I've noticed that the fuel gauges do not go down even if the airplane flies thousands of miles.  I've fiddled with all the boost pump switches and the bypass valves and the fuel indicators don't move.  I've reset the aircraft  and tried different variants.  Same thing.

Lordish

Fly for awhile then check the Aircraft>Fuel And Payload. Go to Change Fuel and Payload and then see if the fuel is going down at all (i.e. too see if it's a simulator issue or a gauge one).

Are you sure you don't have unlimited fuel turned on?

boeing247 wrote on Mar 2^nd, 2011 at 6:38am:

Are you sure you don't have unlimited fuel turned on?

It's a good question.

I never had any kind of problems with C-130's fuel gauges. They work fine.

Pinatubo.

Mine work fine too. But I have to watch out that I don't leave unlimited fuel ON because I turn it on when I'm using Weapon for FSX. :D

Mark

Flying the C-130X one of the issues I've noticed is that the fuel is loaded in pounds (US) and the panel is indicating the fuel burn rate in KGPH.   I can fill all the tanks and externals and register a 13,000 lbs per hour burn rate, that is Double what the plane should burn.   1,000 to 1,100 should be normal cruise with maybe 1,500 lbs per hour per engine on climb out.  

I am also experiencing a fuel issue. The aux and external tanks don't seem to do anything. I can have all valves open but these tanks remain at 100% while tanks 1 through 4 go down. It's a little annoying to have to auto refuel when I still have 4 full tanks I cannot seem to use.

LloydC130,

You have to properly manage the fuel with the pumps and bypass valves for the fuel to be taken from the tanks. If you leave all the bypass valves open and all the pumps on, it will take from the main tanks first. then start pulling from other available tanks. If the pumps for the aux and ext tanks are not on, it will never take from them even if they are full. Play with the bypass valves and pump switches to get a feel for what positions they need to be in for the fuel to be drawn from a specific tank. I regularly pull fuel from belly tanks for both engines to balance the main tanks with the wing tanks. About the only thing I have never figured out is how to transfer fuel from one tank to another. I do not think that is possible, but not a problem since you can use any tank to supply fuel to any engine.

Dave

Thanks Dave. I didn't know that the mains had to be empty first. I never waited that long for fear of running dry. I will try this on my next flight. BTW, I did have all the bypass valves open and pumps on. I had assumed that the tank levels would all drop evenly in this config. I'll try it out and let you know if it worked. Thanks for the input.

Lloyd

There was a comment in a thread somewhere about the real aircraft would empty tanks based on pressure differential of the pump. If one pump was a little stronger, it would overide the others. This does not occur in FSX. I normally keep the bypasses closed (Horizontal) and all the pumps on so the engines will draw from their own individual tanks. If I need to balance the fuel I combine the tanks (move valves vertical) and turn off the pump of the tank I do not want to draw from, this causes both engines on a side to draw from the tank with the pump on. The same can be done for the Aux and Ext tanks. Put all the valves on a side to vertical then turn off the pumps on the tanks you do not want to draw from leaving the Ext or Aux tank pump on to draw only from that tank till the level drops to where you want it. Be careful about the valves and switches, as in, don't turn off a pump until you verify another pump is on to replace it. If you turn a valve off and the pump off that engine will have nowhere to get fuel from and die :0

I normally separate the right and left system with the center valve to the off (horizontal) position.

Thanks, I'll try that and see how it goes

Thanks Sieggie, that method works great. Finally I can use the fuel in the ext and aux tanks  :D

In real life, with all pumps on and valves open, the externals and aux's would empty first due to their higher pump pressures (28-40 psi) over the main tanks (15-24 psi). Primary fuel management dictates burning the aux's first then the external before using fuel from the mains. This helps decrease the lifestress on the airframe.


but it is a sim and pretty darn accurate overall...

I have not tried that to see if Capt Sim coded higher pressure on the Ext and Aux tanks. Would be neat but if not just switching off the wing and mains also works fine. You just have to pay closer attention not to empty the ext/aux without turning the wing/main back on or you get to practice inflight engine restarts :0

Dave

TechRep wrote on Oct 14^th, 2011 at 12:35am:

In real life, with all pumps on and valves open, the externals and aux's would empty first due to their higher pump pressures (28-40 psi) over the main tanks (15-24 psi). Primary fuel management dictates burning the aux's first then the external before using fuel from the mains. This helps decrease the lifestress on the airframe. but it is a sim and pretty darn accurate overall...

Are you sure? I've always heard the opposite. Keeping fuel in the wings and in external tanks is important because it reduces the mechanical stress between the wings and the rest of the airframe by putting a significant portion of the weight to be lifted in the wings themselves. An aircraft with one or more tanks in each wing and external tanks, and one or more tanks in the center, must burn the fuel in the center tanks first during flight, only switching to wing and external tanks when the center tanks are nearly empty. With all pumps on and valves open, the center tanks will empty first. CS aircrafts work this way.

Pinatubo.

Uhhhm, thats not the opposite, that is exactly what I said. the aux tanks are the inboard-most tanks on the aircraft. They are burned first. Next come the externals. One reason for this is in the event of a valve or pump malfuntion in the externals, you will always have your mains which can gravity-feed to the engines if needed. this allows you time to divert if you have an external tank system failure that leaves you unable to use the fuel in that tank. You are exactly right (as was I) about keeping the wings heavy by keeping fuel in them. Primary Fuel Management dictates having not less than 6400 lbs in #2 & 3 tanks and not less than 7060lbs in #1 & 4 tanks if the aux's and external have any useable fuel in them. Tanks #1 & 4 should always have 500-1000 lbs more fuel than #2 & 3.
Additionally, symmetrical tanks should be within 1000lbs of each other and each wing collectively shoud be within 1500lbs of the other wing.

But again, I dont think structural wear is an issue on FSX aircraft...
:D

Quote:

the aux tanks are the inboard-most tanks on the aircraft.

Thanks for that very informative information on the Fuel Tanks, TechRep!
I also thought that the AUX Tanks would have been further out. Like near the wing tips.


Quote:

But again, I dont think structural wear is an issue on FSX aircraft...

I guess we have to "pretend" that it is. ;D

Mark

Hi TechRep,

It seems we were speaking the same thing except about tanks nomenclature. As Mark said I also thought that the auxiliary tanks were those near the wing tips. A misunderstanding happens sometimes. If possible I would like to know the correct fuel tanks nomenclature and their relative position into the airplane.

Thanks.

Pinatubo.

PS: Is the diagram below a valid one?

http://www.ntsb.gov/investigations/fulltext/AAB0401/image002.jpg

Easy enough... Add the following link (can't put the whole link since I have fewer than 10 posts)
avsim.com/pages/0308/C130X/ace%20fuel%20loader%20with%20external%20tanks.jpg

I checked my currect C-130 ACE and fuel is not an option in the preflight section, but this picture accurately describes the tank name and location.
Though almost all C-130H's were delivered with external tanks (under the wing), very few J's were delivered with them. there simply wasn't the need as the engines were more efficient and could carry out the same range as an H withou the additional 18k of fuel.

I'm not sure when or how the Fuel configuration got removed from the ACE. Is it just me?

I guess the above diagram is correct, though I'm not sure what airframe it is. Typically you see main tanks in the wings. externals are usually pods hung below the wings. Aux tanks can be just about anywhere else.
There is also an internal fuel tank that can be on or offloaded to carry additional fuel, but those don't see much use anymore. The ones we used in the Navy were specifically for carry fuel as the cargo. The tank is plumbed into the aircraft fuel system.

One of the issues with CS-130 is it really doesn't reflect the real plane exactly.   Yes the Aux tanks are inboard of #2 and #3 Engines, Main tanks 1 and 2 are Left wing and Main Tanks 3 and 4 are right engine.

Typically the Aux tanks will hold 855 Gallons/5814 lbs, The Externals that hang under the wing between the engines will hold 1309 Gallons/8901lbs and the main tanks will be different on each wing..
#1 and #4 Will be 1222 Gals/8310 lbs
@2 and #3 will be 1126 Gals/7657 lbs

Aux tanks are not always used in the plane.  (CS C-130) For the Aux tanks to drain first is kinda intersting since each engine is directly tied to a main tank (with boost pump) and the aux tanks have to feed the manifold to get to repective engines.  my understanding is real plane you have to transfer fuel to the main tanks from the Aux tank and the same with externals they do not feed directly to the engines.   They are to supplement the Main tanks.  

Now the J model thats a whole new animal and CS hasn't configured the model accurately either internal instrument panel or systems operations.   All the C-130J's models CS has installed still uses instruments and specs from E/H world.   Engine thrust, Fuel usage, prop dynamics are not J model.   Real world yes J's don't need externals, CS world probably since its a fuel hog.