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Old 02-02-2017, 01:15 PM   #11 (permalink)
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Quote:
Originally Posted by Aeroguy View Post
As far as winglets are concerned, I believe you are referring to what are called endplates in terms of cars. There is a good example on Mulsanne's Corner and I have uploaded an image of one of the wings I designed (it has something similar to a NACA 4412 airfoil flipped upside down) and there end plates on it although they are built into the mounts. imgur. com/a/PhFcd (I don't have enough posts to post links yet).

I am having a hard time understanding what you are getting at with the wavy corners. Is there any way you could sketch something out so I could get a better idea. I'm not really knowledgeable enough to understand the acoustic side of aerodynamics. I've never really looked into it.
Will you be testing both wings and spoilers?

Will you be able to test combinations of both?

Yes, F1 cars have one type of plate at the wing ends because of regulations, I'm guessing you are exploring ideas outside of these restrictions - yes?

Just think if these fins below had been curved inward - the possibilities for down-force and stability with minimum surface area/drag.

Looking for 1963 Le Mans Panhard Cd blueprints
Looking for 1963 Le Mans Panhard Cd blueprints


http://www.talkativeman.com/graceful...rbus_a350_xwb/


http://www.autodrome.fr/cd_panhard_l...64_english.htm

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Chin Spoiler:
http://forums.pelicanparts.com/off-t...effective.html

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http://forums.pelicanparts.com/off-t...xperiment.html

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http://ecomodder.com/forum/showthrea...1-a-19525.html

Last edited by kach22i; 02-02-2017 at 01:29 PM..
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Old 02-02-2017, 01:31 PM   #12 (permalink)
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I threw together something similar. Unfortunately in a huge extrusion, inventor wasn't happy so hopefully you can get the gist of it. imgur.com/ a/9pCMY
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Old 02-02-2017, 02:04 PM   #13 (permalink)
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I can basically test anything I can attach to the car and will fit inside the wind tunnel. End plates on F1 cars aren't really a regulation thing, it's more to prevent flow on the very edge of the wing (tip) from bleeding over the sides and creating turbulence. The reason why planes have them like that is that you want to minimize the bleed while also minimizing surface area. Minimizing the bleed means minimizing loss of lift and reducing drag somewhat. Winglets or end plates don't inherently create downforce/lift, they only aid the accompanying airfoil in producing downforce/lift. I'm not an expert but I would imagine curving those fins in wouldn't do much of anything except maybe increase stability. Unless they were airfoils like on the Ferrari FXX
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Old 02-02-2017, 03:06 PM   #14 (permalink)
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Quote:
Originally Posted by Aeroguy View Post
imgur.com/ a/9pCMY
Could you please try reposting that link?

I understand your explanation and the differences and agree with it more or less. However everything is regulated in race car design, which is why you get all those weird and exotic shapes out of them - bending the rules as it were.

How much of your grade is based on understanding and testing basic principals, and how much is for creativity or innovation?

There is the danger of coming up with something so unusual that you encounter an unknown phenomena and get caught unable to explain what is happening.

EDIT-1: When you say senior project, are we talking high school or college?

EDIT-2: I believe some undulations are for simply for rear view via the rear view mirror. Feel free to argue with or against this generalization.

Racin’ Today Ingram: Hello Spoiler, Good-bye Rear Wing


Over or under - what ever works.

2008 Honda S2000 CR Prototype - Rear Spoiler - 1280x960 - Wallpaper


This is certainly different - a fat and aggressive mid-plane.

Race Car Aerodynamics Package


Another twist, must be a reason for not being a continuous section, right?

https://grassrootsmotorsports.com/fo...y/89454/page6/
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Architect, Artist and Designer of Objects

1977 Porsche 911s Targa
1998 Chevy S-10 Pick-Up truck
1989 Scat II HP Hovercraft

Chin Spoiler:
http://forums.pelicanparts.com/off-t...effective.html

Rear Spoiler Pick Up Truck
http://forums.pelicanparts.com/off-t...xperiment.html

Roof Wing
http://ecomodder.com/forum/showthrea...1-a-19525.html

Last edited by kach22i; 02-02-2017 at 03:29 PM..
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Old 02-02-2017, 05:28 PM   #15 (permalink)
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There was a deliberate space in the link due to my then low post count. Anyway. As far as grades go, I'm not really sure. It's basically whether or not I make it to the conference (I got approved yesterday). I have plenty of wings to complete the project, I just wanted to see if anyone wanted me to test anything for them and also I have a bit of spare time and I'm always looking for cool ideas. It is a high school senior project. I'm 18 BTW.

I've already had a few weird things happen that I don't really know how to explain. It's not a big deal. I think it's pretty cool actually.

So as far as I understand, the reason why wings are twisted (basically different angle of attack on the sides vs the center or different airfoil) is because the air coming off the roof is flowing differently than the wing coming around the sides of the roof. This is because different wind characteristics make airfoils stall at different angles. Generally you want the most angle of attack without stalling the wing. You can learn more here (funny coincidence: the guy in this video is one of my mentors). With the NASCAR spoiler, I imagine that that is partially due to aerodynamics and partially due to visibility. Or if you recall that Ferrari FXX, really the place you need the downforce is on the sides (ie where the rear tires are) so the middle section is less important.

I have considered doing twisted wings and anhidrel/dihedral wings but that's only very recently. Basically every wing (aside from a few) have been sort of variations on that NASCAR spoiler you posted or flat drag style wings.
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Old 02-02-2017, 06:10 PM   #16 (permalink)
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Do some research on vortex generators. The waves put a spin on the air (saw teath in center of the drag wing from pose #8).
I think the vortices form a kind of air curtain bridging the gap and contributing to faster reattachment when reaching the body.
---
Look inth aviation vortex generators they alow the air to turn faster than a general curves (template) insted of separation from the backglass being too steep ( in the green zonepost #4)
https://youtu.be/SXwVyxorvno
This guy duse a decent job of explain
https://youtu.be/9Whd_KnsLKE
At about 2:44 he gets into how to get more angle of attack wile maintaining attached flow.

Yes VG s add drag ,however, they prompt reattachment/ prevent sepperation .

I think you will see a massave change in the effectiveness of the spoiler/ wings you have already tested by wsing VG at the top of the rear window like an Evo Mitsubishi
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Old 02-02-2017, 09:54 PM   #17 (permalink)
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Thanks for the suggestion gumby79, I have given some thought into shall we say, aero accessories (strictly to differentiate that sort of thing from a wing/spoiler). Other ones include, diffusers, front splitters, ground effects, etc. All would be very interesting to investigate. My worry is that they are beyond the scope of the project. The actual stated goal (or really the goal that got approved) is to find the optimal wing/spoiler/rear trunk attachment. Properly implementing any of these would require a significant amount of more testing. We shall see if I can fit it in, and if I can, I will.
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Old 02-02-2017, 11:17 PM   #18 (permalink)
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Welcome to Ecomodder.

It's always entertaining to watch posters go right into the weeds. Let's step back.

An air tunnel at 1/24th scale? How many horsepower does this tunnel have? what's the cross-sectional area of the test section? Vortex generators at 1/24th scale?

Have you looked at graysgarage? He only posted for 4 months in 2015, so you sort of have to know to look for it; but that is a scenario that has some hope of returning viable results at 1/24th scale upside down in water with hydrogen bubble jets.

Sawtooth trailing edges are used in High-bypass turbojets to moderate the acoustic signature.
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Old 02-03-2017, 12:01 AM   #19 (permalink)
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I have no idea how much HP the wind tunnel has, It is the school's wind tunnel. I'm fairly certain it is a Pitsco Airtech 40. The top speed is 40 mph. The internal dimensions of the tunnel are 8" x 8". I actually made a mistake earlier in saying the car model itself is 1:24th scale, it is actually 1:25th.

As far as vortex generators go, I'm pretty certain I can print parts that small, but I am unsure if I will be able to detect any difference depending on how minute it is.

I have actually seen a number of their videos, very interesting stuff. I'm not super concerned about having data that can be transferred into real world values. The more important thing is comparing different setups.
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Old 02-03-2017, 01:31 AM   #20 (permalink)
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Sounds like a fun project. But what are you optimising for? Downforce or low drag or a mix? I would experiment with a full boat tail and a half boat tail, with a vertical cutoff, oval shape. Low angle difuser underneath.
A boat tail is like a low drag baseline. I assume you've seen the aero civic?
Im sure you've heard of reynolds numbers right? Your paper wont mean much unless you test with similar reynolds numbers to real conditions. Good luck!

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