How Big does a helium balloon need to be.....

[Tony*T3]

to lift a single grown man (assuming 100kg weight)....?

How much helium would be needed? How small could the containing canister be?

Not to fly off into the great unknown, but just enough to get them a few feet off the ground.

One for the PH scientists....

[jammy_basturd]

Mythbusters did this one, albeit it for a small child, with Helium balloons. Took a few hundred I believe. Not much help, but there you go, it is a Friday 'noon.

[kambites]

Helium 0.1786 g/l
Nitrogen 1.251 g/l


0.1786 x V + 100,000 = 1.251 x V

100,000 = 1.251 x V - 0.1786 x V
= 1.0724 x V

V = 100,000/1.0724
= 93249 litres



So lots? 93 Cubic meters or there abouts.

ETA: That's assuming that the man has zero volume, but it's close enough because even a fast bd is less than a cubic meter.

Edited by kambites on Friday 17th October 15:31

[bigandclever]

http://www.cockeyed.com/science/helium/helium.shtm...

[lawrence567]

basically how many balloons do we need to get from the fayre then?

[HundredthIdiot]

Don't get carried away.

http://www.deccanherald.com/Content/Jul72008/forei...

[mel]

They used to have a couple at RAF Bicester with baskets under them for parachute training from 800ft, they were fooking terrifying, they were about 12 ft diameter and would take 4 people at a time up in a winch.

[johnfm]

kambites said:

Helium 0.1786 g/l
Nitrogen 1.251 g/l


0.1786 x V + 100,000 = 1.251 x V

100,000 = 1.251 x V - 0.1786 x V
= 1.0724 x V

V = 100,000/1.0724
= 93249 litres



So lots? 93 Cubic meters or there abouts.

ETA: That's assuming that the man has zero volume, but it's close enough because even a fast bd is less than a cubic meter.

Edited by kambites on Friday 17th October 15:31

why have you used the density of nitrogen? Shouldn't you use that of air?

[crofty1984]

johnfm said:

kambites said:

Helium 0.1786 g/l
Nitrogen 1.251 g/l


0.1786 x V + 100,000 = 1.251 x V

100,000 = 1.251 x V - 0.1786 x V
= 1.0724 x V

V = 100,000/1.0724
= 93249 litres



So lots? 93 Cubic meters or there abouts.

ETA: That's assuming that the man has zero volume, but it's close enough because even a fast bd is less than a cubic meter.

Edited by kambites on Friday 17th October 15:31

why have you used the density of nitrogen? Shouldn't you use that of air?

Air's mostly Nitrogen, so it's not far off.

[NoelWatson]

http://vids.myspace.com/index.cfm?fuseaction=vids....

[Neil_H]

Not planning to do this are you?

[swiftpete]

Although it's a different thing altogether, if you want to fly then a powerkite will easily let you get a few feet off the ground. I went on mine yesterday and even when I wasn't deliberately jumping and I was holding it still in the sky, it was lifting me a couple of feet off the ground every few seconds. Good fun but aching today though..