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Alright I have seen bits and pieces of this issue talked about here and there, none of which seems to have been answered by any CS staff, or really make any sense for that matter. �If I set Externals 1-2, R-L tip and L-R aux to 0 the plane go's dead. �If I set them to 10% each and 100% on the rest, the plane go's dead. �The only way I can fly this thing without engines dying is by running everything with fuel at 100%. �There has to be something I'm missing or this plane's fuel system is not working correctly. �Can any CS staff once and for all explain how to remove fuel without the engines dying so I don't have to fly a 600nm flight with 100% fuel? Any help would be much appreciated. �By the way, on the Fuel and Payload with fuel at 100% it says that the plane is 20,832 pounds over gross weight? �Is this supposed to be like that. �Again very confusing.

I could be totally off, but are you sure you're drawing fuel from the correct tank?

I believe I am but I might be wrong. �Basically I flew it for a few hours straight to see what tanks it was drawing from first. �It always drained from Externals 1-2, R-L Tips and Center 3 first. �So I set all those at 10%(except Center 3), to see what it would draw from next. �But alas the engines would end up dying out shortly after takeoff. �The only thing that seems to work is to bring everything down to 60% and on a 1600nm flight I had no issues. �Also again in "Fuel and Payload" it says I'm 20,832 over gross weight. �Does anyone else have this? �Again thanks for any info here.

Hi crashbar.

It's hard to explain. So take a look at the two images I have here to see the settings I am using to fly the B-52 with the fuel being fed from the Left Tip fuel tank only. All the other tanks are empty. I was able to do a flight from YMML, out to about 50nm before returning and landing again. I did that using only 7725 lbs of fuel.

This first image show the setting of the knobs. The explanation for the colored circles is on the image but I'll write them here.
The red circles means the knobs are closed/off.
The green circles mean the knobs are open/on.
The yellow circles means I'm not sure if they are in the open/on or closed/off position. I assume they are open/on.
The blue circle shows that this knob is the only one below or beside a fuel gauge that is open/on.

The second image show that all the engines are running using only the Left Tip fuel tank.

Hope this helps

Mark

I believe I do. �So after a tank goes empty I need to close it right? I was also hoping to know what order the tanks empty so I know how to properly add fuel.

I think it is of greater importance to have the fuel flowing from ALL the fuel tanks feeding ALL the engines. That way, there are no engine flame outs. Once a fuel tank is empty, you can turn the Fuel Pump for that tank OFF.

The best way to find out in which order the fuel tanks are used, is to put a small amount of fuel (~100 lbs) in each tank and see which ones empty first.

Mark

Thanks much Mark I'll set up some flights and try to do some thorough tests and Ill post later what I come up with. Thanks again.

There might be something in the manual... I'll read through mine and post if I find anything on the order of fuel draw.

OK well I flew around the Denali range in Alaska. �Took off with everything set to 40% fuel. �I flew about 150km and all but 1 engine went dead because they ran out of fuel, but yet I had 35% fuel left. �I'm sorry but the fuel system here is way to confusing and out of all my add-on planes is the only one that gives me problems. To me the only reason any of my engines should go dead is because fuel level reaches 0%.� Hopefully the fuel will be addressed in patch, but until then I'm grounding the fleet. :'(

My recollection is that once fuel went below 20,000 lbs it was critical to limit bank to less than 20 deg, ie - 20,000lbs is nearly empty. Don't know if CS BUF is so accurately modeled that it duplicates real BUF limits, but BUF fuel mgmt was a bear and required a lot of co-pilot attention. Just the recollection of an old-time BUF vet.

crashbar wrote on Mar 6^th, 2011 at 2:16am:

That's strange, because once I have all the crossflow knobs/switches open/on and the fuel pumps for the tanks, with fuel, open/on, then I never get any engines flaming out. As I showed in the pic, I can fly easily and with all engines running, on one tank with fuel in it.

Mark

Hi All.

I've been doing some experiments with the fuel. What I found is interesting, to say the least.

For the following explanation to work as I say, you need to have the Fuel Valve Switches ON/OPEN as in the image I have included below. The numbers correspond to the numbers near the Fuel Valve that I'm referring to. I have also written the numbers in yellow on the switches (the yellows numbers are the same as the white ones on the panel texture).

CENTER �- feeds fuel to the engines if either of ANY of the following fuel valves are OPEN/ON - 25
CENTER 2 - feeds fuel to the engines if either of ANY of the following fuel valves are OPEN/ON - 26
CENTER 3 - feeds fuel to the engines if either of ANY of the following fuel valves are OPEN/ON - 27, 28
LEFT - feeds fuel to the engines if either of ANY of the following fuel valves are OPEN/ON - 19, 20, 21, 22
RIGHT - feeds fuel to the engines if either of ANY of the following fuel valves are OPEN/ON - 19, 20, 21, 22
LEFT AUX - �feeds fuel to the engines if either of ANY of the following fuel valves are OPEN/ON - 19, 20, 21, 22
RIGHT AUX - feeds fuel to the engines if either of ANY of the following fuel valves are OPEN/ON - 19, 20, 21, 22
LEFT TIP - feeds fuel to the engines if either of ANY of the following fuel valves are OPEN/ON - 23
RIGHT TIP - feeds fuel to the engines if either of ANY of the following fuel valves are OPEN/ON - 18
EXTERNAL 1 - feeds fuel to the engines if either of ANY of the following fuel valves are OPEN/ON - 17
EXTERNAL 2 - feeds fuel to the engines if either of ANY of the following fuel valves are OPEN/ON - 24

Don't worry, it gets stranger.

All the engines can be started or WILL run, even with ALL the Fuel Valve Switches CLOSED/OFF, providing the Main Tank Boost Pump Switches (the four switches under the red covers)are ON AND you have fuel in the Left Aux, Right Aux, Left Main and Right Main tanks. Once the fuel tank providing fuel DIRECTLY to the engines using those Main Tank Boost Pumps is empty, the engines will shut down. This means:

LEFT AUX directly feeds fuel to 1 & 2
LEFT directly feeds fuel to 3 & 4
RIGHT directly feeds fuel to 5 & 6
RIGHT AUX directly feeds fuel to 7 & 8

So basically, if those tanks have fuel and the Main Tank Boost Pump Switches are ON (they aren't OFF in the Cold-n-Dark saved flight), you should be able to get your engines started.

I don't think I have covered it all. There is more there involving Fuel Valve Switches that I have not covered at all. It really is bl**dy complicated. I have no problems setting up the fuel to feed all engines with one fuel tank that I choose to feed from. I just messed around to see what does what and sorted most of it in my head.

Hope this helps.

Mark

I have been building a fuel panel mod with a visual usage tree similar to the -1, I should hopefully have it posted by the end of this week.

First and foremost, it is critical that you install my updated fuel panel textures, they have the correct flowlines and flowbars. The additional fuel panel camera also makes control much easier. (Remember, source-force-and-a-place-to-go)

Second, you can feed any engine from any tank, the only exception that I have found is the aft body tank. For some reason Pylon 3 will shut down if the main pumps are off and it is the only tank available. (Remember, source-force-and-a-place-to-go)

Third, using this acft.cfg fuel tank setup:
[fuel]
//Tank, Longitudinal (feet), Lateral (feet), Vertical (feet), Usable(gallons), Unusable (gallons)
LeftAux � = � �-14.0, �-52.14, � -6.8, � 4905.0, � �6.0 //No. 1 Main
RightAux �= � �-14.0, � 52.14, � -6.8, � 4905.0, � �6.0 //No. 4 Main
LeftMain �= � � �5.6, �-25.68, � -4.3, � 6834.0, � 25.0 //No. 2 Main
RightMain = � � �5.6, � 25.68, � -4.3, � 6834.0, � 25.0 //No. 3 Main
LeftTip � = � �-31.46, -78.9, � �-8.9, � 1160.0, � �7.0 //Left Outboard Wing
RightTip �= � �-31.46, �78.9, � �-8.9, � 1160.0, � �7.0 //Right Outboard Wing
Center1 � = � � 16.4, � �0.0, � -12.3, � 2053.0, � �4.0 //Fwd Body
Center2 � = � � �7.2, � �0.0, � -12.3, � 3240.0, � 12.0 //Center Wing
Center3 � = � � -6.7, � �0.0, � -12.3, �15652.0, � 21.0 //Mid + Aft Body
External1 = � �-23.0, �-77.3, � -11.5, � �705.0, � �5.0 //Left External
External2 = � �-23.0, � 77.3, � -11.5, � �705.0, � �5.0 //Right External

and the -1 fuel usage sequence, the CS B-52 will follow a perfect tech-order fuel burn. It is actually really impressive when you get it right. NOTE: �drop the �Center 3� to 80% in the fuel and payload window prior to takeoff or you will be overweight.

And finally fourth, the ultra-simplified overall concept for the B-52 fuel burn is:

Rules:
1) Main pumps always stay on
2) Main valves (19,20,21,22) always stay closed
3) Crossfeeds (9,10,11,12) stay closed (horizontal) unless any main tank is below 5K

Sequence (Remember, source-force-and-a-place-to-go) :
CTR and AFT to Pylon 1 and 4 -- MAIN 2 and 3 to own pylon for takeoff
On climbout:
AFT and CTR to all pylons till CTR is empty,
AFT and FWD to all pylons till FWD is 3K
AFT and MID (same tank in FSX) till 6K each
AFT and MID to pylons 1 and 4, MAIN 2 and 3 to own pylons till AFT and MID are empty
Mains to each pylon till Green band on MAIN 1 and 4 (10K)
L + R external �to 1 + 4 pylon (respectively) till empty
L + R outboard to 1 + 4 pylon (respectively) till mains are even (10K each)
L + R outboard and FWD to all pylons till empty
Each MAIN to own pylon till 5K
Below 5K in any MAIN, all system valves closed, crossfeeds (9,10,11,12) open (vertical)

For ALL landings / touch and goes (regardless of weight). Takeoffs may be made in this configuration also.
Each MAIN to own pylon till 5K
Below 5K in any MAIN, all system valves closed, crossfeeds (9,10,11,12) open (vertical)

--Dan

Markoz wrote on Feb 28^th, 2011 at 12:40pm:

So, it sounds as if the simulation is not sensitive to center-of-gravity issues...? If I had done something like this in the real world, it wouldn't have been long before I lost control of the aircraft.

TrojanBUFDriver wrote on Apr 18^th, 2011 at 8:16pm:

You had better bet that it is sensitive to center-of-gravity issues. I wouldn't want to try flying this plane (without the help of the A/P), because if the weight distribution is too uneven, it will pull very hard to the heavier side! :D

Mark

CAPTAIN SIM FORUM
B-52 Driver >> B-52 Driver >> Fuel Order https://www.captainsim.org/forum/csf.pl?num=1298763618 Message started by crashbar on Feb 26^th, 2011 at 11:40pm