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-   Aerodynamics (https://www.miataturbo.net/aerodynamics-119/)
-   -   Aerodynamic Discussion Thread (https://www.miataturbo.net/aerodynamics-119/aerodynamic-discussion-thread-70612/)

motormechanic 10-15-2013 10:47 AM

The purpose of serrated edges/slats on the bottom of wing edplates, in regards to F1, is to straighten turbulent air ejected off the tire sidewall. They also help with the upwash of the rear wing by accelerating airflow at the base of the endplate.

ThePass 10-15-2013 11:48 AM

Interesting. So they are multiple vortex generators in a single file line then.

mx5autoxer 10-17-2013 05:15 PM

I've been wondering why airfoil shapes are still being developed and are team secrets. I would have thought that an optimal shape would have been found long ago and would be public knowledge now. I mean they're all slight variations of a teardrop shape, right? Just find the shape with the best ratio of drag vs. lift.

Leafy 10-17-2013 07:23 PM


Originally Posted by mx5autoxer (Post 1064078)
I've been wondering why airfoil shapes are still being developed and are team secrets. I would have thought that an optimal shape would have been found long ago and would be public knowledge now. I mean they're all slight variations of a teardrop shape, right? Just find the shape with the best ratio of drag vs. lift.

Not even close. You can find the optimum shape for a single element at different speeds in an open environment pretty easy, they're not all published still. Adding more elements, making it interact with the ground, the car, the wall, the cars around you, cross winds, rain, etc all takes a dick load of modeling.

Supe 10-23-2013 07:39 PM

1 Attachment(s)
Going back to this picture, is there any other practical place on the car for the exit duct? Wondering what options would be for an RX7 where you don't have a trunk or have extremely limited spacing between the tail lights. Alternately, would you still see a benefit, albeit a diminished one, if you had to neck down the exit to be narrower than the inlet?

https://www.miataturbo.net/attachmen...ine=1382571542

Leafy 10-23-2013 07:39 PM

I'd aim for somewhere in the middle of the rear hatch glass, lol.

Supe 10-23-2013 08:02 PM


Originally Posted by Leafy (Post 1066145)
I'd aim for somewhere in the middle of the rear hatch glass, lol.

Don't think I haven't given it thought! Glass is coming out for lexan anyways!

carbon 10-30-2013 08:41 PM

1 Attachment(s)
Supe, what about the 2 exits on the side of the car in the rear? Make it look like a GT car or something. Here is kind of what I am talking about on a modeling of an s14.

https://www.miataturbo.net/attachmen...ine=1383180096

1993ka24det 12-24-2013 01:53 AM

I haven't been on here in sometime, since my computers charge cord broke. Is there any updates to any aero ideas? I'm about to start working on my vented radiator hood vent.

Supe 12-24-2013 08:40 AM

I'm in a bit of a vent conundrum.

I was making a fiberglass outlet duct coming off the radiator that would exit the sides of the hood so as not to direct air into a forward facing hood scoop. However, the duct is very large and is creating issues with brake duct locations, accessibility to engine accessories, coolant hose routing, and is occupying space I may need for future "upgrades".

This drives me back to the traditional center-exit ducted radiator vent which is fine. However, I'm also not wanting to force feed warm air into my throttle body. Does anyone foresee this being an issue if I were to use a cowl induction setup with a center exit radiator duct? Options are very limited, though an offset cowl induction setup may be possible now that the brake booster/master cylinders are gone.

vintagerust 12-24-2013 12:25 PM

Assuming you are using the old style filter that sits on top of the "carb" (I noticed you're running Holley EFI), I would run a standard hood vent, and then get an air filter cover that you can attach hoses/pipes to, to route air from the front bumper or fenders.

Also, if you were to go that route, you would probably want to close up that forward facing scoop.

Supe 12-24-2013 01:32 PM

My problem is hood clearance. Presently running no air filter other than a mesh screen. Between the low hood clearance and the strut tower brace, I don't think I'd be able to route anything without some serious hood surgery.

ThePass 12-24-2013 02:55 PM

I would not want to have my motor intaking the hot radiator exhaust air.

"Ram air" is virtually a myth (until you're talking about a well-engineered setup at 150mph like on the yamaha R1), so given that you can't find a packaging solution other than a center hood vent just forward of the hood scoop for the intake, I would say close off the front of the scoop and open up the back side. Essentially changing it from a 'scoop" to a "cowl" , although this won't solve the issue entirely because the warm air will still be passing over the hood and get inhaled from the back side, it would give the cooler air around the car more time to mix with that warm air before it reaches the intake, so probably net effect would be cooler intake air.

Another option might be a vertical flap ~1-2" forwards of the scoop opening, same height as the scoop - basically a big gurney flap to create some lower pressure right in front of the scoop opening. This could help push hot air up to pass above the scoop, and the scoop would source air from the sides more.

-Ryan

vintagerust 12-24-2013 05:51 PM

I would go for a cowl induction hood, and a sealed vent up front for the rad.
I think a hood scoop in the path of the rad vent would be kind of counter intuitive, and creates more drag.
Either way, I'd try to graft something on your hood, so you can at least run some sort of filter.

Supe 12-24-2013 06:06 PM

Sorry, probably not giving a good image here.

Radiator will be a sealed duct that exits just forward of the hood centerline, with a small gurney flap on the leading edge. The rest of the hood right now is flat.

My line of thinking is along the lines of ThePass right now - the radiator exit air would likely be drawn through a cowl opening, which is why I was contemplating trying to offset a cowl-induction based intake that was biased off to one side.

mx5autoxer 12-24-2013 09:29 PM

Why not vent the radiator underneath the car? There should be low pressure there to pull air through the rad. Lower the splitter a little bit to return the air flow volume to what it was before the vent so as not to lose downforce. Or maybe it will need more air (raise splitter) to keep the under-car air moving and therefore pressure low.

1993ka24det 12-24-2013 11:15 PM

I the reason I want to run a hood radiator is 1 the radiator has more air flow to disperse the heat and 2 is because, look at the CFD of a Miata. There is a big negative pressure zone right where the vent would exit.

ThePass 12-25-2013 12:28 AM

Radiator exhaust exiting hood is preferrable over under car, but it's very difficult to accomplish on a miata without relocating the radiator. On an FC with that engine config, might be entirely possible to fit the necessary ducting. If that's the case, definitely better to try to make that happen than go the easy route of letting it exit under the car.

-Ryan

Supe 12-25-2013 02:12 PM


Originally Posted by ThePass (Post 1085770)
Radiator exhaust exiting hood is preferrable over under car, but it's very difficult to accomplish on a miata without relocating the radiator. On an FC with that engine config, might be entirely possible to fit the necessary ducting. If that's the case, definitely better to try to make that happen than go the easy route of letting it exit under the car.

-Ryan

The radiator is very low, moved forward a bit, and significantly angled forward (maybe 30 degrees from flat). It's a straight shot in with the duct work with plenty of room to exit out the hood right in a low pressure zone. No conceivable way to efficiently duct under the car given the current configuration and space limitations.

vintagerust 12-25-2013 03:01 PM

http://l2.yimg.com/bt/api/res/1.2/d1...y-series-1.jpg

Too much fabrication?


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