Wing vs spoiler vs none on an X

Discussion in 'Discussion Forum' started by autox19, Jun 28, 2018.

  1. autox19

    autox19 True Classic

    Location:
    East Lansing, Mi
    Ok. This might be a religious conversation, so please keep it friendly. On an x19 which is more useful for autocross, road race etc.
    Was thinking about it. Personally I am going for a wing for looks, but was wondering what people have discovered, researched etc...

    Odie
     
  2. The answer is always wing.

    But you will also need a splitter, and/or a vented hood.
     
  3. kmead

    kmead True Classic

    Location:
    Michigan
    My car won’t go fast enough to generate downforce from an aero aid :) That or its driver can’t drive it fast enough to take advantage of the downforce from an aero aid...
     
    Kevin Cozzo, AKimball92 and Eastep like this.
  4. :D

    Actually, that's not true. A wing begins producing lift as soon as there is sufficient flow to produce the Bernoulli effect. How much effect is dependent on velocity. The real question is whether the driver is capable of extracting the resulting additional performance at a given speed. ;)

    I remember having to cover the wings with a blanket on a Mod Class autocross car when weighing it outside in the Kansas wind. A gentle breeze would produce enough downforce that you could see the numbers change on the scale's display.
     
    Last edited: Jun 28, 2018
    kmead likes this.
  5. Pete Whitstone

    Pete Whitstone True Classic

    Location:
    McKinney, TX
    If just for looks, then to me it depends on the car. For a later, mostly stock car with full elephant ears and bumpers, the stock wing spoiler looks great. For an earlier look car, especially one that has flairs, then a ducktail is the ticket. Brayden's car is a great example of that look.

    Pete
     
    Brayden_connolly likes this.
  6. autox19

    autox19 True Classic

    Location:
    East Lansing, Mi
    I personally am going for looks (i like the wing look) but it got me thinking about actual function. with the quick drop after the targa bar, would one make a difference more than another. so far according to Steve, he sees a bigger benefit from the wing.
    just sparking up conversation and hope to learn

    Odie
     
    Last edited: Jun 28, 2018
  7. JimD

    JimD Waiting for Godot... Moderator

    Location:
    Missouri, USA
    Odie,

    Are you thinking a Dallara sized wing? Or something midway in size between that and the stock wing?
     
  8. autox19

    autox19 True Classic

    Location:
    East Lansing, Mi
    I personally love Bob Nelsons wing. the height of the wing being almost level with the top I love. If I had the time, I might do something like the dallara wing. i do like the larger and my "look" is more of an obnoxious semi-racer/mad max look rather than concourse.

    Odie
     
    Mechanogeek likes this.
  9. JimD

    JimD Waiting for Godot... Moderator

    Location:
    Missouri, USA
    Bob Nelson's wing? I don't think I know what that looks like. Do you have a picture?
     
  10. autox19

    autox19 True Classic

    Location:
    East Lansing, Mi
  11. Bob Nelson's car. K20 NASA Time Attack track car.

    bob nelson.jpg
     
  12. JimD

    JimD Waiting for Godot... Moderator

    Location:
    Missouri, USA
    Ah, yep I have seen that style of wing before. It does have the racer look and it isn't oversized. :)
     
  13. Wings and spoilers do different things.

    A wing is an airfoil that produces lift (or if mounted upside down on a car, downforce).

    A spoiler's original intent and design "spoils" the airflow over the rear of the car. The idea is to redirect the airflow to prevent the airflow from detachment and eliminate (or reduce) drag inducing turbulence and lift. If you make the spoiler big enough you can create a significant pressure delta between the upper and back sides of the spoiler which by default produces downforce. A spoiler's primary benefit is reducing or eliminating lift and drag. Making a BIG spoiler, which produces more downforce, also produces its own drag.
     
    mkmini likes this.
  14. The rule set for my DP autocross car prohibits wings but permits spoilers with a 10" height limit. Front splitters are permitted but heavily restricted. Consequently I maxed out both. The spoiler does create quite a bit of downforce and gets most of its flow off the sides of the greenhouse instead of over the roof. Without the splitter/hood vent to balance out the rear downforce, the car understeers badly.

    Wilmington Grid Crop.jpg
     
  15. avusblue98

    avusblue98 True Classic

    Location:
    SoCal
    I used to think at American legal speeds, there can't be any effect worth mentioning - but then I got a helmet for my m/c that has a little ducktail on the back - wow, no longer does the helmet try to suck itself off my head! So, yeah, what Steve H. said.
     
    Steve Hoelscher likes this.
  16. Dr.Jeff

    Dr.Jeff True Classic

    Location:
    Sin City
    Strictly speaking for "looks", I'm with Pete, it depends on the rest of the build. If your project car is a more modern style full-race look (like Bob's), then a wing like in his photo might work. For the most part however, I consider the X to not be a modern car. So a more 'period' look with a spoiler and flares (and bumperless) would be my personal choice. But I'm stuck in the 70's. I even wonder how a Dalara type build would look with a large spoiler (something like on Steve's MR2 racer) instead of a wing?

    Speaking of the photo of Bob's racer, that front spoiler/splitter is interesting. Appears to be like the normal old-school spoiler that incorporates with the front flares (FAZA style?), with enlarged corners and a splitter added. Kind of blends the old style with a new style.
    And at the rear of Bob's car, I've wondered if there is anything to be gained (for a track car) by creating more of a diffuser tunnel in the center? Something like below, where the blue lines are inside the bodywork (making a negative area)...not sure if my lines make any sense, but basically a tunnel sloping up from inside:

    bob nelson.jpg
     
  17. Dr.Jeff

    Dr.Jeff True Classic

    Location:
    Sin City
    Seems I've always heard that around 60MPH is where any significant aero effects begin to happen. Not sure if that is current info, and there would be a ton of other factors to consider. But as a general rule.
     
  18. You know there are airplanes that will fly at less than 60 mph right?

    The speed at which the aero becomes effective is dependent on the amount of lift produced. As I noted above, the principles involved work as long as there is enough air velocity over the airfoil to generate the Bernoulli Effect. From there it depends on how much velocity, area and efficiency as to how much lift is produced.

    25 years ago virtually nobody made any serious attempt at using aero in Autocross because it was always assumed that the speeds involved, 30 to 70 mph, were too slow to produce any net improvement. Then somebody put a big wing on top of a Mod class car and went a LOT faster. It wasn't long before somebody had a wing on the back of a full bodied production based car and it started winning. Now all of the modified class cars have extensive aero because it has been proven to work, if designed to be effective at lower speeds.

    There is an obvious trade-off between lift and drag for most wings and aero devices. A wing designed to produce say, 200 lbs of downforce at 40 mph, for a typical autocross car would create so much lift (downforce) at 80 mph that creates massive understeer. Not to mention its effect on fuel mileage. Given that most street cars operate at between 40 and 80 mph, and fuel mileage is of significant design influence, even supercars like Porsche Turbos incorporate wing designs that have limited aero drag and produce their target downforce at the upper end of the car's speed range so as to keep their less capable owners out of trouble when they inevitably explore the car's 2+ mile/minute speed capabilities.

    Racing cars are of similar design criteria. Aero needs to produce useful downforce when cornering, the slowest points on a given lap, while having minimal effect on straight line speed. Given the corner speed ranges on a typical North American racetrack are in the 40 to 60 mph range, that's where the effect would start being noticed.
     
    AKimball92 likes this.
  19. carl

    carl True Classic

    Location:
    Virginia
    Just stick your arm out the window of your car at 60mph and you will realize air is very thick.
     
    Steve Hoelscher, autox19 and mkmini like this.
  20. Dr.Jeff

    Dr.Jeff True Classic

    Location:
    Sin City
    Love to move my hand up and down through the air, in big arching curves as I'm driving. Feels like I'm flying. Then I make sounds like.....(ooops I've said too much).
     
    bpimm and autox19 like this.

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