Functional canards

Has anyone used canards on their Mustang? I'm not a huge fan of chin splitters as they are usually the first thing to break on a street car. I'm wondering if canards generate any appreciable downforce or is it literally something to make the car look more aggressive.

And yes, I know some race cars use them; however, they do a significant amount of aerodynamic work to generate the right amount of downforce at the right speeds. I haven't the foggiest what the aerodynamics look like on an S550.

Based on the design, I am thinking that this probably has negligible downforce generated due to the small surface area of the canards.

Ford's turnkey racers have them and there are a couple designs available for our cars. What are you hoping to achieve? I wouldn't say it would be worth the weight for street legal and autox applications.

Performance nut said:

Has anyone used canards on their Mustang? I'm not a huge fan of chin splitters as they are usually the first thing to break on a street car. I'm wondering if canards generate any appreciable downforce or is it literally something to make the car look more aggressive.

And yes, I know some race cars use them; however, they do a significant amount of aerodynamic work to generate the right amount of downforce at the right speeds. I haven't the foggiest what the aerodynamics look like on an S550.

Based on the design, I am thinking that this probably has negligible downforce generated due to the small surface area of the canards.

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In general a front splitter, rear diffuser and wing do the bulk of the aero work on a track car, the front canards are usually added to add some additional downforce at mid-level speeds. They are usually added to help balance the rear bias that the rear diffuser and wing add to the car. Any aero mods added to a car will effect the car differently at different speeds, you can dial in the aero for the type of track you will be running but it takes a lot of time and testing to get it right. Also without a wind tunnel to test you need a very consistent driver with a very touchy butt dyno at the wheel to understand what each change is doing.

There is not much data in the open to go by, there is a company called Velox Motorsports that has published some computational data on the S550. Take it for what it is as the data is from a computer model not real world measurements but at least it is something. I have their rear diffuser on my track only car and along with the 3" front splitter and Carbon Dynamics GT350R rear wing the car is very balanced on corner entry speeds of the low 100 mph. Anything above 60mph and the aero can be felt. Read through the white paper from Velox and you will start to understand some of the issues.
http://media.wix.com/ugd/b6c8d9_c8c654e8e8024ca1b3e1e66eb7b598cf.pdf

The stock body work generates lift as early as 40mph, with a diffuser and splitter alone negative lift (downforce) is achieved according to their test data. They make some big assumptions in their model and are not calculating airflow through the grill (this has a big impact of lift at the front end), but since Ford has not put out any data and no one else has either this is what we have to work with.

The front end will never be balanced to the rear end if you add either a wing or a diffuser and do not add a front splitter. There are many designs that will allow you to quickly remove the front splitter for street duty and then add it back on for track duty. The other thing that is needed to allow the front aero to work is to remove the pressure build up under the hood. A lot of guys complain about hood flutter on the S550 and most of it can be removed if the hood is properly vented and the air packing under the hood is managed better. As a last resort after you have done all of the other aero add-ons and the car still seams rear biased at speed then you can add the canards to help the front end out. The addition of the canards are much less effective then adding another 1/2" to the front splitter depth so for big changes play with the front spitter design, ride height, and rake before you waste time on canards. Something else to consider when playing with aero is you have to combine all these mods with higher spring rates to take full advantage. There are a lot of variables in play.

On the other hand if you think they look cool and want to add them go for it as without the other aero bits they will not do much.

Dave

This is why I really like this forum. This is an extremely awesome response, thank you very much.

Ok, I read through the paper, really awesome stuff here. From what I saw on the coefficient of pressure model, the canards would have very little affect like you said.

I do not have a PP car so my choice of splitters seems to begin and end with APR. Is there another option? The APR piece looks like it may extend too far for street use, anything short of very mild incline will likely scrape. It looks like it can be removed but it may be a pain in the butt. All the other "splitters" look more cosmetic than functional. One made me lol when it specifically said it wasn't recommended at high speeds.:doh:

The vents are something I have been considering for awhile for multiple reasons. Seems it just got bumped higher on the list.

I built my own, I needed something that fit within the rule of SCCA T3/T4 and I needed something that was inexpensive and easy to repair track side. I used a material called PolyMetal due to its price during the testing process and built the finish piece out of AlumaCore because it is even lighter than the PolyMetal but is more expensive. Both of these materials are very rigid and quite durable.

I made the structure out of 1" aluminum angle stock and it attaches to the front bumper mounting bolts, I used large button head bolts to secure the splitter to the mounting structure. The angle stock has floating nutserts for the button head bolts to thread into, I can replace the splitter in about 10 min track side on jack stands.

I made the template out of sheet foam, then trasnfered the final design to 3/8" masonite, then use the masonite and a router to cut out as many splitters as needed. The Polymetal and AlumaCore cut like butter with the router and leave a nice finished edge. The AlumaCore has hollow spaces so the edges have to be filled with black RTV to have a nice finished look.

These are pictures of the Polymetal test piece during the design process.

Dave

I really like what you did there. Have you noticed any stress cracks on the bumper? Not sure how fast you drive but it looks like it is really well secured and should hold up well so long as the bumper material holds.

How is a GT T3 or T4 legal? You have to run a restrictor in T2.

I agree that a canard is more a trim device than a primary aerodynamic device. Many races cars are setup so you can quickly add or subtract them, and often have different sizes to quickly tune the front aero.

Grintch said:

How is a GT T3 or T4 legal? You have to run a restrictor in T2.

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I simply followed the rules that define a legal splitter for the class, at the time of my build they had not really classed the 2015+ Mustangs. The rules are ever changing and the S550 Mustangs are still trying to finding their place in SCCA, but the rules regarding the the splitter dimensions are generally not vehicle specific. Either way we are talking about a bolt on part that can be changed as needed for any class or series of racing. Also the part could be produced and sold to any Mustang legal for any series that allows a 3" splitter so the V6 guys may have a need for the part.

Dave

AJ Hartman makes Canards if you want to still find them.

I spoke with a guy the other day who has some insider knowledge, the canards on the GT4 were absolutely necessary for what they needed. He brought up that he likes what Chevy did with the ZL1 1LE, how they went with less splitter and more canard. It makes it more street friendly.