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Old 11-27-2013, 06:31 PM
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Originally Posted by Rokomis
I don't disagree on the optimization, any reason you're stopping production on the GT-250s?
Demand is light and the cool guy pricing only came with a big order. So I just send folks directly to APR now. When we get around to producing our frame rail mounts, we'll produce some matching foils to complete a PnP kit. Low priority right now though, sorry.
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Old 11-27-2013, 06:43 PM
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Just finished mounting the new fiberglass front end. It's an E-prod setup, but the fenders are made to mount flush to the door. I was VERY tight on tire clearance and wanted to vent the rear fenders, so I just made some stanchions to hold them out and flex the fender slightly. Thankfully, the fiberglass is so damn thin, it has a good bit of flexibility and doesn't put up much of a fight. Nose and fenders come off in one piece, mounted to a pair of tubular frame rails after I cut most of the front end off.
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Old 11-27-2013, 06:44 PM
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Originally Posted by emilio700
Demand is light and the cool guy pricing only came with a big order. So I just send folks directly to APR now. When we get around to producing our frame rail mounts, we'll produce some matching foils to complete a PnP kit. Low priority right now though, sorry.
Makes sense, I know a lot of people they are turned off by anything that involves some effort to DIY. I could see a PnP kit doing much better! I am rocking the GTC-200 & Air Dam you sold for a while, serves my purposes just fine!
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Old 11-28-2013, 10:40 AM
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Originally Posted by jpreston
Brooks Motorsports has some nice looking wings and seem pretty open to custom stuff. Last time I saw one of their wings was a few years ago before the company changed hands, and it was a little rough around the edges but overall pretty nice. The only real complaint I had was a very rough leading edge from the mold parting line, and they've supposedly changed the molds to eliminate that. I don't know anything about the foil profiles they're using, though.
Recently checked out a Brooks airfoil, owner said it was from after the change of ownership and while the swan neck element was cool (custom $$$ request by the customer), the finish/quality of the airfoil was not very impressive. Very rough front edge and wavy surface. You could run your hand over it and feel it dip and rise.. customer also wasn't very happy with the finish of the swan neck mounts either (can't remember why) which is a shame for how much they probably cost him.

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Old 01-26-2014, 09:21 AM
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After trying my gt200 wing from the grey 400whp mx, on the stock(ish) powered red one, my friend had to have a wing too.

Shaved a clean 1.5 sec of pr lap on a 1.48 min lap on our local track(rudskogen , norway)

the wing on the red one is " china special " mounts are 4mm titanium plate(yup.. steel was heavy and he had access to titanium)

legs for the wing are custom made for this setup, and the mounts underneath the wing moved out to match..

Will complement with a frontsplitter similar to the one i have posted aerlier to balance it all out.

hope you guys approve of Einars new aero





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Old 01-27-2014, 03:24 PM
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I like it, did a similar set up with mine. Put my wing a bit higher but unfortunately my uprights bent under the downforce. I remember reading somewhere you should be able to sit on your wing without it shifting. Like you say the front splitter will help balance things. Then you play around with the wing angle.
I managed 1.13G on some bends in the morning. Only managed .99G in the afternoon without the wing after I bent things :( and like you my times were quicker too.
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Old 01-27-2014, 10:54 PM
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Originally Posted by HeresJohnny
I remember reading somewhere you should be able to sit on your wing without it shifting.
A proper wing/upright setup should be able to take several people sitting on it I would think. 500 pounds is a nice round number, that should be easy enough for a well designed and built setup. Each upright only has to take half of that...

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Old 01-28-2014, 05:08 AM
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stress testing already done.


Post your DIY aero pics-1603444_10153652628220251_1352863679_o.jpg
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Old 01-28-2014, 10:49 AM
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Originally Posted by ThePass
A proper wing/upright setup should be able to take several people sitting on it I would think. 500 pounds is a nice round number, that should be easy enough for a well designed and built setup. Each upright only has to take half of that...

-Ryan
Yeah my uprights will take that. I'd be concerned about that kind of point load on the wing. It'll take the weight as a distributed load though. But my wing isnt designed to go over 100mph, so much drag, hundreds of pounds of drag.

Canards, anyone have info on these that goes beyond basic. I really only ever see non-aerofoil canards, basically just a flat profile sometimes curved a curve. I get 0.6sqft on each side, cant go wider than the rest of the front bodywork, cant extend more than 6" in front of the car. Area is measured by chord X length. 1 end of the canard must be mounted to a surface of the car (IE no front wings). So I can camber, and fatten the **** out of it to get all of the downforce without a real penalty besides drag, which I dont really care about.
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Old 02-04-2014, 12:49 PM
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Originally Posted by cjsafski
Been working on trying to get my simulation to work right. So far I got the program to calculate the coefficient of drag to be .34 (actual .38). However, Autodesk Falcon is not consistent in its results. Either it gives a reasonable value near .34 or something ridiculous with successive trials. As such I have very little confidence in any results. I guess that is what I get for using freeware. The computer in my laboratory has Comsol on it which can do the calculation. Just need to find a time when it is not being used for micromagnetic simulations.
Did you ever figure out why your sims were inconsistent? I'm running into that issue now trying to design canards with COSMOS. It wasnt an issue with the wing, the results would change by maybe a fraction of a percent each time, but with the canard its varying by well over 10% I'm assuming its because I have some conditions setup wrong. But I dont have the right version of solidworks anymore to check what I did to make the wing work. Something is seriously buggered anyways since the results seem otherwise wrong and non-aerofoil canards are making more downforce than aerofoil ones at the same AOA with the same amount of camber.
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Old 02-04-2014, 06:04 PM
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Usually inconsistent results= poor mesh.

To learn the software & validate your results you should start simple with something you can analytically solve with equations "easily". Then you can validate that you are using the system correctly and build complexity from there. Automated meshing tools are not always your friend.

Take this with a grain of salt. I haven't done CFD since college (4 yrs ago), but I do use quite a bit of FEA at work and poor meshes are always a cause of inconsistency.
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Old 02-04-2014, 06:21 PM
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The guy that made my lightweight hardtop and doors just came out with this for the NB.
97 06 N B Mazda Miata Fiberglass GT Wide Body Kit | eBay
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Old 02-04-2014, 06:24 PM
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I never really played much more with the software since I got busy with actually working on the car, then breaking just about everything on it at a trackday and subsequent repairs. The problem with the software was probably mesh size. I haven't been to up to date in buying any sort of technology, which is funny since the lab I am in deals with novel computing tech.
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Old 02-04-2014, 09:14 PM
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Originally Posted by 240_to_miata
Usually inconsistent results= poor mesh.

To learn the software & validate your results you should start simple with something you can analytically solve with equations "easily". Then you can validate that you are using the system correctly and build complexity from there. Automated meshing tools are not always your friend.

Take this with a grain of salt. I haven't done CFD since college (4 yrs ago), but I do use quite a bit of FEA at work and poor meshes are always a cause of inconsistency.
This! Mesh quality is one of the most important aspects of quality cfd work. Start with the ahmed model to verify your can run the software correctly and create a decent mesh.

For at least the cfd work I have done, I have found that a mesh under 5 million cells for half car model yields bad results. I usually fall in the range of 10-20 million cells using mesh dependency study depending on the complexity of the model.
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Old 02-04-2014, 09:47 PM
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Originally Posted by circuitmstr74
The guy that made my lightweight hardtop and doors just came out with this for the NB.
97 06 N B Mazda Miata Fiberglass GT Wide Body Kit | eBay
I personally know the guy who owns the car in the picture. It is a very nice looking set of body work.
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Old 02-04-2014, 09:49 PM
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Originally Posted by plucas
This! Mesh quality is one of the most important aspects of quality cfd work. Start with the ahmed model to verify your can run the software correctly and create a decent mesh.

For at least the cfd work I have done, I have found that a mesh under 5 million cells for half car model yields bad results. I usually fall in the range of 10-20 million cells using mesh dependency study depending on the complexity of the model.
I need to figure out if there's even a way to change this in COSMOS besides just changing the resolution. FEA meshes make sense, cfd meshes are magic.
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Old 02-05-2014, 02:12 PM
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Originally Posted by Leafy
I need to figure out if there's even a way to change this in COSMOS besides just changing the resolution. FEA meshes make sense, cfd meshes are magic.
I would think there would be, but I do know as I do not use that software. I know in most meshing softwares for cfd, you have a lot of control over the mesh. Is that the only software you have access to?
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Old 02-05-2014, 02:31 PM
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There probably is in COSMOS. I could also use open foam I left like 100gigs open on my desktop's hard drive for a linux partition that I never got around to installing.
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Old 02-05-2014, 02:37 PM
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Originally Posted by Leafy
There probably is in COSMOS. I could also use open foam I left like 100gigs open on my desktop's hard drive for a linux partition that I never got around to installing.
I would switch to openfoam as I know it can create a quality mesh and give repeatable results.
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Old 02-05-2014, 02:54 PM
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Yeah I just need to figure out a linux cad program then so I dont have to keep rebooting.
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