Re: Where can I buy floater balloon?
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Some science here.
Balloons lift (are buoyant) on the basis of Archimedes principle (cite: https://en.wikipedia.org/wiki/Archimedes%27_principle) which has the corollary that less dense material will rise above more dense material. It’s the same principle that causes oil to float on water… and with gases, it causes the lightest one (less dense gas) to rise above a heavier gas. Even hot air will rise above ambient air just because the density of the air in the balloon is less than that of ambient air.
In the buoyancy calculation, the force of lift is proportional to the relative differences between the densities of the gases… and in this case, that would be H2 (or whatever the lift gas is) and air. Now, the density of a gas can be calculated from the ideal gas law… P*V=n*R*T, or rewriting, P=p*R*T/Mw where “p” is the gas density and “Mw” is the molecular weight of the gas. The ratio for lift is then [P1*Mw1/T1]/[P2*Mw2/T2]. Plug in the numbers and you can determine where the lift will cease. Of course you need to do a force balance for the real lift and include the weight of the payload and the balloon.
The point here is that the buoyancy can vary based on the ambient temperature and pressure… even of the temperature and pressure of the gas in the balloon stays constant.
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
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Big Signal Ranch – K9ZC
Owner – Operator
Villa Grand Piton – J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com
Moderator – North American QRO Group at Groups.IO.
From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Mikael Dagman
The balloon was filled and stored in the same room in the house.