Aerodynamics working WITH the Car?

[tyoneal]

To All:

I really didn't see another catagory for this so if it needs to be moved, please have at it.

Our 1st Gen Camaros have the Factory spoiler that looks nice and is probably pseudo functional. I've notice the larger spoilers that some people are running, and I have actually seen a few Camaros with wings on them.

The question I have is:

When you are adding something truely functional in providing downforce, shouldn't it be anchored to the frame, maybe a horizonal crossmember of some sort directly over the third member?

You would get the downforce exactly where you want it, and you could benefit by the use of leverage by creating the downforce as far back in the car as you can.

Surely there is a point when the deck lid is insufficient to carry such a load.

Hypothetically, wouldn't it be the most productive on the axel housing itself, so it wouldn't load the suspension up so much?



Am continuing my search, but I haven't (So far) found anything addressing this.

Thanks for any help you can offer.

Best Regards,

Ty

[Tom Welch]

If I remember Dave Pozzi has some info that is useful to this discussion, GM did do research on the 1st gen spoilers, they do work. I believe that there has been some discussion about this topic but not specifically about tying directly to the axles and stuff like that, Check out any small plane that you can get close to, the structure is really fragile and seems very weak for what it does with airflow and wind loading etc.

[Jim Nilsen]

To All:

I really didn't see another catagory for this so if it needs to be moved, please have at it.

Our 1st Gen Camaros have the Factory spoiler that looks nice and is probably pseudo functional. I've notice the larger spoilers that some people are running, and I have actually seen a few Camaros with wings on them.

The question I have is:

When you are adding something truely functional in providing downforce, shouldn't it be anchored to the frame, maybe a horizonal crossmember of some sort directly over the third member?

You would get the downforce exactly where you want it, and you could benefit by the use of leverage by creating the downforce as far back in the car as you can.

Surely there is a point when the deck lid is insufficient to carry such a load.

Hypothetically, wouldn't it be the most productive on the axel housing itself, so it wouldn't load the suspension up so much?

Am continuing my search, but I haven't (So far) found anything addressing this.

Thanks for any help you can offer.

Best Regards,

Ty

When ever in doubt about how strong things are, look up the tensile strength of a 1/4-20 standard grade fastener. also think of lifting a $20,000 engine with a motor plate on a manifold with 4 5/16 -18 fasteners !!

The spoilers work , they stay on longer at speed than they do in parking and look good too. The after market spoilers probably do more but Van Prothero did 200 mph in 1967 without one on the rear , so you decide how important it is?

[Chris 68]

To All:

I really didn't see another catagory for this so if it needs to be moved, please have at it.

Our 1st Gen Camaros have the Factory spoiler that looks nice and is probably pseudo functional. I've notice the larger spoilers that some people are running, and I have actually seen a few Camaros with wings on them.

The question I have is:

When you are adding something truely functional in providing downforce, shouldn't it be anchored to the frame, maybe a horizonal crossmember of some sort directly over the third member?

You would get the downforce exactly where you want it, and you could benefit by the use of leverage by creating the downforce as far back in the car as you can.

Surely there is a point when the deck lid is insufficient to carry such a load.

Hypothetically, wouldn't it be the most productive on the axel housing itself, so it wouldn't load the suspension up so much?

Am continuing my search, but I haven't (So far) found anything addressing this.

Thanks for any help you can offer.

Best Regards,

Ty

Plus i dont think there could be enough downforce to really put too much stress on the deck lid that it cant handle. I think the most down force made from that rear spoiler is around 300-350lbs, spread out over a couple square feet is about 288 square inches which translates to 1.25 lbs per in^2

[Twentyover]

I'm thinking most production car spoilers are lift deterrents rather than downforce enhancers. If one wants downforce without some big wing, take a look at diffusers.

Wings attached directly to suspension uprights were tried in the mid 60's (http://images.thetruthaboutcars.com/.../lotus-49b.jpg shows a Lotus; I think Lola and Brabham also ran front mounted wings), but after a series of spectacular crashes due to fatigue caused by the required articulation, were pretty much banned by most sanctioning bodies. The last attempt was probably the twin tub Lotus in the 80's that was banned before it even turned a wheel in anger

[tyoneal]

When ever in doubt about how strong things are, look up the tensile strength of a 1/4-20 standard grade fastener. also think of lifting a $20,000 engine with a motor plate on a manifold with 4 5/16 -18 fasteners !!

The spoilers work , they stay on longer at speed than they do in parking and look good too. The after market spoilers probably do more but Van Prothero did 200 mph in 1967 without one on the rear , so you decide how important it is?

----------------------------------------------------
I appreciate your reply.

I know what you are saying, and I understand the tensile strength of dfferent metals, and I probably should have rephrased my question, and put it into a different context.

Lets try this, a Indy, F1 Racer, GT1 Car have a wind placed on the rear. There are no down force restrictions, What do they do to mount the tremendous downforce that the wings produce?

Sorry about relating it to first gens. I did see these wings and thought they were pretty cool, but expensive.

http://aeromotions.com

Thanks again for your time.

Ty

[tyoneal]

I'm thinking most production car spoilers are lift deterrents rather than downforce enhancers. If one wants downforce without some big wing, take a look at diffusers.

Wings attached directly to suspension uprights were tried in the mid 60's (http://images.thetruthaboutcars.com/.../lotus-49b.jpg shows a Lotus; I think Lola and Brabham also ran front mounted wings), but after a series of spectacular crashes due to fatigue caused by the required articulation, were pretty much banned by most sanctioning bodies. The last attempt was probably the twin tub Lotus in the 80's that was banned before it even turned a wheel in anger

----------------------------------------------------------
Thanks for the message and the picture. I remember those cars as a kid, even with no wings. (Sorry to admit) Yes, I agree the diffusors work really good if done correctly, as well as the tunnels.

Thanks again for your answer.

Ty O'Neal

[tyoneal]

Plus i dont think there could be enough downforce to really put too much stress on the deck lid that it cant handle. I think the most down force made from that rear spoiler is around 300-350lbs, spread out over a couple square feet is about 288 square inches which translates to 1.25 lbs per in^2

=================================
Thanks for the message:

It's not just the weight. With 350# pounds tied into the deck lid, would that be the same as puting 350# or 10% of your cars weight at 3.5-4.0 feet in the air?

I would think it would have a quite a detrimental effect on the handling of the car. If you mounted a 2 or 3 element wing on the back and could run fast enought to get 1000-1500+ pounds downforce wouldn't you be in deep Ca Ca at this point?

The now you have 1/3 (Or really a 1/4) or the entire weight of the car up inthe air at 3.5 feet. I would guess something would hve to be done at this point.

How would the Downforce/weight be carried then?

Another thing, even with 350# of downforce, which I guess would be doable, then having it levered out rearward, wouldn't that have a much greter effect than having 350# downforce on the truck?

Thanks for your time and patience.

Regard,

Ty

[David Pozzi]

Do a search here I think the old threads will come up.

Read this: http://www.camaro-untoldsecrets.com/...article_fs.htm
Hot rod magazine did test of their LSR 2nd gen spoiler in a wind tunnel, interesting results. I don't have a link to it but it was in the old thread here.
David

[Yoda4561]

=================================
Thanks for the message:

It's not just the weight. With 350# pounds tied into the deck lid, would that be the same as puting 350# or 10% of your cars weight at 3.5-4.0 feet in the air?

I would think it would have a quite a detrimental effect on the handling of the car. If you mounted a 2 or 3 element wing on the back and could run fast enought to get 1000-1500+ pounds downforce wouldn't you be in deep Ca Ca at this point?

The now you have 1/3 (Or really a 1/4) or the entire weight of the car up inthe air at 3.5 feet. I would guess something would hve to be done at this point.

How would the Downforce/weight be carried then?

Another thing, even with 350# of downforce, which I guess would be doable, then having it levered out rearward, wouldn't that have a much greter effect than having 350# downforce on the truck?

Thanks for your time and patience.

Regard,

Ty

On the cars we drive, that downforce (usually net 50 lbs or less at high speed) just serves to neutralize lift so that handling is less compromised than it would be with no spoilers at all. On cars that generate huge downforce on the order you're thinking of, it needs to be balanced front and rear, there's a variety of ways to do it which are a bit over my head, but usually involve more under-body air flow tricks than big wings (the car gets "sucked" to the ground). Remember that downforce has zero mass, so there's no detriment as long as it's well balanced front to rear. Increase one end too much and it will cause the car to over or understeer as you might expect.

[Chris 68]

=================================
Thanks for the message:

It's not just the weight. With 350# pounds tied into the deck lid, would that be the same as puting 350# or 10% of your cars weight at 3.5-4.0 feet in the air?

I would think it would have a quite a detrimental effect on the handling of the car. If you mounted a 2 or 3 element wing on the back and could run fast enought to get 1000-1500+ pounds downforce wouldn't you be in deep Ca Ca at this point?

The now you have 1/3 (Or really a 1/4) or the entire weight of the car up inthe air at 3.5 feet. I would guess something would hve to be done at this point.

How would the Downforce/weight be carried then?

Another thing, even with 350# of downforce, which I guess would be doable, then having it levered out rearward, wouldn't that have a much greter effect than having 350# downforce on the truck?

Thanks for your time and patience.

Regard,

Ty

Not exactly, we should really think of it in terms of DOWNWARD force, not mass. That 350# of down force is only acting down on that spoiler because of air resitance, not gravity. If you were to put a 350# lead block inplace of your spoiler, you would have gravity acting upon that block which would still give you a downward force BUT that weight would also factor into the handling of the car in terms of lateral movement, creating more intertia. Lets say a stock camaro weighs 2650lbs, 3000lbs with the lead block. If you were to take a sharp turn, you would be moving 3000lbs with you. Now with that lead block removed and the spoiler in place, you would still get your 350 lbs of down force at speed but when you mave that turn, you are only moving 2650lbs of camaro. I hope that makes sence, I'm not a physics guro but physics is part of my major; I wish this was part of my homework!

[tyoneal]

Not exactly, we should really think of it in terms of DOWNWARD force, not mass. That 350# of down force is only acting down on that spoiler because of air resitance, not gravity. If you were to put a 350# lead block inplace of your spoiler, you would have gravity acting upon that block which would still give you a downward force BUT that weight would also factor into the handling of the car in terms of lateral movement, creating more intertia. Lets say a stock camaro weighs 2650lbs, 3000lbs with the lead block. If you were to take a sharp turn, you would be moving 3000lbs with you. Now with that lead block removed and the spoiler in place, you would still get your 350 lbs of down force at speed but when you mave that turn, you are only moving 2650lbs of camaro. I hope that makes sence, I'm not a physics guro but physics is part of my major; I wish this was part of my homework!

===================================
Chris:

Thanks for the information.

I appraciate the clarification. My Physics was a long time a ago as well, and going back over some fundamentals is very helpful.

Working with Venturi's (I don't know if that is the right way to spell that in a "Plural" tense) Is a facinating part of Aerodynamics that I have been reviewing, and think is a good practical way of helping our cars without all the "Clutter", of wings.

Vortex Generation is also something I think is under used in the hobbey. As the edges are pushed further out, I would be surprised if, "working", ground effects doen't become popular.

Anything information you would care to add to anything I write is always welcome. I know the information is in my head somewhere, it just takes a bit of reconnection sometimes to get it back.

Thanks again,

Ty

[tyoneal]

Do a search here I think the old threads will come up.

Read this: http://www.camaro-untoldsecrets.com/...article_fs.htm
Hot rod magazine did test of their LSR 2nd gen spoiler in a wind tunnel, interesting results. I don't have a link to it but it was in the old thread here.
David

==================================
David:

This was very interesting. Thank you for posting it.

TY

[David Pozzi]

Here's the Hot Rod Camaro aero article I mentioned:
http://www.hotrod.com/techarticles/b...ics/index.html

[Randy67]

Here is some info on the bracing used on Daytonas & Superbirds on the rear wing:
Just under the trunk opening sides, we see the inner edge of the brace that goes under the quarter panel (Photo hsrs10-1). That brace was used to strengthen the quarter skin so that when the wing is under high load and high speed, it doesn't warp the quarter panel. The brace is spot welded and this is a very important part when you are looking to see if a SuperBird is an original or just made up. If you look inside the trunk rain trough, you would see many spot welds-it looks like about 15 of them or more.
Inside the trunk are the wing braces. At the bottom [near the trunk floor] is a bracket that measures about 4 1/2" by 4". This little bracket is white-the color of the car-and is welded to the trunk floor with bead welding. That bracket has a little lip that faces forward on the bottom and the rear side of the bracket is bolted to the wing "V" brace. The "V" brace is made out of heavy sheet metal and is always black (Photo hsrs10). It's purpose is to connect the trunk floor to two of the four studs that protrude down from the wing and its overall purpose is to keep the wing straight and to keep it from warping the quarter panel. At high speeds, even with a street car, there would be significant downforce. The bottom bracket on the floor was welded in before the car was painted, in the metal shop when the car was being framed up, so it will be body color. There will be no white [or body color] overspray on the "V" braces because they were put in after the car was painted. The wing was also painted off the car.

Here is a picture of the brace:
http://wwnboa.org/jpgs/hsrs10-1.jpg
and the text came from this page about 1/2 down:
http://wwnboa.org/hsrs.htm

So if you go fast enough, then bracing is necessary. But how many of us are hitting 200 mph?

[tyoneal]

Here is some info on the bracing used on Daytonas & Superbirds on the rear wing:
Just under the trunk opening sides, we see the inner edge of the brace that goes under the quarter panel (Photo hsrs10-1). That brace was used to strengthen the quarter skin so that when the wing is under high load and high speed, it doesn't warp the quarter panel. The brace is spot welded and this is a very important part when you are looking to see if a SuperBird is an original or just made up. If you look inside the trunk rain trough, you would see many spot welds-it looks like about 15 of them or more.
Inside the trunk are the wing braces. At the bottom [near the trunk floor] is a bracket that measures about 4 1/2" by 4". This little bracket is white-the color of the car-and is welded to the trunk floor with bead welding. That bracket has a little lip that faces forward on the bottom and the rear side of the bracket is bolted to the wing "V" brace. The "V" brace is made out of heavy sheet metal and is always black (Photo hsrs10). It's purpose is to connect the trunk floor to two of the four studs that protrude down from the wing and its overall purpose is to keep the wing straight and to keep it from warping the quarter panel. At high speeds, even with a street car, there would be significant downforce. The bottom bracket on the floor was welded in before the car was painted, in the metal shop when the car was being framed up, so it will be body color. There will be no white [or body color] overspray on the "V" braces because they were put in after the car was painted. The wing was also painted off the car.

Here is a picture of the brace:
http://wwnboa.org/jpgs/hsrs10-1.jpg
and the text came from this page about 1/2 down:
http://wwnboa.org/hsrs.htm

So if you go fast enough, then bracing is necessary. But how many of us are hitting 200 mph?

=============================
Randy:

Thank you for the great information. I had read that special bracing was necessary for the large downforce structures. I do understand about, "Who will be going 200 mph?"

I sincerely doubt it will be me, however even when going at 140-180 mph, the actual size, shape and pitch of the spoiler or wing will determine proper bracing. Is this wrong?

I know the sprint cars run huge wings and are going considerable slower than the speeds mny street car are capable of.

I'm looking forward to reading the entire article.

Thanks again.

Ty

[Randy67]

You mean huge wings like this A-mod?
http://carphotos.cardomain.com/ride_...0001_large.jpg

Much like the sprint cars, the A-mods are going for max downforce at moderate speeds. So much downforce that their top speed is quite limited, but they get there very fast. Not very practical (or attractive) spoilers/wings for pro-touring cars.

If you use a factory spoiler, then extra bracing beyond factory probably isn't needed, but couldn't hurt either. I bet pedestal type spoilers require more bracing than duck tail styles do with the force being directed into the two legs.

[tyoneal]

You mean huge wings like this A-mod?
http://carphotos.cardomain.com/ride_...0001_large.jpg

Much like the sprint cars, the A-mods are going for max downforce at moderate speeds. So much downforce that their top speed is quite limited, but they get there very fast. Not very practical (or attractive) spoilers/wings for pro-touring cars.

If you use a factory spoiler, then extra bracing beyond factory probably isn't needed, but couldn't hurt either. I bet pedestal type spoilers require more bracing than duck tail styles do with the force being directed into the two legs.

-------------------------------------------
Thanks for writing.

That was a very interestng picture.

I agree, not to great for a Pro-Touring car.

I appreciate your thoughts, and your perspective.

I'll think about this and see about adding something to this post.

Thanks again,

Ty

[Ash]

Not to pimp my own thread, but if whole car aerodynamics is what your curious about, check out https://www.pro-touring.com/forum/sh...ad.php?t=61936. Spoilers can only go so far. Under-trays, Diffusers, Splitters, Vortex Genrators, and Canards is what I've been interested in for some time. I'm going to order "Race Car aerodynamics" by Robert bentley, as some have suggested it as a good read.

[tyoneal]

Ash:

Thanks for the tip.

I will grab a copy myself.

I think the underside of the car is a very underdeveloped part of this hobby.

I've got several projects, one being a F-Body, that I have been coolecting information about. I know some of my questions are somewhat scattered, but since I am looking at a couple different applications, nothing seems to be done the same way. I washopeing for the simularities between them.

The theories are consistant, it's the methods of implimentation that is different.

I love thi subject matter.

Thanks,

Ty