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Designing better APR GTC200 Endplates

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Designing better APR GTC200 Endplates

 
Old 04-18-2018, 11:21 AM
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Originally Posted by sirbikealot7 View Post
Singular Motorsports Wing Endplates: APR GTC-200 Singular Motorsports

These are another good option. I had to take a lot of angle out of my GT250 to match the balance of the car when I installed their endplates.
Do the GTC-200 plates bolt right on to the 250?
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Old 04-18-2018, 01:26 PM
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I'm not sure if it does. Snap a picture of yours straight on and I can see if it has the same bolt pattern.

Finally got some time to work on this further and I am super excited by the preliminary results. Not only do the 12"x12" endplates work, but the placement of them is super critical!

I easily got an increase of 10.8% in downforce just by going to 12"x12" plates, but playing with the location of them greatly varied drag results. I got it in the location right now that barely increases drag, even with the larger plates, but kept the increase in downforce. I haven't even started working on the other ideas yet. I hope to have results on my blog this weekend and start working on producing mine towards the end of the weekend.

Right now the efficiency of the wing is increased by 9%.
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Old 04-18-2018, 03:44 PM
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Originally Posted by thomsbrain View Post
Do the GTC-200 plates bolt right on to the 250?

No they have GT250 plates too if you email them. They aren't on the website for some reason
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Old 04-18-2018, 04:13 PM
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Could you put up a picture of what you consider an optimal location for the 12x12?
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Old 04-19-2018, 03:05 AM
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Originally Posted by pmptx View Post
Could you put up a picture of what you consider an optimal location for the 12x12?
I can't post up my secret sauce . Even .25" in the wrong direction leads to massive efficiency losses.

I finished dialing in the location last night so now I can start working on the other mods. As it sits, I'm at a 25% increase in downforce and 12% increase in efficiency.

The hardest part so far is a cooler looking endplate doesn't translate to faster
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Old 04-19-2018, 08:16 AM
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I don't have access to your elaborate tools and likely would be able to use them if I did. I use generic data from APR and other online resources. I find your ability to make these tests very interesting and I have two questions about the methodology.

Question 1: According to APR their standard Gurney flap adds much more downforce and is more efficient at increasing downforce than adjusting the AOA. I see in step 5 you plan to add a flap. I assume the optimal size/shape would be different with the flap. If the goal is to maximize downforce, why not add the flap to maximize the existing foil design first, then add the end plates to the optimized foil?

Question 2: I've read the downward airflow off the OEM hardtop is -12 degrees, but this test was done without a wing. Furthermore, simply subtracting 12 degrees to get an AOA relative to level does not account for turbulence. If 1/4" placement of the end plates can have a profound impact, the airflow off the top could have a larger impact. Are you including the profile of the S2000 in your CFD to have a more accurate representation of the downward angle and turbulence off the OEM hardtop?

Thanks for allowing us to see and participate in your research. Again, it is very interesting.
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Old 04-19-2018, 09:31 AM
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Originally Posted by will010100 View Post
I don't have access to your elaborate tools and likely would be able to use them if I did. I use generic data from APR and other online resources. I find your ability to make these tests very interesting and I have two questions about the methodology.

Question 1: According to APR their standard Gurney flap adds much more downforce and is more efficient at increasing downforce than adjusting the AOA. I see in step 5 you plan to add a flap. I assume the optimal size/shape would be different with the flap. If the goal is to maximize downforce, why not add the flap to maximize the existing foil design first, then add the end plates to the optimized foil?

Question 2: I've read the downward airflow off the OEM hardtop is -12 degrees, but this test was done without a wing. Furthermore, simply subtracting 12 degrees to get an AOA relative to level does not account for turbulence. If 1/4" placement of the end plates can have a profound impact, the airflow off the top could have a larger impact. Are you including the profile of the S2000 in your CFD to have a more accurate representation of the downward angle and turbulence off the OEM hardtop?

Thanks for allowing us to see and participate in your research. Again, it is very interesting.
I'll try and answer your questions as best I could.

1. The gurney flap is not the subject of these tests. I'm only investigating the endplates at this point. I don't own the flap and haven't seen anyone with it before. I tend to make things I want for my car, then just make it available for everyone else.

What I have been doing so far is trying to optimize one step at a time. For example: a notch with a certain endplate location had no effect, but had a slight improvement with another. So far I have run 67 different configurations and I've only looked at size, shape, and the rear notch. When I begin looking at the different design ideas I'll have a better idea of how they behave and if tweaks need to be made to the existing configurations. So I am looking backwards while moving ahead, if that makes sense.

2. For these preliminary tests, I am running just the wing and endplates, just as APR did (since it's a universal wing). However, I do have a rough S2000 model that I plan on running full CFD on. At home I only have my laptop to run on, which is nowhere close to powerful enough to run the model. To give you a better idea, at a previous job we had 528 computing cores of computing in the lab to run CFD on an aircraft wing, and it still took 4 days to compute. I do have some friends that have impressive rigs at home so I'm trying to get them to run the full model, when it's ready. It's just not possible for me to do so with every iteration.

Hope I was able to answer your questions.
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Old 04-23-2018, 04:24 AM
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I finished these over the weekend. I need to get around to posting the data here and to the site.

Quick conclusion:
1. 12"x12" with rounds produced the most efficient design
2. Location was critical
3. Rear notch imporoved performance when in line with airfoil; location is critical here too
4. Slots and gills helped reduce drag, but not enough to warrant machining costs

I ordered some material to begin producing these later this week. I hope to have them installed on my car and a few others for testing very very soon.

Off the top of my head, I think it was 25% increase in downforce, 14% increase in efficiency at a 0AOA.

My plates look similar to the Singular plates as it turns out. Would be cool to see their mounting location to compare data.

Last edited by roel03; 04-23-2018 at 04:27 AM.
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Old 04-26-2018, 03:13 PM
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Final results can be seen on my site here:

https://baero.tech/blog/2018/4/26/fi...-endplate-data

I am currently working with a few machine shops, including PuddyMod, to see how much it would cost to produce these. Once I get a decent amount milled I will add them to the site for purchase.
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Old 04-26-2018, 03:30 PM
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