# It's a bird, It's a plane... It's a flying man?

Discussion in 'Community Discussion' started by lowhugchain, Jun 23, 2008.

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Jun 17, 2008
2. ### EricNau Moderator emeritus

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San Francisco, CA
3. ### .Andy macrumors 68030

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Jul 18, 2004
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The Mergui Archipelago
#3
Spoil sport .

*cancels order for helium*

4. ### Chundles macrumors G4

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Jul 4, 2005
#4
Some helium - and a healthy dose of reality.

That much helium isn't nearly enough to lift a man.

5. ### sushi Moderator emeritus

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#5
Fun video.

If you look closely, you can see the supporting wire pivot points a couple of times.

6. ### EricNau Moderator emeritus

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San Francisco, CA
#6
Not to mention, Helium isn't going to stick around in a pair of jeans, with or without duct tape.

7. ### Chundles macrumors G4

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Jul 4, 2005
#7
Yeah well that too.

8. ### 28monkeys macrumors 6502

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9. ### egor macrumors regular

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Jun 3, 2004
#9
Serious question, forgetting about helium - how much hydrogen would it take to lift the average man? And what kind of area would that hydrogen occupy?

10. ### gauchogolfer macrumors 603

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#10
Balloons work by displacing a volume of air that is equal in weight or greater than the load being lifted. So, if an average man weighs 175 lbs (79.4 kg) then the volume of air would have to weigh that much. At sea level dry air has a density of 1.3 kg/m^3, and hydrogen has a density of 0.09kg/m^3. So, to displace 79.4 kg of person we need 79.4/(1.3-.09) = 65.6 cubic meters of hydrogen. This would exactly balance you. Any more and you'll be lifted.

</nerdy scientist>

11. ### dllavaneras macrumors 68000

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Caracas, Venezuela
#11
Oh.

*returns helium containers*

12. ### Hawkeye411 macrumors 68000

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Canada EH!!!
#12
One small step for man ..... One giant leap for mankind!!!!

Cheers,

13. ### egor macrumors regular

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Jun 3, 2004
#13
Amazing post, thanks

Pity about the space requirement, especially considering there was only the one Hindenburg.

14. ### .Andy macrumors 68030

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#14
I worked it out differently (and far more slowly! )

From this Mythbusters experiment we can get a bit more of an idea experimentally. It takes approx 3500 ballons to lift a 4 year old off the ground (lets assume a 4 yo girl is about 15kg). Therefore an average man of 75kg would need 5 times that amount, 17 500 balloons worth of helium. Each balloon is 10L so ugh. It would take you a lot off hydrogen balloons, assuming you could find some that would hold hydrogen!

From this site helium apparently has 93% the lifting capacity of hydrogen, so you'd only need ~16 250 balloons (keeping calculations simple!).