Flight Dynamics - The Cold, Hard Facts (and some Opinio...

[Johan_Dees 84]

I dont believe either that there is a conspirancy. Only an development way with no looking back, and a bit like " we do our thing, take it or leave it"We have to take it, since there is no alternative, but its discouraging to be thrown back in development for 3th party developpers every two years. The time we are back on track, they release a new FS version, and we can start all over again.Johan[A HREF=http://www.phoenix-simulation.co.uk]Phoenix Simulation Software[/A]-----http://www.people.zeelandnet.nl/johdUnofficial PSS Website

[Guest]

I believe that some people have the wrong opinion on what is happening in regards to this discussion. While I personally don't believe the conspiracy theory, as it were, it is frustrating to have to take many steps back once the knowledge is finally getting to a usable level.Now I myself have not produced an FDE yet, but I have been working to produce an accurate G-V flight model for about 4 months now, and let me tell you, the dynamics gurus like Ron have been most helpful with thier information. I'm swimming in aero data, and I feel like I'm just scratching the surface.The way I see it, MS has merely changed the "direction" that must be taken when authoring flight dynamics, and while it is frustrating to have to relearn your craft every two years, generally the additions/subtractions made by MS turn out for the better.So perhaps before everyone gets worked up about these discussions, I think it should all be put into perspective first. These may just be the first steps toward even more accurate models.

[Guest Jimbofly]

It seems perfectly clear to me that many FDE developers out there are jumping to conclusions. Why would some of the default aircraft have spin capabilities if MS was trying to dumb down the flight dynamics???Most people are of the opinion that the flight dynamics of the default aircraft has greatly improved, and that to me is a clear indication that the overall fidelity of FS2004 MUST be better than it was with FS2002.Instead of people concluding that MS must have dumbed down FS2004 because of slight differences with the FDE parameters, they should be trying to properly understand what they all mean. MS may have made some changes that in fact enhance the fidelity of the flight models possible. It is obviously in Microsoft's best interest to want to retain its openness to third party addons, and any argument that MS is trying to dumb down anything and alienate freeware and payware developers is ludicrous to say the least!!!btw IMO FS2004 is a simulator/game, as it simulates flight in the real world but is not a dedicated simulator, as it contains entertainment characteristics aswell!Must fly...James

[Tabs 2,790]

FS Aviator's consipracy theory is total BS - if MS really wanted to shut out "competitors" to their default planes they would simply seal off the engine to modification, stop producing SDKs and defintely stop giving payware developers the freaking beta version months in advance so they could get their planes working! MS is the most powerful softwar company in the world and if they wanted to end payware FS addons, they wouldn't have to use subtle tweaks to aircraft flight dynamics to do it. That is an absurd notion.And by the way, I've seen Lou Betti say on many occasions that they wish FS was a little more realistic in certain areas so that they could properly model something (like the C310 fuel system). He's not "in MS's pocket" - he made a lot of money on his own family business before starting Dreamfleet...Ryan

[MadDog 353]

Hi Again,The discussion about Microsoft deliberatly trying to make life difficult for FDE editors got me to thinking. As others have expressed, I don't believe it's true because it just doesn't make good business sense. However, the paranoids among us DO have one good reason to believe Microsoft is not being totally honest... the assertion that"The .AIR files contain proprietary data that aircraft manufacturers have provided to us. To help protect that information, we don't release the internal details of the .AIR file."The Lone Gunmen realize this statement is "hogwash", so does everybody else, and the whole debate is rekindled. It's also on this point that I tend to agree with the conspiracy theorists... what kind of manufacturing data is SO SENSITIVE that it prevents MS from being just the slightest bit helpful in making improvements to these files? Personally, I think it's because the .AIR files really are proprietary - but for reasons vastly different than what Microsoft claims.Before I present my own "conspiracy theory" - here are some facts:1. Bruce Artwick (the father of Flight Simulator) along with his flight instructor, Stu Moment, founded Sublogic in 1978.2. In 1988, Bruce Artwick left Sublogic and created a new company - BAO. When Bruce left, he took some of Sublogic's employees and the copyright to Flight Simulator with him.3. In 1990, Sublogic released Flight Assignment: ATP (which is near and dear to the hearts of many old-timers around here) and proved that, even without Bruce, they still had the tools to make a darn good simulator.4. In 1996, Bruce Artwick sold the Flight Simulator copyright to Microsoft. In that same year, Sierra bought out Sublogic to work on their new flightsim, Pro-Pilot - which ended up being a "flop".***WARNING!!! The rest of this post is NOT factual and is probably more like that mindless drivel I complained about in my original post - but I'm bored ;-).***Based on this history, I wonder if Sublogic/Sierra still owns a patent or some other proprietary right on .AIR files? If it's true, MS may still be subject to a license agreement with them. Artwick had the FS copyright; but ATP proved that Sublogic still retained plenty of the technology. Remember, the original Flight Simulator was written in machine language - there wasn't any Visual C++ back then - and it's pretty obvious MS wasn't too concerned with flight dynamics until the early 90's. With that in mind, it's likely that the legacy code which relies on .AIR file parameters is probably still buried deep within the program. I'm not a software expert (I'm a conspiracy theorist); but I would imagine that converting the old code into a more modern language without the help of the original programmers might prove difficult. Ironic, ain't it - Microsoft may actually be in the same boat as the FDE experts. If my theory is correct, Microsoft has successfully updated the base code to use aircraft.cfg parameters in many key areas; but they still rely on 20-year-old .AIR file technology to keep their baby alive! If and when they are finally able to free themselves from the "oppression" of Sublogic's terms, MS may finally be able to release an SDK... but don't expect to see it next week!Once again, I want to reiterate that there is a 99% chance that my theory is pure fantasy. However, don't you agree that it's a little more believable than the notion that Microsoft is actively trying to prevent us from having more accurate flight models for no apparent reason? Addendum: Could somebody that still has a copy of Flight Assignment: ATP check out the file listing and see if it also uses .AIR files. If it does, I may actually be on to something here :-)Take Care,Marc

[Guest]

You could very well be mostly correct here.The scenario with more and more being moved out of the airfile into the aircraft.cfg would certainly suggest that Microsoft are slowly changing the way their FD engine works to not need the airfile anymore.If that were an easy process they'd do it all in one go and have it over with, so apparently it's tough for them.Not having the original code available (or having it but not having the expertise to understand it fully which is more likely as they were able to recompile it into a 32 bit module) would be a very good reason for that.

[robert young 2,897]

Hi Johan,I agree...there is no conspiracy against 3rd parties, only some fiddling about with parameters, some good (a/p functions) some not so good (removal of wing incidence)and some other extra params which we are still trying to work out. We'll no doubt overcome the new challenges in time and at least get back to where we were.Not a great deal of fun, but keeps the brain active!Regards,Rob Young - RealAir Simulationswww.realairsimulations.com

[Guest Ron Freimuth]

>Hi Again,>> ............ However, the paranoids among us DO>have one good reason to believe Microsoft is not being totally>honest... the assertion that>>"The .AIR files contain proprietary data that aircraft>manufacturers have provided to us. To help protect that>information, we don't release the internal details of the .AIR>file.">>The Lone Gunmen realize this statement is "hogwash", so does>everybody else, and the whole debate is rekindled. Yes, if any of the AIR file data is 'propriatory' to an AC or Powerplant mfg, then why do I have to change turbine tables, etc. to get close to real AC? ;)>theorists... what kind of manufacturing data is SO SENSITIVE>that it prevents MS from being just the slightest bit helpful>in making improvements to these files? Personally, I think>it's because the .AIR files really are proprietary - but for>reasons vastly different than what Microsoft claims. The AIR file showed that the MSFS 'flight model' is more or less standard. Why should it be anything else? However, there is ONE NEAT IDEA in it. It took thousands of hours for this to be worked out (mostly by others than myself). ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Rather than base induced drag on CL^2, they base it on AoA^2. This makes it easy for Ground Effect to work, also "Mach Lift Slope".+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ **** I'd say any 'propriatory' MS/BAC SECRET is OUT OF THE BAG! *** It hasn't been a secret for a several years. Thus, I see no reason for MS to continue to claim anything 'propriatory'. OTOH, the AIR file has been figured out so well we hardly need MS to tell us what is in it. ;) It would be nice if they explained aircraft.cfg lines better. The FS2K2 'SDK' is confusing and nearly useless. Info for the FS2K aircraft.cfg covered the important things. >Before I present my own "conspiracy theory" - here are some>facts:> ...........>.............>4. In 1996, Bruce Artwick sold the Flight Simulator copyright>to Microsoft. .........>Based on this history, I wonder if Sublogic/Sierra still owns>a patent or some other proprietary right on .AIR files? If>it's true, MS may still be subject to a license agreement with>them. Assuming the newer flight and powerplant models in the AIR file were done by BAC. As I said, the 'flight model structure' is essentially standard. That was figured out a few months after FS2K came out. The only thing I can see that is unusual is the way the Induced Drag Parabola is set. Driven by AoA rather than CL. This is understood so well that a unique test app was written to do many of the same calculations. Reading the AIR file and some tables directly, we could see that it gave the same drag and other results FS2K(+) did.>experts. If my theory is correct, Microsoft has successfully>updated the base code to use aircraft.cfg parameters in many>key areas; but they still rely on 20-year-old .AIR file>technology to keep their baby alive! If and when they are>finally able to free themselves from the "oppression" of>Sublogic's terms, MS may finally be able to release an SDK...>but don't expect to see it next week!...........>Take Care,>Marc Bruce Artwick or whoever did the recent 'FM code' should be made aware of what I've explained above. Any 'secret' has been discovered. Virtually all of the other things set by the AIR file are elements in standard engineering models. Though, it has taken some time to understand them. --- Years. Ron

[Guest DreamFleet]

Hi MadDog,Sorry for the late reply to your post here.VERY well said. Yours are among the reasons why we were, and are not losing any sleep over this, and neither should anyone else. :-)What a shame that this "issue" got blown so far our of proportion, and in some other threads resulted in specualtion / assumptions that were so far off the wall that to call them "delusions" would be an understatement.For the most part this is just routine "transition" stuff. We deal with it with every new sim, and in more areas than just FD. I can't wait to hear what the gauge programmers tell me next! ;-)It all get's dealt with. Regards,http://www.dreamfleet2000.com/gfx/images/F...RUM_LOUF_A2.jpg

[MadDog 353]

Hi All,There has been a lot of discussion here lately about the FDE threads over in the A&P Design forum. Based on what I've read, there is a lot of misunderstanding over here about what is actually going on over there. So, I'd like to list a few facts about MSFS that the "everyday, ordinary" sim-pilot might find enlightening.... I may also express some opinions; but I'll clearly identify those as being IMOP (In My OPinion).1. FACT - Microsoft has changed some of the flight dynamics parameters in FS2004.2. FACT - Microsoft has changed some of the flight dynamics parameters in every version since the series began back in the 80's.3. FACT - Third-Party Flight Dynamics Authors are the most talented, intelligent, patient, and self-less individuals that you will ever find in the Flight Sim community. This is not an opinion - it is a fact... and I'd be willing to prove it in a court-of-law! :-)4. FACT - Microsoft has never released a comprehensive Flight Dynamics SDK to explain what all the parameters in the relevant files actually do. FDE developers have relied on experimentation, knowledge of real-world aerodynamics, trial-and-error, endless testing, and more than a few miracles to produce some fantastic flight models over the years.5. FACT - With every new release of Flight Simulator, the FDE experts complain bitterly about Microsoft's changes... and who can blame them! Any changes create more work for the experts because edits or ommisions of one parameter can have a profound influence on other, "known", parameters. Without any help from Microsoft, determining these influences takes a lot of time.6. IMOP - So far, the FDE complaints about FS2004 are much more subdued than those offered when FS2002 was released. If you were around 2 years ago - the uproar was enormous! The FDE developers hated the new aircraft.cfg settings and emphatically declared that realistic flight modeling with FS2K2 would never be possible!7. FACT - FDE developers began to understand the new format and produced flight models for FS2K2 that were vastly superior to any previous version (including the ability to sustain a spin... which had never been accomplished before).8. IMOP - So far, I have yet to see any "SAD NEWS" about the flight dynamics in FS2004. While I've seen some "concerns" (elimination of angle-of-incidence, wing twist, etc.), Ron Friemuth has actually been somewhat "up-beat"... and he's easily the most recognizable personality in that thread.9. IMOP - FSAviator has made some valid points; but his "long-winded" conclusions may not be all that relevant in the long run. It seems quite possible that the "show-stoppers" might indeed be corrected by adjusting alternate parameters.10. IMOP - Although there has been 'some' intelligent discussion; in this particular forum, most posts related to this topic have amounted to a bunch of MINDLESS DRIVEL. I apologize for being critical, but it blows my mind to see so much mis-information being posted (pro and con) by folks who don't have a clue as to what they're talking about.11. IMOP - I could be wrong; but I expect Ron, Steve, Rob, and all the other "miracle-workers" to produce some fantastic FS2004 flight models for us in the coming months and years - despite the fact that Microsoft "screwed" them... again.Regards,Marc

[tgibson 11]

If you had bothered to read his posts, he clearly states that he altered both the values in the air file AND the new values in the cfg file. Geez, try reading things before bashing the author!And I find your anti-MS conspiracy theories as laughable as the other's MS conspiracy theories!--Tom GibsonCal Classic Propliner Page: http://www.calclassic.comFreeflight Design Shop: http://www.freeflightdesign.comDrop by! ___x_x_(")_x_x___

[Guest]

>including the ability to sustain a>spin... which had never been accomplished before).Are there any light aircraft for FS2002 in the avsim file library that will do this?Mike

[michal 44]

>The Lone Gunmen realize this statement is "hogwash", so does>everybody else, Marc,I wouldn't be so sure about it. I work at NASA Ames and we develop complicated aircraft prediction-trajectories for the product called CTAS (now tested at DFW Center) - an ATC software tool. To predict aircraft trajectories complex equations have to be solved that involve a lot of aircraft-specific performance data. You would think that NASA-FAA would have no problem getting such data from Boeing or Airbus. The reverse is true. It is extremely difficult to get them and what we have was derived indirectly. I heard on multiple occasions that aircraft manufacturers for reasons known only to them are very reluctant to release the data.For some other work we also need airline specific data - for example which flight # correspond to what aircraft N#. Again, airlines flatly say 'no' to such requests citing all kinds of reasons.Michael J.http://www.reality-xp.com/community/nr/rsc/rxp-higher.jpg

[Bert Pieke 7,584]

You've got to buy the RealAir Marchetti.. Rob Young is the author.www.realairsimulations.comWonderful plane BTW... and it flies well in FS9 as well..

[Guest WorkingStiff]

The Valmet L-70 Vinka spins and its freeware. I'm not sure its in the AVSIM file library but you can find it at the Flight Simulator Nordic website: http://www.fsnordic.net/