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DK2ZA > INFO 21.07.02 12:35l 53 Lines 1584 Bytes #999 (30) @ WW
BID : L7CDB0MRW02B
Read: DB0FHN GUEST
Subj: re2: balloons (G0TEZ)
Path: DB0FHN<DB0ZWI<DB0HOT<OK0PBX<OK0PHL<OK0PKL<DB0MRW
Sent: 020721/1328z @:DB0MRW.#BAY.DEU.EU [Wunsiedel, JO60AB] Bcm1.46 LT:030
From: DK2ZA @ DB0MRW.#BAY.DEU.EU (Helmut)
To: INFO @ WW
X-Info: Sent with login password
Hello Ian, hello balloonists!
Regarding the lifting force of a balloon filled with hydrogen as compared
to a balloon filled with helium.
I am afraid I did not express myself clear enough.
So here I try again:
It is true, helium has twice the density of hydrogen. That was not the
error in Ian's statement. But then he wrote: " so there is only half
the lifting force". This conclusion is false.
The law of Archimedes states:
The lifting force is the weight of the displaced fluid (water, air ..)
A balloon of 1 cubic meter displaces 1 cubic meter of air, which has
a mass of 1.293 kg and weighs 12.67 N (Newton). So its raw lifting
force is 12.67 N.
This of course is not the useable lifting force, because the weight
of the balloon material (latex) has to be subtracted!
And, of course, the weight of the gas inside the balloon has also to
be subtracted!
1 cubic meter hydrogen weighs 1.74 N
1 cubic meter helium weighs 0.88 N
--------
Difference: 0.86 N
So a balloon filled with helium has a lifting force which is 0.86 N
smaller than that of a balloon filled with hydrogen.
A helium balloon of one cubic meter can lift about 88 grams less than
a hydrogen balloon. Not a big difference considering that a hydrogen
balloon can lift about 1100 grams = 1.1 kg!
vy 73 de Helmut, DK2ZA
btw, what is BS (that baffles brains) ?
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