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Originally Posted by Supe
(Post 1190754)
Yes, to both photos. On AB's car, it's suspended between the two vertical strakes. Bit dark, but you can still make out the end plates and all.
https://www.miataturbo.net/attachmen...ine=1419032835 |
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Could be wrong, wonder if its been changed? Thought there used to be an open section forward of the diffuser/wing/whatever it is, but you're probably right.
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I've often wondered if you could do both... Using the picture of the c6r vette as a reference. One could use the a diffusor like this, albeit a large one with more clear space behind it... and drop an aerofoil in behind/beneath it. Although I'm not sure one could achieve this with the proper angle of egress for the speeds for our typical none of the horsepower speeds.
http://gearheadsmag.com/wp-content/u...ngTest2220.jpg the C7 used a similar setup but it was adjustable instead of fixed angle. http://i.ytimg.com/vi/tlo005zpq2c/maxresdefault.jpg Just to show the evolution - The c5r had a more standard diffusor/strake setup that us meer mortals are more familiar with. https://www.miataturbo.net/attachmen...ine=1419187379 |
Originally Posted by EErockMiata
(Post 1191010)
I've often wondered if you could do both... Using the picture of the c6r vette as a reference. One could use the a diffusor like this, albeit a large one with more clear space behind it... and drop an aerofoil in behind/beneath it. Although I'm not sure one could achieve this with the proper angle of egress for the speeds for our typical none of the horsepower speeds.
http://gearheadsmag.com/wp-content/u...ngTest2220.jpg the C7 used a similar setup but it was adjustable instead of fixed angle. http://i.ytimg.com/vi/tlo005zpq2c/maxresdefault.jpg Just to show the evolution - The c5r had a more standard diffusor/strake setup that us meer mortals are more familiar with. https://www.miataturbo.net/attachmen...ine=1419187379 edit--check out that massive transaxle cooler with fan on the back of the Corvette. :) |
Originally Posted by cordycord
(Post 1191015)
A diffuser only really works well when you also have a flat under-body. Unlike a standard wing, it is free aero as the only induced drag is already there (the car).
edit--check out that massive transaxle cooler with fan on the back of the Corvette. :) |
Wasn't the change to the new-style short/wide flat rear planes due to a change in the rules by IMSA that no longer allowed diffusers with vertical fins?
So an airfoil builds pressure on the top surface, and for a diffuser you want less pressure/faster moving air on the underside. These two interests clash a bit. A pressure map of a typical diffuser shows the majority of the vertical force happening at the beginning of the angle change, so that is where you would least want to have an airfoil undernath - that's ok because that wouldn't work anyways as there is no ground clearance there. So then looking further back... even though the forces are towards the front of the diffuser, the air's behavior all along the length of the diffuser dictate how effective it is. Placing the airfoil underneath the diffuser surface near the back (like the BMW on the last page) is going to create an obstruction to the diffuser's airflow as the topside of the airfoil slows air and builds pressure in the region between it and the diffuser. I think the best application of the idea would be for the airfoil to be placed behind the diffuser exit. Use a wing with swan-neck style mounts or mount via endplates, suspended from the rear of the car, and the wing aoa adjusted for the airflow angle coming out of the diffuser. This way, the pressure build up above the wing can occupy the space behind the center of the rear of the car, and the diffuser's function isn't jeapordized. That's how I'd do it at least.. but if the concept can work or not? Only one way for someone to find out. -Ryan |
Bloody Hell that has Mad Max or Back to the Future written all over it!
Pretty cool and intriguing to see that. |
How come my race cars always look more like the test mules than the production cars? :dunno:
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Originally Posted by ThePass
(Post 1187627)
On an F1 car, upwards of 50% of the downforce can come from the underbody/diffuser, and that is with significant limitations on what they can do. An unrestricted car built around the most effective floor/tunnels their engineers dream up could produce incredible downforce without the use of relatively high-drag elements like conventional wings.
-Ryan It's one of the most appealing and creative uses of unrestricted aero that I've ever seen. For My Ally Is The Force, And A Powerful Ally It Is - Speedhunters Not much obvious on the outside: https://www.miataturbo.net/attachmen...ine=1421510459 But inside: https://www.miataturbo.net/attachmen...ine=1421510459 https://www.miataturbo.net/attachmen...ine=1421510459 https://www.miataturbo.net/attachmen...ine=1421510459 Using the low pressure behind the car to suck air out from under the car. Lots of downforce with extremely minimal addition in drag, if any at all. It might even be a drag reduction since the low pressure zone behind the car is partially pulling on air under the car, and less on the car itself |
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This is something I am working on this weekend. I will be placing a quite a few NACA ducts in my underbody to help move air for cooling.
Before resin https://www.miataturbo.net/attachmen...ine=1421517444 and finished for now https://www.miataturbo.net/attachmen...ine=1421517444 https://www.miataturbo.net/attachmen...ine=1421517444 https://www.miataturbo.net/attachmen...ine=1421517444 |
What are you trying to achieve with the fibreglass rear?
Is there more to come? |
Originally Posted by yenadar
(Post 1197439)
https://www.miataturbo.net/attachmen...ine=1421510459
https://www.miataturbo.net/attachmen...ine=1421510459
Originally Posted by 1993ka24det
(Post 1197463)
But that's might be what RJ's showing? |
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I should show those NASA jocks how to REALLY torture the air with a Hornet!
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In the article I found these pictures, they were talking about outer most part of the diffuser isn't getting proper flow.
Rear Diffuser Issues - Forum - F1technical.net https://www.miataturbo.net/attachmen...ine=1422673187 https://www.miataturbo.net/attachmen...ine=1422673187 https://www.miataturbo.net/attachmen...ine=1422673187 https://www.miataturbo.net/attachmen...ine=1422673187 |
seems as though the strakes aren't doing what they are designed to do.
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So I was looking around again at diffuser designs and I seen what slimjim8201 wrote on f1technical.net.
Interesting data on Straight, convex and concave diffusers. Each are tested at 5, 10 and 15 degs. https://www.miataturbo.net/attachmen...ine=1422740199 https://www.miataturbo.net/attachmen...ine=1422740199 https://www.miataturbo.net/attachmen...ine=1422740199 https://www.miataturbo.net/attachmen...ine=1422740199 https://www.miataturbo.net/attachmen...ine=1422740199 https://www.miataturbo.net/attachmen...ine=1422740199 https://www.miataturbo.net/attachmen...ine=1422740199 https://www.miataturbo.net/attachmen...ine=1422740199 https://www.miataturbo.net/attachmen...ine=1422740199 https://www.miataturbo.net/attachmen...ine=1422740199 https://www.miataturbo.net/attachmen...ine=1422740199 https://www.miataturbo.net/attachmen...ine=1422740199 https://www.miataturbo.net/attachmen...ine=1422740199 |
From that first set of images it looks like the strakes need to extend in front of the start of the diffuser. And thats on a car that already has a flat floor. Imagine how much of a disaster it looks like on a car without a flat floor.
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