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Aerodynamic Discussion Thread

 
Old 01-24-2013, 02:22 AM
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I wanted a place to put mixed info about all Race Car Aero, not just Miata's but Ideas. Yes I know there is Treads currently about "Miata DIY Aero", "New Wing toTest" and some Miata under body Aero from ThePass and me. I was going to put some ideas and questions up on my "Miata Underbody Aero" but that would be off topic and can not share what your ideas are. And maybe "plucas" can share what he is thinking of since he has the knowledge and programming with data to give us.

The one of the things that I was looking at that brought up the idea of this thread was this found on the Nissan GTR GT1 race car. What is the function of this vent? or what is it?

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Old 01-24-2013, 02:50 AM
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I like the idea for the thread, although with such a broad subject of discussion, I expect it will wander around a lot!

I love "under the skin" pics of race cars, they can be very inspiring.

As for the duct in that pic, there's what looks most likely to be an oil line at the base of it - and I would put my top bet on that being for a differential oil cooler. Looks like the duct supplies air to it, and it looks like the duct then takes the exiting the cooler and sends it off to the side - I would also bet that that air is evacuated over the top of the rear diffuser somewhere...

I can't embed the photo here because it's copyrighted, but the pic in this link shows the duct opening in the trunk. It's an interesting location...:

Nissan GTR R35 FIA-GT1 | Flickr - Photo Sharing!
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Old 01-24-2013, 05:45 AM
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Id have thought that would be a low pressure area there?

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Old 01-24-2013, 06:26 AM
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Originally Posted by nitrodann View Post
Id have thought that would be a low pressure area there?
Most probably depends on the roof/trunk, and the exists can be placed in an even lower pressure area.
That exact solution might not work that well on a Miata with OEM-style hardtop, but you might be able to fetch air from below and dump it op there instead. Or fetch air from around the diff, pass it though a cooler and exit in the number plate area. I'm not completely sure what panel area in the rear is best suited for exiting air (low pressure and not disturbing diffusor and/or wing). Quarter panels, just in front of the rear lights?

Trying to apply Aero solutions from other racecars can be interesting, you never know what you will learn (about your car, the original car or the restricting regulations that have "inspired" the solution).
Pike Peaks and Time Attach series are some of the few areas where the Aero is free, and the focus is to make it go faster, many others are restricting in one way or another (or travels at speeds where we will never dare to go).
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Old 01-24-2013, 09:03 AM
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Any thoughts on the fenders autokenexion is working on?


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Old 01-24-2013, 09:56 AM
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They're cheap (kevlar is only like $650!), light (kevlar is ~3 pounds!), supposedly fit well, and clear 275's on 10's I'm not sure what else you really need to justify buying them. Of if you're a cheap bastard fiberglass are like $270 and weigh around 9 pounds, that is cheaper than you will be able to make them.

And some more aero food for thought.
Nerd's Eye View: The MCA Suspensions "Hammerhead" Silvia S13
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Old 01-24-2013, 10:06 AM
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Originally Posted by Dot3 View Post
Any thoughts on the fenders autokenexion is working on?

I kinda working on the same thing (waiting until I get almost done with the design, Top Secret). I just picked up a fender from a local Pcola Junkyard, but I TDY (sent to another state for Military business) here so I don't have tools. I will be making mine 30mm wider and will allow the air to be removed from the front fender. I am making a mould so if anyone else wants one I can make them. It will be made out of prepreg carbon (about 11 ounces each). Mine will more or less copy the Lotus 300RR, but will also have anti-lift vents on top of the wheel arches.

A friend built vented fender on his VW Golf and the problem he ran into was the pinch weld in the wheel well didn't allow the air to move smoothly out.

I like to see The MCA Suspensions "Hammerhead" Silvia S13 on a wind tunnel because I dont think its as efficient as the think.
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Old 01-24-2013, 10:12 AM
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Pre-preg? How do you have access to an autoclave big enough to do fenders? Lucky bastard.
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Old 01-24-2013, 10:24 AM
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Originally Posted by Leafy View Post
Pre-preg? How do you have access to an autoclave big enough to do fenders? Lucky bastard.
Anyone can do it, we don't need a pressurized oven. The oven just needs to be big enough to run the parts and be stable enough using ramp up schedule.
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Old 01-24-2013, 10:43 AM
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Regarding the duct in the OP, it might actually be a decent place on the miata, judging by the below picture (shamelessly stolen from a post by plucas in the flat underbody thread)

There appears to be a high pressure zone right where the top meets the trunk. The air could come in there and vent where the license plate is, or just above a diffuser. The question is, who'll be the first to try it and report back?!?

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Old 01-24-2013, 10:45 AM
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Originally Posted by krazykarl View Post
Regarding the duct in the OP, it might actually be a decent place on the miata, judging by the below picture (shamelessly stolen from a post by plucas in the flat underbody thread)

There appears to be a high pressure zone right where the top meets the trunk. The air could come in there and vent where the license plate is, or just above a diffuser. The question is, who'll be the first to try it and report back?!?

Dump it into the diffuser where the air is already "straightened" and moving.
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Old 01-24-2013, 10:53 AM
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Use the high pressure zone to bring air to differential?
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Old 01-24-2013, 01:29 PM
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This is used on F1 cars, active aero with no moving parts. Just like when you have the A/C on and when we take a corner quickly moves to the opposite way that we are turning.

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Old 01-24-2013, 02:20 PM
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Question: Why is the airflow in the Acc/Decell module follow the G-force and in the Left/Right module moves against the G-force?
Or is there any other phenomena that steers the airflow?
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Old 01-24-2013, 05:13 PM
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Autokonexion fenders:

I did custom fenders just like these and have run them for the past few years. Works pretty well. Eventually though, I was dissatisfied with how the vent only addresses about 1/3 of the wheel well, so I designed new ones. For an off-the-shelf option though, I think those are pretty good.

Trunk duct topic:

That pic courtesy of Plucas does show a small high pressure area at the rear base of the hardtop, but look at its position and remember that miatas have a 4" or so panel behind the base of the hardtop before it becomes trunk, which means that a trunk duct would be further back than where the high pressure is. In the pic of the GTR GT1, you can see they don't have that problem - the duct is right at the base where the rear window slope hits the horizontal trunk surface.

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Old 01-24-2013, 06:11 PM
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After know what I wanted to do as far a fender design, I looked up it on google to see what I'm picturing and this is the closes thing. So know I have junkyard parts sitting in my hotel for the next 2 months lol.

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Old 01-24-2013, 07:42 PM
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Originally Posted by NiklasFalk View Post
Question: Why is the airflow in the Acc/Decell module follow the G-force and in the Left/Right module moves against the G-force?
Or is there any other phenomena that steers the airflow?
I saw an article on this. I think Braun GP (Ross Braun, the man himself) originally came up with this system. Anyway, it is actually an aero device that through virtue of its profile multiplies the incoming angle of attack at the port. If the air enters the incoming slot at say 2 degrees (from a turn maneuver) then it leaves the slot at say 10 degrees in a focused stream. This is used to direct the airflow into a series of ports behind the slot (like mailbox cubby holes) that through a series of duct tubes direct the flow into the flaps and out through bleed ports in a manner that augments the downforce for cornering or straights. Nothing moves in the wing, all fixed, yet the airflow gets redirected passively depending on which way the car is turning. It is a fantastic example of how innovative F1 aero can be when working around the rules for an advantage. Genius.
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Old 01-24-2013, 08:18 PM
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Originally Posted by 1993ka24det View Post
This is used on F1 cars, active aero with no moving parts. Just like when you have the A/C on and when we take a corner quickly moves to the opposite way that we are turning.

https://www.youtube.com/watch?v=mJybR-uWTUc


The only F1 team with air channels in the front wing is Mercedes for its double DRS that even if they werent banning it for next season said that they wouldn't do it again for next season because it takes too much damn money, work, and time to iterate a new wing. And, with out doors to change which outputs are open. Air just doesnt magically move like that from inertia or any other bullshit quasi physics.
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Old 01-24-2013, 10:50 PM
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Originally Posted by Leafy View Post


The only F1 team with air channels in the front wing is Mercedes for its double DRS that even if they werent banning it for next season said that they wouldn't do it again for next season because it takes too much damn money, work, and time to iterate a new wing. And, with out doors to change which outputs are open. Air just doesnt magically move like that from inertia or any other bullshit quasi physics.
Oookay I guess tell us all about Aerodynamics Mr. Adrian Newey
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Old 01-24-2013, 11:09 PM
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Sorry, but F1 teams don't scrap ideas because it's too complex to make the part. If anything, expect new ideas to be more complex and expensive to make, not less. And rules won't stop that - they'll just come up with a new crazy way to go faster while working around the rules.

On a slightly related note, the RedBull cars have been running rubber noses that flex as a unit so that at speed they get closer to the ground. Cool.
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