Valve question

[CROC]

While browsing NerfHaven, I came across a topic that was discussing the following valve:

http://www.instructables.com/id/Airg...Release-Valve/

Would this work in a WBL, or would the flow be too high? If you upsize it so that it uses something like 3/4" PVC and another material, would it always burst balloons, or would it successfully launch them without any issues at a lower PSI than normal launchers?

Original NerfHaven topic:
http://nerfhaven.com/forums/index.ph...pic=12200&st=0

[cantab]

I reckon you'd get burst balloons.

[aEx155]

That kind of valve is practically the same as a sprinkler valve if you scale it up. You'll basically have the same thing happen, so I wouldn't suggest it. There's not much benefit to it anyways.

If you really want to get a balloon as far as possible, you would need a fairly large high pressure air tank, an outrageously long barrel, and a bunch of small valves. That way, the air is released slowly into the barrel, and the balloon accelerates slowly. (not battle practical)

But even in a situation like that, a balloon probably wouldn't be able to withstand the speed.

To sum up what I've said: any fast-opening valve of any sort will likely need to use lower pressure than any launcher using a slower opening valve; what we have now is good enough, since balloons probably wouldn't be able to go any further.

[cantab]

Yeah, launchers are going to reach their limits. You could go still further with some sort of powered aircraft, but that would be expensive and dangerous.

[CROC]

If you used a special sabot, similar to the one waterwolf has on this site, but on the bottom, put a cone or something on it, it would not pop balloons, quite simply because the air would distribute along the back, not flooding the center and potentially destroying the balloon... correct?

[aEx155]

Originally Posted by CROC

If you used a special sabot, similar to the one waterwolf has on this site, but on the bottom, put a cone or something on it, it would not pop balloons, quite simply because the air would distribute along the back, not flooding the center and potentially destroying the balloon... correct?

I don't quite get what you mean by "flooding the center". Could you explain your reasoning?

If you put a cone on the back of the sabot, you would still have the same amount of surface area on the back of the sabot for the air to push on. If you reduce the area that the air can push on (or the pressure, same thing) then you can reduce accelerating speed. I don't think a cone would do that.

[cantab]

I don't think so. The bursting occurs because of excessive acceleration, causing the skin of the balloon to be unable to exert the force required to accelerate the water.
Thicker balloons would help, but they have their own problems, like not bursting on impact.

[CROC]

I meant that all the air does not hit the center, but it hits the sides, and is not as concentrated in the middle. Thicker balloons, with enough velocity will definately burst on impact, esp. with the speed they go.

By the way, it doesn't necessarily need to be a cone.

[Silence]

The perfect sabot would be able to completely encapsulate the balloon, with rounded contours. Too much acceleration makes the balloon flatten, and I'm having the balloon touch the bore isn't good at these velocities.

chluaid's valve, from what I remember (from a month ago), is just a variant of a pull valve. According to Captain Slug, it's a sleeve valve, but tons of names could apply. The neat part is it's compact and well documented. You may have to scale it up in size, but then it's not so effective for its size. The bottom line is that nearly any valve can work in water balloon launchers thanks to the limit imposed by balloons.

[Ben]

I think small QEVs would be best if you want efficiency, ease of construction, and a small size. This valve might open fast but the flow rate will be terrible unless scaled up. If you scale up you might as well use a piston valve or a simple pull valve (which this is a variation of).