Daifly, Re your fuel burn question:. .Most aero engines still use carburettor's, although late model engines use fuel injection.. .I suspect you think the height of the fuel above the carburettor can effect the fuel flow through the carb, and therefore the fuel consumption. Not true. (It is true that the height above the carbutettor will increase the fuel pressure delivered to the carb marginally, but the volume of fuel available has no effect) The carburettor will control the amount of fuel entering the float chamber via a float controlled valve, the higher the level in the chamber the harder the valve presses aginst it's seat to prevent excess fuel entering the chamber. So the carb will deliver only the amout of fuel it is designed to. Remember, you the pilot, control the air fuel mixture! . .With fuel injected engines, the fuel is always delivered under pressure by pumps to the injection metering unit. The pumps are always capable of exceeding both the volume and pressure needs of the system, so pressure/volume is controled by a pressure relief valve. The excess fuel is returned to the fuel tank. . .White Bear.