Is it true that Megane has inverted aero ??

Discussion in 'ISI cars and tracks' started by Jeepy, Dec 4, 2014.

  1. Jeepy

    Jeepy Registered

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    Hi guys
    I really enjoy the ISI Megane and have great time driving it online in a league.
    To me the car reacts and drives like I expect it to.
    I know people that don't stop saying that the ISI Megane is horrible and that the aero is inverted !
    They say they looked into the physics to confirm their affirmations.
    Is that true that the aero is inverted and that my feeling can be so wrong ?
     
    Last edited by a moderator: Dec 4, 2014
  2. Minibull

    Minibull Member

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    So you are saying that it gets lift from its wing, not downforce? It certainly doesn't feel that way, that thing sticks super well to the road.
     
  3. Lazza

    Lazza Registered

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    2 lessons to be learnt here... don't trust what people say, and learn to check yourself ;)

    Both the front and rear wings produce negative lift, as you'd expect. Maybe that confuses the people you know.

    The body produces lift but that's not unusual, and it's easily cancelled out by the negative lift produced by the front and rear wings and the diffuser. That's about the end of the story.
     
  4. gorgias1976

    gorgias1976 Registered

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    Aero is fine. The less rear wing you add the more the car starts to be oversteery. Just test it at any high speed corner.
     
  5. Jeepy

    Jeepy Registered

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    I don't really know what they mean by "inverted". I don't get an answer when I ask. Maybe they mean front and rear are inverted.
    I think these people are wrong and I'd like to find a way to bring them to the light :cool: without offensing them, cause some are good friends.
    But maybe I am wrong and I don't know it.
     
  6. Denstjiro

    Denstjiro Registered

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    I don't know either but I do know that if ISI did something wrong there will be no end to it on these forums.
    And I have not seen any sh*tstorms and/or endless debates/requests/demands in this regard so that makes it pretty simple for me, no problems appear to have appeared :)
     
  7. Guimengo

    Guimengo Guest

    The only thing I can think of inverted is the idea of the aero effect, like early 80s F1 for example. If too much air got under the car it'd cause it to lift and take off. I've never come across an experience that led me to have that happen in the Mégane though I find it quite unlikely the car would have such aerodynamics and undertray work.
     
  8. Jeepy

    Jeepy Registered

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    I managed to get an answer. I've been told that there is much more downforce on the front than on the rear and that it should be the opposite.
    Well, I don't know how the aero is balanced on the real car and if it really should be the opposite.
    Maybe someone has the answer ?
     
  9. Lazza

    Lazza Registered

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    First question is what information they're comparing to... easy to look at figures and say they're wrong when you don't have any other reference. Maybe they do have a reference, but it'd be easier to discuss this if we knew.

    As for wing downforce, the front is locked on -0.760 and the rear starts at -0.246, up to -0.426 on full setting. So sure, the front has more.

    There's also a diffuser which generates up to -0.420 at 65cm forward of the rear axle.

    The diffuser figure is of course the maximum, and probably won't happen much if at all. But you could say the same for the front wing. And unless you have raw aero figures to compare to, you're probably trying to judge apparent (or indeed real) driving balance against purely aero figures when the handling is also affected by the suspension, weight distribution, throttle application and effects, and whatever else.

    Ultimately if the aero balance was well off, especially if the rear were much lower than it should be, it would manifest itself in easy spinning at high speeds. That's where aero effect is maximum. I'm pretty sure that at speed, under power, the higher rear wing settings aren't producing a great deal of oversteer.

    Unfortunately or not, opening up a text file and finding a few figures doesn't really give you the full picture.
     
  10. MikeeCZ

    MikeeCZ Registered

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    in HDV file of any car there are negative numbers for aeros, thats because the units are in lift, not downforce, lift and downforce are exact opposites of each other, so if you say that you have -1 lift, it is the same as +1 downforce
     
  11. Jeepy

    Jeepy Registered

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    Thank you to the guys who answered.
    I'm sure there's nothing wrong with the ISI Megane. After further discussion with the guys I mentioned, I know now that they don't know anything about the real car.

    Sorry for the inconvenience.
     
    Last edited by a moderator: Dec 7, 2014
  12. Guimengo

    Guimengo Guest

    It's no inconvenience, it is functional discussion ;).
     
  13. MystaMagoo

    MystaMagoo Registered

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    Renault said when the new Megane came out that it had a LOT more downforce at the front than the oldversion.
    Cannot remember the exact figure but the new designed front is way better at downforce than the old.
     
  14. Jeepy

    Jeepy Registered

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    Interesting information.
    Thank you MystaMagoo.
     

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