Different values of fuel flow

[Eugene Kremlev]

I see this picture. The gauge on instrument panel has a lower fuel flow than the SHIFT+2 window shows. Different is 1 gph nearly (9.6 on gauge - 10.4 in window). The fuel flow gauge is OK in the hangar. On other models data from SHIFT+2 window and the data on the fuel flow gauge are almost identical. What could be the problem? And what fuel consumption in this case will be real?

[Caldemeyn]

Hmm...have you tried to tap the gauge a couple times ? Also, maybe the value is not great enough to register in the hanger as a fail yet ? Other models don't have this gauge wear mechanic implemented...yet they show no discrepancies so thats a lead to this new feature at least, i think.

[Nick - A2A]

Yes, I believe any small discrepancies could be explained away by the simulated gauge physics. For example, in my installation of the Bonanza which only has about 62 hours, the difference between the Shift 2 panel and the gauge seems to be about 0.5 or 0.6 gph.



In this case, the Shift 2 panel reports the actual variable from Accu-Sim, so should be the more accurate.

Thanks,
Nick

[Eugene Kremlev]

Wow, Bonanza surprises more and more! I have 60 hours but difference between gauge and Shift+2 panel was from the start. Yep, I tap the gauges.

[EnDSchultz]

I've replaced my fuel flow gauge at least twice in 150 hours, as before long it ends up reading a few gallons too low. It may or may not need to be tweaked because this seems like a rather extreme rate of degradation.

[Eugene Kremlev]

I've replaced my fuel flow gauge at least twice in 150 hours, as before long it ends up reading a few gallons too low. It may or may not need to be tweaked because this seems like a rather extreme rate of degradation.

Well my instrument panel is fully functional in the hangar. No "red" gauges.

[Oracle427]

The fact is that the real instrumentation is not super precise. There are analog sensors that are not perfect and then there is degradation of the information as it is sent to the guages in either an analog or digital format. The fuel for sensor is a small turbine in the fuel line that rotates and generates electrical pulses. The rate of pulses per second is then translated to a full flow rate.

This also assumes that the fuel flow sensor are calibrated correctly in the first place and that usually requires several long test flights in individual aircraft. The diameter of the fuel lines, the position of the sensor along the fuel lines and the type of sensor all play a role in calibration.

I would argue that a figure within .5 GPH is great and as good it will probably get IRL.

[AKar]

The fuel for sensor is a small turbine in the fuel line that rotates and generates electrical pulses. The rate of pulses per second is then translated to a full flow rate.

And that's the fancy version. The regular old-school one simply responds to the fuel pressure while the gauge face is in units of flow. That's fine, but it reads somewhat dangerously in the wrong direction in case of any issues: with obstructed injector, for instance, the meter indicates high whereas the actual flow goes down.

Indeed, it is good that flight simulators start to deal with inaccuracies of real life. Even while a hi-tech Airbus may indicate, say, 821 °C TGT...well, it really isn't. Or can be, but more likely isn't. This applies to just about every measurement.

-Esa

[Eugene Kremlev]

So, after the difference in fuel flow between the gauge and the Shift-2 increased to 2 gph (70 hours), the inspection in the hangar showed a faulty fuel flow gauge. But one nuance - the fuel flow gauge was not repaired manually (singly) no matter how much I tried, only a "repair all" helped. it's the capital of simulations