water Balloon Cannon Optimization

[ab500]

Originally Posted by RyanN

I would not increase the pressure for safety concerns. Although you already stated that you know the dangers of PVC, increasing the pressure will not help. I've posted before that a kid at school was charging his PVC potato cannon and it blew up in his face at 40PSI. This was the same tank that was on our t-shirt shooter before I revamped it last summer. PVC is dangerous and should not be used for storing air pressure, and certainly not anything above what you are already trying! Please at least put duct tape or something around the tank. Make a wooden box or something to go around it when it explodes.

I am perfectly aware of the dangers of PVC pipe. I'm testing the cannon from behind a half inch glass door as I stated, doing the testing outside, and there is a large block of wood separating it from me. From the time the cannon has pressure in it to the time it's fired I am no where near the cannon. The valve and compressor are controlled remotely from my laptop and I don't feel like I'm in danger.

[JesseK]

In order to put enough backspin on a balloon to significantly attribute to its overall distance, one would have to consider how the balloon would react to the backspin while in flight. It's not hard to setup an experiment to show this; however for the experiment to be accurate, one would need to put a true tangental force on the exact edge of the balloon so that the rotational axis is the balloon's center of mass. Since the balloon is not a rigid solid shape, the water would be pushed to the outside of the balloon and eventually form two almost identical pertrusions out of the balloon (much like how galaxies spin). As time progresses, the balloon would look like a spinning dumbell. Eventually the forces on the middle of the dumbell would be great enough to break the balloon mid-flight, therefore sprinkling the target rather than drenching it.

At least it would make some cool rainbows though

[EricH]

Originally Posted by JesseK

In order to put enough backspin on a balloon to significantly attribute to its overall distance, one would have to consider how the balloon would react to the backspin while in flight. It's not hard to setup an experiment to show this; however for the experiment to be accurate, one would need to put a true tangental force on the exact edge of the balloon so that the rotational axis is the balloon's center of mass. Since the balloon is not a rigid solid shape, the water would be pushed to the outside of the balloon and eventually form two almost identical pertrusions out of the balloon (much like how galaxies spin). As time progresses, the balloon would look like a spinning dumbell. Eventually the forces on the middle of the dumbell would be great enough to break the balloon mid-flight, therefore sprinkling the target rather than drenching it.

At least it would make some cool rainbows though

Which is about what I figured would happen. Assuming you could get a decent backspin by shortening the lower half of the barrel or some other method, and the mouth of the balloon isn't in the way, you'd get the air burst effect instead of the shell effect. At least until they make stronger balloons.