FWMaxHeight - saloon/GT style vehicles

Discussion in 'Car Modding' started by MileSeven, Apr 8, 2022.

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  1. MileSeven

    MileSeven Registered

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    Code:
    FWMaxHeight=(0.3) // maximum height to take account of for downforce
    A comment made in an old thread by @Lazza has made me question if I understand this entry - especially in the context of a vehicle that derives front downforce (or lift!) from a solid nose (as opposed to an open-wheeler F1 style wing). I’m away from my rig most of the day today otherwise I’d put this brainworm to bed with some dev mode testing!

    The root of my confusion is probably derived from the diffuser settings where the dynamic ground clearance (can have)/has a key impact on the forces.

    Are we saying:
    …or am I barking completely up the wrong tree?:rolleyes:

    Or, to put the question very simply - as a broad 1st order generalisation, is it sensible to set the FWMaxHeight of a solid-nose car to be in the ballpark of the height of that nose at the defined wing location?
     
  2. Lazza

    Lazza Registered

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    FWMaxHeight just limits the 'height' used in the calculations - it doesn't actually change any of the calculated values.

    The rest is a little confusing at least on first edit, with the 'quote' a bit strange as well, not too sure what you're asking.

    The position of the "front wing" is completely arbitrary. For a normal car without a splitter you'd probably want to back the height parameters off completely so that hugging the road with the 'wing' doesn't have a big influence on front downforce, and position the "front wing" such that your diffuser can reasonably be configured to use the front wing height as part of its calculations.
     
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  3. MileSeven

    MileSeven Registered

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    Ok - so I think you’re saying that the FWMaxHeight *is* basically the ‘box’ height (probably easiest to envision this in terms of a Formula rear wing) - but for a ‘normal’ car I’d probably want to treat it as virtually flat (I.e. back it off to a minimal height)?

    (Not having the PC to hand) - but your last point is confusing me now - I thought the diffuser settings worked off the four main undertray points, not the front wing elevation (deliberately not using the word ‘height’ in this context).?
     
  4. MileSeven

    MileSeven Registered

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    Thanks by the way;)
     
  5. Raintyre

    Raintyre Registered

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    'FWMaxHeight' sets that the downforce calculated will be the same for the specified height and for every height which is higher.

    Example:

    FWMaxHeight=(0.3) >>>> Front wing downforce may vary for height values smaller than 0.3, depending on the other parameters. For height=0.3 and bigger values, the downforce will be constant.

    It is just avoiding that front downforce gets extreme values when the car is higher than a certain height.
     
    Last edited: Apr 10, 2022
  6. Lazza

    Lazza Registered

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    Yep, my mistake. Ignore all that, I typed out a quick reply and didn't really think about what I was saying.

    The box analogy isn't at all how I'd think of it, but I suppose if you end up at the same place it'll work.

    FWLiftHeightPlus determines what extra effect happens based on front wing height. Everything else in the front wing parameters isn't influenced at all by the height of the wing (or car).

    It's that LiftHeightPlus that you'll want to 'flatten off' when you aren't doing a car with a sizeable front wing/splitter, as you need that surface area to produce the extra downforce at very low elevation (good word!). So your curve should be much more benign, but there should still be a curve - even a 'normal' car will have a little variation in aero at different ride heights. You just set MaxHeight to limit the elevation used in the calculations, so your curve doesn't run away from you in extreme situations.
     
  7. Raintyre

    Raintyre Registered

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    I think rake parameters (mainly 'FWNegRakeLift' and 'FWPosRakeLift') are influenced by height, too.
     
  8. Lazza

    Lazza Registered

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    Not directly, no. Whether that rake happens at ground level or at 1000m altitude makes no difference.
     
  9. Raintyre

    Raintyre Registered

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    If front height increases while rear height is the same then rake will change, hence downforce calculation will also change.
     
  10. Lazza

    Lazza Registered

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    Yeah, but that's not related to overall height, unlike the Height param. I guess I wasn't clear enough on what I meant.
     

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