Jump to content
Smike

CMC Wing Development - Am I Nuts? (likely)

Recommended Posts

MHISSTC

Cool. Thanks for the followup Adam.

Share this post


Link to post
Share on other sites
bluebandit48

 

In the ~45 mins of seat time I got with my new-to-me CMC car; the back end is very loose on faster sweepers. I ran with car without any rear wing (OEM or otherwise). Saw most went with a NASCAR style trunk flap with some adjustment for rake. I mocked up that as well; however, it severely limited how much I could see out of my rear mirrors. CMC is much like TT - you race with your mirrors. So NASCAR for me is out.

 

In the spirit of CMC...I have the OE wing from the car, bunch of metal stock, and time.

 

Contours of the OE spoiler follow the body and it is a semi-symmetrical airfoil. Should create a low pressure under it and high pressure above (negative lift / downforce).

 

Mock-up last night (nothing bolted correctly - just to see it):

IMG_20120820_182105.jpg

 

IMG_20120820_182059.jpg

 

IMG_20120820_182115.jpg

 

Rear bracket has 2 bolt holes to add more height to the rear of the wing (increase rake). Right now its level. Wanted to over engineer the brackets. Not a fan of having it rip off at speed. I am sure you guys wouldn't appreciate that either.

 

I remember a time when all the cmc cars had these big a$$ ugly wings..

 

My first comment.

Not sure if this will pass NASA 50/50 rule

 

Second, you have 45 mins of seat time in the car. Get some more then make changes.

 

Third, your mustang is loose, loose is fast and on the edge of out of control Cole Trickle!

Be happy it is loose and not understeering! (pushing) seems like there are some NASCAR terms being thrown around here!

 

You don't want a whole lot of wing at mid o. Most of the tracks in the great lakes region don't need a lot of wing. I would first check your rear track width, then maybe a bar change. I believe the v6 mustang has the smallest bar, that would tighten it up. Im sure I'll be corrected on that statement but there are many things you can do for a little extra stability.

 

Thats my 2 pennies.

Share this post


Link to post
Share on other sites
Smike
I remember a time when all the cmc cars had these big a$$ ugly wings..

 

My first comment.

Not sure if this will pass NASA 50/50 rule

 

Second, you have 45 mins of seat time in the car. Get some more then make changes.

 

Third, your mustang is loose, loose is fast and on the edge of out of control Cole Trickle!

Be happy it is loose and not understeering! (pushing) seems like there are some NASCAR terms being thrown around here!

 

You don't want a whole lot of wing at mid o. Most of the tracks in the great lakes region don't need a lot of wing. I would first check your rear track width, then maybe a bar change. I believe the v6 mustang has the smallest bar, that would tighten it up. Im sure I'll be corrected on that statement but there are many things you can do for a little extra stability.

 

Thats my 2 pennies.

 

Ha, I did used to drive an Evo 8 with its giant OEM wing.

 

Painted and boxed in brackets last night. Some adjustability in rake added and it can be removed for different tracks.

 

I just want to go fast!

 

th_IMG_20120823_192255.jpg

(Not finished - did some of both. Wing can come off and leave the wicker bill).

 

I feel obligated to get in touch with my inner NASCAR driver now that I am back to v8 racing Setting up for lift oversteer is how I have my S197 setup; just what I am used to as a driver too.

 

I might have some room to play with rear track width. Have to see what spacers I have.

Share this post


Link to post
Share on other sites
wheelhopper

I don't think I could do that wing on my car. It is just weird looking, even if it does work.

 

I have never seen a CMC car with a Saleen spoiler. Anyone know if they are legal. I would guess that they are somewhat effective at adding some down force since Saleen developed them and used them on the track.

Share this post


Link to post
Share on other sites
Smike
I don't think I could do that wing on my car. It is just weird looking, even if it does work.

 

I have never seen a CMC car with a Saleen spoiler. Anyone know if they are legal. I would guess that they are somewhat effective at adding some down force since Saleen developed them and used them on the track.

 

458391966_oGg7E-L.jpg

 

Looks normal to me.

 

I think of Saleen as usually more about speed than handling.

 

Per the rules, should be legal as well.

 

Covered mounts:

th_IMG_20120824_163903.jpg

 

th_IMG_20120824_163914.jpg

Share this post


Link to post
Share on other sites
cozog1548534733
I remember a time when all the cmc cars had these big a$$ ugly wings..

 

My first comment.

Not sure if this will pass NASA 50/50 rule

 

Second, you have 45 mins of seat time in the car. Get some more then make changes.

 

Third, your mustang is loose, loose is fast and on the edge of out of control Cole Trickle!

Be happy it is loose and not understeering! (pushing) seems like there are some NASCAR terms being thrown around here!

 

You don't want a whole lot of wing at mid o. Most of the tracks in the great lakes region don't need a lot of wing. I would first check your rear track width, then maybe a bar change. I believe the v6 mustang has the smallest bar, that would tighten it up. Im sure I'll be corrected on that statement but there are many things you can do for a little extra stability.

 

Thats my 2 pennies.

 

Ha, I did used to drive an Evo 8 with its giant OEM wing.

 

Painted and boxed in brackets last night. Some adjustability in rake added and it can be removed for different tracks.

 

I just want to go fast!

 

th_IMG_20120823_192255.jpg

(Not finished - did some of both. Wing can come off and leave the wicker bill).

 

I feel obligated to get in touch with my inner NASCAR driver now that I am back to v8 racing Setting up for lift oversteer is how I have my S197 setup; just what I am used to as a driver too.

 

I might have some room to play with rear track width. Have to see what spacers I have.

 

I see a wing AND a spoiler in that pic. I'm pretty sure that will not be allowed. The rules say any rear "spoiler/wing", not "spoilers/wings".

Pick one or the other.

Share this post


Link to post
Share on other sites
Smike

I'll be testing with a PCA day. Pick between the two and go from there.

Share this post


Link to post
Share on other sites
Smike
I see a wing AND a spoiler in that pic. I'm pretty sure that will not be allowed. The rules say any rear "spoiler/wing", not "spoilers/wings".

Pick one or the other.

 

Todd, after looking/reading the rules. I'd say the truck section is not a spoiler. Its a Gurney Flap. 1.5 inches tall.

 

Can we get a clarification on this?

Share this post


Link to post
Share on other sites
MHISSTC
Todd, after looking/reading the rules. I'd say the truck section is not a spoiler. Its a Gurney Flap. 1.5 inches tall.

 

Can we get a clarification on this?

 

I disagree.

 

I see two spoilers.

 

A Gurney Flap or Wicker Bill is a small tab extending from the rearmost portion of an airfoil whose intent is to effectively increase the camber of an airfoil which allows it to produce a greater amount of lift (downforce for race cars) at a lower angle of attack and also helps to keep the boundary layer flow attached to the airfoil instead of causing a turbulent or "stalled" condition.

 

The 1.5" extension you have at the back edge of the trunk lid is a spoiler. Spoilers "spoil" lift with the relative placement of high and low pressure areas and creating turbulence or detached flow (drag) in a desired location instead of it occurring at an undesired or less predictable location. It may be somewhat effective at producing a net downforce if the laminar flow around the car stays attached down the back window and across the trunk lid. The spoiler will create a "damming" of the air and a region of higher pressure ahead of it and a lower pressure area behind it. This localized higher pressure area over the trunk lid will provide a small amount of downforce on that horizontal surface while it also provides a specific detachment point on the back end of the car from which the turbulent flow will emanate...and actually help keep the remainder of the flow less turbulent around the rest of the back end of the car and decrease overall lift at the back end of the car.

 

The OEM piece is also a spoiler. Take a close look at it and picture it's cross section in a side view perspective. The "front" of it has a thinner more tapered profile while the "rear" of it has a thicker and more rounded profile with a larger radius. It is also cambered, or somewhat concave, on the "upper" surface. Draw that out on a piece of paper and what you have is somewhat of an airfoil shape, but it is pointed "backwards" to what you would expect it to be if it was actually supposed to produce downforce. Turn it around backwards and I think you will see it create real downforce instead of just drag as it is going to produce in the OEM configuration. Of course a bunch of drag mounted high atop a long lever-arm may effectively produce some downforce, but at a great expense of increased drag.

 

Here is a little diagram that may help.

 

gurneyflap.gif

Share this post


Link to post
Share on other sites
Adam Ginsberg
I have never seen a CMC car with a Saleen spoiler. Anyone know if they are legal. I would guess that they are somewhat effective at adding some down force since Saleen developed them and used them on the track.

 

458391966_oGg7E-L.jpg

 

Looks normal to me.

 

That's an AI car, using a true wing as well as a splitter (neither in that pic are CMC legal). Using it as an example WRT CMC isn't a very good idea. It can be confusing to those reading the forum.

 

th_IMG_20120824_163914.jpg

 

That is two items - a wing, and a spoiler. One or the other is permitted. Not both.

 

Smike - if you haven't already done so, it would be a huge benefit to your goals to talk to your local regional director. He can help steer you in the right direction before spending a bunch of your hard-earned $$ on parts that may not be CMC legal.

Share this post


Link to post
Share on other sites
Glenn
Todd, after looking/reading the rules. I'd say the truck section is not a spoiler. Its a Gurney Flap. 1.5 inches tall.

 

Can we get a clarification on this?

 

I disagree.

 

I see two spoilers.

 

A Gurney Flap or Wicker Bill is a small tab extending from the rearmost portion of an airfoil whose intent is to effectively increase the camber of an airfoil which allows it to produce a greater amount of lift (downforce for race cars) at a lower angle of attack and also helps to keep the boundary layer flow attached to the airfoil instead of causing a turbulent or "stalled" condition.

 

The 1.5" extension you have at the back edge of the trunk lid is a spoiler. Spoilers "spoil" lift with the relative placement of high and low pressure areas and creating turbulence or detached flow (drag) in a desired location instead of it occurring at an undesired or less predictable location. It may be somewhat effective at producing a net downforce if the laminar flow around the car stays attached down the back window and across the trunk lid. The spoiler will create a "damming" of the air and a region of higher pressure ahead of it and a lower pressure area behind it. This localized higher pressure area over the trunk lid will provide a small amount of downforce on that horizontal surface while it also provides a specific detachment point on the back end of the car from which the turbulent flow will emanate...and actually help keep the remainder of the flow less turbulent around the rest of the back end of the car and decrease overall lift at the back end of the car.

 

The OEM piece is also a spoiler. Take a close look at it and picture it's cross section in a side view perspective. The "front" of it has a thinner more tapered profile while the "rear" of it has a thicker and more rounded profile with a larger radius. It is also cambered, or somewhat concave, on the "upper" surface. Draw that out on a piece of paper and what you have is somewhat of an airfoil shape, but it is pointed "backwards" to what you would expect it to be if it was actually supposed to produce downforce. Turn it around backwards and I think you will see it create real downforce instead of just drag as it is going to produce in the OEM configuration. Of course a bunch of drag mounted high atop a long lever-arm may effectively produce some downforce, but at a great expense of increased drag.

 

Here is a little diagram that may help.

 

gurneyflap.gif

 

MF'ing Tech Bitches!

Share this post


Link to post
Share on other sites
Smike

down.jpg

 

Tunneling the air is partly what I was going for in that version.

 

Not the final versions of anything yet. Working on a different version as well.

Share this post


Link to post
Share on other sites
cozog1548534733
Tunneling the air is partly what I was going for in that version.

 

Not the final versions of anything yet. Working on a different version as well.

Mike,

I'm not sure what tunneling you're trying to achieve or what "version" you're referring to, but I can tell you that running more than 1 device that even looks like a wing/spoiler/gurney/etc. on the car will get you DQ'd.

Pick a single option and work with it.

I hope this clears things up.

Share this post


Link to post
Share on other sites
Smike

It's not posted here and its only a wing.

 

Just one. I know. For the rest of this year I'll be running PTB. It will come off after. I promise.

Share this post


Link to post
Share on other sites
CMC#11

Smike, if your Mustang is that loose I have to think there are other areas you could tune that would help the entire car and not just the back. You could be adding downforce to cover up a problem in the front.

Share this post


Link to post
Share on other sites
DrC

Mike keep developing new approaches for the wing I am also working on the same approach of modifying the current wing to be more effective and not just a thing on the back that causes drag.

Share this post


Link to post
Share on other sites
Smike

Thanks Dan.

 

We'll have to talk more at RA on SN95s.

Share this post


Link to post
Share on other sites
D Algozine
Mike keep developing new approaches for the wing I am also working on the same approach of modifying the current wing to be more effective and not just a thing on the back that causes drag.

 

My opinion..

Any of the stock wing/spoilers will provide approximately 6lbs of down force and any speed, however the forces will not change as a function of speed. My attempt at being sarcastic. There weight is the only down force they provide. Making adjustments to the stock wing will not result in any benifit. They simply do not have the proper shape of a real wing with the exception of the 2000 Cobra R, but it is limited.

Based on the current rule set, I would strongly suggest getting rid of the stock parts and install a "circle track stock car style" rear spoiler. Examples can be seen in some of these photos http://www.camaromustangchallenge.com/forum/viewtopic.php?t=4214

Share this post


Link to post
Share on other sites
DrC

So does anyone have a new wing for 2013? I will if I have time to complete it. So far it is only in my head but should have it ready by race day, just need to get another 4 x 8 sheet of plywood.

Share this post


Link to post
Share on other sites
D Algozine

Here is the section of the rules for wings/spoilers (see below)

My questions are:

 

What does this mean ?? " readily available to the public from a retail source for less than $700."

define retail source?

new / used?

In a class of "do it yourself" and "you'll have to fabricate it (spring perch, oil drains, etc.....", why can't an individual make a wing?

 

 

7.5.5 Any rear spoiler/wing that fits the following criteria may be used:

1. A vertical line from every point on the spoiler/wing and end plates must intersect the car body/bumper cover when the car is on a level surface.

2. The maximum height of any point on the spoiler/wing from any point on the deck lid/rear hatch may not be greater than 12 inches.

3. The overall depth (leading edge to trailing edge) including end plates may not be more than 12 inches.

4. The spoiler/wing and mounts as installed must be readily available to the public from a retail source for less than $700.

5. The wing must be fixed for competition and may not be adjusted from the driver’s seat

Share this post


Link to post
Share on other sites
Glenn

If you home brew a wing and a fellow racer wants one, you have to build it and you can't charge him more than $700. If you refuse, your wing becomes illegal.

Share this post


Link to post
Share on other sites
soundguydave1548534741

And here I thought this whole series was about fabricating "home-brew" parts... Seems we had a discussion about springs and things and the bottom line was to "home brew" something....

Share this post


Link to post
Share on other sites
jsbumed

I always figured a home brewed wing or spoiler was considered being available from an availalbe retail source. If someone asks what your retail source is tell them Lowes. Give them a detailed item list and be sure to tell them "some assembly required."

Share this post


Link to post
Share on other sites
D Algozine
I always figured a home brewed wing or spoiler was considered being available from an availalbe retail source. If someone asks what your retail source is tell them Lowes. Give them a detailed item list and be sure to tell them "some assembly required."

 

Exactly !!

I can buy parts from a "retail source" for far less then $700 to fabricate my wing.

I can also buy a wing used for less then $700.

Share this post


Link to post
Share on other sites
D Algozine
If you home brew a wing and a fellow racer wants one, you have to build it and you can't charge him more than $700. If you refuse, your wing becomes illegal.

 

Glenn,

Are you wearing your directors hat or racers hat?

Is this your opinion/interpretation , or is this managements?

Share this post


Link to post
Share on other sites

×
×
  • Create New...