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Originally Posted by Leafy
(Post 1201862)
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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It looks to me like the cell size for the simulation might not be small enough to pick up the thin walls of the diffuser. I can't see how that air could flow across the back like that.
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Maybe, but you'd think someone making a model that good would know to use automated mesh control to set a minimum wall thickness and pick those up. Or just use a dense enough mesh if whatever they were using didnt support that.
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Originally Posted by Leafy
(Post 1201886)
Maybe, but you'd think someone making a model that good would know to use automated mesh control to set a minimum wall thickness and pick those up. Or just use a dense enough mesh if whatever they were using didnt support that.
Still that flow looks very wrong for some reason. If the air was really flowing past the verticals then you would surely see very high pressure zones under each. Maybe there is a large gap to the ground where the air can cross but the whole point of those fins is to prevent that happening. If the sim is correct why have the fins at all? |
What I was pointing as is that, thats a pretty nice solid model. Its just surprising someone is able to make something that nice on the model side but then not do something fairly simple like that, or even fail to catch it when just looking at the results. It really does look like the sims are ignoring that the strakes even exist.
Theres some other oddities, like how the flow separated on the inside of the tires without significant turbulence. And there's also quite a few surface errors as well which certainly arent helping. Looking closer I dont think this is a solid model, I think someone scanned this in. |
Originally Posted by Leafy
(Post 1201909)
What I was pointing as is that, thats a pretty nice solid model. Its just surprising someone is able to make something that nice on the model side but then not do something fairly simple like that, or even fail to catch it when just looking at the results. It really does look like the sims are ignoring that the strakes even exist.
Theres some other oddities, like how the flow separated on the inside of the tires without significant turbulence. And there's also quite a few surface errors as well which certainly arent helping. Looking closer I dont think this is a solid model, I think someone scanned this in. It looks ok but I know from my sims you sometimes need to bulk up the thin walls up to bigger than your cell size otherwise with the size of the cells let the air through like they are permeable. |
Originally Posted by 1993ka24det
(Post 1201861)
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 Bearing in mind the data reservations above, should I be pencilling a concave, or a convex, shape? |
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Saw the Silver-Car at the MSX yesterday. Was surprised to see these roof rails feeding the rear wing:
https://www.miataturbo.net/attachmen...ine=1424610790 The car has a DTM type flat bottom/rear diffuser and fiberglass skirts in addition to the wing. One of the tech guys said they saw significant gains with those roof fins during their wind tunnel testing, and they made it on to the final version of the production car. That thing weighs 900 lbs and has 200HP... |
Originally Posted by Supe
(Post 1208532)
Saw the Silver-Car at the MSX yesterday. Was surprised to see these roof rails feeding the rear wing:
https://www.miataturbo.net/attachmen...ine=1424610790 The car has a DTM type flat bottom/rear diffuser and fiberglass skirts in addition to the wing. One of the tech guys said they saw significant gains with those roof fins during their wind tunnel testing, and they made it on to the final version of the production car. That thing weighs 900 lbs and has 200HP... |
One the K1, those double as a swan neck wing mount. In the Silver-Car, the wing mount is separate. These are only for guiding airflow.
That car is rear engine and has a firewall behind the driver, so visibility is moot anyways in this case. It also doesn't extend all the way down the rear body work, it was about 4" deep after the immediate roof line. I understand it can act as a safety feature if sliding sideways, but I wonder if extending them to the leading edge of the wing provides benefits similar to spill plates on a splitter. |
Looking at this picture, the roof fins make sense. The roof has a nice gentle slope to "put the air back together" and feed air to the wing, but I'm sure the air gets super dirty once it drops over the edge onto the rear hatch window. The roof fins should help keep the air from the sides of the car from spilling in. Seems like just raising the wing up into cleaner air would have been more effective, though.
https://silvercarusadotcom.files.wor...fromtibet1.jpg |
many racing bodies don't allow the wing to be higher then the roof.
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OGRacing, what wing are you running 200 or 300?
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i got the 200. i am about to raise it to the roof line.
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Mazda Skyactive Diesel Dive Planes
https://www.miataturbo.net/attachmen...ine=1427148200 Mazda Skyactive Diesel Side https://www.miataturbo.net/attachmen...ine=1427148200 Prototype Corvette powered Rear Diffuser https://www.miataturbo.net/attachmen...ine=1427148200 |
Awesome pictures. Interesting step in the wing. I would think that the purpose there is to slow down the air and create a higher pressure differential between the top and bottom of the wing.
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That is a pretty serious gurney on the Ferrari.
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it's interesting to see that the ferrari and DW almost don't want the high pressure air in the center of the splitter. the DW is flush with the front of the bumper, and the ferrari have big gaps. wonder why?
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The DW doesnt appear to want the drag, and the ferrari seems more concerned about getting as much air to its underbody aero as possible.
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I agree with Leafy, at least for the ferrari. When you're making a lot of downforce with the underside of the car, you really have to worry about the splitter bottoming out and cutting off airflow to the underside. As soon as the splitter bottoms and you lose airflow, you lose the underbody downforce and the car lifts up off the ground. Airflow is restored when the car lifts, so downforce returns and sucks the splitter back onto the ground, cutting off airflow again. It's a vicious cycle that results in the car violently bouncing up and down, usually in heavy braking. A lot of cars that have serious underbody aero have a raised (or non-existent) center section on the splitter, so that the splitter can touch the ground without choking airflow to the underbody.
This problem doesn't just exist with flat floors and diffusers either. One of my friends tried a large, low splitter/undertray with really soft front springs, and he said the car was dangerous to drive in braking zones. It was so bad that he pulled the splitter off after the first session of the day. |
Love the diffuser on the Corvette prototype.
I've wondered for a while about the vortex generating "foot" on the outside edge of the Mazda Skyactiv splitter which is pointed right at the front tire. If it were outboard of the front tire (which I'm sure they can't do due to splitter width restrictions) it would make more sense, but as-is it's puzzling. -Ryan |
Ryan,
I spoke to Henry from KazeSpec. He told me that they probably want to offset the front tire wake away from the underside of the car. Most of the tire wake is shed off the sidewalls and shedding a vortex in front of the tire will help deflect it outwards. This is true too of F1 cars, which have 2 vortex channels, one on the endplate and one pointed at the tire. |
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Interesting feedback on the guys using his services. Essentially guaranteeing a 3 second lap time reduction for $2k in consulting... not too shabby if you're looking to win.
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One thing we really haven't talked about, besides downforce. I want to know more about reducing Drag since alot of our cars don't produce more than 300 hp.
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Originally Posted by 1993ka24det
(Post 1221332)
One thing we really haven't talked about, besides downforce. I want to know more about reducing Drag since alot of our cars don't produce more than 300 hp.
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Originally Posted by 1993ka24det
(Post 1221332)
One thing we really haven't talked about, besides downforce. I want to know more about reducing Drag since alot of our cars don't produce more than 300 hp.
http://kazespecengineering.com/wp-co...ero-101-20.pdf |
interesting to get a figure....1/3 of the cars drag is cooling....
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Originally Posted by motormechanic
(Post 1221551)
this might be a good place to start:
http://kazespecengineering.com/wp-co...ero-101-20.pdf |
Originally Posted by 90civichhb
(Post 1221764)
Well that was sorta short. Got anything else as cut-and-dry to read?
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Long Beach Grand Prix
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I went to the Long Beach Grand Prix yesterday with a pit pass, which allows unbelievable access to all the cool cars, from Indy to GTLM. The Indy cars are all basically built to "spec", so there are no aero secrets out there. Teams were perfectly happy to let anyone poke around their cars, take pictures of the steering wheels, everything. The GTLM and prototype cars were spectacular, and there's something cool about a massive Bentley set up for racing.
Attachment 138129 Attachment 138130 Attachment 138131 Attachment 138132 Attachment 138133 Attachment 138134 Attachment 138135 Attachment 138136 Attachment 138137 Attachment 138138 |
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I posted this a while back, but I need more cooling and downforce on the front end to make up for the new rear wing I have planned.
https://www.miataturbo.net/attachmen...ine=1429489152 |
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Originally Posted by 1993ka24det
(Post 1224743)
What is this a picture of?
Gurney flap - Wikipedia, the free encyclopedia |
Originally Posted by cordycord
(Post 1224749)
THAT is a Gurney flap, or Wickerbill. It's appropriate that I took the picture in Long Beach, as that's Dan Gurney's home track. :)
Gurney flap - Wikipedia, the free encyclopedia |
Originally Posted by 1993ka24det
(Post 1224757)
I knew it was a gurney flap, i just didn't know what car it belonged to or where it was located
I knew what you meant.. Lol. I believe it the wing in front on the rear tire on an Indy car. |
Originally Posted by 1993ka24det
(Post 1224757)
I knew it was a gurney flap, i just didn't know what car it belonged to or where it was located
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Originally Posted by 1993ka24det
(Post 1224746)
I posted this a while back, but I need more cooling and downforce on the front end to make up for the new rear wing I have planned.
https://www.miataturbo.net/attachmen...ine=1429489152 |
Originally Posted by 1993ka24det
(Post 1224746)
I posted this a while back, but I need more cooling and downforce on the front end to make up for the new rear wing I have planned.
https://www.miataturbo.net/attachmen...ine=1429489152 |
Definitely an Apollo. That splitter looks a lot like mine.
-Ryan |
Originally Posted by humming
(Post 1224964)
What car is that? looks like a gumpert apollo maybe?
It is a Gumper Apollo
Originally Posted by Der_Idiot
(Post 1224954)
Is that a picture of the front end? Looks like it has a splitter followed by a recess to allow in air between the flat tray and the car? Could that feed air through the transmission tunnel and out the back by the diffuser?
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Just wanted to say,the lift that Apollo is on is awesome. I've never seen adapters like that.
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Sorry if this has been posted before- I skimmed and didn't see it: Developing the Nissan GT-R LM NISMO
Pretty interesting advantages to running FWD http://roa.h-cdn.co/assets/15/05/160...-pruett-58.jpg http://roa.h-cdn.co/assets/15/05/160...tt_11repl.jpeg |
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I found this diffuser made from Factory 5 Racing's 818. I emailed them for the measurements, but now I can't find that email.
818 Carbon Fiber Rear Diffuser - Factory Five Parts Catalog https://www.miataturbo.net/attachmen...ine=1438547719 https://www.miataturbo.net/attachmen...ine=1438547719 https://www.miataturbo.net/attachmen...ine=1438547719 https://www.miataturbo.net/attachmen...ine=1438547719 https://www.miataturbo.net/attachmen...ine=1438547719 |
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Hey, asking the brain trust on this. I'd like to know what this wing is as I'm not entirely sure. I'm pretty sure that I know what it is but I would like to be sure.
Just under 61" wide. Legs just under 47" apart. Difference in AOA from center to end about 16 degrees. https://www.miataturbo.net/attachmen...ine=1440093725 https://www.miataturbo.net/attachmen...ine=1440093725 https://www.miataturbo.net/attachmen...ine=1440093725 https://www.miataturbo.net/attachmen...ine=1440093725 https://www.miataturbo.net/attachmen...ine=1440093725 https://www.miataturbo.net/attachmen...ine=1440093725 https://www.miataturbo.net/attachmen...ine=1440093725 |
looks like a replica APR GTC.
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61" wide with 47" mount spacing matches GTC-300
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Spring load DRS
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<p>Could that be done with a trunk spoiler? Like the lexan type. Some really strong springs, so it is upright at low speeds and pushed out of the way at higher speeds? Or would that fail?</p>
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Wow, no idea the science behind that. However, I love the idea of it. I hope someone with knowledge chimes in.
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Not spring-loaded. According to SVA:
Originally Posted by SVA Imports
appearances can be deceptive, it is hydraulically operated & ecu controlled based upon speed, lateral G & braking , the video was of the wings first test before the actuation perimeters were tuned!
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<p>But would spring loaded work?</p>
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"Work" is a little broad ;) but my $0.02:
For a DRS system you want a solid fixed position when ON and solid fixed position when OFF. Most springs are linear if you ignore the far extremes of their range, so a simple spring system would be passive (uncontrolled by driver or ecu - not good) and continuously variable as speeds changed (not good). I'm sure a complex spring system could be concocted that worked around that to some degree, but likely no less complicated than other systems, with no benefit (cost doesn't count - there are other low-budget options without these drawbacks, like Keith has done).. |
Originally Posted by ThePass
(Post 1261957)
The reason nobody would assume that it is controlled by ECU/GPS based on the video is because the activation and deactivation timing is wayyyy off, but it's obviously a work in progress.
Originally Posted by ThePass
(Post 1261984)
"Work" is a little broad ;) but my $0.02:
For a DRS system you want a solid fixed position when ON and solid fixed position when OFF. Most springs are linear if you ignore the far extremes of their range, so a simple spring system would be passive (uncontrolled by driver or ecu - not good) and continuously variable as speeds changed (not good). I'm sure a complex spring system could be concocted that worked around that to some degree, but likely no less complicated than other systems, with no benefit (cost doesn't count - there are other low-budget options without these drawbacks, like Keith has done).. |
Are any of you guys cutting away behind the front wheel to allow better pressure release?
https://scontent-lhr3-1.xx.fbcdn.net...c3&oe=567BD7E9 Im sure Ryan will comment(I can see he has done some work on his to help) Relieving the pressure there isnt just about reducing lift, while thats one of the reasons its not the primary. Wheels and tyres make really good vacuum cleaners, in which they suck all the air into the wheelarches, but then if it has nowhere easy to go, the pressure increases and creates lift, you can vent from the top of the arch and also the rear part of the arch. One of the important things about venting arches is to keep the pressure as close to ambient as possible. Your splitter works by forcing the air that travels underneath it to speed up and as such becomes a low pressure area.........now if you have low pressure heading straight into a high pressure area, thats exactly what it doesnt want to do. Imagine opening a bottle of fizzy pop, the air always wants to go from high pressure to low pressure The only way you can force it is with lots of velocity, but effectively its still like hitting a brick wall. If you can reduce that wheelarch pressure you reduce the 'wall' and the splitter allows more air to pass out of it and hence works better. This is also why I suggest front diffusers to allow that pressure gradient to be more gradual to reduce the 'wall' scenario. So your now making more front downforce, you can then add more to the rear to balance the car for a net increase in overall downforce more than just a little reduction in lift in the wheel arch. Its not as easy on a miata to remove as much as I have but it will be possible with some chopping and welding, a very good example of this would be Under Suzuki This is what i did with my car, I know its not a miata, but one of the guys on here has said it would help if i joined in with my thoughts https://scontent-lhr3-1.xx.fbcdn.net...92&oe=56798A31 |
So this is what I found a couple of days ago
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Originally Posted by Oh4One4
(Post 1258795)
Just under 61" wide. Legs just under 47" apart. Difference in AOA from center to end about 16 degrees.
https://www.miataturbo.net/attachmen...ine=1460957031 |
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He was one of the first guys to start using the COT wings. I ran across his build thread back before I started the big COT wing thread on here.
On another note, I have also been watching those videos for the F1000 composites on youtube...there is some great tech in there, specifically the materials etc. |
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