modifying aircraft performance
Results 1 to 19 of 19

Thread: modifying aircraft performance

  1. #1
    SOH-CM-2019
    Join Date
    Jan 2014
    Location
    Front Royal, Virginia, United States
    Posts
    405

    modifying aircraft performance

    I have been flying fs2004 since the beginning and have never messed with any aircraft performance. Now I am the proud owner of my own airplane in real life I would like to modify its FS9 counterpart to fly more like the real thing. What are the tools, tips and procedures for doing this kind of modifying?

    Thanks,
    Sean

  2. #2
    Try starting here

    https://www.aero.sors.fr/fsairfile.html

    http://www.mudpond.org/

    What aeroplane are you trying to match?

    Ttfn

    Pete

  3. #3
    SOH-CM-2019
    Join Date
    Jan 2014
    Location
    Front Royal, Virginia, United States
    Posts
    405
    Quote Originally Posted by Motormouse View Post
    Try starting here

    https://www.aero.sors.fr/fsairfile.html

    http://www.mudpond.org/

    What aeroplane are you trying to match?

    Ttfn

    Pete

    Challenger 2 CWS

  4. #4
    Quote Originally Posted by jackryan172 View Post
    Challenger 2 CWS
    Same variant as Bill Lyons did?

    Ttfn

    Pete

  5. #5
    SOH-CM-2019
    Join Date
    Jan 2014
    Location
    Front Royal, Virginia, United States
    Posts
    405
    Quote Originally Posted by Motormouse View Post
    Same variant as Bill Lyons did?

    Ttfn

    Pete
    Thats what I am running now. Its pretty close but it is too fast and isnt draggy enough.

    Sean

    Here is my real life Challenger:

    Attached Thumbnails Attached Thumbnails 0608190947a.jpg  

  6. #6
    SOH-CM-2019 Mick's Avatar
    Join Date
    Jun 2005
    Location
    Easthampton, Mass., U.S.A.
    Age
    71
    Posts
    2,689
    How about this:

    In the [flight_tuning] section of the aircraft.cfg file, experiment with these two values:

    parasite_drag_scalar = 1.0
    and
    induced_drag_scalar = 1.0

    Then in the [piston_engine] section, fiddle with:

    power_scalar = 1.0
    or
    max_rated_hp= 65

  7. #7
    SOH-CM-2019
    Join Date
    Jan 2014
    Location
    Front Royal, Virginia, United States
    Posts
    405
    Quote Originally Posted by Mick View Post
    How about this:

    In the [flight_tuning] section of the aircraft.cfg file, experiment with these two values:

    parasite_drag_scalar = 1.0
    and
    induced_drag_scalar = 1.0

    Then in the [piston_engine] section, fiddle with:

    power_scalar = 1.0
    or
    max_rated_hp= 65
    Wow! That fixed a lot of the issues. It cruises at the right speed now and it climbs right, slows down correctly. Spot on. The only other issue is that it is a very rudder dependant airplane. Turns always start with the rudder then you add in in aileron to adjust the turn bank. Any suggestions to fix that?

    Sean

  8. #8
    SOH-CM-2019
    Join Date
    Apr 2011
    Location
    Deux-Sevres, France
    Age
    81
    Posts
    1,427
    Have you got Auto rudder selected in Aircraft> Realism Settings?
    If not then what exactly is the problem; if you are initiating a turn with rudder - is there no bank associated? If the latter, then you will need to delve into the .air file block 1101 & play, by trial & error the rudder values & maybe the aileron values.
    Hope this is of assistance
    Keith

  9. #9
    SOH-CM-2019
    Join Date
    Jan 2014
    Location
    Front Royal, Virginia, United States
    Posts
    405
    Quote Originally Posted by Dev One View Post
    Have you got Auto rudder selected in Aircraft> Realism Settings?
    If not then what exactly is the problem; if you are initiating a turn with rudder - is there no bank associated? If the latter, then you will need to delve into the .air file block 1101 & play, by trial & error the rudder values & maybe the aileron values.
    Hope this is of assistance
    Keith
    I have seperate rudder pedals so I have auto rudder turned off. In the real aircraft, you fly it with much more rudder, and not so much aileron. Its the opposite of flying a Cessna, where you give it aileron and it turns, the rudder is almost an afterthought. In a Challenger you learn to "Play the pedals". a turn is generally started by initiating it with pedals and then the roll is adjusted to coordinate the turn. Does that explain better?

    I am poking around in this area of the config:

    [flight_tuning]
    cruise_lift_scalar=0.8
    parasite_drag_scalar=1.0
    induced_drag_scalar=1.0
    elevator_effectiveness=1.0
    aileron_effectiveness=1.0
    rudder_effectiveness=1.0
    pitch_stability=1.0
    roll_stability=1.0
    yaw_stability=1.0
    elevator_trim_effectiveness=1.0
    aileron_trim_effectiveness=1.0
    rudder_trim_effectiveness=1.0

    I assume I want to adjust:
    aileron_effectiveness=1.0
    rudder_effectiveness=1.0
    or
    roll_stability=1.0
    yaw_stability=1.0

    Am I in the right ballpark?



    Sean

  10. #10
    Quote Originally Posted by jackryan172 View Post

    I assume I want to adjust:
    aileron_effectiveness=1.0
    rudder_effectiveness=1.0
    or
    roll_stability=1.0
    yaw_stability=1.0

    Am I in the right ballpark?



    Sean
    Try increasing rudder effectiveness by 0.1 at a time,
    I'll have to check in the sdk how much each adjustment varies... its by a percentage factor of 1 IIRC, so rudder effectiveness to 1.1 is 10% more than 1.0... back in a bit with an answer (unless anyone else answers first) I wouldnt adjust the stability, that can make things very unflyable.

    here we go
    [flight_tuning] section

    Flight control effectiveness parameters

    The following parameters are multipliers on the default "power" of the control surfaces. For example, a value of 1.1 increases the effectiveness by 10 percent. Likewise, a value of 0.9 decreases the effectiveness by 10 percent. A negative number reverses the normal effect of the control. Omission of a parameter results in Flight Simulator defaulting to a value of 1.0.
    Note: elevator_effectiveness, aileron_effectiveness, and rudder_effectiveness are adjustable using the Flight Simulator Aircraft Editor.
    and for stability

    Stability parameters

    The following parameters are multipliers on the defaultstability (damping effect) about the corresponding axis of the airplane. Forexample, a value of 1.1 increases the damping by 10%. Likewise, a value of 0.9decreases the damping by 10%. A negative number results in an unstablecharacteristic about the axis. A positive damping effect is simply a moment inthe direction opposite of the rotational velocity. Omission of a parameter willresult in Flight Simulator defaulting to a value of 1.0.


    Ttfn

    Pete

  11. #11
    Hi Jack,

    If you'd care to visit the first link posted in Motormouse's first post, and download a copy of AirEd V1.52, I'll describe what I think you may need to edit. ( There's an updated ini file also.....DON'T bother with it for now. Just for this exercise, it's not needed.)

    Looking at the photo you've posted of the Challenger, one can see it's got plain ailerons and a narrow, wasp-like waist, pusher prop and engine amidship. I'll bet if you're cruising a straight line and initiate a roll with only ailerons, the nose will yaw opposite the roll, and she will slowly side slip into an uncoordinated turn, loosing speed and altitude at the same time.

    Am I right...?

    Okay.

    Any adjustments you've made to the rudder & aileron inputs in the aircraft.cfg scalars, return them to original values. (1.0?)

    Unzip AirEd, open the program, go up to "file" and left click on that, then as the menu drops down, left click on "open". A window will open, and if it's the first time you've used AirEd, you'll need to browse all the way to the sim, and right to your Challenger model until you see the air.file, and then open that.

    Now you're looking at the real blood and guts of the thing.

    Scroll down to section 1101 Primary Aerodynamics. Left click on the header and that section will open up for you.

    Scroll down and pay attention to these following entries:

    *Cn_beta Yaw Moment - Sideslip (Weathervane Stab)=

    ----and----

    *!Cn_da?Yaw Moment - Aileron?=


    >>>For the (Weathervane Stab) entry, the higher the number, the greater the model's quality to simply turn (or weathervane) into a roll. Reduce the number, and it will resist. ( The Challenger will resist, so look at lowering the existing number.)

    >>>For Yaw Moment - Aileron, it's a negative number. For instance, the unmodified AI Piper PA-28 in my sim shows the value of -13.

    At that level, an aileron roll would be very clean, without any adverse yaw. Crank that value up to -200, and you'll see some real difference. (Maybe too much...)

    These two entries are not so sensitive, so you can really lay on the numbers to create a noticeable effect.

    Also, scroll that section back up just a bit and check *Cl_da Roll Moment - Rudder= ....and ensure that it has a negative value....-10, -25, whatever. This will ensure that your rudder input will roll the plane in the correct direction. (inboard the yaw)

    I frequently find models that refuse to roll with rudder input and find that entry created with a positive value instead of negative.

    Also make sure that you back up the original file before you start carving it up.

    How this helps make the Challenger more accurately challenging.....

  12. #12
    SOH-CM-2019
    Join Date
    Jan 2014
    Location
    Front Royal, Virginia, United States
    Posts
    405
    Thanks everybody, this is going to be a more involved endeavor then I originally imagined so I am going to bury myself in the document provided. I am looking forward to learning this stuff, and making the Challenger more challenging

    Sean

  13. #13
    Oh yes....you are reloading the aircraft after changes to test...right?

    What's the keyboard command in FS9....is it Ctrl + Shift +R ?

  14. #14
    SOH-CM-2019
    Join Date
    Jan 2014
    Location
    Front Royal, Virginia, United States
    Posts
    405
    The original values are

    *Cn_beta Yaw Moment - Sideslip (Weathervane Stab)= 270
    *!Cn_da?Yaw Moment - Aileron?= -30

    I Have modified them to be:

    *Cn_beta Yaw Moment - Sideslip (Weathervane Stab)= 150
    *!Cn_da?Yaw Moment - Aileron?= -40

    the aircraft behavior is getting closer

    I couldn't find the
    *Cl_da Roll Moment - Rudder=

    entry but I did find

    *Cl_da Roll Moment - Ailerons (Control) =-466
    and
    *CL_dr Roll Moment - Rudder=30

    So I'm not sure which one to modify. Any suggestion would be helpful.

    Since I have been poking around I noticed some additional variables I hadn't heard of before but may be useful. In real life, when you apply power to the Challenger, due to it having a pusher with a high thrust line, it will pitch nose low initially then the nose will eventually start to climb up as air speed increases. The opposite is true in reducing power, pull back and the nose rises until airspeed starts to decrease, then the nose will drop.

    Thanks,
    Sean

  15. #15
    Ooops.....one small typo and I could totally mess you up. My apologies.

    It is *CL_dr Roll Moment - Rudder= that's what I meant to direct you to, not da.......

    So yes....

    *CL_dr Roll Moment - Rudder=30 .........change that to maybe .....ummm......-15....and see how it flies. Add or subtract to taste.

    *Cl_da Roll Moment - Ailerons (Control) =-466 ......are the ailerons too strong, to weak..? Lower the number to reduce effect, raise the number to increase.

    *Cm_dT Pitch Moment - Thrust= is a scalar that can provide a pitch value, essentially thrust across the tail plane. The default AI-Pa-28 shows a value of -0.0512.

    That's be typical for a tractor engine/prop setup. Power on, nose up. Power off, nose down.

    If your model displays a negative value, try changing to a positive value and see what it does. Also, this is an entry that can be sensitive to number value, a little can create a big effect. I would think 0.03 would be normal.....but that doesn't take other factors into account on the existing flight model.

    Try & test.

    ....And.....noting others who have already piped in....welcome to our world. You may find it addictive after some initial frustration is overcome.

  16. #16
    Okay Jack, I'm going to complicate things for you.

    The Challenger being a "shoulder" engine pusher design is going to fly different than most modern types. It make me think a lot of the Curtiss CW-1 Junior.

    In order to really get cooking with this, one can begin by sorting out the virtual dimensional model, matching as close as possible to the graphic visual model. This can transform the flight qualities, especially if you're familiar with the type in real life.

    The program to do this is an old ex-payware proggie called Aircraft Container Manager (For FS2004 only!).

    You can pick it up at Simviation , page one of FS2004 utilities section, scroll down three entries.

    https://simviation.com/1/browse-Utilities-41-0

    One issue is installing in Windows 8 or higher. Some folks are installing into Win7 and then copying over to the newer OS.

    Still not done.

    To get it to run on Win7 64bit or higher, you need to google & download three file and add them to the ACM root folder.

    They are:

    VCL40.bpl

    VCLJPG40.bpl

    VCBX40.bpl

    Once you've got it running.....an entirely new world of distraction will open up for you.

  17. #17
    SOH-CM-2019
    Join Date
    Apr 2011
    Location
    Deux-Sevres, France
    Age
    81
    Posts
    1,427
    Just a thought on the rudder sensitivity - is the real aircraft sensitive to power on/power off, seeing as the prop thrust is close to the rudder? I think there is a feature in 1101 that caters for that.
    Magoo, some nice insights into your descriptions that I have previously blundered into, thanks!
    Keith

  18. #18
    SOH-CM-2019
    Join Date
    Jan 2014
    Location
    Front Royal, Virginia, United States
    Posts
    405
    Quote Originally Posted by Dev One View Post
    Just a thought on the rudder sensitivity - is the real aircraft sensitive to power on/power off, seeing as the prop thrust is close to the rudder? I think there is a feature in 1101 that caters for that.
    Magoo, some nice insights into your descriptions that I have previously blundered into, thanks!
    Keith

    It is sensitive in pitch as you pull back power the nose will initially pitch up then drop as air speed bleeds off. Opposite for adding power. I dont really have any issues in rudder, but I will have to pay more attention next time Im up.

    Sean

  19. #19
    SOH-CM-2019
    Join Date
    Apr 2011
    Location
    Deux-Sevres, France
    Age
    81
    Posts
    1,427
    Quote Originally Posted by jackryan172 View Post
    It is sensitive in pitch as you pull back power the nose will initially pitch up then drop as air speed bleeds off. Opposite for adding power. I dont really have any issues in rudder, but I will have to pay more attention next time Im up.

    Sean
    Yes I would expect that seeing as the thrust line would appear to be above the expected centre of drag. One can play with the thrust dimension of course, but there is a value for adjusting the reaction I think in 1101. Will try & find it.
    BTW have you visited Herve Sors website & downloaded his software - he has a program Aircraft Airfile Manager - the big difference is that one can read tabular info in Air Ed can be viewed as a graph, but the values are shown as coefficients as opposed to M$ values.
    Another useful program is AFSD which can be run during a flight & see what the value of some things are.
    Gets very addictive, good luck.
    Keith

Members who have read this thread: 83

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •