That’s a great quick visual reference Raynen - thanks.
LATER . . .
Right, I’m getting somewhere now. They basically Frankensteined another fuel system to create the F/A-18 fuel system. We have fuel being sent to Centre Tank Reserve tanks and Right Reserve Tanks, etc; tanks that don’t exist in the F/A-18.
No wonder it’s a mess.
Making slow progress down this particular rabbit hole.
The weather outside continues miserable so might as well continue on down.
They’ve got it someways right - they just haven’t deleted out the the bits they should have done.
Everytime I start getting overwhelmed by the complexity I go and take a quick look at the Fuel System .cfg for the B748i and feel better.
That’s the feeling I was getting from what little programming knowledge I have. “InputLine=ReserveTank3, where in the world did ReserveTank3 come from?”
FWIW can confirm left engine out after reaching “Bingo fuel” on first flight on Saturday (?). Enjoyed the challenge of finding an airport below the clouds w/o knowing how to work the avionics, saw dense traffic ahead, figured there must be a major airport and landed parallel to another F/A-18 on the other runway and among all the Airbus drivers in (“Huh? How did I get here so fast?”) EDDF.
So, some success today.
We now have Centre Tank 1 and 4 correctly transferring to Centre Tanks 2 and 3 - remember - ONLY Tanks 2 and 3 supply the engines (so it is these tanks that MUST remain with fuel after all the others have been emptied after transferring their contents to 2 and 3.
And we now have Left Wing and Right Wing Tanks topping up Tanks 2 and 3!
This means that Tanks 2 and 3 will have the last drops of fuel in them when all the others have been emptied and their contents turned into hot exhaust gasses.
I have also attempted to rationalise transfer rates to prevent rapid upset of C of G - which I had noticed as a consequence of the erroneous transfer process.
The pictures below were taken taken approx 20 secs apart and you can see at a glance we have successful fuel transfer from the wing tanks to those all important Tanks 2 and 3. Tanks 1 and 4 have already emptied themselves into Tanks 2 and 3.
It is worth noting that in Afterburner mode the fuel transfer is unable to keep pace with the Fuel Flow to the engines and therefore - although use of Afterburner is perfectly fine pilots should keep an eye on this fact and to moderate use until supplies have built back up in Tanks 2 and 3 from replinishment from the wing tanks. I’m looking at speeding up Transfer rates from the wing tanks and I’m looking at ways to keep Balance Transfers between Tanks 1, 2, 3 and 4 to not only keep good stocks in Tanks 2 and 3 at all times but to keep the C of G from going too far north or south of Datum.
There’s still much to do but at least we now have ALL fuel ending up in Tanks 2 and 3 - so that if THEY go dry - then you’ve burned the lot and it’s probably time to lose some altitude and speed and punch out - because you’ve only got yourself to blame!
I’ve started a similar post a few days before this one (F-18 can't use fuel from all tanks). But, as the involvement and progress being achieved here is much greater, I would ask some moderator to merge my topic into this one.
Starting a flight with 100% fuel, the plane can’t use fuel from every tank, specially the auxiliary wing tanks. Also, the consumption from the tanks doesn’t seem to be flowing correctly, since the left engine starves much earlier then the right engine. When the left engine is starved, if I look at the fuel menu, the tanks seem to be very unbalanced, indicating the flow may be incorrect. This problem is very similar to the 747 which also can’t consume the fuel in its auxiliary tanks.
Steps to reproduce:
Spawn with 100% fuel
Fly until left engine flames out
Look at the fuel menu and note that auxiliary tanks are at 100% and internal tanks are being consumed unevenly.
Ah, so that’s what’s going on. I’ve had two flights trying to get from Fallon to Miramar overflying Nellis. It’s easily done in one flight according to the cruise page but on both flights the port engine failed with indicated fuel around 5klbs and the starboard engine gave up just under Bingo set at 4.5k.
Engine damage and random failures were turned off so it shouldn’t have been overstressing the engines that did it (I was pushing into a supercruise for most of it).
I’ve observed the tank flows a little more. There is a fuel page on the MFDs that shows every tank in real time.
It seems that each engine takes fuel from one of the side fuselage tanks (left and right). It seems that the front and back tanks are pumped to the side tanks, but with an emphasis to the right tank, making the left engine starve first by design. Now that I though about it, it makes sense. It puts the plane in a enforced economic mode if the fuel is so low.
The problem is that the wing tanks are never pumped in, just like the stock 747. More than a year after launch and this problem not only persists, it seems to have been replicated in a new plane.
There are some key bindings for several fuel transfers. Some I remember were used in the late Concorde (may it rest in peace, unless it returns). With luck and patience maybe we can find something that works.
Good CassiKess, yep, that’s basically what’s going on. I’ve managed now to get ALL tanks transferring in to Tanks 2 and 3 - including the Wing Tanks - as they MUST.
The delicate operation now is to try and balance those transfers so that Tanks 2 and 3 remain at equal quantities to each other so neither engine quits before the other - but also that we retain a workable C of G within Limits.
Well, that’s my work cut out for tomorrow.
Keep the ideas coming. If testing make sure Engine Damage and Unlimited Fuel is OFF, etc. All the obvious stuff - but with the current BUG where ASSISTANCE keeps reverting to EASY - One has to check before each and every flight.
I have no idea how an F-18 manages its fuel, but after overcoming the surprise of the left engine starving, I gave it a thought and figured it might make sense if we admit that it could be an automatic and compulsory low consumption state to try to make the plane endure enough to get to base. So, I’m quite satisfied with the behavior you described above (drooling to get my hands in your mod).
By the way, I only got the EASY settings in assistances the first time I launched after the GOTY update. Now the sim seems to be keeping all my settings between sessions.
On the real F/A-18 there’s a FADEC but in terms of Fuel Management - it’s down to you, the pilot, and of course - the nature of the Sortie you’re flying.
There are various Flight Fuel Configs that you’ll deploy from - FULL POWER AFTERBURN (GET ME OUT OF HERE NOW!!!) down to MAX CONSERVE - which does what it sounds like - lowest possible fuel consumption for distance traveled.
The problems we face in providing fuel is to ensure the correct amounts are in the correct tanks at the appropriate time in the Sortie whilst maintaining a serviceable C of G condition appropriate tor the flight path and vector and load out.
It’s fascinating exploring this stuff and it’s pushing me ever closer to actually signing up to that Aeronautics Degree course I’ve been promising myself I’ll do for years now.
I mean - if you look at a typical Sortie for a Carrier based F/A-18 - you can see Fuel Demand plotted as a parabolic curve on the Mission Duration from start to finish. . .
It’s incredible and the fact that we’re here, collaborating, in near real-time - in MSFS, exploring this - honing it - to get it correct - is just awesome.
F/A-18C/D fuel system is very different to your scheme, was it changed so dramatically for E/F?
main differences: wing tanks connected with 2 and 3 respectfully; fuel flow between 1-2, 3-4 at bottom level, not top (or maybe your picture does not represent feed level)
Yes - everything got bigger by about 25% but fundementally, no the fuel system in the E/ F is how it is there.
The low level Interconnects are what’s missing in the MSFS Fuel System. Instead it’s done via Line Transfer at a givien rate - which doesn’t out pace the fuel flow.
Luckily the line transfer rates are editable to pretend the Interconnects are present.
Just to clarify then, the f18 modeled in MSFS should have the fuel system as depicted in thealx2901´s scheme above?
I´m dabbling myself on this too, all was going fine until the sim started to CTD. It turns out that any error in the cfg file seems to lead to a sim crash… bummer.
Are you working within the editor (developer mode) or just modifying the file by hand?
Pretty much yep - 4 center tanks inline and with Interconnects and the two wing tanks - we don’t have EXT’s to worry about yet! -
Using a bit of both - Dev Mode and Notepad but yes, absolutely CTD if you get it wrong - like some hideous thug standing there with a club ready to do you over head the minute you put a “;” in the wrong place.
Tedious isn’t it?
