Bug? Fuel Burn.
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Hi all.
Is the aircraft consuming fuel on the ground while connected to external power? Is this expected behavior? (XBOX Series X - MSFS 2020).
Alan / From Brazil
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Do you possibly have a fuel leak failure? Or are you possibly looking at fuel transferring via gravity from the auxiliary tanks to the main tanks?
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Do you possibly have a fuel leak failure? Or are you possibly looking at fuel transferring via gravity from the auxiliary tanks to the main tanks?
@Black-Square said in Bug? Fuel Burn.:
Do you possibly have a fuel leak failure? Or are you possibly looking at fuel transferring via gravity from the auxiliary tanks to the main tanks?
There are no active failures. Right now, for example, it didn't happen. It seems intermittent. Could you explain when exactly this gravity-based transfer between tanks is supposed to occur?
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@Black-Square said in Bug? Fuel Burn.:
Do you possibly have a fuel leak failure? Or are you possibly looking at fuel transferring via gravity from the auxiliary tanks to the main tanks?
There are no active failures. Right now, for example, it didn't happen. It seems intermittent. Could you explain when exactly this gravity-based transfer between tanks is supposed to occur?
@alanfernandes My Starship knowledge is a little rusty, but I think it should happen at all times.
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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.
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
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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.
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
@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.
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.
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@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.
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.
@alanfernandes that essentailly tracks with my own (amateur sim pilot's) understanding based on the POH. Gravity flow is one-way only (like the Lear). In sim, you can manually simulate the 100 gal at-a-time, but if you refuel using GSX it fills both sides simultaneously. I don't know offhand if GSX could be configured to simulate Starship's actual procedure, that would be pretty cool. In the Lear, you fill the tip tanks from the EFB app, and waaaaaaiiiitttt for it to drain into the wing tanks. It does take a while there if you do it the "right" way.
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@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.
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.
@alanfernandes said in Bug? Fuel Burn.:
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.
I recall discussing this in one of my videos. Here is what I said in the manual:
"Most of the fuel in the aft tanks will transfer to the main tanks by gravity, and the rest can be transferred by the aft tank transfer jet pumps. Should the aft tank transfer jet pumps fail, the total usable fuel may be reduced."
Here is what the Flight Safety manual says:
"Although a small amount of fuel may gravity-feed from the aft tank without the motive-flow system, the pilot should consider all fuel in the aft tank as unusable and plan the flight accordingly."
Without looking right now (sorry, I'm leaving to record sound from the Twin Commanders in a few hours), I recall that I assumed this statement was made out of abundance of caution, and implemented the system such that it would slowly equalize to a certain point, so long as the jet pumps had not failed (emulating a blockage). Given the arrangement of the jet pumps and their no-moving-part nature, I assumed that there would be flow through them, so long as the pressure on the auxiliary tank side is high enough.
