Aerodynamic Discussion Thread
#262
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I do, and if you stick a big flow restriction below it, it wont work. He is spot on, wings work by having low pressure high velocity air under them and higher pressure low velocity air above them. Radiators work by having higher pressure air in front of them and low pressure air behind them, and slow down the air passing through them. I know a cambered wing like that has a pool of stagnant air in the cambered pocket of varying size, and the back 1/3-1/4 of the bottom experiences flow separation. The boundary layer is going to be no more than 1/2" off the surface of the wing unless the surface finish is WAY too smooth.
If you stick the radiator at the back of that wing duct it will raise the pressure of ALL the air under the wing. If you put it at the front, the turbulence will completely **** with how the air interacts with the wing, but at least there'll be low pressure under the wing. However there is going to be more surface area and higher speeds on the lower section of the rad duct so that would likely end up making more lift. Along that line of thinking, if you want to use a rad duct to make downforce, shape it like an inside out wing.
If you stick the radiator at the back of that wing duct it will raise the pressure of ALL the air under the wing. If you put it at the front, the turbulence will completely **** with how the air interacts with the wing, but at least there'll be low pressure under the wing. However there is going to be more surface area and higher speeds on the lower section of the rad duct so that would likely end up making more lift. Along that line of thinking, if you want to use a rad duct to make downforce, shape it like an inside out wing.
#266
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I changed it up to a more realistic size
![](https://www.miataturbo.net/attachments/aerodynamics-119/79100-aerodynamic-discussion-thread-20130611_071836_zpse68dc700.jpg?dateline=1370958749)
And another idea that would be even more realistic
I am in a seminar so i will change to different designs through the day
I haven't got to show what the frontal view looks like yet
![](https://www.miataturbo.net/attachments/aerodynamics-119/79100-aerodynamic-discussion-thread-20130611_071836_zpse68dc700.jpg?dateline=1370958749)
And another idea that would be even more realistic
I am in a seminar so i will change to different designs through the day
I haven't got to show what the frontal view looks like yet
![](https://www.miataturbo.net/attachments/aerodynamics-119/79101-aerodynamic-discussion-thread-20130611_074448_zps69792e9f.jpg?dateline=1370958749)
#270
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Also, I checked out Andrew Brilliant's youtube cannel and he has a few videos of Matt Andrews in his time attack miata featured on there.
Last edited by mx5autoxer; 06-11-2013 at 10:38 AM. Reason: Derp
#273
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The radiator duct wing looks like it's way too complex to build for something that even in theory has shaky logic at best.
The second version with a wing placed above the cutoff line between the hood and the bumper has some problems with the theory too, but even if that was okay there's a significant practical issue - you can't see through the wing.
Remember that the air doesn't flow @ 0 up there, so even to set the wing to 0 AOA you'll be running it probably 20+ degrees AOA relative to the ground.
Moti
The second version with a wing placed above the cutoff line between the hood and the bumper has some problems with the theory too, but even if that was okay there's a significant practical issue - you can't see through the wing.
Remember that the air doesn't flow @ 0 up there, so even to set the wing to 0 AOA you'll be running it probably 20+ degrees AOA relative to the ground.
Moti
#275
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The width of the NA hood at the front is roughly 29" IIRC, put a 26-27" stick of 2x4 in your line of sight where you're thinking of putting the wing and see how you like it.
I suspect you're not going to like it at all even if it's flat, and it won't be.
If you were building it for track only with zero street usage, it might be okay, heck some of the cages that I'm building include a windshield diagonal and that's totally okay on track -
![](https://www.miataturbo.net/attachments/aerodynamics-119/79188-aerodynamic-discussion-thread-pt-cage-079w.jpg?dateline=1370978327)
For anything that has street use planned I'd avoid it.
I suspect you're not going to like it at all even if it's flat, and it won't be.
If you were building it for track only with zero street usage, it might be okay, heck some of the cages that I'm building include a windshield diagonal and that's totally okay on track -
![](https://www.miataturbo.net/attachments/aerodynamics-119/79188-aerodynamic-discussion-thread-pt-cage-079w.jpg?dateline=1370978327)
For anything that has street use planned I'd avoid it.
#276
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Some cool CFD work on a Pikes Peak Subaru. Should be interesting to follow, but even the creation of a mesh for CFD is neat to see.
Subaru Impreza Pikes Peak
Subaru Impreza Pikes Peak
#277
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Some cool CFD work on a Pikes Peak Subaru. Should be interesting to follow, but even the creation of a mesh for CFD is neat to see.
Subaru Impreza Pikes Peak
Subaru Impreza Pikes Peak
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#278
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I believe that earlier in this thread we were discussing active rear wings for drag reduction..
This UK time attack Evo rocks just that. You can see the actuator on the rear of the upright:
![](https://www.miataturbo.net/attachments/aerodynamics-119/79405-aerodynamic-discussion-thread-time-attack-snetterton-28.jpg?dateline=1371109802)
This UK time attack Evo rocks just that. You can see the actuator on the rear of the upright:
![](https://www.miataturbo.net/attachments/aerodynamics-119/79405-aerodynamic-discussion-thread-time-attack-snetterton-28.jpg?dateline=1371109802)
![](https://www.miataturbo.net/attachments/aerodynamics-119/79406-aerodynamic-discussion-thread-time-attack-snetterton-29.jpg?dateline=1371109802)
#279
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Any idea how they control it? How does it know when to reduce/increase the AOA? I guess you could reduce AOA after cornering G's fall below a threshold value, and then increase it again as brakes are applied... but then what about corners you don't brake for? You wouldn't want to wait for cornering G's or steering input, because by then its too late. Maybe a button on the steering wheel?
Or you could map out the course and pre-program it using GPS.
Or you could map out the course and pre-program it using GPS.