@MarkS said in Bug? Fuel Burn.:
This excerpt from the Starship Pilot's Operating Manual, page 3-22, seems to indicate that the gravity transfer is always active, unless of course the aft tank is full, in which case transfer would occur once fuel started being drawn from the aft tank.
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This is somewhat similar to the fueling on the Learjet 35A, where you only refuel into the tip tanks, and the tip tanks gravity feed into the wing tanks if room exists in those tanks.
Link to the POH on Bob Scherer's Starship Resources site: Starship Pilot's Operating Manual
From what I've gathered from the manual, the aircraft's fuel system consists of four tanks: a main tank set (divided into forward and aft compartments) and one auxiliary tank in each wing. On the ground, refueling must prioritize the main tanks over the auxiliary ones, observing an alternating pattern between the wings in increments of no more than 100 gallons to maintain aircraft balance. Although fuel flows by gravity from the forward to the aft compartment within the main system during refueling, there is no gravity transfer between the auxiliary and main tanks. In flight, this transfer relies exclusively on jet pumps operated by engine motive flow, which renders the fuel in the auxiliary tanks unusable should the pump system fail. Each system has independent filler ports, requiring the main and auxiliary tank caps to be handled separately.
