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Question re aircraft dynamics -wing roll

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I have this 1940's aircraft which looks great, sounds even better and flies like I can imagine it should!! - slow and lumbering!! (But I'm not going to say what it is - showing respect to the author/creator)But I have one problem with it - if you put it into say a 20 degree left bank , it seems to do this correctly -- but when you ease back on the stick to level out, it wants to quickly overcorrect itself and go into a RIGHT bank. It is almost impossible to bring the aircraft back onto a straight and level without this overcorrection in the opposite bank direction.I don't know if this is a real modelling of this aircrafts' characteristics , but I haven't noticed such a thing with other similar aircraft like the DC3s. But anyway, in the Sim, it makes it very difficult to fly and I am wondering if there are some simple adjustments I could make to the aircraft.cfg file.Barry

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Barry,I never noticed anything like that. Some planes respond too fast (especially pitch) but they do it the same in both directions.The only thing I can suggest is to use FSedit to open the cfg file. Look for the roll moment of inertia (MOI) and increase it big time, maybe double. Another thing is the slider for airleron effectiveness. You would have to back that off. You can use Notepad instead of FSedit if you prefer.This type of tweaking can be very effective unless something else needs changing in the air file.John Woodward

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Find the Roll MOI entry in the aircraft.cfg... Lower the number there. The higher the number, the more difficult it will be to stop the role. -John

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Below is the data I recorded from the Debonair, by Geof, doing a 360 degree roll with my new multi channel digital recorder. I wasn't checking the recovery, only trying to determine the roll rate. http://ftp.avsim.com/dcforum/User_files/3dd9b80b2c1565a7.jpgWe can get this data on any aircraft flying in FS2002. From it you can make certain your aircraft will be accepted by "most" of your customers.If you can feel confortable about it, please email me the name of the plane so I can add its performance to my data collection as a possible floor value --- don't be here value. We will not be attaching names to the "poor" acceptance aircraft. Thanks,Bob

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Wasn't any need. The author of Version 8,Ignacio Hernandez-Ros (ihr@mail.ddnet.es or ihr@recol.es) has made a very nice itnerface where you can name the output file; decide to append it or create a new one, select from a list the parameters you wish to monitor, and select the sample frequency. the output can also be saved as a binary file or a XML file. The xml file falls into Excel very nicely. Having worked with "similar" type data for CAT engines, I didn't use the Excel templetes that Ignacio provided. My project next is to increase the MOIs and show how that impacts the performance. Good part about all this is I don't come home with grease and diesel fuel on me any more. And with FS I don't even get air sick from the testing. ;-) Got any good test pilots who can roll the aircraft, spin it, stall it, and follow a script of needed tests? We could do it via multiplayer on your new product -- You fly, I record the data and reduce/analysis it and help tweak it into the performance package you want to publish. (Gregory Abbey -- interested?). Doing this, we can make sure an aircraft will be accepted by "most" of your targeted customers.sidebar ...Nice thing about FS is that you can increase/decrease MOIs withOUT changing mass. They errored on that part of the simulator, no problem, just not real world. If the mass increased/decreased with the MOIs then we would impact the climb rates, angle of attacks ... they made it easier for us. Thanks MS.Bobwe r rsam@mtco.comAs it says in the readme ...The latest version of FLTREC.DLL may be downloaded form the NAV2 home page at: (Ignacio Hernandez-Ros) http://avsim.com/hangar/utils/nav

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>Find the Roll MOI entry in the aircraft.cfg... Lower the >number there. The higher the number, the more difficult it >will be to stop the role. >>-John I have been playing around with the Roll MOI -- but it is not affecting the situation with this aircraft. From my "playings around" , it appears to me that the Roll Moi affects the ease and speed with which you can roll the aircraft.But , this problem relates to the way in which the aircraft wants to return to the straight and level while in a bank . It wants to return to straight and level so much that it overcorrects and goes into an opposite bank.Barry

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A question of roll stability rather than inertia then?Another thought. Are you getting any yaw associated with the over correction? It might be worth checking yaw stability as well.

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>A question of roll stability rather than inertia then? >>Another thought. Are you getting any yaw associated with the >over correction? It might be worth checking yaw stability as >well. No problems with Yaw -- just this roll overcorrection.Will have a look at the Roll Stability setting -- I think it is the default setting of 1 right now.Barry

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>>The author of Version 8,Ignacio Hernandez-Ros >(ihr@mail.ddnet.es or ihr@recol.es) has made a very nice >itnerface where you can name the output file; decide to >append it or create a new one, select from a list the >parameters you wish to monitor, and select the sample >frequency. the output can also be saved as a binary file >or a XML file. >>The xml file falls into Excel very nicely.>>Having worked with "similar" type data for CAT engines, I >didn't use the Excel templetes that Ignacio provided. My >project next is to increase the MOIs and show how that >impacts the performance. Good part about all this is I >don't come home with grease and diesel fuel on me any more. >And with FS I don't even get air sick from the testing.>>Got any good test pilots who can roll the aircraft, spin it, >stall it, and follow a script of needed tests? We could do >it via multiplayer on your new product -- You fly, I record >the data and reduce/analysis it and help tweak it into the >performance package you want to publish. >>(Gregory Abbey -- interested?)>>Doing this, we can make sure an aircraft will be accepted >by "most" of your targeted customers. > [/p] [/p]FS2002 data collectionHello and compliments on this thread..Thanks for bringing this power little module to our attention.. have not heard of it before. Went ahead and got it working in order to capture a RADICAL 767 takeoff profile.http://www.edwinn.com/flightsim/767_data.gifInteresting notes 1) Engines initially set to low 90's - crept up well over 100 2) Radical climb rate with instantaneous of over 8,000 fpm 3) IAS hold can be seen to `ring' as a control/feedback loop 4) V_rate also cyclic - is nature of Autopilot 5) V_rate scaled /100 - IAS scaled /10 for charting [/p] [/p] [/p]Gregory Abbey - Edwinnengineering

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>I just posted my latest work at: >http://ftp.avsim.com/dcforum/DCForumID8/13798.html#0 >>The title is "You can feel the difference and I can find >it." >>>Much progress today! Now have to turn into a real student >and do my ProE homework for early in the morning. >>Thanks, >Bob Bob I downloaded this Flight Recorder programme this morning , installed it, ran it and had VERY quick look at the documentation. It seems that you need to use Microsoft Excel to do anything with the output ? Is this true? During my very brief reading of the documentation, I quickly came to the conclusion that the instructions on how to use this programme were not all that clear??I don't have Excel but do have the spreadsheet programme incorporated into Microsoft WORKS. Can I use that? I have never used the Works spreadsheet much -- why is it that everything I look at associated with FS2002 has such a steep learning curve for me!!!! :)Barry

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"you need to use Microsoft Excel to do anything with the output ? Is this true?"The data is saved as in xml format which is nothing more then text delimited with ". Any program that can import text and generate plots can be used."how to use this programme were not all that clear" I had no problem. But my background and real world job used this type of data. the nice part is I don't have to hope the data recorder that I brought along will still work following a trip to Lima in the belly of a 747 and the back of a service truck driven by a guy who thinks his next job is going to be a formula one driver. ;-)"programme incorporated into Microsoft WORKS. Can I use that?"I don't know of that program package. However, I bet if it is a spreadsheet program it will have the ability to graph the data."never used the Works spreadsheet much" The data reduction will be a large challenge for you without any experience. You won't be able to generate similar results without a LOT of work learning the ins-and-outs of your spreadsheet program. Plotting several parameters on one graph takes a little experience/practice to get them to look correct and be of value.I worked most of the day on the two 172 data sets and I have done this many times on CAT engines for real. It would take me a day for them also. It is "easy", but it does take time and experience.What impact did the change in Moi have for you? Make it smaller as Jon suggested. Iterate, cut it half and see what happens. If that is too much, PUT IT BACK TO 75% ....Good luck,Bob

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The tendency to return to level flight from a bank sounds more like a supercharged dihedral effect.Check the air file section 1204 and make sure wing dihedral is less that say ... 4.00 depending on your aircraft design. Milton

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>The tendency to return to level flight from a bank sounds >more like a supercharged dihedral effect. >>Check the air file section 1204 and make sure wing dihedral >is less that say ... 4.00 depending on your aircraft design. >>Milton Thanks Milton I had "kind of" worked this out myself after doing some reading -- but I thought that the number entered for dihedral in the aircraft.cfg file would be determined by the real life aircraft design (just like length , etc)and input accordingly. The dihedral for this aircraft was 6.25 -- I had already lowered it to 4 before you posted and that had improved things a lot . I will try it a bit lower and see how it works.Barry

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