Sign Task

[Paradox21]

Hmm, a custom mylar balloon the size of a Mission Possible would be quite heavy. My partner weighed a deflated standard 2 sheet 18 inch mylar balloon and told me it weighed about 50 grams. I wonder if it is possible to get more concentrated helium. I'm sure that the average helium tank is not pure helium, I wonder how much of the gas is actually helium and if it would be possible to somehow purify it further.

[sj]

We poked did some research and found that the tank we have is 95 -98 percent pure. Also are you sure a mylar balloon weighs that much. I don't think it does but i may be wrong...

[chalker7]

Hmm, a custom mylar balloon the size of a Mission Possible would be quite heavy. My partner weighed a deflated standard 2 sheet 18 inch mylar balloon and told me it weighed about 50 grams. I wonder if it is possible to get more concentrated helium. I'm sure that the average helium tank is not pure helium, I wonder how much of the gas is actually helium and if it would be possible to somehow purify it further.

You can get nearly pure helium from welding supply companies, that's what I did when I was running balloon launch glider competitions. However, it comes in big tanks that might be tough to take to nationals. I bet a couple teams might have some and may share if you ask nicely. Otherwise, you might be able to find one in Madison if you are willing to get one there.

Also, I'm sure you could find thinner mylar online somewhere. The stuff we use on helicopters, wright stuff planes, etc is probably too thin to be useful but there must be something in between that and the thick stuff you measured.

[boomtech]

My guess is they have an insanely large balloon; one that takes up half or more of the device, maybe custom made. Then, if the competition is in a gym or some place with a really high ceiling, they use the momentum of the balloon itself to pull up the weight. To do this, you just need a really long string between your balloon and the sign (weight). As the balloon rises, it will gain momentum. Once the string runs out, it yanks the sign over the top of the device. Keep in mind, there is not a requirement saying the sign must remain above the device. Another way to get more weight up is to minimize the height of the device, which in turn minimizes the distance the weight has to travel.

Even if the height of the device were minimized, wouldn't the top of the balloon be considered the top of the device? So the balloon would have to lift the sign past where its original top was... or am I wrong about that

[boomtech]

Yup after seeing what Solon can do round balloons simply won't cut it. Also a side not the momentum idea does not work very well. Perhaps i works for lifting the mass an extra 5 inches but not 50 cm.

We have done tests with the momentum idea, and it seems that there's an optimal length of string that varies depending on the size and shape of the balloon.

...also, 177 grams.....

[sj]

So you've been able to lift 177 grams?

If so can you describe how you did it?

[chalker]

So you've been able to lift 177 grams?

If so can you describe how you did it?

My guess is he displaced about 177 grams of air with the balloon;)

[illusionist]

That's so smart chalker!! Why didn't I think of that!

[boomtech]

Hahaha. Well, I didn't do it; I'm not from Solon. But evidently they figured out a way to do so - props to them!
In the meantime, nationals is coming up and I still haven't figured out how I'm going to ship my stuff... sigh

[illusionist]

A large crate? with extra-extra packing peanuts?
Are you taking a bus? ( I can't tell since idk which state you're from)