Originally Posted by
scifi
Double Barrel, you mention about the fuel selector switch. When this is set to 'Both' the supply pipes from each wing tank are joined together, before they go to the Carburettor. So if there is any difference in height of the tanks, the fuel will drain from the higher one into the lower one.
I parked at Shobdon one day with one wheel in a hollow, when we returned from our lunch, the left tank was overflowing and the right tank was down to half full. The fuel only moves slowly between each tank, so if that happened in flight, you would be holding progressively more aileron for S+L flight.
Thanks, that is clear. I had wondered if there was a non return valve to prevent such cross-flow - in my other world we work to keep fuel tanks isolated from each other in case one is contaminated.
Originally Posted by
custardpsc
And the fuel selector on low wing doesn't have a 'both' because in a low fuel situation it would prefer to suck air from the empty tank , rather than fuel being drawn from the tank with fuel remaining. ...
Aha! I did not know that. Again super helpful for me to understand these things. I guess that means that a dodgy fuel gauge on a high wing is not much concern if the tanks have been dipped, but more problematic on a low wing.