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Guest Ron Freimuth

Serious FDE bug in FS2004?

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I am in no rush to purchase FS2004 but the question of compatibility of my freeware FS2002 flight models with FS2004 has already arisen. Today I spent several hours testing this issue on a friend's computer. The preliminary results cause me sufficient concern to ask those of you who have substantial expertise in writing FDE to repeat my tests to determine whether you can confirm my findings set out below.Please fly all the initial tests with FS2004 default aircraft so that you are not testing for potential mistakes in imported third party FDE. Maximum realism should be set.Two key components of aerodynamics are wing twist and wing incidence. FS2000 reads these data from section 1204 of the air file. FS2002 instead reads these data as;wing_incidence=wing_twist=from the aerodynamics section of aircraft.cfgDrag relating to fuselage pitch v wing incidence at AoA=0 is 'corrected' using data from section 1101 of the air file in both sims. My testing indicates that FS2004 cannot read (or cannot process) incidence or twist from either data location. I further conclude that having failed to process AoI it is not reading changes of the AoA v AoI drag 'correction' from section 1101.To test make large changes of first incidence and then twist within the default FDE to confirm that FS2004 is unable to read or process wing incidence and twist data from either a default FS2004 air file or from a default FS2004 aircraft.cfg. In FS2004 large changes of incidence and/or twist added to, or subtracted from, default files appear to produce no change of pitch, IAS or drag in level flight at constant power.Proceed to test whether FS2004 can read these data from an imported third party set of FS2002 FDE with the data correctly stated and matched in Sec1204 and the aircraft.cfg. I found that it could not. Choose an aircraft which has large incidence. Any of my propliner FDE will do, or else consider testing with the new FS2004 v 1.5 upgrade of the B-25J from RCS (AoI = 3.0 degrees with zero twist). Establish the chosen aircraft in the cruise on autopilot at normal cruise power and design cruise altitude and observe the aircraft pitch in FS2002 and then in FS2004 at the same MAP and RPM using the same accurate attitude indicator.I believe you will see the aircraft excessively pitched up by an angle equal to;(declared angle of incidence, plus or minus, declared mean aerodynamic twist)in FS2004 compared to FS2002. It will develop extra drag in FS2004 'appropriate' to the 'extra angle of attack' due to the 'missing angle of incidence'.The aircraft will not attain the known (real or FS2002) performance envelope in FS2004 due to the extra induced drag.As far as I can tell the missing angle of incidence is credited as extra angle of attack for both visual display and dynamic purposes. This needs further testing to determine whether this is precisely true.There is potential for some interaction in FS2004 with the new payload altering module. Note however that the new v1.5 RCS B-25J is very nose heavy at default load (due to another 'problem' in FS2004) and that in FS2004 all my FDE have CoG well forward at exactly zero wing chord (I know why, but that is a separate FS2004 issue/bug). For the moment note that these false NOSE HEAVY default CoG conditions in FS2004 (compared to correctly processed default CoG in FS2002) cannot be causing the observed NOSE UP condition in FS2004. The excess cruise pitch and increased induced drag in FS2004 appears to be (solely) due to the inability of FS2004 to read or process twist and incidence data from either the air file or the aircraft.cfg.Conclusion:All aircraft in FS2004 are displayed on screen and have their dynamic performance calculated as though their wing has zero twist and zero incidence because the relevant twist, incidence and consequential drag modification variables are not being read or processed and consequently default to zero.If you are an FDE expert can you verify this result for both the MS FS2004 defaults and FS2002 imports?I really hope I am missing something obvious, but if FDE authors do confirm my preliminary results then we must contemplate three possibilities.Either;1) FS2004 has at least one show stopping FDE bug, or2) Current air file editors are not loading or displaying new unknown sections of the FS2004 air file to which some aerodynamic variables have migrated, or3) MS have now split the FDE into three files one of which is now secret and hidden, which we must locate and decode in order to declare and manipulate aerodynamic variables such as twist and incidence.Unfortunately pronouncements by MS concerning backward compatibility and the lack of a 'converter' all point to the probability that FS2004 cannot read or process key aerodynamic variables from its own (default) FDE files.Please tell me I am wrong (and why).FSAviator

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>............... Today I spent several hours testing this>issue on a friend's computer. The preliminary results cause>me sufficient concern to ask those of you who have substantial>expertise in writing FDE to repeat my tests to determine>whether you can confirm my findings set out below.>>Please fly all the initial tests with FS2004 default aircraft>so that you are not testing for potential mistakes in imported>third party FDE. Maximum realism should be set.>>Two key components of aerodynamics are wing twist and wing>incidence. FS2000 reads these data from section 1204 of the>air file. FS2002 instead reads these data as;>>wing_incidence=>wing_twist=>> ..............>My testing indicates that FS2004 cannot read (or cannot>process) incidence or twist from either data location. I>further conclude that having failed to process AoI it is not>reading changes of the AoA v AoI drag 'correction' from>section 1101. I checked this out a couple of hours ago.EVERYTHING in aircraft.cfg and the AIR file appear to be ignored unless FS9 is killed, then restarted from scratch!I edited the Baron 58 wing incidence in aircraft.cfg, also in the AIR file. No effect on pitch after reloading AC. Not even if I switched to the King Air, then back to the Baron.Same with changing Stall Warning AoA from 13 to 3 degrees.Only when I quite the MS-F***U 9.0 sim, then restarted FU #9 and returned to my "saved in midair flight", did I see a difference in pitch!This makes it virtually impossible to tweak flight dynamics. I'll be damned if I'm going to kill and reload FS9 100's of times to make adjustments!I noted about the same was thing was mentioned with Scenery reload in an AVSIM message a couple of days ago. you can't reload Scenery to test changes! You have to restart MSFU #9.0MS doesn't give a damn about developers! Or, expects them to create the same kind of crap it does.Unless there is a good way around this I'm about done with FS FD. And, I doubt many other FD people will have the patience to take 10X as long to adjust FD parameters as before. 10X 100 hrs is 1000 hrs. >I really hope I am missing something obvious, but if FDE>authors do confirm my preliminary results then we must>contemplate three possibilities.>Either;>>1) FS2004 has at least one show stopping FDE bug, or>>2) Current air file editors are not loading or displaying new>unknown sections of the FS2004 air file to which some>aerodynamic variables have migrated, or>>3) MS have now split the FDE into three files one of which is>now secret and hidden, which we must locate and decode in>order to declare and manipulate aerodynamic variables such as>twist and incidence.>>Unfortunately pronouncements by MS concerning backward>compatibility and the lack of a 'converter' all point to the>probability that FS2004 cannot read or process key aerodynamic>variables from its own (default) FDE files.>>Please tell me I am wrong (and why).>FSAviator If one has to kill, then reload MSFU- #9 to adjust aerodynamics, it will be the end of good FD's. I'm waiting to see what others find out.RAF

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Under Settings, Assignments, Search/Select "Reload User Aircraft" and assign a unique key combination/joystick button. See if this causes your FDE updates to appear when you press your unique key combination/joystick button.W. Sieffert

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Has anyone even bothered to check out the new aircraft.cfg entries?[Airplane_geometry]Wing_area=128.091 //Square feetWing_span=32.71 //FeetWing_root_chord=4.085 //FeetWing_dihedral=6.3 //DegreesWing_incidence=1.5 //DegreesWing_twist=-3.0 //DegreesOswald_efficiency_factor=0.7 //Measure of lift effeciency of wingWing_winglets_flag=0 //Are winglets available?Wing_sweep=0.0 //Degrees, wing leading edgeThese are just a few of the new entries. It's almost as though they're trying to get rid of the .air file! :)BillAVSIM OmbudsmanFounder and Director,Creative Recycling of Aircraft Partshttp://catholic-hymns.com/frbill/FS2002/images/fartslogo.jpg

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>Under Settings, Assignments, Search/Select "Reload User>Aircraft" and assign a unique key combination/joystick button.> See if this causes your FDE updates to appear when you press>your unique key combination/joystick button.>>W. Sieffert Ah. Saved! Just assigned it to Ctl-Shft-R and it appears to work. I also set 'Refresh Scenery'. Ron

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>Has anyone even bothered to check out the new>aircraft.cfg entries?>>[Airplane_geometry]>Wing_area=128.091 //Square feet>Wing_span=32.71 //Feet>Wing_root_chord=4.085 //Feet>Wing_dihedral=6.3 //Degrees>Wing_incidence=1.5 //Degrees>Wing_twist=-3.0 //Degrees>Oswald_efficiency_factor=0.7 //Measure of lift effeciency>Wing_winglets_flag=0 //Are winglets available?>Wing_sweep=0.0 //Degrees, wing leading>>These are just a few of the new entries. It's almost as>though they're trying to get rid of the .air file! :)>Bill New? Hardly. Same as in FS2K2. Only not all work as one might think. ;)Ron

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>>Has anyone even bothered to check out the new>>aircraft.cfg entries?>>Wing_dihedral=6.3 //Degrees>>Wing_incidence=1.5 //Degrees>>Wing_twist=-3.0 //Degrees>>Wing_winglets_flag=0 //Are winglets available?>>Wing_sweep=0.0 //Degrees, wing leading>>>>These are just a few of the new entries. It's almost as>>though they're trying to get rid of the .air file! :)>>Bill>> New? Hardly. Same as in FS2K2. Only not all work as one>might think. ;)Ron, I don't remember seeing any of those in the SDK...Nor any of these:[autopilot]default_pitch_mode=0default_bank_mode=0max_pitch=10.000000max_pitch_acceleration=1.000000max_pitch_velocity_lo_alt=2.000000max_pitch_velocity_hi_alt=1.500000max_pitch_velocity_lo_alt_breakpoint=20000.000000max_pitch_velocity_hi_alt_breakpoint=28000.000000max_bank=25.000000max_bank_acceleration=1.800000max_bank_velocity=3.000000max_throttle_rate=0.100000nav_proportional_control=9.000000nav_integrator_control=0.250000nav_derivative_control=0.000000nav_integrator_boundary=2.500000nav_derivative_boundary=0.000000gs_proportional_control=9.520000gs_integrator_control=0.260000gs_derivative_control=0.000000gs_integrator_boundary=0.700000gs_derivative_boundary=0.000000yaw_damper_gain=1.000000BTW, the last entry for yaw_damper_gain defaults to 0, so those a/c with a yaw damper need to be hand-edited... :(BillAVSIM OmbudsmanFounder and Director,Creative Recycling of Aircraft Partshttp://catholic-hymns.com/frbill/FS2002/images/fartslogo.jpg

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>>>Wing_dihedral=6.3 //Degrees>>>Wing_incidence=1.5 //Degrees>>>Wing_twist=-3.0 //Degrees>>>>Wing_winglets_flag=0 //Are winglets available?>>>Wing_sweep=0.0 //Degrees, wing leading>>>>>>These are just a few of the new entries. It's almost as>>>though they're trying to get rid of the .air file! :)>>>Bill>> New? Hardly. Same as in FS2K2. Only not all work as one>>might think. ;)>Ron, I don't remember seeing any of those in the SDK... They are in the FS2K2 'aircraft container SDK'. However, that SDK is nearly useless. I had to comment an aircraft.cfg file to explain what they really do, and which ones have no effect. >Nor any of these: The below are new in aircraft.cfg. I think they are from the restored REC 1199 "autopilot gains" record. And, a couple of other records. Which were eliminated in FS2K2, but are now back (good!). >[autopilot]>>default_pitch_mode=0>default_bank_mode=0>max_pitch=10.000000>max_pitch_acceleration=1.000000>max_pitch_velocity_lo_alt=2.000000>max_pitch_velocity_hi_alt=1.500000>max_pitch_velocity_lo_alt_breakpoint=20000.000000>max_pitch_velocity_hi_alt_breakpoint=28000.000000>max_bank=25.000000>max_bank_acceleration=1.800000>max_bank_velocity=3.000000>max_throttle_rate=0.100000>nav_proportional_control=9.000000>nav_integrator_control=0.250000>nav_derivative_control=0.000000>nav_integrator_boundary=2.500000>nav_derivative_boundary=0.000000>gs_proportional_control=9.520000>gs_integrator_control=0.260000>gs_derivative_control=0.000000>gs_integrator_boundary=0.700000>gs_derivative_boundary=0.000000>yaw_damper_gain=1.000000>>BTW, the last entry for yaw_damper_gain defaults to 0, so>those a/c with a yaw damper need to be hand-edited... :(>Bill Small AC should have it set to 0.0 or 1.0, I'm not sure which eliminates the YD. If any. The rest of the 'new' [autopilot] entries make sense to me. ;) Ron

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>>yaw_damper_gain=1.000000>>>>BTW, the last entry for yaw_damper_gain defaults to 0, so>>those a/c with a yaw damper need to be hand-edited... :(>>Bill>> Small AC should have it set to 0.0 or 1.0, I'm not sure>which eliminates the YD. If any.All of the jet a/c I've already ported over to FS9 have had the parameter yaw_damper_gain=0.000000 set automatically, even though all of 'em have a yaw damper switch. That's why none of those a/c's YD switches would work! :(BillAVSIM OmbudsmanFounder and Director,Creative Recycling of Aircraft Partshttp://catholic-hymns.com/frbill/FS2002/images/fartslogo.jpg

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I had some time this morning to investigate some of FS Aviator's findings concerning the wing AOI and twist, and Fuselage AOA at Min Induced Drag settings being inop in FS9, and after some testing I produced nearly the same results as he did - until I restarted the flight sim per Ron F's observation.I'm sorry to say that the "reload user aircraft" function doesn't work for me as far as changes to wing AOI and twist, or Fuselage AOA at Min Induced Drag are concerned, I can only see the results of any changes I make after shutting FS9 down and starting it again. I'm using Windows ME which has a really interesting way of managing RAM, and suffice to say that after two of these shutdown/startup sequences following .air or .cfg file changes FS9 runs only a little faster than grass grows!I must then use FreeMem to allocate and free up some RAM, adding an additional step to the long sequence of this festival of good fun. I'm not sure if FS Aviator managed to choose the only three flight dynamics parameters to which this applies, and as obligations to the business of survival prevent me from pursuing this investigation full time, I'm unable to offer an in-depth analysis just now.I can say that as a quick and simple check I made a change to CM_de Pitch Moment-Elevator in the airfile and this change was recognized immediately after reloading the aircraft by both the keyboard "reload user aircraft" event and by re-selecting it from the menu so the mystery deepens.As far as this is concerned:>2) Current air file editors are not loading or displaying new unknown sections of the FS2004 air file to which some aerodynamic variables have migrated, orThere is potential for some interaction in FS2004 with the new payload altering module. Note however that the new v1.5 RCS B-25J is very nose heavy at default load (due to another 'problem' in FS2004) and that in FS2004 all my FDE have CoG well forward at exactly zero wing chord (I know why, but that is a separate FS2004 issue/bug). For the moment note that these false NOSE HEAVY default CoG conditions in FS2004 (compared to correctly processed default CoG in FS2002) cannot be causing the observed NOSE UP condition in FS2004.Has anyone even bothered to check out the new aircraft.cfg entries?Yes Bill, I've looked into them, and besides the entries already mentioned regarding the autopilot, we now have these:New entry added to the GeneralEngineData sectionmin_throttle_limit=0.0 //Minimum percent throttle. Generally negative for turbine reverserAnd these new sections[brakes]parking_brake=1 //Parking brake availabletoe_brakes_scale=0.68 //Brake scalar[hydraulic_system]normal_pressure=0.0 //PSI[turn_indicators]//Type: 0=None, 1=Electric Gyro, 2= Vacuum Gyroturn_indicator.0=1,1 //Turn AND Bank[stall_warning]type=1Also, the .mdl files have some new content, possibly related to gauges or the "clickable" VC's. The vintage aircraft .mdl file sizes are huge, the Jenny's .mdl file is 2.55 MB!Edited to format message in plain text

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Now that other experts have confirmed that the bug I reported exists, it is essential that we resolve whether a user aircraft reload in addition to a user aircraft selection forces FS2004 to process incidence and twist. I have now tested again and cannot agree that it does. Before this thread drifts off to discuss things which hardly matter could I please ask Ron Freimuth, William Sieffert and Milton Shupe in particular to carefully re-test the consequence of reloading the flight model in FS2004 using the reload user aircraft keyboard assignment proposed by William. Please make sure you test at full realism so that we are not testing changed functions of the realism slider by mistake. Please be very careful to retest whether FS2004 is forced into processing incidence and twist data after a user reload, and not whether the files get (re)loaded from disk. We know the files get reloaded from disk. It's not the point.If the internal flight model equations have been simplified at full realism what FS2004 loads or reads may no longer influence what it processes. That was my point. I fear you have only tested whether things get loaded.Whatever means I use to load or reload a flight model into FS2004, I cannot force FS2004 to process non zero incidence and twist data. We all know it can load, reload and process some of the other aerodynamic data, but this thread is not about that other data. This thread is about the variables in the pitch attitude equation and my finding that two key variables are no longer in the FS2004 equation. If I am correct then frankly not much else in the aircraft.cfg matters as very few FS2004 FDE will ever be written and none will be worth the effort.We don't have any test gauges for FS2004 so don't bother looking for anything subtle or realistic. The question is; can FS2004 load +10 into the incidence variable during a user aircraft reload and will it process that value within the pitch attitude equation thereafter?If any readers who are less than expert do not understand how this should work and how it should look before and after the change is processed please fly the test in FS2002 first. You will see what happens in a flight simulator which is actually able to process a realistic pitch attitude equation when a large change of incidence is entered and processed. It is really easy to see whether the software is processing incidence or not.Let's keep this simple.1) Load the default BE58. Observe cruise pitch with AP applied. Change incidence to plus ten in the aircraft.cfg (and/or Sec1204).2) Assign and then use CTRL+SHIFT+R to reload the flight model.3) After you hear the reload from disk, and the hour glass goes away, does the BE58 re-establish in the cruise pitched down by about 9 or 10 degrees or not? This bug and the reported fix is a simple YES / NO thing.No big pitch change - no pitch data processing. Do you really see the same thing in FS2002 and FS2004?If you don't then Ron is correct when he says 'Microsft really screwed us this time'.I also fear that everyone is missing the full horror of this. This isn't just a problem FDE authors have to solve at design time. This is a problem every user of FS2004 has to solve every time they select any aircraft using the menus. Even the first aircraft they fly after starting the program! Even if I am wrong about the reload being a fix and a reload really does force FS2004 to process these data then persuading a hundred thousand downloaders they need to do a reload after every aircraft selection is the next problem ! Five minutes after they read about it they won't remember to do it anyway.When they select a second aircraft which is not the one in the startup file, either there is no incidence and twist , (my informed view in this thread), or the incidence and twist from the first aircraft is mixed with the FD from the second unless they do a reload of the second, (the other informed view in this thread).Has the consequence of either sunk in yet? There is no acceptable news in this thread.In another forum Milton Shupe has suggested that if the reload discussed above does not work then there is a solution which involves turning FS2004 off, making the change and restarting FS2004. I believe Milton says he has tested this and it works.During my borrowed computer time today I also tested that 'conclusion'.Unfortunately I cannot verify that test either..Everything I see indicates that FS2004 does not process incidence or twist under any circumstance. I had already tried assigning an aircraft with large incidence as the default flight, then turning off the entire computer and then turning it on again. I still see FS2004 failing to process incidence or twist at all, even when the sim is invoked with a default flight containing an aircraft of large incidence, or when selecting a flight from the select flight screen for an aircraft with large incidence as the first flight after program invocation, or when either is subsequently user aircraft reloaded.I still believe every aircraft defaults to zero incidence and zero twist and I cannot change this by any means so far proposed in this thread or elsewhere. Those of you who write FDE know how critical this is to the future of significant FS2004 add ons.I confirm that after careful re-testing the full retail UK version cannot process these aerodynamic data , with or without a user reload of the data files, whether or not it reads the data after reloading. It is of course just possible that the bug is somewhat different in the US and UK retail versions, but I doubt it, and what we all need next is a careful retest of the ability to *process* these data within the pitch attitude equation by FDE experts with access to the US retail product.. To Douglas K whose post I read after composing this off line whilst testing - I believe there are other parameters which are no longer read or not processed by FS2004 including CG parameters, but those discussed in this thread are the most important. Obviously FDE authors need to check each in turn and it takes a long time to find all the new bugs. If the other experts confirm what you have just confirmed about reloading not forcing FS2004 to process incidence and twist (in the US retail version?) I will start to post about those other issues in new threads over the next few days.However I fear that you underestimate what a show stopper it is for FDE authors if a computer shut down is required to test every FDE change and everything else may then not matter.I will try to beg more borrowed time tomorrow to see if I can verify your shut down and restart success. I am also testing with ME as the operating system, but I doubt it stops FS2004 processing data reloads that I can hear and see happening, so for the moment I still think the pitch attitude equation has altered.Could you also try the Baron test above in FS2002 and in FS2004 and see if you can repeat the FS2002 result in FS2004.Thank-you all for your co-operation.FSAviator

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Hi,Probably very stupid, don't have 2004 and to much busy with 2002, but can those problems have something to do with the "Obligatory Disk 4" in the CD-drive??Jan"Procul Negotiis"

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In FS2002 you had to load another airplane and switch back to your own when there was a panel edit at runtime. FDE worked with only relading the a/c.Did you test to reload another plane, and then the one you test?If this doesnt help then we are really screwed. Is it only the two values you discuss, or are there more who dont work?Still awaiting my copy here, so all I say is pure speculation.Thanks for the good workJohan[A HREF=http://www.phoenix-simulation.co.uk]Phoenix Simulation Software[/A]-----http://www.people.zeelandnet.nl/johdUnofficial PSS Website

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To FSAviator:You are quite correct in your finding that FS9 does not process pitch data from either the wing_incidence or wing_twist aircraft.cfg file entries.I must offer my humblest apologies for my earlier statement that the changes would take effect after restarting the sim, this evening I did some testing with the Baron as you suggested and found that altering either wing_incidence or wing_twist has absolutely no effect in FS9.In my defense, I was testing this morning after a 12 hour night shift and was certainly not at my best.In FS2002 the expected occurs, positive wing incidence or wing twist will pitch the nose down and negative wing incidence or wing twist will cause the nose to pitch up. In FS9 no amount of change, whether plus or minus 10 or even 100 degrees will affect the aircraft in the slightest.I found that reloading the aircraft or restarting the sim would not change this fact.I further confirmed these findings with the default C-172.I am very chagrined and dispirited by all this nonsense, it seems Microsoft has decided to prove that FS is only a game after all.When I consider the terrible performance of some imported flight models in FS9 (flight models that worked beautifully in FS2002), the many graphics anomalies in land, sea, and sky, the stutters and crashes that FS9 is prone to (FS9 has crashed more in 6 days than FS2002 has in 2 years, including locking up the O/S 3 times - something FS2002 NEVER did), along with the really disappointing default aircraft flight models it seems to me that the older version of FS offers more as far as my needs are concerned.Again, let me reiterate that I can confirm your findings that FS9 DOES NOT process the pitch data from the relevant aircraft.cfg file entries, and apologise once again for introducing an unecessary element of confusion into this topic through my earlier ineptitude.>No big pitch change - no pitch data processing. Do you really see the same thing in FS2002 and FS2004?If you don't then Ron is correct when he says 'Microsft really screwed us this time'.

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