[aprssig] OT: TransAtlantic Buoyancy on 28 MHz (signal)

[Steve Noskowicz]

  OK.  Forced to think, I get it.  With the same size balloon, you are displacing the same amount of air, 10 units.  The gas is 0.5 less weight.

Your use of the word "to" caused me to think ratio.  Buoyancy is the *difference* in weight of gas and (displaced) air, not the ratio.
  Like the old puzzle - Which makes the water rise more?  Throwing a penny into the water. or into the boat.

  Reminds me of a really neat fuel tank gauge a friend has on his boat. "Tank Tender". It blows bubbles into the tank.  the deeper the fuel, the more pressure it takes.  It's like taking your blood pressure with a hand pump and a gauge.  Really slick to try with the Home sphygmomanometer-cuff.  I did the math and for water it is fairly close to 1 mm per inch of water depth.  A real Mr. Wizard demo.

-- 
 73, Steve, K9DCI   USN (Vet) MOT (Ret) Ham (Yet)



--- On Thu, 2/23/12, Bob Bruninga <bruninga at usna.edu> wrote:

> >> ...Air-to-Helium 
> (10-to-1) and
> >> air-to-H2 (10-to.5) so the difference in lifting
> capacity is
> >> only 0.5 out of 10 or about 5%.  Now it makes
> sense.
> 
> > This hurts my brain.  It sure looks like 10:1 vs
> 20:1...  
> > Time to revisit buoyancy class.
> 
> Yep, that's why I posted it.  All my life I never
> understood it till now...
> It’s the displaced air side of the equation that matters.
> Nine units vs 9.5
> units is only about 5% Better.  
> 
> Bob, Wb4APR
> 
>