Air-powered water balloon launcher, Which weights to use?

In summary, the conversation discusses a homemade air compressor-powered water balloon launcher and the need for "sighting charts" to predict where the balloons will land. The question is raised about whether the mass of the water used as wadding needs to be included in calculations for muzzle exit velocity. Suggestions are made to use a sabot or account for varying air pressure and air drag during flight. The use of glycerin or vegetable oil in the wadding is also mentioned. The conversation ends with a friendly sign-off.
  • #1
ThirtyWest
2
0
Hi all, first post. Bare with me.

I've got a simple air compressor-powered water balloon launcher made using PVC. It works extremely well. But, I'm needing to make some "sighting charts" to predict where everything will land based on angle, loaded psi, size of balloon---and the wadding used. By wadding, I mean an amount of water to act as a cushion and also a seal to transfer the pressure from the air reservoir to the balloon (both to cradle it and not tear it apart).

I ran some tests with known psi and balloon sizes and time and the physical results were close enough to the paper results to suspect friction/balloon deformation/water separation/et al.

But I wasn't using the wadding water in the figures.

The question I'm stuck on:

As I'm determining Vf (muzzle exit velocity), does the mass of the 'wadding' need to be included along with the mass of the ballon?

It's a small barrel (2" pipe). The balloons are about 1.75" diameter and weight about .15lb (.07kg) using some rough assumption that the 1.75" balloon is in fact a sphere. At 2" pipe, about 1 cup of water will cover the ballon. I know less water helped the hang times which makes me think it's included.

Also, working out gravity on the 'weight' of the balloon to use f=ma (to get an "a" to put into Vf=Vo + (a)(t)) yield paper results that didn't match actual.

balloon: .07kg
pipe diameter: .002"
psi: 50 (35153 kgf/m^2)

Thanks for taking a look.
 
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  • #2
ThirtyWest said:
By wadding, I mean an amount of water to act as a cushion and also a seal to transfer the pressure from the air reservoir to the balloon (both to cradle it and not tear it apart).

ThirtyWest said:
suspect friction/balloon deformation/water separation/et al.
Try using a sabot (look it up). One or a few could be made from paper mache for testing.

ThirtyWest said:
As I'm determining Vf (muzzle exit velocity), does the mass of the 'wadding' need to be included along with the mass of the ballon?
Yes. Everything that is moved must be included. Also, take account of the varying pressure of the air as it expands into the barrel, and perhaps the pressure buildup in the barrel in front of the accelerating projectile.
ThirtyWest said:
Also, working out gravity on the 'weight' of the balloon to use f=ma (to get an "a" to put into Vf=Vo + (a)(t)) yield paper results that didn't match actual.
Probably because the "wadding" is leaking past the balloon; and did you account for air drag during flight? (Not easy, that balloon will not be a sphere during flight. You will be surprised at its shape if you take a video of it and play back in slow motion!)

Pure speculation here, but try adding a little glycerin to the "wadding"... or maybe use light vegetable oil in, or instead of, the water "wadding."
ThirtyWest said:
pipe diameter: .002"
Umm. Maybe pipe area: 0.002sq.m. ?

Cheers,
Tom
 

Related to Air-powered water balloon launcher, Which weights to use?

1. What is an air-powered water balloon launcher?

An air-powered water balloon launcher is a device that uses compressed air to launch water balloons at high speeds and distances. It works by filling a balloon with water, loading it into the launcher, and then releasing the compressed air to propel the balloon forward.

2. How does an air-powered water balloon launcher work?

An air-powered water balloon launcher works by using the force of compressed air to launch a water balloon. The launcher has a chamber where the air is compressed, and a release valve that allows the air to escape and push the balloon forward.

3. What weights should I use with an air-powered water balloon launcher?

The weights used with an air-powered water balloon launcher will depend on the specific launcher and its design. Some launchers may have weight recommendations, while others may not. It's important to follow the manufacturer's instructions for the best results and to avoid damaging the launcher.

4. What happens if I use the wrong weights with an air-powered water balloon launcher?

If you use weights that are too heavy, the balloon may not be able to launch as far as it should, or the launcher may become damaged. If the weights are too light, the balloon may not launch at all. It's important to use the recommended weights or experiment with different weights to find the best option for your launcher.

5. Can I use any type of weight with an air-powered water balloon launcher?

The type of weight used with an air-powered water balloon launcher will depend on the design of the launcher. Some launchers may require specific weights, while others may be compatible with a variety of weights. It's important to check the manufacturer's instructions to ensure you are using the correct type of weight for your launcher.

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