In article ,
brian whatcott wrote:

Alan Baker wrote:
/snip/
I have never noticed the fabric lifting on my wings, however I have
seen the fuel siphon out of a wing tank due to an improperly applied
fuel cap.
And greater pressure in the tank than outside of it...

Right, but in a sealed metal tank, is all that other fuel PUSHING the
fuel out of the vent since air can't PULL it out?

First of all, the tank is not completely sealed. If it were, the fuel
pumps would soon have difficult pumping the fuel out of the tank.

So, yes, the greater pressure inside the tank is pushing the fuel out.


Hmmm...it probably goes more like this: there's a 100 mph? wind past an
open port, with some venturi effect certainly, but plenty of
turbulence. If you beat up the surface with a gusty blow, it gets
wavelets which can lap the filler and blow out the fuel.

Which reminds me of that trick that suction pumps use for high lift.

As you probably know, if you pump down even to a vacuum above a tall
3water pipe, the water will not rise more than about 30 ft - (if it were
mercury, it would not rise more than 29.92 inches on a standard day,
remember?)

Anyway, the mine engineers who want to pump up water MORE than 30 ft,
say 40 ft without placing a force pump at the foot of the head, blow air
into the water column which has the effect of reducing the density of
the mix. If the relative density goes down from 1.0 to 0.5 they COULD
pump up to nearer 60 ft. How bout that!

Brian W

How about it? It still doesn't change the physical reality that air
doesn't *pull* on the wings.

--
Alan Baker
Vancouver, British Columbia
http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg