Originally Posted by
Lead Balloon
Then...
It seems to me that there must be components in the fuel system on a Chipmunk that mitigate the risk of air being drawn into the fuel system due to one tank emptying before the other.
Either that or the design somehow manages to position the fuel selector and inlet to the fuel components of the engine below the outlets from the tanks.
Rather than endless, unproductive PPRuNe speculation, the answer can be given by someone with first-hand knowledge of the fuel system 'plumbing' and components on a Chipmunk.
Looking at the fuel system schematics on the Chipmunk they do seem to have solved this by having the fuel selector position lower than the tanks. So there is still a gravity feed to where the lines join and the selector, from the sump outlet, as well as built in non return valves in the tank outlets.