Version: 1.0.77.0
Frequency: Consistently
Severity: Blocker
Marketplace package name: C-22J Ventura
Context: C-22J Ventura MSFS-2020, community folder
Similar MSFS 2020 issue: Works in FS-2020
Bug description: Modern FUEL_SYSTEM: fuel lines connecting to the engines drain. If the throttle setting is large enough, they will empty and starve the engines. Then they instantly jump back to 100% and the cycle repeats.
Repro steps: Using the C-22J Ventura package, and advancing the throttles, the engines will shut down, then re-ignite. This is because the fuel lines connecting the fuel valves to the engines drain of fuel. This does not happen in FS-2020.
Note 1: it was thought that this was due to the absence of the “Version=” parameter within the FUEL_SYSTEM section, but this has been tested not to be the case. The FUEL_SYSTEM was tested with different values for “Verion=” (max 5) in both simulators simultaneously, and it always worked in FS-2020. It never did in FS-2024.
Note 2: increasing the volume of the fuel lines connecting to the engines allows it not to drain. However this is behaving different than FS-2020.
Note 3: At lower throttle settings this does not happen.
Note 4: none of the other fuel lines drain out.
Note 5: The lines that show volume 0.000 are actually 0.0002.
These jet engines are very tiny, hence I reduced the fuel in the lines to have reasonable sut-off times when a valve is closed (in reality, if a valve is closed, the fuel may hydraulically lock, as no air can enter the system past the valve, and the engine cannot consume this fuel)
Two screenshots form FUEL_SYSTEM debug illustrate the problem:
After draining to zero, the two fuel lines LMPump2Eng & RMPump2Eng instantly return to 100%. If throttle setting is high enough, they will drain to zero and the cycle repeats.
The gravity flowrate for these lines is slightly more than 2x larger than the maximum fuel flow at 100% throttle.
FUEL_SYSTEM CFG:
FUEL_SYSTEM]
Engine.1 = Name:LeftEngine #Index:1
Engine.2 = Name:RightEngine #Index:2
Tank.1 = Name:Center1 #Title:Collector Tank #Capacity:1.0 #UnusableCapacity:0 #Position:0.00,0.00,0.00 #Priority:3 #InputOnlyLines:LeftMain2Coll,RightMain2Coll #OutputOnlyLines:Coll2LShut,Coll2RShut
Tank.2 = Name:LeftMain #Title:Left Main #Capacity:38.3 #UnusableCapacity:0 #Position:0.940,-7.382,0.7644 #Priority:2 #InputOnlyLines:LeftTip2Main #OutputOnlyLines:LTank2Valve
Tank.3 = Name:RightMain #Title:Right Main #Capacity:38.3 #UnusableCapacity:0 #Position:0.940,7.382,0.7644 #Priority:2 #InputOnlyLines:RightTip2Main #OutputOnlyLines:RTank2Valve
Tank.4 = Name:LeftTip #Title:Left Tip #Capacity:18.5 #UnusableCapacity:0 #Position:0.566,-14.632,1.138 #Priority:1 #OutputOnlyLines:LeftTip2Main
Tank.5 = Name:RightTip #Title:Right Tip #Capacity:18.5 #UnusableCapacity:0 #Position:0.566,14.632,1.138 #Priority:1 #OutputOnlyLines:RightTip2Main
Line.1 = Name:LeftTip2Main #Source:LeftTip #Destination:LeftMain #GravityBasedFuelFlow:260 #Volume:0.005
Line.2 = Name:RightTip2Main #Source:RightTip #Destination:RightMain #GravityBasedFuelFlow:260 #Volume:0.005
Line.3 = Name:LeftMain2Coll #Source:LBalValve #Destination:Center1 #GravityBasedFuelFlow:220 #Volume:0.005
Line.4 = Name:RightMain2Coll #Source:RBalValve #Destination:Center1 #GravityBasedFuelFlow:220 #Volume:0.005
Line.5 = Name:Coll2LShut #Source:Center1 #Destination:LeftEngineValve #GravityBasedFuelFlow:120 #Volume:0.0002
Line.6 = Name:Coll2RShut #Source:Center1 #Destination:RightEngineValve #GravityBasedFuelFlow:120 #Volume:0.0002
Line.7 = Name:LShut2LEPump #Source:LeftEngineValve #Destination:LeftElecPump #GravityBasedFuelFlow:120 #Volume:0.0002
Line.8 = Name:RShut2REPump #Source:RightEngineValve #Destination:RightElecPump #GravityBasedFuelFlow:120 #Volume:0.0002
Line.9 = Name:LEPump2LMPump #Source:LeftElecPump #Destination:LeftEngPump #GravityBasedFuelFlow:120 #Volume:0.0002
Line.10 = Name:REPump2RMPump #Source:RightElecPump #Destination:RightEngPump #GravityBasedFuelFlow:120 #Volume:0.0002
Line.11 = Name:LMPump2LEng #Source:LeftEngPump #Destination:LeftEngine #GravityBasedFuelFlow:120 #Volume:0.0002
Line.12 = Name:RMPump2REng #Source:RightEngPump #Destination:RightEngine #GravityBasedFuelFlow:120 #Volume:0.0002
Line.13 = Name:LTank2Valve #Source:LeftMain #Destination:LBalValve #GravityBasedFuelFlow:120 #Volume:0.005
Line.14 = Name:RTank2Valve #Source:RightMain #Destination:RBalValve #GravityBasedFuelFlow:120 #Volume:0.005