Hallo John,1. I mean, that i cannot visible empty the left tank in the right one.BTW. With both selectors on eg. left main, this tank empties, while right and center remain full, vv.Of course this is not real crossfeed, but what the heck.You really get imbalance and warnings (FUEL CONFIG) and you can correct this.The is only a control to see if everything is working properly,....and it does!2. The 767 has 6 fuelpumps, Left and Right FWD and AFT, Left and Right Center.The nr 1 and 2 Elec fuelpumps must be on to get Fuelpressure.This value works as a trigger to SET the FUELSELECTORS.Nr 3 and 4 are not functional but i need them for some logic:When 1 and 3 are OFF, you have a left engine failure.When 2 and 4 are OFF, you have a right engine failure.Pressing nr 1 (Left Aft) on, SETS the SELECTOR to "2", Left Main.Pressing nr 2 (Right Aft), SETS SELECTOR_2 to "3", Right Main.Pressing nr 3 (Left FWD pump) is necessary to start the APU.Nr 4 (Right FWD)is only functional with nr 2, the failure!The Center pumps are "dummy's", real switches though!, but no pumps.Pressing them SETS the SELECTORS to 6, Center tank.BTW. using the X-Feed commands, SET SELECTORS 14&15, works ok.Both engines are using then either Left or Right main tanks.3. Boeing needs a few 100 man to build a 767 and i'm all alone.So there is no plane/panel (yet).Jan"Procul Negotiis"

I see it mentioned the Concorde is the only AC that can transfer fuel. I wonder if one of the UNKNOWN switches in AIR files controls this. Looking at Concorde-RF.air using my *current* Aired.ini, I see the second parameter in REC 1522 is set True. The Info suggests only the Concorde has it set True. Incidiently, Parameter one of REC 1522 is "Thrust Reverser Available". It might be set in aircraft.cfg in FS9. Unknown Bool 1516 (was Concorde Speed Table) is also True. That appears to be Concorde specific. There is also a small change the Bool in really an Integer that controls several functions, depending on '0, 1, 2, ...'. Incidently, Bool 1517 is "Variable CG Limits". So, there are only two likely unknow parameters in the AIR file that could affect fuel transfer. One might add those records or Bools to any AIR file that one wants to use the Concorde Transfer Pump with. And, experiment to see if they have a effect. It could also be that the Concorde "Airframe Type" (5943) affects this. We know that Type number increased default SFC from 0.5 to 0.7, and also forced the Concorde Overspeed warning On. It also makes PPH increase greatly when Reheat is turned on. I installed the FS2 Concorde into FS9 and it added the common new lines in aircraft.cfg. I got a warning about loading the .mdl, but it seemed to work OK. LG and Nose moved. The Yaw Damper was dead, even though I set the 'Yaw Damper Gain=1.00' in aircraft.cfg. FS9 includes a Concorde.gau file in gauges. It is the same length as in older FS versions. Howver, a COMPARE showed a lot of changes. Perhaps one simple change in the source moved bin around in the DLL, the panel and gauge worked OK (but for the lost Yaw Damper). Ron

I looked into it and made a gauge ( way over the top !!!! ) That shows how the center transfer can happen. ( Notes in the XML )It works somewhat right for the DC9-41 I think ????? Thats the closest you can get I think.. Probably can be written much lees complicated too.It still hinders us all.. For years now this X-feed transfer bug has been there.ATTACHED -> A ZIP of A TEST GAUGE SETUP.Regards,RomanGREEN BAY PACKERS][/i :-ukliam :-beerchug

>I looked into it and made a gauge ( way over the top !!!! )>That shows how the center transfer can happen. ( Notes in the>XML )>Regards,>Roman Very good. I'll give it a try. Ron

Ron,Great code sample! (...I'll be testing it out later tonight)I want to touch again on the cross-feed functions in FS. "Left to Right" and "Right to Left" when using the FUEL_SELECTOR_SET commands.I'm hearing from multiple sources that "it's not currently possible to do cross-feeds" while at the same time others are saying "it is possible to do cross-feeds."Some have suggested that a bug exists that causes problems when using the Left Main and Right Main tanks in a system and to get around the bug it was recommended to use External1 and External2 instead ...and the cross-feed commands will work. How? (I was under the assumption the left to right was hardcode for exactly the left to right tanks)If I'm understanding this ...the left to right command will send fuel from the left tank fuel directly to the right engine. If so, isn't setting FUEL_SELECTOR_2_SET to draw from the Left Main tank doing the same thing? What is the differance between these two options?Also, could you explain in more detail what the X-Feed bug really is?Thanks,John

Roman, the compliment on the code sample was meant for you.Ron, your support is also greatly appreciated.John

Roman,Listen to this: I had started a small Excel spreadsheet at work today to map out the various Fuel Pumps states and how they could be coded using the FUEL_SELECTOR_SET commands. My matrix is very close to what you have coded in your sample gauge.check it out.

Hi Guys,Yes your sheet is very close :-) Here is a new test gauge.. Crossfeed is available.. Better notes in XML.Couple Notes -- -- The switches donot do anything inside FS.. Just give their logic states. ONLY TANK SELECTORS ARE USED IN FS sans AN OPTION FUEL VALVE OPEN see XML. That leaves actual fuel pump switches in FS still avaiable for logic / pressure etc...The TANK SELECTORS are driven by the logic states of switches and fuel %age.-- The pedestal valve is NOT the FS Fuel Valve just logic for TANK SELECTORS. -- There is an auto-leveling involved for ALL (3), LT CTR, LT RT. If there is an imbalance of over 0.5% it will try to level them out before switching to center. -- Tried to make autolevelling work for LT and RT only available.. ( THATS A TUFF ONE.) -- THIS IS ALL OPEN SOURCE, USE AS YOU'D LIKE.. Just mention a kudos if used in your project..Regards,RomanGREEN BAY PACKERS][/i :-ukliam :-beerchug

Harry,YES! Would like to take a peek at it too! :-) Regards,RomanGREEN BAY PACKERS][/i :-ukliam :-beerchug

>Roman, the compliment on the code sample was meant for you. As it should be! >Ron, your support is also greatly appreciated.>John I will certainly play with Roman's tank switching code. Some 'front end' logic might make it very general. BTW, it's been said here you can't add fuel to a tank. That old TC-FuelStat.gau could dump or ADD fuel. It was for FS98, but sorta worked in FS2K (it didn't support all the new tanks). I'm doing the FD on a project that has all the gauges in XML. That code also handles the fuel system and other systems. However, I don't think it handled automatic fuel transfers to the center tank. Ron

Roman,Thanks for your work!After analyzing, to my surprise, it comes very close to my fuelsystem(2002!).Differences are the amount of center tanks(1) and my usage of the "Eng1-4 Elec Fuel Pumps and Fuel Cutoff K-events and and the Pump On A:var's"Also it is possible for me to override the logic and make imbalances and correct them myself.Par example: Left Engine off, Right engine can take fuel from left, right, center or all tanks, depending of the position of the fuel pump swiches, which drive the tank selectors.The logic, as in yours, will give an even usage preventing 1800 lbs lateral imbalance and or shutting off the center tank when more than 1200 lbs usable fuel left.Pressing the X-feed valves (SET 14&15) shows engines taking fuel from either Left or Right Main.In fact every thinkable combination of engines taking fuel from certain tanks is possible,I 'm happy with it.Jan"Procul Negotiis"

Roman, Ron or Jan,Based on this thread, I feel I'm very close to being able to design a DC-9-41 fuel system that is close to the real thing. Thanks to everyone for the advice and contributions.I do need a few more clarifications on some points.1)It seems that setting the FUEL_SELECTOR_SET to "Right Main" or "Right to Left X-Feed" is really the same thing. It does not make sense that they should be the same. Please explain.2)This thread seems to be a good place to dive into another part of the FS fuel system. These commands:KEY_FUEL_PUMPKEY_TOGGLE_ELECT_FUEL_PUMPKEY_TOGGLE_ELECT_FUEL_PUMP1KEY_TOGGLE_ELECT_FUEL_PUMP2KEY_TOGGLE_ELECT_FUEL_PUMP3KEY_TOGGLE_ELECT_FUEL_PUMP4Where do they fit into the picture if one has chosen to use the FUEL_SELECTOR_SET commands?Someone said earlier they would be needed to trigger fuel pressure warning lights. Can someone expand on this?3)These seem to be the main fuel cutoff vales for each engine. On the DC-9 these are located on the center pedistal. Does anyone have additional comments on these?KEY_TOGGLE_FUEL_VALVE_ALLKEY_TOGGLE_FUEL_VALVE_ENG1KEY_TOGGLE_FUEL_VALVE_ENG2KEY_TOGGLE_FUEL_VALVE_ENG3KEY_TOGGLE_FUEL_VALVE_ENG4One thing I've done with my fuel gauges is this: Because there are numerous switches and levers all over the cockpit that I want to monitor collectively, I have created a central gauge (jok_fuel_system.xml) that tracks all of the other fuel gauges and it is in this file where I have put all the "logic code". This central gauge has no graphics at all ...just logic code. (I will upload the gauge set for you all once I'm done.)Thanks,John

Hi again,I thought I would upload a sample pic of my DC-9-41 panel backgrounds to give you all a chance to see my project.I've been corresponding with a DC-9-41 pilot and he has been a tramendous source of information on the aircraft. (His name is Stellan Hilmerby and he already has a pretty famous DC-9 panel on the web.)Tell me what you think.Thanks,Johnhttp://forums.avsim.net/user_files/29050.jpg

John,The bitmaps look great !!!1)It seems that setting the FUEL_SELECTOR_SET to "Right Main" or "Right to Left X-Feed" is really the same thing. It does not make sense that they should be the same. Please explain.Yes it is.. When using 1 tank selector it becomes wrong. 2)This thread seems to be a good place to dive into another part of the FS fuel system. These commands:KEY_FUEL_PUMPKEY_TOGGLE_ELECT_FUEL_PUMP(X)Where do they fit into the picture if one has chosen to use the FUEL_SELECTOR_SET commands?These have no purpose whatsoever. ( didn't test just KEY_FUEL_PUMP ) They only work if electric_pump=1in the Aircraft.cfg. They have very bad logic to them :1. The ELECT_FUEL_PUMP(X) has no affect on engine operation whatsoever. All they do is provide fuel pressure to a fuel pressure gauge before engine start. ( Act like a boost pump )2. They are electric so.. If the pumps are on and electricity gets cut to them -- They stay on!!! Until you turn them off..Then they will follow the rule of being electrically driven.3. When on, and fuel tanks -or- fuel is empty they will still provide pressure !!!!( My newest version of the test gauge has this and a workaround to these problems, still no affect on engine operation though ) Try this with the gauge - Fuel Valves OFF, Boost pumps OFF, Turn over engine for start --- Still get pressure !!!! Someone said earlier they would be needed to trigger fuel pressure warning lights. Can someone expand on this?They could.. I would code them as transfer pumps between tank pumps and engine pump, if they are not on then Fuel valves could not open or if not on they would force tank select to each respective engine to OFF. They would work marvelous in this respect. ( My example coded differently just to see whats going on with them..) 3)These seem to be the main fuel cutoff vales for each engine. On the DC-9 these are located on the center pedistal. Does anyone have additional comments on these?KEY_TOGGLE_FUEL_VALVE(X) Yes they are meant for what you describe and act accordingly.. In earlier versions of FS you could of used and still maybe yet : (>K:MIXTURE1_RICH) for open valve and (>K:MIXTURE1_LEAN) for closed.. I.E. CTR-SHFT-F1 or CTR-SHFT-F4. Easier to use KEY_TOGGLE_FUEL_VALVE(X)Enclosed is my last FUEL TEST gauge ( got what I needed ). It addresses all these and provides a workaround for the bogus ELEC_FUEL_PUMP. Crossfeed now works with all 3 tanks available. The auto levelling feature can be disabled in 1 section. And Autostart is fully implemented.( see .xml )I'll tell you to make a gauge like this with alot more tanks and 4 engines would be a nightmare !!!!Good idea for the code -- keep it nice and tidy :-) Regards,RomanGREEN BAY PACKERS][/i :-ukliam :-beerchug

Just an additional comment on the toggle fuel valve events; I've used these with success in the past on light aircraft to simulate a working primer. If outside and engine temperatures were cold, and a personal bool was not set, then hitting the start switch would toggle the fuel valve if on, preventing an engine start. Hitting the primer would restore both the fuelvalve and my personal bool.I haven't checked the "normal" primers, if they are required in cold weather yet, but I sure don't expect them to be required...I've also used the toggle fuel valve events to simulate an engine driven fuelpump "failure". That is, if the left engine draws fuel from the right fuel-"system" (crossfeed), pressurized by the right engine, and the right engine suffers a failure, then the left engine would "fail" (due to fuel starvation). This was rather complex to setup though, but it worked :) Some code had to be runtime, but some of the logic was setup in the fuel selectors. The same thing can be used to cause fuel starvation due to wrong tanks used in unusual attitudes.