Wing Question

[wpbcobra]

I am looking to Add a Wing to my 97 AI cobra.

What is a ideal height for the wing in the 97 body style.

Thank you

[Mystic_Cobra]

Without getting into a bunch of aero-physics, the short answer is... The most efficient wing is set as high as the rules allow. Look at the G-Stream wing that most AI guys are running. It is nearly the standard for AI.

 

I'm sure someone else will give you a longer answer.

[SNAKBITN]

You can check out Fulcrum Aero as well.They also have splitters for that car.

 

Robert

[obzezzed350]

Fulcrum is nice stuff! That is what I run Carmine

[AJ Hartman]

The short answer, since we don't have a height rule, a few inches above roof line. Any higher and you don't see any more gains.

 

The long answer... well it depends on a few things. What span are you considering? The wing setback rules for our class are not written very clear. Since your 97's rear bumper has a curve to it, and most wings are straight (unless you get an APR "twisted" wing which I don't recommend after looking at the flow chart for it), you have to hang a plumb bob off the very tips of the trailing edge on both sides. The measurement from the string to the bumper can not be more then 1 inch. The rules are not 1 inch from the rear most part, so be careful there. So, what this does, if you get a wider wing it has to be slid forward to be legal. If you get a shorter wing, you can slide it farther rear ward, which would give you a better leverage ratio. Which means you can run less wing angle and get the same effect of Df, which means less drag. Then you have to consider if you are running a diffusor. Lowering the wing will actually supplement the diffusor, giving the same Df at less drag. Given our class rules for setback, I don't really think this is the best solution tho cause no matter what, we can't get a wing far enough rear ward to really take advantage of this.

 

Now for wings, people mentioned the Fulcrum, which is definitely a very nice wing with its 14" chord, but comes at a price. The G stream is also nice, but comes at a price as well as you only get 1 choice of width, which is far too wide for your car. The wing I like, and have installed on several people cars here in the NE is the Kognition wing. Pretty much the best bang for the buck wing I have came across and you can order it in 1 inch increments so you can get it to fit your car.

 

Heres a picture of mine from the other weekend. I have a 61" span. If I had to again, I think I would get a 59" so I could set it back a few more inches. I ended up setting it a few inches above roofline. This keeps it in clean air so the wing is more efficient.

[wpbcobra]

The short answer, since we don't have a height rule, a few inches above roof line. Any higher and you don't see any more gains.

 

The long answer... well it depends on a few things. What span are you considering? The wing setback rules for our class are not written very clear. Since your 97's rear bumper has a curve to it, and most wings are straight (unless you get an APR "twisted" wing which I don't recommend after looking at the flow chart for it), you have to hang a plumb bob off the very tips of the trailing edge on both sides. The measurement from the string to the bumper can not be more then 1 inch. The rules are not 1 inch from the rear most part, so be careful there. So, what this does, if you get a wider wing it has to be slid forward to be legal. If you get a shorter wing, you can slide it farther rear ward, which would give you a better leverage ratio. Which means you can run less wing angle and get the same effect of Df, which means less drag. Then you have to consider if you are running a diffusor. Lowering the wing will actually supplement the diffusor, giving the same Df at less drag. Given our class rules for setback, I don't really think this is the best solution tho cause no matter what, we can't get a wing far enough rear ward to really take advantage of this.

 

Now for wings, people mentioned the Fulcrum, which is definitely a very nice wing with its 14" chord, but comes at a price. The G stream is also nice, but comes at a price as well as you only get 1 choice of width, which is far too wide for your car. The wing I like, and have installed on several people cars here in the NE is the Kognition wing. Pretty much the best bang for the buck wing I have came across and you can order it in 1 inch increments so you can get it to fit your car.

 

Heres a picture of mine from the other weekend. I have a 61" span. If I had to again, I think I would get a 59" so I could set it back a few more inches. I ended up setting it a few inches above roofline. This keeps it in clean air so the wing is more efficient.

]

 

Ok so the wing cant be wider than the rear bumper or cant be further back of the bumper more than 1 inch?

Also how tall do you have your wing. What is the cost of your wing from Kognition wing for something you got. Do they sell wings for mustang allready set up or do you have to special order them thu them.

Thank you for any info

[SNAKBITN]

Rear wings or rear spoilers installed on AI cars must not extend rearward more than 1.5 inches beyond the outline of

the rear bumper and may not have an airfoil width not to include endplates or bolts greater than 72 inches.

 

Straight from the AI rules.

 

Robert

[AJ Hartman]

Robert has it word for word. So if you were to measure from the center of the wing and its within 1.5 inches, since the wing is straight, the tips of the wing will be way more they 1.5 inches rear ward of the outline of the bumper. So yeah, you are technically allowed to get up to a 72 inch wing, but you can't fit it cause it will be way wider then your bumper.

[rpoz27]

Aj, your interpretation would disqualify MANY cars. It was clarified years ago that it is 1.5" past the furthest point of the "box" that the car would fit into. You could move your wing back a bunch....but i love your car!

[Mystic_Cobra]

Sounds like we need to add a drawing to the rules to clarify.

[edhunter]

As someone who's going to be mounting a wing soon I'd appreciate clarification. My understanding was it couldn't extend past the outline of the rear bumper (at any point) more than 1.5"... But if it's no more than 1.5" at the most rearward point on the car, that'll change things a bit.

[Mystic_Cobra]

Ed-

We'll get an official clarification posted here soon to answer the question based on the current rule.

 

Also, expect a written rule clarification sometime after September.

[rpoz27]

It is here in the forums. Just search back about three or four years.

[Pantera1889]

How about we get rid of the RIDICULOUS looking wings all together????????

 

Ron

[SNAKBITN]

That would be CMC.Keep all the AI rules as is for 3 or 4 years and watch the class grow.With the rule changes from last year seems like all the cars are pretty equal at least in our region.I guess thats for another tread after nationals.....

 

Robert

[T&A Racing]

That would be CMC.Keep all the AI rules as is for 3 or 4 years and watch the class grow.With the rule changes from last year seems like all the cars are pretty equal at least in our region.I guess thats for another tread after nationals.....

 

Robert

 

I totally agree the rules for the most part need to stabilize for a few years to see how things evolve. Of course I am sure each year there will be some things we need to clarify the original intent.

[wpbcobra]

Ok so how i read the rule i Can put the APR GTC 300 67" on there as long that the back of the wing is not more than 1.5 inchs away from the bumper. I am going to be ordering a wing in about a wing

[AJ Hartman]

Aj, your interpretation would disqualify MANY cars. It was clarified years ago that it is 1.5" past the furthest point of the "box" that the car would fit into. You could move your wing back a bunch....but i love your car!

 

I'm aware of this. Which is why I plan to put in an RCR at the end of the year to make it more clear (and make a lot of cars legal). Something along the line of "a wing, not to include endplates, may not extend more then 1.5 inches past the most rearward point of the original bumper cover and be no wider then the quarter panels, including flares. There is no limit to wing height." Its simple, easy to understand, and clearly defines the "box" we can play in. Just a thought.

 

And thanks for the compliment. I still have a ton a aero stuff I want to play with.

[donovan]

As far back as I can remember it was always 1.5" from centerline, and centerline only.

 

This is also how my wing was checked back in 2007 at Mid-Ohio (Nationals), it was actually checked twice!

I remember because I had to remove the endplate for the 72" check and someone was checking the 1.5" at same time.

 

This NEW Re-interpretation of the rules would put lots of cars including mine out of compliance.

 

Donovan

[rpoz27]

 

And thanks for the compliment. I still have a ton a aero stuff I want to play with.

 

AJ, looks like you are taking a few notes from the V8 supercars and the recent C6 vettes in ALMS. Nice work.

 

The Mustang will have your canards on it shortly as well as similar side skirts and hopefully, if I finish some customer work soon, ducted radiator through the hood. I need to do some research about dealing with under hood temps with that setup but should end up with a "vacuumed to the ground" car!

 

I also have Misty's camaro to play with and I am pretty sure BOTH of our wings are 1.5" at centerline of rear bumper....not that we are racing AI right now but they were both AI legal in the past. Mine was checked at 2 national events IIRC and was legal. Part of that clarification needs to start covering diffusers too. Some I have seen stick out so far they are begging to get torn off from light contact and become debris on track or an easy black flag. When I built mine I took that into account and it survived being hit several times at Miller in 2009.

 

Those of us that have been around for a while know of the clarification. those that are new do not. The clarification would be smart.

[AJ Hartman]

^^^ I've only been around a few years so I missed the whole wing ruling deal. So some clarification in the rules needs to be done cause now I have to remake my uprights. The diffusor rule I thought was pretty clear. It states 1.5 inches as viewed from the most rearward direction.

 

A quick note on the ducting the radiator through the hood idea. I tried it and found that it killed the aero over the windshield and top of the car really bad. I also went fairly big with size of the opening tho so I'm sure that had a negative effect over a smaller opening, but make sure you don't go too small. With the position of the alternator ( I have a 2v) it was really difficult to make a smooth transition back to the hood. Theres just not really enough room in there unless you want to get into using a different rad and moving/leaning it forward along with moving the alternator. It would be nice if you could get it to work cause it would help augment the splitter, but at a cost of much increased drag.

[T&A Racing]

AJ, and any one else.

 

Please don't change any thing just yet. The directors have been having a related conversation. We have not concluded any thing for sure, but I am confident that we will get to a practical way to clarify the current rule.

[rpoz27]

 

A quick note on the ducting the radiator through the hood idea. I tried it and found that it killed the aero over the windshield and top of the car really bad. I also went fairly big with size of the opening tho so I'm sure that had a negative effect over a smaller opening, but make sure you don't go too small. With the position of the alternator ( I have a 2v) it was really difficult to make a smooth transition back to the hood. Theres just not really enough room in there unless you want to get into using a different rad and moving/leaning it forward along with moving the alternator. It would be nice if you could get it to work cause it would help augment the splitter, but at a cost of much increased drag.

 

core support on the mustang has been gone a long time. Radiator is moved forward and leaned forward and also about 4" narrower for a trick ram air setup...I think you would like it! Even with the fan in place, you could almost put a wheel/tire between the radiator and motor. Started that design 3 years ago, but after mothballing the car for nearly 18 months, things got put on the back burner while I completely re-worked the camaro, and restored an old Grand National....and rebuilt our lemons car. too many projects AND I have been taking on some side work. If I do finish it, I plan on taping a million pieces of yarn all over the hood and shooting video before and after. Just need to get back in the shop and hit it hard.

[tacovini]

I always know when a hot topic comes up because all lines of communication from PM's, IM's, Facebook, telephones, emails, etc. start lighting up like a christmas tree! LOL

Looks like we have some miscommunication, misinterpretation and a good opportunity to clarify things with regards to wings.

 

AJ...your car/prep is creative and you've done some good homework, but there are a few flaws in your original interpretation.

The rule in question is 7.4.10, and the diffuser language in 7.4.14 supports the rearward measurement listed in the rulebook:

 

http://www.nasaproracing.com/rules/american_iron_rules.pdf

 

There are 2 mutually exclusive measurements of the AI wing. Chord width and rear setback.

a) The wing max width of 72" is the same for all cars regardless body style.

b) The wing rear setback is to be no more than 1.5" rearward from the bumper (silouette, outline or box as Misty mentions)

 

Hope this helps! As some have mentioned, it is the AI Leadership Team's intent to keep rules changes to a minimum every year, and this year is no exception. However, aligning/clarifying the rear diffuser and rear wing language for "outline of the rear bumper" & "bumper silouette" & "rearmost dimension" may be in order next year to avoid similar confusion.

[AJ Hartman]

 

A quick note on the ducting the radiator through the hood idea. I tried it and found that it killed the aero over the windshield and top of the car really bad. I also went fairly big with size of the opening tho so I'm sure that had a negative effect over a smaller opening, but make sure you don't go too small. With the position of the alternator ( I have a 2v) it was really difficult to make a smooth transition back to the hood. Theres just not really enough room in there unless you want to get into using a different rad and moving/leaning it forward along with moving the alternator. It would be nice if you could get it to work cause it would help augment the splitter, but at a cost of much increased drag.

 

core support on the mustang has been gone a long time. Radiator is moved forward and leaned forward and also about 4" narrower for a trick ram air setup...I think you would like it! Even with the fan in place, you could almost put a wheel/tire between the radiator and motor. Started that design 3 years ago, but after mothballing the car for nearly 18 months, things got put on the back burner while I completely re-worked the camaro, and restored an old Grand National....and rebuilt our lemons car. too many projects AND I have been taking on some side work. If I do finish it, I plan on taping a million pieces of yarn all over the hood and shooting video before and after. Just need to get back in the shop and hit it hard.

 

Would definitely be a good idea to stick a camera to the top of your windshield and take video of the yarn test before and after.