Most Effective Wing?
01-24-2011, 08:40 PM
#121
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Ok, what is the camber of a wing?
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Larry Herman
2016 Ford Transit Connect Titanium LWB
2018 Tesla Model 3 - Electricity can be fun!
Retired Club Racer & National PCA Instructor
Past Flames:
1994 RS America Club Racer
2004 GT3 Track Car
1984 911 Carrera Club Racer
1974 914/4 2.0 Track Car
CLICK HERE to see some of my ancient racing videos.
01-24-2011, 08:46 PM
#122
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There is a relavent article in the current issue of Racecar Engineering. They look at a former ALMS RSR and change the wing used (span and profile) as well as the mounting height and location and get some serious gains (see attached). In the previous article they showed big improvements at the front and overall balance with a simple splitter (see here https://rennlist.com/forums/porsche-...p-front-2.html). Simon McBeath is the author of the articles and runs his own aero consulting/wing manufacturing firm. If you are serius about getting the a better wing than the off the shelf options you might make a phone call to the UK...
Interesting to note that both wings tested have approx 15% camber to chord. The predator wing on the other hand has much less camber and is nearly flat on the pressure side (top), while the suction side (bottom) has pretty extreme curvature (too much? flow separation?). Some of the newer racecar wings I have seen, like the factory Corvette GT1 and GT3 cars, have even more camber.
There is local company called "Kognition" that makes wings for a lot of time attack cars that also feature significant camber. The wings look pretty nice and they have some basic CFD numbers on their website to review. It's hard to judge with the time attack cars though because most of them look like they produce a ton of drag, but they have high-strung turbo engines with enough power to overcome it. Worth a look anyway.
Interesting to note that both wings tested have approx 15% camber to chord. The predator wing on the other hand has much less camber and is nearly flat on the pressure side (top), while the suction side (bottom) has pretty extreme curvature (too much? flow separation?). Some of the newer racecar wings I have seen, like the factory Corvette GT1 and GT3 cars, have even more camber.
There is local company called "Kognition" that makes wings for a lot of time attack cars that also feature significant camber. The wings look pretty nice and they have some basic CFD numbers on their website to review. It's hard to judge with the time attack cars though because most of them look like they produce a ton of drag, but they have high-strung turbo engines with enough power to overcome it. Worth a look anyway.
Hope you have permission to post this
01-24-2011, 08:52 PM
#123
Drifting
01-24-2011, 09:17 PM
#124
So, Cory, please explain "15% camber to chord". Is that the thickness of the wing at its apex to the chord?
01-24-2011, 11:52 PM
#125
Drifting
The % camber to chord is just a measurement between the curved mean camber line and the straight chord line, divided by the chord length. A picture is worth 1000 words:
http://www.grc.nasa.gov/WWW/K-12/airplane/geom.html
So by using % camber to chord you would know that a 20% airfoil has twice as much curvature than a 10% airfoil for a given chord length.
01-25-2011, 03:20 PM
#126
Rennlist Member
Thanks for the post . good stuff.
remember that the camber part, is only i part, talking about the top of the race car wing. its really the bottom (curved side) that is most relevant.
remember, airplanes in the old days, didnt even have flat sides, they were just arcs with no bottoms (or flat side) . "separation" on the flat side or even if it is missing a flat side, (just an open arc) still flys (or creates lift or downforce). closing the wing off, just makes it more efficient.
My point was really getting at that you can make a wing have as much downforce as you want (generally, and to the limit of that size and design) certainly, the radical high lift wings produce more lift for a given size than more traditional counterparts, but usually at a little worse L/D ratio. the difference between most wings is their L/D ratios and their Cl values. any wing that puts out 300lbs of downforce at 100mph, that number will pretty much go up with speed the same as any other configuration. what changes though is the AOA, due to the deflection of the air stream off the top of the car. if it is out of this stream, its less of an effect as speed increases.
remember that the camber part, is only i part, talking about the top of the race car wing. its really the bottom (curved side) that is most relevant.
remember, airplanes in the old days, didnt even have flat sides, they were just arcs with no bottoms (or flat side) . "separation" on the flat side or even if it is missing a flat side, (just an open arc) still flys (or creates lift or downforce). closing the wing off, just makes it more efficient.
My point was really getting at that you can make a wing have as much downforce as you want (generally, and to the limit of that size and design) certainly, the radical high lift wings produce more lift for a given size than more traditional counterparts, but usually at a little worse L/D ratio. the difference between most wings is their L/D ratios and their Cl values. any wing that puts out 300lbs of downforce at 100mph, that number will pretty much go up with speed the same as any other configuration. what changes though is the AOA, due to the deflection of the air stream off the top of the car. if it is out of this stream, its less of an effect as speed increases.
There is a relavent article in the current issue of Racecar Engineering. They look at a former ALMS RSR and change the wing used (span and profile) as well as the mounting height and location and get some serious gains (see attached). In the previous article they showed big improvements at the front and overall balance with a simple splitter (see here ). Simon McBeath is the author of the articles and runs his own aero consulting/wing manufacturing firm. If you are serius about getting the a better wing than the off the shelf options you might make a phone call to the UK...
Interesting to note that both wings tested have approx 15% camber to chord. The predator wing on the other hand has much less camber and is nearly flat on the pressure side (top), while the suction side (bottom) has pretty extreme curvature (too much? flow separation?). Some of the newer racecar wings I have seen, like the factory Corvette GT1 and GT3 cars, have even more camber.
There is local company called "Kognition" that makes wings for a lot of time attack cars that also feature significant camber. The wings look pretty nice and they have some basic CFD numbers on their website to review. It's hard to judge with the time attack cars though because most of them look like they produce a ton of drag, but they have high-strung turbo engines with enough power to overcome it. Worth a look anyway.
Interesting to note that both wings tested have approx 15% camber to chord. The predator wing on the other hand has much less camber and is nearly flat on the pressure side (top), while the suction side (bottom) has pretty extreme curvature (too much? flow separation?). Some of the newer racecar wings I have seen, like the factory Corvette GT1 and GT3 cars, have even more camber.
There is local company called "Kognition" that makes wings for a lot of time attack cars that also feature significant camber. The wings look pretty nice and they have some basic CFD numbers on their website to review. It's hard to judge with the time attack cars though because most of them look like they produce a ton of drag, but they have high-strung turbo engines with enough power to overcome it. Worth a look anyway.
01-26-2011, 01:02 AM
#127
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Don't be fooled about the higher HP Time attack cars overcoming the drag...if the drag is very high, its increasing exponentially...while their 600whp could seem like a lot, they might need more like 1000whp to overcome substantial drag at 150mph for example. Obviously, if your circuit only has a top speed of 140mph, and average corning of 80-100...go as big as you can 
BTW....has the OP bought a wing yet?
BTW....has the OP bought a wing yet?
01-26-2011, 01:35 AM
#128
Race Car
Thread Starter
No, not yet. My car is being built and we don't need the wing just yet.
I contacted the folks in England. The wings are a bit pricey to start with, and then add the cost of getting it to California, the price is prohibitive for me.
This looks interesting:
http://kognitiondesign.com/
Scott
I contacted the folks in England. The wings are a bit pricey to start with, and then add the cost of getting it to California, the price is prohibitive for me.
This looks interesting:
http://kognitiondesign.com/
Scott
01-26-2011, 02:47 AM
#129
Rennlist Member
you got the drag figures right there! actually, the drag is quite little coming from the wing alone. you can figure this out with the Cd and the frontal area.
generally, most downforce wings have about 10:1 lift/Drag ( L/D). this means the drag will be 1/10th that of the downforce it is producing. So, if you have 500lbs of downforce at 140mph, that will be 50lbs of drag. If you have 24" diamter tires, this will be 50ft/lbs of torque lost at the wheels. divide that by the 4th gear ratio, and you get the torque at the engine. (this would be around 3 to 4:1. so, its only 15ft'lbs at the engine lost NOT 1000hp or 1000ft-lbs. for our cars , generally, the power to drive 150mph (car in total) is around 200hp, not any more than that, even with a big wing on the back. Then, if you get to 200mph, that number jumps to near 500hp. the drag goes up with the square of velocity, while the power required to push through the drag, goes up with the cube of speed. double the drag, 8x the power required.
generally, most downforce wings have about 10:1 lift/Drag ( L/D). this means the drag will be 1/10th that of the downforce it is producing. So, if you have 500lbs of downforce at 140mph, that will be 50lbs of drag. If you have 24" diamter tires, this will be 50ft/lbs of torque lost at the wheels. divide that by the 4th gear ratio, and you get the torque at the engine. (this would be around 3 to 4:1. so, its only 15ft'lbs at the engine lost NOT 1000hp or 1000ft-lbs. for our cars , generally, the power to drive 150mph (car in total) is around 200hp, not any more than that, even with a big wing on the back. Then, if you get to 200mph, that number jumps to near 500hp. the drag goes up with the square of velocity, while the power required to push through the drag, goes up with the cube of speed.
double the drag, 8x the power required.Don't be fooled about the higher HP Time attack cars overcoming the drag...if the drag is very high, its increasing exponentially...while their 600whp could seem like a lot, they might need more like 1000whp to overcome substantial drag at 150mph for example. Obviously, if your circuit only has a top speed of 140mph, and average corning of 80-100...go as big as you can
BTW....has the OP bought a wing yet?
BTW....has the OP bought a wing yet?
01-26-2011, 03:11 AM
#130
Rennlist Member
The wing comparisons was flawed with too many changes. the distance rearward for example, would give it more leverage and you can calculate that change, just by knowing the distance from the fulcrum points. they talk about it in the article, but seem to kind of discount it. based on the graphs, I would think that most of the gains were due to the new position. quite often, out in clean air doesnt really get that much of a gain, in fact, the deflected flow, if laminar, can create as much downforce, as the air stream can be relatively clean. (also the air coming off the roof line, is handled by the wing, rather than without the wing in that area of flow, it can flow into massive turbulence coming off the rear of teh car. this is why rear spoilers are used in conjuction with wings that are up high, like the new cup car and hybrid racer. If you look at the graphs, for the same downforce, the original wing seems to have better L/D ratios, and I wonder why. could be due to the increased drag off the rear of the car because the wing is now up higher, not helping that flow off the roofline and to the rear of the car. interesting comparison. I bet if you calculate the greater leveage, you find the difference in downforce being due to the wing position, but thats just a guess.
01-26-2011, 06:16 AM
#131
Rennlist Member
Can't seem to get much out of that link?
No, not yet. My car is being built and we don't need the wing just yet.
I contacted the folks in England. The wings are a bit pricey to start with, and then add the cost of getting it to California, the price is prohibitive for me.
This looks interesting:
http://kognitiondesign.com/
Scott
I contacted the folks in England. The wings are a bit pricey to start with, and then add the cost of getting it to California, the price is prohibitive for me.
This looks interesting:
http://kognitiondesign.com/
Scott
01-26-2011, 06:57 AM
#133
Rennlist Member
The link opens up to just a full brown grey page with nothing on it. I then googled them and got a home page but when trying to open up 'products' etc it goes to the same brown grey page, so, not sure what's going on?
I'm also curious why you're looking offshore as there seems to be a lot of product in the US? Not much down here, so I'm interested in what you find though.
I'm also curious why you're looking offshore as there seems to be a lot of product in the US? Not much down here, so I'm interested in what you find though.
01-26-2011, 12:41 PM
#134
Race Car
Thread Starter
The link opens up to just a full brown grey page with nothing on it. I then googled them and got a home page but when trying to open up 'products' etc it goes to the same brown grey page, so, not sure what's going on?
I'm also curious why you're looking offshore as there seems to be a lot of product in the US? Not much down here, so I'm interested in what you find though.
I'm also curious why you're looking offshore as there seems to be a lot of product in the US? Not much down here, so I'm interested in what you find though.
Why offshore? Because someone posted an article about an interesting wing design and it happened to be made offshore. The world is pretty small these days...our being able to discuss this is a case in point. Odds are I will buy a wing made here in the USA.
Scott
01-27-2011, 10:58 AM
#135
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Did Someone say Wings?
Zing! this is the key and has been lost in the charts and graphs parade. Just as we tune a motor with a cam wings can be tuned to a car. the AoA is part of the tuning. The wings sweetspot is another.
compound wings seem to beyond the basic level of the off the shelf racer. It seems to me that they have to be planned out from A to Z for a car and use. car shape and wing placement are far more complex. Unless you can do this straight wing in clean air seems to be the safest bet. Tuning the wing to the car is the real question.
Carefull that your testing is not altering the test itself too.
compound wings seem to beyond the basic level of the off the shelf racer. It seems to me that they have to be planned out from A to Z for a car and use. car shape and wing placement are far more complex. Unless you can do this straight wing in clean air seems to be the safest bet. Tuning the wing to the car is the real question.
Carefull that your testing is not altering the test itself too.
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Your Source For Motorsports Equipment
WWW.OGRACING.COM
800.934.9112
703.430.3303
info@ogracing.com
Sparco's Largest Distributor for 28 Years
PFC Distributor for 27 Years
Pagid, Alpinestars, MOMO, OMP, Hawk, Bell, Aim, G-Force, HJC,
HANS, Arai, Simpson, Brey Krause, Longacre, CoolShirt!
Supplying Track Junkies for 34 Years.
PCA Club Racing - National Sponsor Since 1998
A Veteran Owned Business
Check out our blog!