Aircraft front gear deflection: Modification visible?
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Thread: Aircraft front gear deflection: Modification visible?

  1. #1

    Aircraft front gear deflection: Modification visible?

    Hi all,

    just testing to improve the behaviour of my Wilco Harrier.
    So here is an interesting part that maybe some wise man can answer:

    I am playing around with some aircraft.cfg settings and got some fine improvements indeed (better suspension behaviour, smaller turning cicle etc.) Now I want to bend the Harrier's front gear when the aircraft is staying on ground approx 90 degrees like in reality



    The Wilco model's front gear unfortunately always remains like the gear is still in the air:
    Here the real aircraft:


    ...and here the Wilco on the ground but with a front wheel like still in the air. It looks completely unreal (not to mention the much too small front wheel in comparison to the tail wheel):


    The suspension should let the bottom part of the front gear move a lot more back.

    So I played around with the gear settings in the aircraft.cfg but have no success to see the changes when testing it in the sim. The suspension works and I can see it deflecting while touch down, but it doesn't stay bended when the Harrier stays on the ground...

    Any ideas how to solve this? Thank you for each hint...
    See you, Manfred.

  2. #2
    Hi Manfred,

    First, I think you better post such a question in the regular FSX forum; this Acceleration subforum gets hardly any attention (I just stumbled on it only by accident).

    Second,
    I understand what you are trying to solve; but I'm convinced you can't improve this in the FDE (contact points); this is just a limitation on how the (fixed) visual model animation code reacts to read FS variables.

    That said:
    If you are really interested in such detail, maybe it's time to look at other Harrier addons.
    The Wilco HJJ was a great addon at the time it was developped (and I'm still using it myself because it's a really nice step-in-and-fly addon), but by todays standard there are far better Harrier addons (in FDE, Visuals and systems) with much more attention to such detail.
    More specifcally: the SSW and Razbam Harriers.

    What my personal preference is (in view of the chosen solution to emulate VSTOL) is easy to guess ... But I'm biassed ... LoL

    Cheers,

    Rob Barendregt

  3. #3
    Quote Originally Posted by Manschy View Post
    Hi all,

    just testing to improve the behaviour of my Wilco Harrier.
    So here is an interesting part that maybe some wise man can answer:

    I am playing around with some aircraft.cfg settings and got some fine improvements indeed (better suspension behaviour, smaller turning cicle etc.) Now I want to bend the Harrier's front gear when the aircraft is staying on ground approx 90 degrees like in reality

    The Wilco model's front gear unfortunately always remains like the gear is still in the air:
    Here the real aircraft:

    ...and here the Wilco on the ground but with a front wheel like still in the air. It looks completely unreal (not to mention the much too small front wheel in comparison to the tail wheel):
    The suspension should let the bottom part of the front gear move a lot more back.

    So I played around with the gear settings in the aircraft.cfg but have no success to see the changes when testing it in the sim. The suspension works and I can see it deflecting while touch down, but it doesn't stay bended when the Harrier stays on the ground...

    Any ideas how to solve this? Thank you for each hint...

    If you have a backup of the original contact point.0, post it here.

    I will show you and explain how to adjust it to get the maximum static compression while maintaining some stiffness necessary for landings.

    I assume that other than the angle and amount of static suspension used, that the tire always sat correctly on the tarmac.

    EDIT: This assumes of course that the model has enough animated suspension to show the realistic profile.
    Milton Shupe
    FS9/FSX Modeler Hack

    My Uploads at SOH - Here
    Video Tutorials - Gmax for Beginners

  4. #4
    Rob, Milton - thank you very much for answer. Nice you found it here in "Acceleration". Thank you for suggestion for sure!

    @ Rob: Okay, hope dies last
    Regarding the Wilco: Why is it my favorite Harrier? I also own the fantastic Razbam GR7/9 just because I see them in the 90s doing operations in the Senne-Range area. But let me explain why my heart belongs to the Harrier GR3:
    I am addicted to the Harrier GR3 since these jets did their field operations nearby my hometown. We were 8 to 10 years old when the Harriers land 300 meters away from our house. We watched them landing while breakfast and lunch. Or rather, we HEARD them landing around the clock. With my friend, we took our bicycles and used a small field path to get to the Hides. I remember a day we reached the manoeuvre area just as a GR3 did a take off and we got the engine blow out directly into our faces. I remember the dirt between my friends teeths and and the stunned soldier who catched us and we were laughing the rest of the day because of this incredible adventure.
    So why do I tell this? For better understanding why especially the Harrier GR3 model (end of the 70s to beginning of the 90s) is now part of my simming.
    The Wilco - in all objectivity - is not the best FSX model I own. Most of the dimensions are wrong - particularly in parking position. There are so many things I can't improve (model-oriented):
    - Air intake too large and not semi-circular
    - Nozzles too big while baffles behind the back nozzles too small
    - Nose wheel and tail wheels much too small compared with the wing tip gears
    and so many other parts, finally the nose gear wrong suspension.

    As I wrote, I did some fine improvements with the contact points section:
    - The significant seesawing while breaking or when accelerating now is almost perfect like the Harriers those days
    - Now I can do almost a spot turn with the Harrier
    - Nozzle function now by keys on the joystick etc etc

    So but there are some missing options to make this aircraft more real:

    The nose gear suspension

    I did some experiments with the dumping ratio (that helped me a lot with the seesawing), hereby I hoped the nose gear plunges a little more while touch down. So just a little question:

    WHEN I RAISE THE DUMPING RATIO PARAMETRES A LITTLE MORE AND REDUCE THE GEARS CONTACT POINTS HEIGHT SIMULTANEOUSLY, may this let the Harrier sink down a little, also in the models animation maybe?

    Another odd behaviour of the Wilco: The take-off in STO mode. Regardless of whether option I use - full tank, half full tank, nozzles at 25, 45, 65 degrees, the Harrier never "struggles" upwards like the original aircraft, but "jumps" abruptly into the air. This is really not pretty to watch nor real in any way. For comparison here some minutes of a Harrier manoeuvre those days. The take off is at 7:10 and shows the real STO behaviour. Looks like heavy work for the aircraft .

    https://www.youtube.com/watch?v=y3X32JnXKZ0

    Each hint how to get the Wilco take off more sluggish is much appreciated...

    @ Milton:

    Yes, my hope is to use the existing suspensions animation. I can watch the suspension hardly bend when the nose gear is doing touch down, because I changed the dumping ratio. So this change shows a result in animation indeed.
    Here I come to the conclusion this bending will hold on when
    a) enough weight or
    b) shorter gear contact points

    are existing. Not sure if it helps, but here are my contact points settings:

    // 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
    point.0 = 1, 8.5000, 0.0000, -6.80, 16574.803, 0, 1.100, 60.3, 0.500, 3.0, 0.355, 5, 5, 0, 300, 250
    point.1 = 1, -5.0000, 0.7113, -4.76, 16574.803, 2, 1.150, 0.00, 0.500, 1.5, 0.945, 5, 5, 3, 300, 250
    point.2 = 1, -5.0000, -0.7113, -4.76, 16574.803, 1, 1.150, 0.00, 0.500, 1.5, 0.945, 5, 5, 0, 300, 250
    point.3 = 1, -7.0000, 9.8000, -4.76, 16574.803, 2, 0.573, 0.00, 0.141, 3.5, 0.945, 5, 5, 2, 300, 250
    point.4 = 1, -7.0000, -9.8000, -4.76, 16574.803, 1, 0.573, 0.00, 0.141, 3.5, 0.945, 5, 5, 3, 300, 250

    Thanks again mates for thought.
    See you, Manfred.

  5. #5
    Hello Manfred,

    point.0 = 1, 8.5000, 0.0000, -6.80, 16574.803, 0, 1.100, 60.3, 0.500, 3.0, 0.355, 5, 5, 0, 300, 250

    The static compression is in RED. This represents how much of the total suspension is used sitting static on the tarmac.
    The max-static ratio is in BLUE. This represents the ratio of the static compression to total available compression.
    The Damping factor is in GREEN. This represents how fast the up and down oscillations will be dampened with 1.0 being fast and .3 being slow.

    To adjust suspension correctly in the sim, one must know (or determine) the total animated suspension by the modeler. If he matched the contact point data with the suspension, you should have no problem with your adjustments.That is total animated suspension equals total available compressionand is properly represented in contact points.

    Assuming that is the case, to find total animated suspension by the modeler, multiply static compression by max-static ratio.

    Once you have thetotal animated suspension by the modeler, you can accurately change static compression and compute the new max-static ratio by dividing total animated suspension by the new/changed max-static ratio.

    So, now we know that the total animated suspension by the modeler is a fixed number and can not be changed because it represents the animated suspension in the model.

    We can change
    static compression and recompute max-static ratio so that we maintain the total animated suspension and the visuals in the sim stay correct.

    The final thing you must do once you make these changes is adjust the
    Vertical distance to ground and the static pitch (aircraft attitude) in the contact point section.

    So, in your contact point above, (assuming data is accurate) to increase amount of available suspension used so the nose will sit lower, increase static compression.

    Then divide total animated suspension by the new static compression. The result is the new max-static ratio.

    Example:
    0.500 X 3.0 = 1.5 feet total animated suspension movement
    Let's change 0.500 to 1.00 and the new max-static ratio is 1.500 (1.5 feet divided by 1)

    Original: point.0 = 1, 8.5000, 0.0000, -6.80, 16574.803, 0, 1.100, 60.3, 0.500, 3.0, 0.355, 5, 5, 0, 300, 250 (The original static compression used 1.3rd of the available suspension)

    Modifiedoint.0 = 1, 8.5000, 0.0000, -6.80, 16574.803, 0, 1.100, 60.3, 1.000, 1.5, 0.355, 5, 5, 0, 300, 250 (The modified static compression uses 2/3rds of the available suspension)

    I hope this helps.
    Milton Shupe
    FS9/FSX Modeler Hack

    My Uploads at SOH - Here
    Video Tutorials - Gmax for Beginners

  6. #6
    Hi Manfred,

    As to the Short takeoff question:
    Yes, I understand what you mean ...

    First: are you using my latest addon for the Wilco HJJ ? (file rcbwh20-7.zip dated febr. 17 2016, in the SOH library FSX-Other section)
    If you do:
    I'm afraid there's no way to do that properly (as in the video).
    Has to do with some inherent flaws in the original FDE of the Wilco Harrier.
    Like: this Harrier FDE has the tendandy at high roll speed to pitch nose-down into the ground; I have corrected that by adding auto-elevator trim, which results in a probably too smooth liftoff (no high pitchup) in a STO.

    I'll have another look at this, but I don't think I can make this work more realistically given it's basic FDE.

    Two other example of FDE "flaw"s you might have noticed:
    - If you do a conventional landing (like at 120-140 Knots, flaps down, nozzles 0), this Harrier won't stay on the ground at that speed and will swirll all over the place if you move ailerons.
    I "tricked" that problem, by commanding a fast (way too fast compared to real life) decelleration from touch down speed to appr. 50 knots.

    - Try to get this Harrier in a Stall in conventional flight (nozzles 0); it won't, untill airspeed has dropped to 50-60 Knots, which is way too low.

    Remember, my VSTOL coding it on top of the standard FDE; it can't compensate all flaws without adverse implications.

    Cheers, Rob

  7. #7

    OFF TOPIC, Sorry

    Hi Milton,

    Long time we spoke.
    Good to see your contribution here ....LoL

    After the glory we had with the Bounty, I sucked my teeth in Maryadi's MV22B Osprey in the past year.
    Gave me as much pleasure (and sleepless nights) as the Bounty project.
    Another example of a "niche" addon that supposedly couldn't be simulated in FSX with any realisme ..

    Cheers, Rob

  8. #8
    Quote Originally Posted by rcbarend View Post
    Hi Milton,

    Long time we spoke.
    Good to see your contribution here ....LoL

    After the glory we had with the Bounty, I sucked my teeth in Maryadi's MV22B Osprey in the past year.
    Gave me as much pleasure (and sleepless nights) as the Bounty project.
    Another example of a "niche" addon that supposedly couldn't be simulated in FSX with any realisme ..

    Cheers, Rob
    Hello Rob, great to see you as well. Your "magic" on the Bounty produced amazing realism. That was an awesome project thanks to you. I really appreciated everything you made possible. Thanks again. :-)
    Milton Shupe
    FS9/FSX Modeler Hack

    My Uploads at SOH - Here
    Video Tutorials - Gmax for Beginners

  9. #9
    Hi guys,

    thank you for answer and that deeply explanations.

    @Milton:
    I will play around with these settings and let you all know about my success (or not )

    @Rob:
    Thanks for offer to try some more enhancements. Yes, I tried your improved settings a while ago but I came back to my own mix of the Wilco and the UKMIL Harrier - that worked fine for me. But regarding the "swirling" you are quite right and I consider to install your file again.
    See you, Manfred.

  10. #10
    Okay, no matter what I am doing, the front gear animation remains in the same position. So it seems to be unalterable by the aircraft.cfg. I can live with it - at least I HAVE a GR3 to bring back my memories . Thank you for effort!
    See you, Manfred.

  11. #11
    Quote Originally Posted by Manschy View Post
    Okay, no matter what I am doing, the front gear animation remains in the same position. So it seems to be unalterable by the aircraft.cfg. I can live with it - at least I HAVE a GR3 to bring back my memories . Thank you for effort!
    Hi Manfred,

    As I suspected (and Milton mentioned as a disclaimer) this is just a limitation of how the model animation code (in the .mdl file) visualises the FS variables (which WILL be different with different of ContactPoints definitions, as Milton explained).
    No way to change that animation, other then in the .mdl source code (which you don't have, I assume ....LoL)

    Cheers, Rob

  12. #12
    Yap, those were my thoughts, Rob. But I have my aircraft's nodding when it brakes and I can get into my Hides accident-free because of the better stearing angle. So that's a success indeed.
    See you, Manfred.

  13. #13
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    These are for a AP Harrier, but would you try them just for fun. You MIGHT have to match the vertical pos of all the gear to match what your Harrier has but it might work 'as is' so try these first. I don't have that Harrier. But I play with cnt pts.
    Chuck B
    Napamule

    [contact_points] //APD Harrier
    point.0=1, 7.453, 0.000, -5.850, 1574.0, 0, 1.100, 38.0, 0.111, 1.1, 0.111, 3, 3, 0, 0, 0
    point.1=1, -4.068, -0.713, -5.000, 1574.0, 1, 1.150, 0.0, 0.333, 2.1, 0.666, 5, 5, 3, 0, 0
    point.2=1, -4.068, 0.713, -5.000, 1574.0, 2, 1.150, 0.0, 0.333, 2.1, 0.666, 5, 5, 0, 0, 0
    point.3=1, -5.560, -8.493, -5.100, 1574.0, 0, 0.573, 0.0, 0.666, 2.5, 0.888, 1, 1, 2, 0, 0
    point.4=1, -5.560, 8.493, -5.100, 1574.0, 0, 0.573, 0.0, 0.666, 2.5, 0.888, 1, 1, 3, 0, 0
    [SIGPIC]i7 2600K @ 3.4 Ghz, Asus P8H67 Pro, Super Talent 8 Gb DDR3/1333 Dual Channel, Sapphire Ati Radeon HD-5700 1 Gb DDR5, Corsair 650 W PSU, Acer 23 in LCD, Windows XP SP2, MS Sidewinder Precision 2 Joy, Logitech K-360 wireless KB & Mouse[/SIGPIC]

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