I'll give it a try tomorrow around 7:30 AM Lisbon time :-) and post the results!Thx for the hint!

So the Archer does roll left on takeoff/climb, and that is acceptable, but the ball keeps almost allways tied to the center. OTOH it show excessive adverse yaw on turns, while the AS-K21 glider, for instance, looks more like an Archer....

Not sure I understand what you mean, but about the adverse yaw I put that in on purpose because thats how I feel the real one is (can be tuned)Also be aware that the amount of adverse yaw can be perceived somewhat different depending on your field of view angle and resolution settings...M

Hi,first of all congratulations for a great model, your ArcherIII !Gave a look into the "airfile" and it looks very complete and exhaustive, with data that I can't confirm but you surely can, including the prop pointing down a litle, but with no lateral cant.I found strange that the incidence at the root is lower, but I don't have data on the real Archer.Contrarily to the default prop aircraft in xplane your Archer while still banking left when climbing at climbing power, does it in a rather acceptable way, and, as some pointed out, apparently it doesn't start banking right when throttle is reduced (well... maybe just a tiny bit - I still have to check...) Anyway, either because that's a bug on xplanes turn&slip coordinator or in the core FM, the ball in the turn coordinator stays practically centered no mater if your using full power on a climb or cruising... I believe that your RL experience will show the opposite, with you right foot having to kick the ball during initial climb at full power (?)Regarding the adverse yaw, I remember from flying with a fellow pilot on his own Archer that turns looked coordinated with yoke input only.Tomorrow I will test further!Panel looks GREAT!

The Archer is my first and only prop aircraft so far so it's been a learning process building it.It probably can be tuned a bit here and there, especially the engine. In fact I have a real engine mechaniclooking at it now.However, I discovered a couple of XP issues building it;As you correctly suspect, the real Archer has a 3 deg lateral engine cant to counter the propwash effect on the tail. If you try this in XP you'll encounter it's more or less impossible to keep the aircraft out of the ditch!This is because of XP's GROUND MODEL issue (I have a long topic about it over at .ORG) which in short is thatXPs sideload gear friction is too low. Or rather, there is computational creep (which I can't even begin to explain)SO, because of this I suspect Austin had no choice but to tone the Pwash effect DOWN to prevent all prop aircraftfrom ditching on takeoff.. . This also explains the ball being too centered on climb and the prop aircraft in generalbeing "too coordinated" at hight power.(For those wondering, XP has a much more advanced groundmodel than FS)So the solution would be to either get Austin fixing it (which Ben S says he probably cant) or make a plugin like we have on the 737that improves the ground model so you can put in the real engine cant.( or write a plugin that manipulates the ball :( )So as you can see, one problem can lead to another and doing flightmodels for EITHER sim is all about understandingthe sim and the real world and try to find solutions to issues.

MortenM, GREAT POST!Great insight on xplane's internals... I wish we met back around 2006 / 2007 when I was a lot more involved with this sim... I had so many questions emails exchanged with Austin, Brett Stumpter, et al.... In a few paragraphs you have beautifuly and efectively explained quite a LOT!Now I am going to tune down xp10 in terms of Graphics settings (didn't find a way to turn OFF all of the useless AI...) to run the test with the K21 gliderMurmur asked for....

The Archer is my first and only prop aircraft so far so it's been a learning process building it.It probably can be tuned a bit here and there, especially the engine. In fact I have a real engine mechaniclooking at it now.However, I discovered a couple of XP issues building it;As you correctly suspect, the real Archer has a 3 deg lateral engine cant to counter the propwash effect on the tail. If you try this in XP you'll encounter it's more or less impossible to keep the aircraft out of the ditch!This is because of XP's GROUND MODEL issue (I have a long topic about it over at .ORG) which in short is thatXPs sideload gear friction is too low. Or rather, there is computational creep (which I can't even begin to explain)SO, because of this I suspect Austin had no choice but to tone the Pwash effect DOWN to prevent all prop aircraftfrom ditching on takeoff.. . This also explains the ball being too centered on climb and the prop aircraft in generalbeing "too coordinated" at hight power.(For those wondering, XP has a much more advanced groundmodel than FS)So the solution would be to either get Austin fixing it (which Ben S says he probably cant) or make a plugin like we have on the 737that improves the ground model so you can put in the real engine cant.( or write a plugin that manipulates the ball :( )So as you can see, one problem can lead to another and doing flightmodels for EITHER sim is all about understandingthe sim and the real world and try to find solutions to issues.

Murmur, and MortenM,I finally got rid of the AI, and there was a rather self-explaining box to check in the Rendering Options screen - "set all rendering options for maximum speed" - I checked it for all my tests.Now, just as Murmur suspected, I was unable to reproduce that weird effect on the AS-k21 :-) I believe that option - number of FMs per frame - isused to decrease the "tick interval" in the simulation cycle, thus increasing it's level of detail (?).Regarding the option Austin took on the "damping" of slipstream effects due to it's interactions with the ground model, if you can talk to him orBen (?) and try to convince them to do something about it, I believe one could end up with an even more interesting simulator, already very complex andexhaustive in terms of design options, but still suffering from this weird limitations, sometimes not very well supported/justiffied IMO.Thank you both for your suggestions and MortenM for the rather important information on xplane physics model details!!!

Hi jcomm, can you try the same with the "flight models per frame" value (menu "Operations & Warnings") upped to, say, 4 or 5?I'm curious to know if it exhibits the same behaviour.Marco

(For those wondering, XP has a much more advanced groundmodel than FS)

Years ago, back in the days of Microsoft's Combat 1 & 2 simulators, the ground model effects were much better than todays. Some were eliminated to increase frame rates as I remember. However, some third party programmers have done some very good work arounds. The RealAir Spitfire is a good example of this. I enjoy the takeoff roll, climb, and landing effects in this aircraft.

Hi MortenM,Have enjoyed many of your creations over almost a decade now and hopefully will continue to. Your countless number of creations and dedication to X-plane is admirable and very much appreciated.May I ask if you have had any personal contact and/or discussions about the X-plane flight model and how it can be improved. If anyone can make suggestions to Austin, it would be you. I believe you are residing somewhere in Europe and Austin seems to prefer having X-plane get-togethers in Europe - he hardly has any in the US - haven't heard of any, so it might perhaps be easier for you two to meet to discuss X-plane's FM. I am sure you would have a few suggestions for him that he could incorporate into X-plane to improve the FM.Thank you for all your wonderful creations over the years and look forward to more - hoping you would create more and diversify your talents - like the Archer III.Thank you again.

Thanks,I've met Austin on a couple of occasions in France over the years and had countless (heated) discussions with him about flightmodelboth in person and offcourse emails. Dozens of issues have been improved/fixed over the years. There are several other keydevelopers - especially in the past - that have played a similar role so I'm far from the only one. I've had an advantage though since I mostly make airlinerswhich probably are the best documented aircraft out there for safety and economy reasons so I'm often the one that discovers issues first andI often can prove it. I also once started XPRT (XP Research Team) which sole mission was to document issues and present them to Austin.About 10 of the best engineers in XP, developers (Murmur here was a member) and a couple of pilots. The problem is Austin has a very pragmatic approach to flightmodel changes. Basically he says "I'm right until you proved me wrong".Which means YOU need to come up with the documentation - and - he usually doesn't show you his logic, so you can't pick it apart.You have to figure it all out yourself by testing in the sim.He offcourse gets loads of e-mails from people making all sorts of stupid claims that don't have a clue without documentation so I don't blame him.This however makes it very time-consuming to convince him you're right - even if you have the documentation. I remember once, we even had toget a written plea from the CHIEF DIRECTOR OF AERODYNAMCS at NASA DREYDEN (!!) to make him listen (Don't ask how we got it, probably the most highly regarded engineer in the world). Then, if you manage you might have to wait months before it gets implemented.So once plugins came along, we find it easier to just fix whatever it is ourself :( . This being said, AFAIK, there are very few issues left in XP subsonic model and it's very possible to make a great flightmodel withoutplugins if you know what you are doing. But plugins can take it to perfection. And I'm convinced this is the way to go and when the bigdevelopers come to XP they'll take this approach.

So, th

Thanks,I've met Austin on a couple of occasions in France over the years and had countless (heated) discussions with him about flightmodelboth in person and offcourse emails. Dozens of issues have been improved/fixed over the years. There are several other keydevelopers - especially in the past - that have played a similar role so I'm far from the only one. I've had an advantage though since I mostly make airlinerswhich probably are the best documented aircraft out there for safety and economy reasons so I'm often the one that discovers issues first andI often can prove it. I also once started XPRT (XP Research Team) which sole mission was to document issues and present them to Austin.About 10 of the best engineers in XP, developers (Murmur here was a member) and a couple of pilots. The problem is Austin has a very pragmatic approach to flightmodel changes. Basically he says "I'm right until you proved me wrong".Which means YOU need to come up with the documentation - and - he usually doesn't show you his logic, so you can't pick it apart.You have to figure it all out yourself by testing in the sim.He offcourse gets loads of e-mails from people making all sorts of stupid claims that don't have a clue without documentation so I don't blame him.This however makes it very time-consuming to convince him you're right - even if you have the documentation. I remember once, we even had toget a written plea from the CHIEF DIRECTOR OF AERODYNAMCS at NASA DREYDEN (!!) to make him listen (Don't ask how we got it, probably the most highly regarded engineer in the world). Then, if you manage you might have to wait months before it gets implemented.So once plugins came along, we find it easier to just fix whatever it is ourself :( . This being said, AFAIK, there are very few issues left in XP subsonic model and it's very possible to make a great flightmodel withoutplugins if you know what you are doing. But plugins can take it to perfection. And I'm convinced this is the way to go and when the bigdevelopers come to XP they'll take this approach.

So the simple statement, "This plane rolls to the right, or rolls way to much" from a qualified pilot with x number of hours in the same plane is NOT ENOUGH for Austin?There is more to this than meets the eye, and I am a simple man.Bob

So the simple statement, "This plane rolls to the right, or rolls way to much" from a qualified pilot with x number of hours in the same plane is NOT ENOUGH for Austin?There is more to this than meets the eye, and I am a simple man.

Correct, because that might as well be an error made by the designer of the aircraft - and it usually is..

Correct, because that might as well be an error made by the designer of the aircraft - and it usually is..

I stand corrected then. I will still say that "I Think", based on Carenado's reputation, that if this were true they would have it fixed by now. Granted, Carenado is new to X-Plane and it may be they are just not familiar enough with X-Plane, which might explain the delay. I guess we wait and see. I think 1 email to Carenado might just explain the issue, maybe. Whatever the issue, I just hope it does not turn into a finger pointing exercise.BobBob

Just for the record, I have not tried the Corenado and I'm not suggesting there is a problem with it.I'm sure they know what they are doing. I'm just speaking in general terms...M

Guys... I'm released from this PITA... with Xplane's FMs intricacies... Sorry to be so honestly crude.... Or crudely Honest....Go figure :-)or....See my signature... :-)

Guys... I'm released from this PITA... with Xplane's FMs intricacies... Sorry to be so honestly crude.... Or crudely Honest....

Trust me, FS and other sims have their FM intricacies as well. I could tell you issues there all day long.The reason you don't hear too much about them is because the designers thereare not as open about them as we are - maybe since there is a lot more money involved.Here is a statement by PMDG which sums it up nicely;"When working within the confines of the rather limited MSFS phyisics model,it is necessary to take some liberties in order to ensure that performance in the end,comes out well balanced."http://support.precisionmanuals.com/KB/a47/why-are-the-contrails-misaligned-i-found-a-hack-to-fix-it.aspxAnd cudos to them for being honest about it.M