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fuel-qty switch is bugged


Shepherd

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Only tried single player - The fuel-qty switch has no function.

 

The fuel gauge reads fuel levels no matter the condition of the switch. When the switch is in the off position the gauge works as if it is switched to on.

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I think this is correct operation. The switch activates the fuel metering device which measures what actually goes to the engines and decreases the indicator accordingly. The fuel gauge does not measure the fuel in the tank like a car does. Instead it is set before flight and "counts down" from input from the fuel metering.

 

I remember older versions of the Shark that behaved like you're describing, but I believe the current behavior is correct. The test if it's working or not is not whether the gauge moves when you turn it off or on, but whether the fuel level decreases as the fuel is used. If the fuel level decreases with the switch to OFF then it is possibly a bug.


Edited by dillio
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It's working as intended. If switched off, you won't notice fuel going down over time. Nothing more.

TASK / ROLES acronyms guide

Black Shark A.I. datalink guide illustrated (v1.2.4 Available on Wiki)

DCS World Codex 1.1 : full units list (Speed/Weapons/Armor thickness/Threat zone/Weapon damage...) (Oct 2013)

BlackShark 2 1.2.x Bug and glitches thread (v1.2.7)

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Page 13-17 of the manual.

 

M63GMfX.png

 

Item 6. Fuel quantity is metered at the tanks, like in car. If it was metered at the valves, you wouldn't see the needles move while the aircraft is fueled up, or as the tanks are emptied by asking the ground crew to remove fuel.

 

But yeah the needles won't move at all (up nor down) when the proper switch is turned off, so it's working as intended.

 

If you refuel with the switch off, or fly for some time, the needles are only going to update when you turn it back on.

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Item 6. Fuel quantity is metered at the tanks, like in car. If it was metered at the valves, you wouldn't see the needles move while the aircraft is fueled up, or as the tanks are emptied by asking the ground crew to remove fuel.

 

Right, good point. I was thinking about how this would work and why the needles would move with fueling. However, I don't know about your car but mine does not meter fuel at the tank, it just has a "sending unit" to measure and report the amount of fuel in the tank. There's different ways to do this but I think mine has a float on top of the gasoline. (I have a pretty old car!) :thumbup:

 

I don't think the Shark has this manner of fuel measurement. Only the fuel meter to keep track of what goes in and out of the tanks. If the meter is turned off while fuel is moving, the indicator will not be accurate.

 

This is just the kind of detail in this simulation that still blows me away after all these years! I've been flying the Shark since about 2010 and I can still learn about something like this. To me the Ka-50 is still the definitive DCS module.

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It does, just not using a float. It uses a capacitive fuel level sensor in the forward and aft tanks.

 

I couldn't find this in the manual, are you sure? If this is so then why can't the fuel qty gauge read independently of the fuel metering system?

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That's fine but my question stands: if the fuel qty is measured by capacitance in the tanks then why don't the gauges read from that measurement? What is the purpose of the fuel level sensor if not for pilot indication? Is it just for the 110 kg warning?

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If this is so then why can't the fuel qty gauge read independently of the fuel metering system?

 

I'm not sure what this means exactly, please forgive me. The fuel gauges read what they are told to read based on the output of the fuel level sensors. I'm not sure what you mean by "metering system" unless you're referring to the manual on page 6-80 where it says "Fuel metering system ON/OFF power switch". Maybe it's a translation issue? The Russian word "ТОПЛИВОМЕР" translates to "Fuel Gauge", not Fuel Metering System.

 

if the fuel qty is measured by capacitance in the tanks then why don't the gauges read from that measurement?

 

They do.

 

What is the purpose of the fuel level sensor if not for pilot indication?

 

That's exactly what it's for.

 

Is it just for the 110 kg warning?

 

They do that as well.

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What you're saying seems to contradict the behavior in the sim, and what was explained earlier in the thread. "Fuel Metering System" is how it's described in the DCS BS2 English manual, see page 6-80 (154 of the PDF) for an example. Thank you for offering your real-world experience to help explain.

 

As I stated before, my understanding based on the sim and the manual is that the gauges are controlled by a flow-sensing system that "meters" the fuel, that is to say counts what goes past the sensor and decrements the fuel gauges accordingly. This matches the behavior in the sim where the gauges only move when the system is on. If you run the engines or add fuel to the tank with the system off, the gauges do not move to report the fuel movement. If you then turn the fuel meter on, the gauge DOES NOT change to report the accurate fuel level. This was mentioned a few times farther up this thread.

 

Again, I appreciate you sharing your RL experience to help me understand! :smartass:

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Okay I understand a bit better now. You're referring to a flow meter that tells you how much fuel has gone through the flow meter, usually placed in fuel lines on their way to the engine. The Ka-50 doesn't have such a thing. If I remember correctly, the gauge moves properly when the gauge is switched on but "sticks" when the gauge is switched off. That is proper behavior. Lots of cars do this exact same thing. When you turn the car off, the fuel gauge "sticks" at the level when the car was switched off, if you then put fuel in it then turn it back on, the needle should move to the correct position. Does this not happen in-game? I'm probably mis-reading something. In other words, the fuel gauge in the aircraft should show the correct fuel level any time the switch is in the ON position and should "stick" any time the switch is OFF, but then return to the proper level indication when turned back ON. If that's not what happens then there is probably a bug to be reported.

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Welp, I stand corrected. I sat down and tried a few things and the behavior of the fuel gauges is NOT AT ALL what I said it was. As AlphaOneSix described above, the needles WILL sync with the actual fuel qty when power is applied. I was remembering wrong or maybe thinking back to the older implementation from BS1. Anyway, big thanks to A16 for patient explanation, and a big facepalm for me! :doh:

 

Meter, metrology, monitor, measure.

 

There exist in some aircraft gauges which work on subtraction principle but nothing about the phrase "metering system" suggests any specific method. Metering system is a generic term.

 

I see your point but I think in the context of fluid moving in a mechanical system, most people would agree that "metering" as a verb refers to the measurement of flow in terms of volume over time. In some applications the term "metering" also means the regulation of flow; for example in some fuel-injection systems the "metering device" is the module that actually delivers the precise amount of fuel for each intake cycle.

It may not be linguistically "wrong," but I think in this case I think it's not the best choice of translation. As AlphaOneSix said above, "Fuel Gauges" would be clearer than "Fuel Metering" even if you don't make the association that I did. But I love the Russian aircraft and ambiguous translation is all part of the fun! Sometimes it even kills you, wheeee! :pilotfly:

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Meter, metrology, monitor, measure.

 

There exist in some aircraft gauges which work on subtraction principle..

 

The gauge is just a display - in some aircraft(e.g. MiG-29) both principles are employed and can be displayed by the same gauge.

 

..but nothing about the phrase "metering system" suggests any specific method. Metering system is a generic term.

 

Yes but then "indication system" would probably be a better one :)

JJ

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Like @AlphaOneSix said, and it's even implied in the drawing.

It can be a sensor, or a sliding float, but what is measured is the level, not the quantity of fuel that leaves the tanks and goes to the engines.

 

The gauges do read from the fuel level sensor ("quantity transmitter"). When you perform high G and angle maneuvers, you'll see the needles jump around - as the gas is shaken around and 'washes' the sensors, making it appear that the tank is full (or empty) for a second - sometimes it'll trigger the EKRAN warnings (rear tank 110, etc) even if the tank is half full.

 

Only, the needles will not move if the switch is off. But they will go back to showing the correct amount of fuel (in kg, calculated from the measured level at the tanks) as soon as you turn the switch back on.

 

Regardless of fuel having been consumed while the switch was off. As long as it's on, it'll always show the correct amount.


Edited by Sh4rk
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