Aircraft TMD Self Help Group

  • I know a handful of people other than IPACS staff have successfully created aircraft for AF2 (Sylvain, Steve, Kai, Dino and Krystoff come readily to mind). The most challenging area seems to be the creation of the necessary config files and most of us will readily admit that any headway that is made is in no small measure facilitated by help from IPACS' Jet-pack (Jan). He is heavily involved with a master's thesis at the moment and will no doubt not have as much time to help us out. What I was wondering is is there a willingness to share what has been learned and help each other whether for payware or freeware projects in a sort of self help group😀 I'm very much in the early stages of learning the ropes myself and will no doubt have questions... but also have stuff that I can share. For example I have created a spreadsheet to work out normalised vector data and pivot points from the coordinates of two points ( after Jan explained the math involved)... found that made things a lot easier trying to get control surface animations to work. Anyway let us know if you're in. We can make this thread a place to share learning.



    OK Here is the promised normalized vector calculator... an EXCEL 2003 created xls spreadsheet. The usual Caveats apply... use is entirely at your own risk. It works ok for me and Jan has looked it over so hopefully it will be a help to others. After I'd filled a full page of my work diary with the calculations needed for just the Left Aileron of my Spitfire I decided something like this would be worth the effort.

    Important Note the XYZ axis in your modelling program may not be the same as in AF2, so you may need to take this into account when you are putting data into the calculator above. That is certainly true in AC3D but the exporter seems to correct for this when exporting the model TGI file. in AF2... X is FORWARD (Direction Nose is pointed), Y is SIDE to SIDE and Z is UP and Down. Its a pain when taking XYZ co-ordinates from my modelling program as I mentally have to transpose them. Changing them in the model program would require a very odd working orientation.

    here is an example of its use.... The prop pitch axis for my Buffalo. I noticed on both the Spitfire and the Buffalo that I was getting a wonky display of the rotating Prop and it turned out it was the incorrect specification of the pitch axis... you got something like this...

    The three blades of the Buffalo are shown here along with the point co-ordinates required to work things out... obtained from the modelling program.

    as an example here is the data for propeller2 put into the calculator… in this instance I only needed the axis and not the pivot

    data added to the TMD code....

    More normally you want the axis and pivot... The Buffalo left Aileron is used here to illustrate.

    Hope above is clear enough and will be of some help to others. I would suggest if anyone adds technical info like this they give it a clear header as above...

    makes it easier when searching.

    KR Matt

    Edited 6 times, last by MDIvey ().

  • Hi Matt,

    That's a nice one. Thank you for sharing it. :)

    Finding the right axis for the constant speed prop took me also quite a while.

    I don't know about your modelling program, but in Max you can set up the local pivot as needed. The export tm.log will spit out the correct axis. In the editor (I use Visual Studio Code) I just place the tmd and tm.log side by side, so it is pretty easy to copy-paste.



  • Unfortunately AC3D doesn't allow for that and has no onboard Animation either


    I'm working on the Main Gear in the TMD on the Spit... man I thought the control surfaces where bad. Got some questions related to this...

    what are the R0 and R1 values required here in this code for the gear hydraulic cylinder? Could also do with knowing what the 2D matrix refers to in the linear Interpolation section

    I've placed a dummy cylinder in the model to represent the gear actuating cylinder (by eye to the sketches I've got) but I'm thinking something more is going to be required here? If that cylinder stroke is what is going to determine the arc the UC leg swings through, that's going to waste a lot of time in trial and error as I have no details of that.

    Thanks Matt

    Edited once, last by MDIvey ().


    As an example here is the Aileron Dynamics Code I've got so far...

    Here is the graphics section so far... left Aileron only as example

    They work but Id like to set the correct throws if its not too involved.

    KR Matt

  • Count me in for the self help group. :)

    Anyone mind if a put up a wiki on and add content from here once we've figured out answers?

    There's so much knowledge about aircraft development already buried in threads in this forum and not on the IPACS wiki. Would be great to collate it all.

    I noticed that the IPACS wiki is Creative Commons licensed so we augment content from that too.


    The Spit has split flaps... a small one on the straight stub of the Wing and a larger one outboard on the main dihedral part of the wing. I managed to get this to work along with that insane 85deg angle without resorting to the complex jointing that was needed on the Corsair. FYI here is the code. It works fine and I cant see any problem with it but Jan can verify.

    KR Matt

    Dynamics Section (doesn't include references to Flaps in airfoils)

    The figure 1.35 above was what seemed to get the desired angle of extention… was 1.0. Arrived at 1.35 by trial and error but would be nice to understand why:)

    Graphics Section

    KR Matt

  • I think that would be ok as far as anything I post here but always with Caveat that you use at own risk. Bare in mind though Nick this is for Aircraft specific development... might be better to have a separate thread for Scenery specific development stuff... otherwise could get confusing possibly?


  • Hi Mat

    Remember insane angle in degrees and TMD uses Radiant

    85 Degrees = 1.48353 rad

    I use a free android app...Unit converter, does everything we need

    Copy of Jan's units post

    Vertical speed would be in m/s,

    Altitude in meter,

    Speed in m/s,

    Ground speed in m/s,

    Rotation speeds in rad/s

    Rotation angle in rad,

    Mass in kg,

    Fuel in fuel_tank in kg,

    All lengths in m,

    Area in meter squared,

    Pressures in Pascals,

    Time in seconds,

    Power in Watts,

    Thrust in Newtons,

    Voltage in Volts,

    Amperage in Amps,

    Resistance in Ohms,

    Heading in rad measured from E going counter clockwise (mathematically positive direction),

    Slowly working my way through forum posts, lots of stuff. Wondering if it should be a single zip file or as Nickhod suggest's we add to a wiki, unofficial one if needed. Perhaps guidance from our Jedi Master on this


  • I think that would be ok as far as anything I post here but always with Caveat that you use at own risk. Bare in mind though Nick this is for Aircraft specific development... might be better to have a separate thread for Scenery specific development stuff... otherwise could get confusing possibly?


    Yeah, I'm not talking about scenery development, just need a domain to host the wiki. One doesn't exist currently.

    Can do is that's clearer. Or someone can buy another domain :)

    • Official Post

    I'd prefer that all infos stay in the official wiki. I created my own wiki before and if I'm was the only one maintaining it so it was very time consuming. With the official wiki we at least have the option that more people can contribute (e.g. write the content and then we can put it online)

    In the last couple of days I added a bit more in regards to the tmd file... (just click through the menu from tmd to DynamicObjects to the different categories like "logic")