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Designing better APR GTC200 Endplates

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Designing better APR GTC200 Endplates

 
Old 04-10-2018, 06:41 PM
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Default Designing better APR GTC200 Endplates

A while back I started a thread about designing my own wing. I ended up getting sidetracked and never finishing it as I found a dirt cheap S2000 specific GTC200 online. However, now that I am finished designing the brake ducts I've diverted my attention to making "better" endplates for my wing.

I took out the 3D scanner tonight and got a profile of the outward profile of the wing, as well as the endplate profile. Made a quick model and ran some CFD to see how the pressure plots looked on the current endplates, which I show below. I used the same profile throughout, even though that is not the case, because my gaming laptop cannot handle CFD any more complicated than this. I can't even save cut plots as is, I can just quickly view them until my computer crashes. I'll try and find a way of saving to show you guys as that is where the best data really is.

Options I plan on exploring:

1.) Size (max being the allowable 12"x12")
2.) Louvres
3.) Slats
4.) Splots
5.) Notch on top aft section
6.) Shape

Pretty much I am going to mimic a lot of the modern F1 wing designs, even though they use a dual airfoil. Whichever one gives me the best results I am going to produce and add to my product line.

Tips/Suggestions/Criticism is very welcome. My first goal is to calculate baseline lift/drag ratio of this wing so I have something to compare against.

Pressure trajectory plot (red is highest pressure, blue is lowest pressure):


Airflow behind the endplate, showing the vortex and trapped air:

Last edited by roel03; 04-10-2018 at 06:44 PM.
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Old 04-10-2018, 07:41 PM
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Quick look and uneducated guess is that you'd want to use most of the allowance in the low pressure areas behind and below the trailing edge. I thought the goal of the endplates is to keep the flow laminar at the ends of the wing as long as possible. Without them the wing ends loose effectiveness due to the pressure differentials bleeding off the end of the wing. The high pressure air is going where ever it wants to. The low pressure areas tend to get filled in by adjacent high pressure air if you let it.
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Old 04-10-2018, 08:05 PM
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Why? Endplates are pretty simple and many are available. It just seems to be working on something too small to measure.

Is your wing use a swan neck mount? Why do you think your APR GTC200 was designed for an S2000? And if so, with which roof? My understanding is the GTC200 and the GTC300 are generic pieces.

The biggest source of drag and in most cases lift is going to be the cooling system. But that can be an expensive, multi-part project all by itself. For example, coatings can reduce the heat transmitted to the coolant. Ring tension/gas porting, bearing clearances/oil viscosity can also affect heat generated. A dry sump removes the oily mist from the crankcase and can aid in cooling provided by the lubricant. Increasing coolant pressure and temperature can increase the heat transfer at the radiator, requiring a smaller radiator.

Which brings up ducting to and from the radiator, often with a separate oil cooler, a/c condenser, and intercooler. Managing that would be big and probably saleable. I'm imagining an inlet that tightly seals between the nose and radiator and an outlet that seals from the radiator to a duct in the hood.

http://www.sm-designs.co.uk/pdfs/rearendplates.pdf

http://www.sm-designs.co.uk/pdfs/rearendplates2.pdf
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Old 04-10-2018, 08:20 PM
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The racer in me says this is awesome that you are exploring this, the pilot in me (what I do for a living) says it is futile labor.

Yes there are some ways it can be improved but it will be so negligible in terms of performance at this level of automotive enjoyment that the .05 sec they may give over a 2 min lap just isn't worth the money. It IS a really cool novelty project though.

On aircraft the primary purpose of winglets is simply to reduce "induced drag" which is essentially drag created as a byproduct of producing lift (or downforce in this case). Those little vortices that you see are wasted energy and by having a fence to block the high and low pressure airs from mixing you reduce the energy going into creating those vortices and thus reduce the drag, essentially making the wing thing it has a longer span than it actually does. The more lift/downforce you are trying to produce in terms of AoA the greater effect the end plates/fences/winglets have. At 100mph this will have some effect, but realistically we would be talking about a 2% reduction in drag from the wing 10% at absolute best. 10% of the 38 lbs the wing produces at 15 AoA ,120mph is still only 4lbs of drag. And yes, by reducing these vortices it is making the wing more effective and thus will produce more downforce, this is sort of a secondary effect though and not as big of improvement as found in drag reduction.

You could start by modeling APR's new end plate design, it is much more rectangular and extends further down. The down part makes sense as you are mostly trying to keep the upper air from mixing with the bottom air. You could also try a design like the new 737 wings with the "split scimitar" style...I'm sure something like this is more beneficial than a flat plate.

It would be cool if you could prove me wrong though
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Old 04-10-2018, 09:16 PM
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Originally Posted by Silver9k View Post
The racer in me says this is awesome that you are exploring this, the pilot in me (what I do for a living) says it is futile labor.

Yes there are some ways it can be improved but it will be so negligible in terms of performance at this level of automotive enjoyment that the .05 sec they may give over a 2 min lap just isn't worth the money. It IS a really cool novelty project though.

On aircraft the primary purpose of winglets is simply to reduce "induced drag" which is essentially drag created as a byproduct of producing lift (or downforce in this case). Those little vortices that you see are wasted energy and by having a fence to block the high and low pressure airs from mixing you reduce the energy going into creating those vortices and thus reduce the drag, essentially making the wing thing it has a longer span than it actually does. The more lift/downforce you are trying to produce in terms of AoA the greater effect the end plates/fences/winglets have. At 100mph this will have some effect, but realistically we would be talking about a 2% reduction in drag from the wing 10% at absolute best. 10% of the 38 lbs the wing produces at 15 AoA ,120mph is still only 4lbs of drag. And yes, by reducing these vortices it is making the wing more effective and thus will produce more downforce, this is sort of a secondary effect though and not as big of improvement as found in drag reduction.

You could start by modeling APR's new end plate design, it is much more rectangular and extends further down. The down part makes sense as you are mostly trying to keep the upper air from mixing with the bottom air. You could also try a design like the new 737 wings with the "split scimitar" style...I'm sure something like this is more beneficial than a flat plate.

It would be cool if you could prove me wrong though
The trouble with the split scimitar winglet is that it increases the width of the wing. In virtually all current racing classes, wing width and often cord are limited by the rules.

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Old 04-10-2018, 10:22 PM
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giant end plates for the GTC-200 by Singular.

Singular Motorsports Wing Endplates: APR GTC-200 | Singular Motorsports
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Old 04-11-2018, 03:21 AM
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Originally Posted by DavidNJ View Post
Why? Endplates are pretty simple and many are available. It just seems to be working on something too small to measure.

Is your wing use a swan neck mount? Why do you think your APR GTC200 was designed for an S2000? And if so, with which roof? My understanding is the GTC200 and the GTC300 are generic pieces.

The biggest source of drag and in most cases lift is going to be the cooling system. But that can be an expensive, multi-part project all by itself. For example, coatings can reduce the heat transmitted to the coolant. Ring tension/gas porting, bearing clearances/oil viscosity can also affect heat generated. A dry sump removes the oily mist from the crankcase and can aid in cooling provided by the lubricant. Increasing coolant pressure and temperature can increase the heat transfer at the radiator, requiring a smaller radiator.

Which brings up ducting to and from the radiator, often with a separate oil cooler, a/c condenser, and intercooler. Managing that would be big and probably saleable. I'm imagining an inlet that tightly seals between the nose and radiator and an outlet that seals from the radiator to a duct in the hood.

http://www.sm-designs.co.uk/pdfs/rearendplates.pdf

http://www.sm-designs.co.uk/pdfs/rearendplates2.pdf
Mainly to further educate myself. I have the means to design and produce my own and have always been intrigued by the subject. It's easier to just buy some already on the shelf, but I get more enjoyment out of making some myself. In fairly confident mine will be better as well.

Also, I meant I bought a wing the S2000 specific mounts. I know it wasn't designed for our profile, but that doesn't mean it can't be improved upon.
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Old 04-11-2018, 03:27 AM
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Originally Posted by Silver9k View Post
The racer in me says this is awesome that you are exploring this, the pilot in me (what I do for a living) says it is futile labor.

Yes there are some ways it can be improved but it will be so negligible in terms of performance at this level of automotive enjoyment that the .05 sec they may give over a 2 min lap just isn't worth the money. It IS a really cool novelty project though.

On aircraft the primary purpose of winglets is simply to reduce "induced drag" which is essentially drag created as a byproduct of producing lift (or downforce in this case). Those little vortices that you see are wasted energy and by having a fence to block the high and low pressure airs from mixing you reduce the energy going into creating those vortices and thus reduce the drag, essentially making the wing thing it has a longer span than it actually does. The more lift/downforce you are trying to produce in terms of AoA the greater effect the end plates/fences/winglets have. At 100mph this will have some effect, but realistically we would be talking about a 2% reduction in drag from the wing 10% at absolute best. 10% of the 38 lbs the wing produces at 15 AoA ,120mph is still only 4lbs of drag. And yes, by reducing these vortices it is making the wing more effective and thus will produce more downforce, this is sort of a secondary effect though and not as big of improvement as found in drag reduction.

You could start by modeling APR's new end plate design, it is much more rectangular and extends further down. The down part makes sense as you are mostly trying to keep the upper air from mixing with the bottom air. You could also try a design like the new 737 wings with the "split scimitar" style...I'm sure something like this is more beneficial than a flat plate.

It would be cool if you could prove me wrong though
Even if it just results in a 2% reduction in drag, I will consider it a a success. I will come out of the project more knowledgeable than I am going in, which is my main goal. Being a 3D wing, these have quite a fair bit of drag, so I think there is something to be gained here.

I also work in the industry (aerospace design) and have always wanted to tailor my knowledge to the car. I've done my own airfoil designs with actual wind tunnel testing, so I know even small changes can have big outcome.

Even a failed test is successful
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Old 04-11-2018, 03:31 AM
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Originally Posted by DavidNJ View Post
The trouble with the split scimitar winglet is that it increases the width of the wing. In virtually all current racing classes, wing width and often cord are limited by the rules.

That's correct. If I remember correctly, the endplates width cannot exceed 10mm. Even doubling that width greatly increases the effective wing span.
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Old 04-11-2018, 03:32 AM
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Originally Posted by Bullwings View Post
giant end plates for the GTC-200 by Singular.

Singular Motorsports Wing Endplates: APR GTC-200 Singular Motorsports
According to their numbers, this is definitely a worthwhile project.

Upgrade the endplates on your APR GTC-200 wing! Up to 40% increase in downforce on the outer 1/3rds of the wing – that is a 25% increase in overall downforce! Raise your top speed! Add these endplates and reduce your wing’s angle of attack to achieve the same downforce as before with far less drag. With the standard APR endplates, the wing is less effective near the outer sides. These improved endplates were designed around real-world airflow and pressure data to improve the downforce and efficiency of your wing
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