Who can make me canards (dive planes) for a 70 RS Clone?

[minoclan]

I haven't had any luck finding any online. I don't want to spend a fortune. My current obsession is downforce, or in my case minimizing lift. Does anyone have a source that they can share with me?

[Flieger]

What does your aero setup currently consist of? A bigger splitter is nearly "free" downforce- no extra drag, just using the existing high pressure area. Dive planes are usually very inefficient, working at high angles. They also affect the flow over the rest of the car, but the wheels will already cause a disturbed airflow in their wake.

[tcar]

What he said... You want splitter enhancement...

[minoclan]

I have the TRE splitter. I am putting on the IROC rear spoiler.

[Flieger]

Make the splitter bigger.

Maybe vent the oil cooler through the hood?

[Noah930]

Steve Wong has an interesting idea on his 911. He has some sort of splitter/spoiler (can't recall which) but because he didn't want to make it too low, for curb clearance issues, he fabbed a flexible piece that extends downward like a curtain from the aft portion of the splitter. The extension can bend if he hits a bump, and is "sacrificial" compared to the rest of the (hard) splitter. It still does the same job of diverting air from passing under the car, though.

[Flieger]

But the splitter adds downforce by having its upper surface area exposed to high pressure (from an air dam or the front of the car). An air dam below a splitter reduces downforce.

[Noah930]

Which is why I think it's a spoiler extension he has, not necessarily a splitter. I think it's on his Carrera, not the GT3.

[Jack Olsen]

(I'm reposting this from a couple of years back.)

I made a set of these, initially thinking they functioned like little wings to generate downforce at the front of the car. The part I didn't understand was why they were usually set at such steep angles of attack -- it seemed like they'd have to be well beyond the point where a wing would basically stall.

Here are mine are in a photograph taken at speed:



As it was explained to me, winglets/canards/diveplanes aren't functioning as wings at all. They're vortex generators, and functionally they have less in common with wings than they do with the fans above open grocery store freezers. They generate swirling air along the sides of the car, most importantly down along the space between the track surface and the rocker panels. Their function is to stop air from getting under the car along its sides. This basically means (at least as far as my non-engineer's brain can get around it) that low-pressure air under the car doesn't suck air in from below the doors.

Here's a useful illustration from the Suzuka Racing site:



And here's a more succinct explanation from a Pelicanite in a previous thread:

Originally posted by BertBeagle
These are/were used on ground effects cars (ie the IMSA GTP cars of the 80's). What they accomplish is creating a vortex down the side of the car, filling the low pressure area that exists along the sides of the car, and that kept the air entering the underside of the car from the nose under the car and effectively increased the down force with a low drag penalty. Aero guys are always looking for something for nothing (ie downforce for no drag penalty) and this was a good find.

My guess would be that they improve downforce/grip at both the front and rear of the car, since they're essentially a component of underbody air management. But like other guys in this thread, I felt the effect as a better planted nose when I added mine.

[Flieger]

Whenever Racecar Engineering does an Aerobytes section involving dive planes, they always say that they are rather inefficient from a negative lif to drag perspective. I seem to recall them saying this with the prototypes, not just the GT cars, suggesting they are stalling, perhaps just piling up air on the splitter? The turbulence behind them should just be adding to the turbulence from the wheels, so they should not really be adding turbulence where there was laminar flow before.

There is a reason why most ALMS-type racing teams remove some, if not all, dive planes for LeMans.

Jack, I like the looks of your shallower ones better. It looks lke being that close to the underside of the bumper might give them a bit of splitter effect, in that the air pressure is increasing as it compresses between the dive plane and the underside of the bumper, then pushing down on the top surface of the dive plane. It would sort of be like moving the splitter up by 6 inches.

[5:04]

Originally Posted by Jack Olsen

As it was explained to me, winglets/canards/diveplanes aren't functioning as wings at all. They're vortex generators, and functionally they have less in common with wings than they do with the fans above open grocery store freezers. They generate swirling air along the sides of the car, most importantly down along the space between the track surface and the rocker panels. Their function is to stop air from getting under the car along its sides. This basically means (at least as far as my non-engineer's brain can get around it) that low-pressure air under the car doesn't suck air in from below the doors.

Here's a useful illustration from the Suzuka Racing site:



And here's a more succinct explanation from a Pelicanite in a previous thread:



My guess would be that they improve downforce/grip at both the front and rear of the car, since they're essentially a component of underbody air management. But like other guys in this thread, I felt the effect as a better planted nose when I added mine.

Like usual Jack and Fleiger are right

Many people that use them without knowing their real effect, however for most people they seem to work. Fleiger is right though in saying that they create a lot of drag and don't directly provide downforce. I'll be testing a couple of very big canards on my car in the next couple of months once I get my wing and finish my aero package so I'll see if they gain or lose time and try to post some numbers with various aero parts added and removed with lap times to back them up.

From my understanding, Canards are a fine tuning aero item and also help by diverting air away from the tires which helps with that planted feel that Jack and many others have felt.

Cars that have lots of trick aero often have giant Canards that work with very low side skirts. I've even seen cars run the garage lining on their side skirts all the way to the ground to try and keep air from under their car.

Here is a picture of a very fast Miata with an extended airdam covering the tires and the aforementioned lining. The Canards will often provide this effect inadvertently and people will comment on a difference.


Also if you want them to make the biggest effect they have to be big i.e. the Cyber or Sierra Sierra Evo.

[minoclan]

Jack-
I also found that taping over the horn grills stopped a significant amount of air from coming in the front and giving me lift. I didn't think that it would make a tremendous difference, but it did.

[Mahler9th]

If you decide they can help in your situation, you can easily make them yourself with aluminum, fiberglass, carbon fiber, et cetera. I have made several different types for my car, which has a Getty Design 993 G-style front bumper.

I use some really big ones at Sears Point, and they help the balance for my car quite a bit there. That is the only place I run the big ones.

Is anyone using Canards?

See this thread... and I'd be happy to describe how I did it if there is interest. I also have some additional pictures.

[Mahler9th]

Also check out Sierra Composites:

Carbon Fiber Sheets Panel Sandwich Panels Angle Tubing Basalt sheets Texalium sheets

[911pcars]

One can try to copy aero devices on other car brands or take an existing aero theory and try to apply it to your car. However, unless you can test air flow via a wind tunnel or use pre-wind tunnel testing procedures (see Jack's airflow test thread), then it's all a guess - unless you're doing it for looks.

Whatever the factory did usually works (except for no wings on the 917). A good guide would be to study Porsche's aero device chronology on their track cars.

Sherwood

[minoclan]

Originally Posted by 911pcars

One can try to copy aero devices on other car brands or take an existing aero theory and try to apply it to your car. However, unless you can test air flow via a wind tunnel or use pre-wind tunnel testing procedures (see Jack's airflow test thread), then it's all a guess - unless you're doing it for looks.

Whatever the factory did usually works (except for no wings on the 917). A good guide would be to study Porsche's aero device chronology on their track cars.

Sherwood

I'm not doing it for looks. I unfortunately don't have the budget for a wind tunnel. This is "seat of the pants".

[Mahler9th]

Seat of the pants can work, if you have a good seat. Whether a particular effort toward solving a particular problem or optimizing some aspect of performance is a waste of time depends on way too many variables to discuss here. But one needn't use a wind tunnel or even do tuft testing in certain situations. The answer is like always... it depends.

[JeremyD]

Have you had your a$$ calibrated? You need to do that every three years to maintain your certification.

SC Aero GT3 race carbon fiber front dive planes / canards

[minoclan]

Originally Posted by JeremyD

Have you had your a$$ calibrated? You need to do that every three years to maintain your certification.

SC Aero GT3 race carbon fiber front dive planes / canards

Saw those, thanks

[Mahler9th]

One of my friends bought a set of those for his race car. Nicely made but very small for a 911 nose (his is 934). So likely difficult to feel a difference. There are lots of parts out there in the import car scene... most are pretty small.