FSX Can't get wheel positions to work correctly

#1
I'm trying to teach myself how to do this whole plane design thing, so please excuse the probably dumb question, but I've got a simple model, and in the aircraft.cfg i've tried to get the wheel placements to work, but it seems no matter what numbers I use, it makes no effect, and if I pause it right when the sim loads, all the wheels appear to be on the ground, like so:
But after I un-pause it immediately crashes.

My contact points in my aircraft.cfg file look like this:
Code:
[contact_points]
point.0=1, 34.3,   0.00, -10.1, 1181.1, 0, 0.6349, 46.8, 0.3000, 2.5, 0.9100, 10.0, 10.0, 0, 260.0, 260.0
point.1=1, -8.5,  -6.74, -9.9, 1574.8, 1, 0.6349,  0.0, 0.4798, 2.5, 0.5456,  9.0,  9.0, 2, 260.0, 260.0
point.2=1, -8.5,   6.74, -9.9, 1574.8, 2, 0.6349,  0.0, 0.4798, 2.5, 0.5456,  9.0,  9.0, 3, 260.0, 260.0
point.3=2, -8.5, -6.7, -9.9,  787.4, 1, 0.0000,  0.0, 0.0000, 0.0, 0.0000,  0.0,  0.0, 5, 0.0, 0.0
point.4=2, -8.5,  6.7, -9.9,  787.4, 2, 0.0000,  0.0, 0.0000, 0.0, 0.0000,  0.0,  0.0, 6, 0.0, 0.0
but I just changed the position relative to the origin in blender, because I don't know what the other values do.

Let me know if you need the blender file or the full aircraft.cfg

Any help would be greatly appreciated.

-Patrick Gelvin
 
#2
Try removing the 2 contact points. Those could be in the way. Once all is good then add the contact points. Go search for the program "Flight Simulator X models Visualizer V1.01" This will show exact location of each contact point.
Also make sure the static_cg_height is slightly lower than the rear wheels. This is for the slew height.
 

hairyspin

Resource contributor
#3
As DG says, remove point.3 and point.4 which are in almost the same position as your left and right gear points. Points 3 and 4 are scrape points (type/class 2) which monitor impacts with ground, buildings, other aircraft and detect crashes.
 
#4
"don't know what the other values do"? Why, look up the SDK help file under "Aircraft Configuration Files" > contact points. Can't really do this plane design thing without reading stuff...

And sooner or later you'll have to use Milton Shupe's "Perfecting Suspension Setup (Repost)" -- googles fine.
 
#5
You can add these comments to the aircraft.cfg to remind you of what the values are:
Code:
       //0  Class
        //1  Longitudinal Position        (feet)
        //2  Lateral Position             (feet)
        //3  Vertical Position            (feet)
        //4  Impact Damage Threshold      (Feet Per Minute)
        //5  Brake Map                   (0=None, 1=Left, 2=Right)
        //6  Wheel Radius                (feet)
        //7  Steer Angle                         (degrees)
        //8  Static Compression           (feet)  (0 if rigid)
        //9  Max/Static Compression Ratio
        //10 Damping Ratio               (0=Undamped, 1=Critically Damped)
        //11 Extension Time              (seconds)
        //12 Retraction Time             (seconds)
        //13 Sound Type
Make sure you have a max_number_of_points=(a number equal to or greater than the number of contact points) entry below the point.x list.
Make sure your c of g is between your wheels. See [WEIGHT_AND_BALANCE] section
Make sure any station_load values to do not unbalance your aircraft.
Comment out point.3 and point.4
If you keep point.3 and point.4 change the 5th value to 0 because scrape points should not be brake mapped.
 

tgibson

Resource contributor
#6
Upon initial load, FS uses the following lines to place the aircraft:

static_pitch= 11.8
static_cg_height= 7.78

These set the pitch and height. The pitch is not 0 in my example because this is from a taildragger. BTW, these are also the values used while in Slew Mode (press the Y key to activate/deactivate), so you can also test these that way.

You apparently have these lines set correctly, but your actual contact point values are not correct. The static lines above should be set just BARELY above those in the regular contact point lines, so the plane settles down a tiny bit after load. If the regular contact points are located too far below the static location then the plane crashes or starts flying, or if located below the static location the plane will "jump up" or dance around and crash.

Hope this helps,
 

Paul Domingue

Resource contributor
#7
Go search for the program "Flight Simulator X models Visualizer V1.01" This will show exact location of each contact point.
Also make sure the static_cg_height is slightly lower than the rear wheels.
This got my attention since it looked like it might be similar to ACM but after some searching I can not find anything like this except for something called Final Approach Visualizer V1.0. Can you provide a link?

With some jumping through hoops I can use ACM for FSX but find it's easier to just use a text editor to edit the aircraft container and getting all my measurements in Max.
 

hairyspin

Resource contributor
#8
...it's easier to just use a text editor to edit the aircraft container and getting all my measurements in Max.
If you have the model source there's no excuse for getting contact point positions wrong. I think most go wrong not understanding what the points are and that FS doesn't care what the model looks like, it just reads these numbers.
 

n4gix

Resource contributor
#9
This got my attention since it looked like it might be similar to ACM but after some searching I can not find anything like this except for something called Final Approach Visualizer V1.0. Can you provide a link?
I put it in the Resources section about a year ago:
http://www.fsdeveloper.com/forum/resources/visualizer-fsx-or-p3d.134/
A simple sim connect tool that displays a host of positional data in real-time using Spot View. Selected items are indicated by red cross-hair(s) while in Spot View. Suggested views are fixed Left, Front, Rear, or Top.

Simply unzip this tiny .exe into a folder of your choice. I use C:\DATA\FS_Tools myself, where I keep all other tools such as ADE, etc. Start visualizer.exe at any time, then click on "Connect" to link with FSX or P3D.
 
#13
Sorry for bumping an old thread but God damn, thanks so much for the reload aircraft after aircraft.cfg edit tip. I kept closing then reopenning the sim after each edit and it got on my nerves. Thanks so much for that and for the Visualizer.
 
#14
Just bear in mind that if you're going to use the Reload User Aircraft key combo, whatever you assign it to, to make certain you have ALL the AI traffic turned OFF. ALL the AI sliders full left, in other words.
If it's not, the various .cfg files, including the one you're working on, may not be read, or not read in their entirety.
This means boats of all kinds, air traffic, vehicles, etc etc.

Have fun!
Pat☺
 
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