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If You Think Your 2002 Planes Fly OK in 2004, Read This...

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Not sure if the post(link below) has become widely read yet in the general FS community, but it should be required reading. Essentially, quite a few very experienced aircraft developers seem to be coming to a pretty scary conclusion- that critical airfile information that's part of FS2002 aircraft is not being translated into FS2004, and that aircraft which seem to transfer without issue are in fact missing critical information for their flight dynamics. Moreover, even aircraft designed to be FS2004 compatible (or compatible with only a few tweaks) are lacking this data in FS2004. It seems that Microsoft may have changed the way certain aspects of flight dynamics are controlled, and not for the better...Take a read and draw your own conclusions, but to me it doesn't sound like good news for those of us who care as much about accurate flight dynamics as we do the new eye candy of 2004:http://forums.avsim.net/dcboard.php?az=sho...&topic_id=12256

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... and this is the main reason I haven't released the Dash 7 and Aero Commander twins updates yet. Still trying to get a better handle on how to compensate for the lack of lift, especially on approach. I am close so I hope by this weekend I will be there.But, yes, many 2002 aircraft will suffer from the "heavy" nose feel due to loss of the wing incidence data. This not only hurts lift, but also drag, and we still must determine the impact on stall effects.You will notice either a need for higher takeoff trim, or higher airspeeds to get the lift. Try doubling your usual trim settings for takeoff and begin pulling back on the yoke about 10-15 knots before VR.Milton

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I've been eyeing the thread, and since I'm an aircraft designer, I share the concern. This post might offer a solution, but I haven't tried it yet:http://forums.avsim.net/dcboard.php?az=sho..._id=12340&page=Still, most aircraft I've ported over to FS2004, including those where I've built the FDE, fly no different than their counterparts in FS2002. When I brought aircraft over from FS2000, the opposite was true and I had to tweak a lot... I don't know the reasons for some of these changes--such as the reason why G/S capture changed from FS2000 to FS2002, and essentially changed back in FS2004.... One thing is a certainty--in order to use FS2004, Microsoft for whatever reason required us to sacrifice FDE and scenery features in the sim, or accept them in a different format. That's happened in every version of MSFS I've ever owned, and since we've all purchased subsequent versions of the sim regardless, I think we've shown that we accept this if not consciously, through our wallets... And moreover, for whatever reason, there's always the chance Microsoft may be trying to protect proprietary information, although in a community of enthusiasts, that's like trying to plug a dam with a finger :)-John

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MS may have decided not to put that data in so as to appear to make the sim...O what do i know im just guessing so im not gonna contribute to this thread...:)

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i tried my SAI MarchettiDid not fly anthing like it did in 2002

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Right on John. Having just gotten the AC520 back to nicely flying again, I think the wing incidence allowed FDE novices like myself to overcome poor setups, unknowingly.At least according to the load manager, my CG was too far forward, but was compensated by correct incidence and twist data. Taking that away allowed me to learn the value of other parameters through lots of testing with test panels.I think I have ended up here with an even nicer flying Commander as a result.We shall overcome these changes and may be better off in the end. :-)Milton

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Hi, When you add news things, there is others thing will be not the same. You have to learn what have changed.Rob young have find and fixed the aircraft spin for fs2004 and he have updated the cessna aircraft air files.Keepin old architecture from anything is always a step back, I would rather see completly new aircraft system and forget COMPLETLY about compatibility, There is absolutly no inovation at this rate of each release crying for backward compatibility. ThanksChris Willis[link:fsw.simflight.com/FSWMenuFsSim.html]Clouds And Addons For MsFs

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Chris,Normally I would agree with that attitude ablut moving forward, but the conclusion to this very important thread- which I can't believe hasn't gotten more press over at the general forum- seems to be that this is a major step backward. Essentially MS has made our sim much more of a game, and prevented payware and freeware developers from even attempting to improve it as they were able to do in FS2002.Here's the relevant post from that thread, word for word (long, but well worth the read):Thanks to all of you for re-testing and to all others who have contributed.I believe we have all reached the same conclusion now with everyone eventually confirming my finding that both incidence and twist, together with their pitch and drag consequentials, default to zero at all times in FS2004. After giving this some thought I now conclude that this is not a mistake. It looks more like a a design time decision. I find it unlikely that the different variables relating to incidence and twist could go missing from the different equations in the flight model unless someone was instructed to go through the code and remove them everywhere they occur. Someone has. If this was an error some of the variables would still be working.Since the terms often get confused let me explain that FS2002 had an excellent flight model but dreadful default flight dynamics. The flight model is in the binary code of the product and is used by every aircraft. The flight dynamics belong to a particular aircraft and are coded in each aircraft.cfg and air file. The people who wrote the original flight model for Microsoft understood aerodynamics. The people who wrote their flight dynamics did not.Since there was nothing significantly wrong with the flight model and it had the capability to support realistic flight dynamics some of us who understand real world flight dynamics set about writing flight dynamics files for MSFS which exploited the capabilities of the flight model better than the proprietary default flight dynamics. By the middle of this year tens of thousands of Microsoft customers were downloading our work for free and enjoying the additional realism which we were able to unlock. Increasingly consumers were also buying payware aircraft because they were obviously superior to the aircraft delivered by Microsoft.What those who have contributed to this thread have just proved is that Microsoft have degraded the internal flight model equations just enough to ensure that realistic flight dynamics will no longer work in FS2004. We have been very careful to test with their SDK compliant default aircraft and at full realism. By carefully altering their proprietary code Microsoft have ensured that their commercial competitors, however small and insignificant, can no longer deliver products which are superior to their own. Some of you will have noticed for instance that Rob Young has posted elsewhere that Microsoft have removed the ability of the SF260 to spin in FS2004, whilst enabling spin within the Extra and Jenny FDE.This is entirely consistent with US law and entirely in accordance with the long term competition strategy of Microsoft as a corporation. Microsoft are perfectly entitled to react to competition by altering their proprietary code in ways which disadvantage others and make Microsoft look good.Opportunity, motive and modus operandi? You decide.The destruction of the pitch attitude and drag equations within the internal flight model stands in stark contrast to the impression which Microsoft conveyed prior to the release of FS2004. We have just proved that FS2004 is not compatible with any existing aircraft flight dynamics, even when they were fully compliant with all Microsoft SDKs. Destruction of the realistic pitch equation has ensured that FS2004 displays such aircraft at fake nose up pitch angles which preclude an appropriate view over the panel or VC. By removing the ability to process the drag correction from air file Section 1101-50h Microsoft have ensured that such aircraft suffer degraded performance in FS2004 because they always have excess drag. They become visually and dynamically incompatible with FS2004.FS2004 does not have an FDE converter. It just ignores key aerodynamic data from earlier SDK compliant FDE, degrading them so that they are no better than the new default FDE. Third party aircraft produced by experienced FDE authors, whether freeware or payware, always had significantly more realistic flight dynamics than MS default aircraft and are therefore degraded more. The Microsoft default FDE were so unrealistic that removal of the chosen aerodynamic variables from the flight model has hardly changed their attributes. I believe this points to careful selection and beta testing of the variables removed from the flight model equations.The implications for payware publishers whose expertise lay in producing realistic aircraft which exploited the internal flight model to the full are obviously grave, but they are not the only ones who suffer. The vast majority of MSFS consumers could never tell that the default aircraft had faulty flight dynamics and are therefore no worse off. The minority who could tell, including aviation practitioners and those who have invested hundreds of hours using the product to learn how to operate aircraft realistically from scratch, have been slapped in the face. The equations in question did not have to be destroyed for the eye candy aspects of FS2004 to work. Microsoft could have ensured that your favourite FS2002 freeware aircraft and your collections of FS2002 payware aircraft continued to work in FS2004, just by doing nothing at all to the flight model. Instead they made changes which ensure that all your FS2002 aircraft are degraded. We have proved that Microsoft have removed key aerodynamic variables from the flight model equations. Accident or design? You decide.Now I need to address a 'what if' that have come up in this thread suggesting that there is an FDE work around which can overcome removal of the variables.Ron, Bob and Douglas are talking about how substituting variation of AoA for AoI still 'works' and will have to be employed instead. Whilst this could restore realistic pitch it cannot restore realistic drag and will make the drag result even worse.Since Microsoft have ensured that FS2004 cannot process the drag data correction from Section 1101-50h the result of using an AoA rotation to substitute for an AoI rotation is a cartoon rotation which produces the wrong induced drag and a very distorted performance envelope. The drag consequences of +4dAoA and +4dAoI are very different. Picture a wing meeting the air and the bottom of the fuselage meeting the air in an aircraft where incidence = 4 and AoA = 4. The fuselage is level (aircraft has zero pitch) but the wing is four degrees nose up and is inducing substantial drag at 4dAOA. In FS2002 we could code the pitch and the drag for that aircraft differently and correctly. Now if we use an AoA rotation to remove the incorrect value of zero AoI which Microsoft have imposed for all aircraft in FS2004 we must make the wing have zero AoA to show the fuselage level again (zero aircraft pitch). Having reduced the AoA by 4 degrees to force the fuselage to zero pitch there is now also zero angle of attack and zero induced drag, producing a huge drag error.The proposal that AoA rotation substitute for AoI rotation ignores the fact that we have just proved that Microsoft have destroyed the drag equation as well as the pitch equation. The induced drag error cannot be corrected even though the pitch error can be corrected by the means proposed. This thread was never about data loading and reloading bugs in FS2004 real as they seem to be for some people. This is about the extent to which FS2004 is still a flight simulator at all.An FDE author can force FS2004 to display aircraft at the correct pitch but not with realistic drag. In FS2004 there is still a link between AoA and drag, but Microsoft have destroyed the link between pitch and drag. To make an MDL 'fly' at the right visual pitch it now has to be 'animated' like a cartoon. The MDLs are no longer 'flying' because in FS2004 as we have just proved they are not following the laws of flight. The consequence is that those who choose to produce FS2004 aircraft and updates will have to invoke a solution which is part video game and part flight simulator. Part cartoon animation and part dynamics code. The implications of this internal code change extend far beyond the world of FDE authors. Would be FS2004 MDL authors and painters of quality products have not understood yet. flight dynamics authors will have to explain it to them.When an aircraft is produced for use in any flight simulator, not just this one, the net flight incidence component of the flight dynamics equations is used by the FDE author to rotate the MDL to allow for wing incidence after it has been produced by the MDL maker. This FDE code also controls what can be seen over the panel or VC at run time. The FDE author then corrects any consequential drag error separately. That the FDE author can no longer do any of this in FS2004 is what this thread proved. For use in a video game which lacks wing incidence as a flight dynamic variable the MDLs have to be produced with their incidence rotation built in by the MDL maker at design time. We have just proved that the incidence variable is absent in FS2004.Let that sink in now and get ready to explain it to your project collaborators. That is what I mean by a *serious* bug in FS2004. The other new bugs are inconsequential by comparison.If producers have the goal of releasing FS2004 aircraft with even somewhat realistic performance envelopes which also fly at the correct displayed pitch attitude the only solution is as follows. 1) MDLs have to be rotated nose down by the net incidence of the real aircraft at design time to display correctly. 2) The MDL animations have to be prepared to match that nose down rotation.3) The textures also have to be rotated nose down in the paint package. 4) The FDE then have to be prepared with an 'overstiff' nose oleo which 'corrects' the nose down sit of the rotated MDL on the runway. Mainwheel oleos of tailwheel aircraft may be stiff enough already. I have tested and this works well.5) The MDL oleo animation may have to be written accordingly and not accurately. 6) The rest of the FDE then have to be written to match an 'equivalent aircraft' of zero incidence and zero twist but retaining the real world lift slope and consequential induced drag. Drag errors can then be 'somewhat corrected' using other data fields in Section 1101 which FS2004 can still process.If AoA rotations are used in lieu of the MDL rotation, as some have proposed, there is no way to correct the induced drag, (consider the zero case to understand why), and FS2004 is just a video game with animated cartoon aircraft. That seems to be the way this product is developing and I acknowledge that the majority of consumers who only use the product as virtual airport spectators and virtual passengers will be quite happy with that. The compromise above will therefore satisfy most FS2004 users, including most payware customers, but it is still a compromise with less accurate flight dynamics than FS2002. The comprise is largest for the fastest aircraft. Consequently I doubt that FDE authors whose expertise lies in creating realistic flight models will choose to spend hundreds of hours over the next couple of years producing or updating 'compromised' FDE for FS2004. They may decide to write payware FDE for FS2004 if the price is right, but their more demanding customers will always expect more realism than we now know is possible in FS2004. Those who have promised to produce FS2004 updates have a larger problem. Rotating pre existing MDLs is simple enough, but rotating all the animations and all the textures of a pre existing MDL may not be at all simple. It depends on the package used to create the aircraft originally. The FDE have to be rewritten anyway. All the other new FS2004 bugs also have to be taken on board and if possible fixed. The most important of these are the CoG bugs. Since I think I have now decoded them I will try to explain them later in a different thread. If anyone wants to design a Whitley for use in FS2004 the only choice will be an MDL rotated at design time, but I expect that most FS2004 third party aircraft will be displayed at fake pitch angles within the video game and most users will not notice. However since the fake pitch angles are always nose high you cannot obtain the correct view over the panel and you will wind up having to cheat in various ways to see where you are going, by scrolling the panel, or using a video game zoom factor, or some other video game cheat, to control the game. This has never been a requirement when flying with realistic flight dynamics.Due to removal of the incidence and twist variables the VIEW_FORWARD_DIR and SIZE_Y variables within panel.cfg, cannot always be used solve the view on approach problem in FS2004 in cockpit view due to ground / air mismatches previously solved by FDE code. There are no equivalents for the VC anyway. Setting the correct view over the VC 'panel' has to be resolved by MDL rotation in FS2004. All of which leads to my position on updating my own 'realistic' FS2002 freeware flight dynamics.My finding that FS2004 is unable to process three key aerodynamic variables essential to realistic flight simulation has now been confirmed by a range of experts. It is therefore not a question of how long it would take to produce FDE updates. FDE which are realistic in FS2002 cannot be updated to be realistic in FS2004. It cannot process the variables and equations which would allow real world inputs from flight manuals to cause the real world outputs. I cannot update my FDE for realistic first person flight simulation use in FS2004. The necessary code has been removed by Microsoft. Of course if the key variables were removed by mistake all Microsoft have to do is restore the old equations. They know where to find them. FSAviator

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Hi FSAviator,Sounds very serious indeed. Not having any expert knowledge in this (or any :) ) area but just wondering. Did you hear about the missing water reflections in FS2004 unless the regional settings are changed to US standards? I'm hoping this FDE problem could be caused by such an oversight instead of just another Microsoft trick

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Hello FSAviator,Well reading you comprehensive description of the FDE problems of MS2k4 I now relise that I just wasted $90+ dollers on a pretty computer game guess Im going to still be useing FS2k2 for my serious simming and fs2k4 for just playing...I was even planeing on upgradeing the vid card in this old systems from a Geforce2 mx-400 but I dont see the point of bothering anymore.Im just wondering when there gonna release the XBOX version of Flight sim 2004.

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Leave it to MS to screw it up royally. Soemone should copy and paste that long thread up above and send it to the MSFS team! I would but I cannot find an email address for them (surprise, surprise).

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FS2006 will be strictly arcade you know ;) lolM$'s way of saying thank you and now bend over.. :-8Seriously though, this is quite worrying. One thing is backward compatability not beeing cared for - quite another when upcoming addons will be equally restricted in performance..

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>FS2006 will be strictly arcade you know ;) lolYeah I figure it would be like Crimson skys HEHE

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Well I must say after reading all the thread I am not suprised at Microsofts latest attempt to screw every one, look at all the windows systems screwups how else can Mr Gates afford the good life I guess I will be sticking to fs 2002 unless they decide to do the right thing and change 2004 regards to all Mike

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From FSAviatorPlease note that I have not cross posting anything and until this morning I was unaware of this thread. Cross posting by others is not helpful.The deletion of key aerodynamic variables from the flight dynamics equations within FS2004 is a complex matter for resolution by the relevant experts and that process is taking place where it belongs in the aircraft design forum.It should not be hard for anyone to understand why degradation of the FS2004 flight model and pitch display characteristics concerns those who design the aircraft you all like to purchase or download. We write the code which exploits the available flight model to the full, and which maximises the enjoyment of those members of this community for whom dynamic and display realism is an important component of flight simulation. We have no difficulty understanding that realism matters more to some users of FS2004 than others. If dynamic and display realism in FS2004 do not concern you, then this issue does not concern you.In the first three steps of a four part ongoing process we have proved that FS2004 cannot process key aerodynamic variables. We have discovered why over 95% of existing aircraft available for download and purchase have flight dynamic and display errors when used in FS2004. We have been able to calibrate the degradation of the flight dynamics and visual aircraft display in mathematical terms. Now that we have agreed the exact nature of the degradation, and its exact mathematical consequences, we are moving to stage four. We are starting to debate the optimum means of creating new build aircraft for FS2004 under these new degraded circumstances. If you have anything constructive to contribute to this very technical debate may I suggest that you do so in the aircraft design forum where it is taking place. I will respond to any constructive input there.

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