Let's Talk Aero

Discussion in 'Road Racing Forum' started by antman450, Oct 21, 2017.

  1. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    Grill openings are vertical and the 'floor' openings are horizontal. So their proportions don't quite matter in the way you're implying.

    As long as you're monitoring your temps, you should be okay.
     
  2. Badger

    Badger TMO Intermediate

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    I finally got around to build some spats and oh boy what a difference they make!
    1BF72CBB-3590-436F-AAD7-B7D039B23683.JPEG
    56130186-C1F4-4069-A52D-70C21248658D.JPEG

    That`s how it used to be:
    B2DF219B-B1E9-4F1E-A547-348670660F22.JPG

    Granted, this is all butt-dyno kind of stuff without any data. But driving the car down the freeway feels a lot more effortless and smoother, while the nose got a bit more darty. I had a similar experience when I added the splitter. This felt about 50% as strong and I might have to add a little AOA to the wing.

    This effect could either be due to covering up the tires fully, framing and stabilizing the edges of the splitter or simply a combination of both. Regardless, this had a way bigger effect than expected.

    The question now is, should I get rid of the canards to reduce drag? Maybe @AJ Hartman can give some insight here.
     
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  3. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    The canards won't be helping or hurting much there. Between the spat and splitter, the canard isn't really doing anything.

    You can easily test it with some white yarn and video. Or a manometer with test points above and below the canard mounted perpendicular to the airflow.
     
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  4. flyhalf

    flyhalf TMO Advanced

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    Flap will create a high pressure zone deleting the already small effort from canard in terms of DF.
    canards are also helpful for reducing drag and pressure on the side of a car ( they reduce the high pressure air creating vortex On the side of the car avoiding the air to get under the car )

    But the canard will find a flap behind there isnt a real benefit. IMO

    Sent from my LG-H932 using Tapatalk
     
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  5. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    A lot of sources cite the side stream-wise vortex as a benefit, but they spin the wrong way to help with underbody air.

    For example looking backward on the driver's side, a canard makes a clock-wise rotation. That would tend to 'feed' more air underbody rather than seal or evacuate air. I'm also not sure it wouldn't normally burst on cars with brake cooling as it passes the front wheel.
     
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  6. ArizonaBOSS

    ArizonaBOSS Because racecar. Moderator

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    In for data/answers.
     
  7. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    I think both. If the source of the buffeting was an interaction with the air coming off the front tire as it rolls forward. Tying the bodywork and splitter together more had to help structurally.

    And not to mention that it looks great too...
     
  8. flyhalf

    flyhalf TMO Advanced

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    Talking about splitter.
    Where does the downforce generate?
    I mean
    Where does happen the real push down?
    Zone #1 or zone #2


    Now i know #2 is fundamental to have a clear fast flow under the belly but it is in order to generate more downforce for #1 or you also have a pushdown on #2?

    This is the pp1 splitter. With a bigger lid

    [​IMG][​IMG]

    Sent from my LG-H932 using Tapatalk
     
  9. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    Zone 1. By far, IMO.
     
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  10. flyhalf

    flyhalf TMO Advanced

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    Morning all.
    I added a seal in my splitter. This allowed me to
    1. Seal the gaps
    2. Increase the AoA angle of attack (from +2° to -2°)

    Question
    Is the AoA important in a splitter?
    I mean the angle of attack makes sense in a wing to create pressure Differential.
    But in a splitter ?
    Have a nice day.
    Alex
    [​IMG][​IMG][​IMG][​IMG]

    Sent from my LG-H932 using Tapatalk
     
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  11. Wingrider

    Wingrider '11 GT500, 99% Track Car. Lots of mods & I coach

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    ...wish you guys would hurry up and figure all this out for the S197's so I can just give someone money and bolt something under the front of my GT500. :D

    Lots of good info in this thread.
     
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  12. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    Despite all the videos and opinions on the matter, I think the single most important part is the height of the leading edge. Effectiveness generally increases down to about 4" and maybe less in some applications. Lower than that and the whole surface of the front end acts more like an air dam, IMO.

    Not that the angles don't matter. They will affect things a bit by moving things around. Maybe think of how the leading edge defines the effective AoA of the entire car. And that's more important than the AoA of the splitter by itself.

    Kind of like the tunnels that seem to be 'popular' right now. Not worth much IMO and might even net reductions in DF for some.
     
  13. flyhalf

    flyhalf TMO Advanced

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    Tunnel are the front diffuser?
    Fwik
    A front diffuser should increase the extraction of air speeding up it for better df in the front and also more df overall( less air = more vacuum suction)

    Sent from my LG-H932 using Tapatalk
     
  14. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    I think there's a lot of theory that works for fully ducted and closed off cars, but actually would just reduce DF for most passenger cars. Reducing the flat floor area will be a tradeoff in some way. But the net reaction is likely less total DF.

    Too much is being ignored on the effects elsewhere, and really how small the effects are from a relatively small element.

    I'd rather keep the flat floor section that terminates in a sharp edge there.

    Unless the air is specifically targeted for a function like brake cooling or energizing a stagnant area, then I wouldn't bother.
     
  15. flyhalf

    flyhalf TMO Advanced

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    Flat floor is definetely a great point of interested.
    IMO
    One element that here in US seems to be undervalue is the side skirt(no side splitter) to seal the undercar flow and together with a diffuser will increase tue overall DF of the car.

    Sent from my LG-H932 using Tapatalk
     
  16. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    I think they make more sense on an air dam car with a sealed floor to the engine bay *not* on a splitter car or one that needs to vent cooling air underbody. That's just speaking broadly on the subject.
     
  17. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    This is what the tunnels are for on your car:

    flyhalf splitter.jpg

    The outer tunnels help direct air both inside and outside of the tire. The floor in the center has a deflector to prevent/reduce air hitting the front of the tire. Good stuff for road cars but not needed IMO for track or race applications.
     
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  18. flyhalf

    flyhalf TMO Advanced

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    Thanks.
    There is also another thing i also heatd many times
    "Oh you have a splitter in plastic it doesnt do anything for DF. "
    Why if zone 1 is where you get all the DF AND
    zone 1 is in plastic and it doesnt bend

    Why having a wood splitter is "better"?
    Respect the nature better ??lol

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  19. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    'People' say a lot of stuff when they don't understand the math or physics. I can't explain that. :D

    My ABS splitter definitely DOES bend at speed. posted in this thread.


    [​IMG]
     
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  20. Mad Hatter

    Mad Hatter Gotta go Faster

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    I like the way that spliter turned out! Will be trying to make one this week along the same lines...
     
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