Oops. Sorry Bass, I gave Shortwave credit for the formula you found...
My bad.

basskisser wrote:
Joey916 wrote:
I hit up one of our chemical engineers and ran the scenario about fuel
expansion by him and he agrees with Shortwave's formula. In other
words, a 40 gal fuel tank that was filled when the fuel temp (not
ambient) was at 60F and then raised fuel temp to 110F (which would be
hard to do) or a difference of 27.78C will only expand 0.1112 gallons,
or less than a pint.

I think what people perceive as fuel expanding in a cold tank is
actually the fuel vapors expanding. They don't have anymore fuel,
they are experiencing fuel vapors expanding tanks, pushing fuel out
vent hoses, etc. Fuel vapors are much more apt to expand, something
like 1.5% per deg Celsius (much higher than the .01% of a liquid), plus
accounting for the low boiling point of gasoline and presto, a cold
tank of fuel becomes a pressure cooker when the ambient temp goes up 15
to 20 deg. No extra fuel, just a lot of extra vapor molecules pushing
on everything else.

So with that info, Shortwave is either A) Getting really good HPG, B)
Didn't fill up the second time as high as the first time, C) Idled
much more than he thinks, D) Is an out right liar... But he didn't
experience significant fuel expansion. My bet is on A.

I agree. If you work the formula that I provided, you'll see that the
fuel expansion idea doesn't fly! On the other hand, I was reading in an
Engineering magazine that the Concorde, because it flies so fast that
friction heats the airframe so that it actually gets 7 to 10 inches
longer!