Aero Devices diffusers, wings, spoilers, etc

[Ian7]

Great thread, this, I'm really enjoying it.

Couple of points: the little tabs on the side of the nose of 'real' race cars are not primarily to generate downforce themselves (as the calculations by others above prove), they are there to guide airflow to the benefit of other more significant areas of the car. On a seven, they are cosmetic at best. Think about the airflow into the engine bay stagnating to essentially zero velocity (in exchange for dynamic pressure increase), exerted upward on the large bonnet area, with no counteracting lower surface under the car. Those 'downforce' tabs are truly insignificant in comparison.

Secondly, having spent decades honing the aerodynamics of race cars in competition, I'm amused to no end that Seven owners spend any time dealing with or worrying about it, our cars are such a hopeless starting point :-)

(says me, the owner of a 100hp clam-shelled brick) LOL

[supersportsp]

Secondly, having spent decades honing the aerodynamics of race cars in competition, I'm amused to no end that Seven owners spend any time dealing with or worrying about it, our cars are such a hopeless starting point :-)

(says me, the owner of a 100hp clam-shelled brick) LOL

 

I think most of our interest lies primarily in reducing front end lift at speed vs. top speed gains or even downforce.

[MightyMike]

Hijack:

 

Mighty Mike, everytime I see a photo of your car I am blown away by how perfect it is.

 

Mike M

 

 

Thanks Mike! :cheers:

[MichaelD]

Here are the photos of my front "SnowPlow" areo device. While it is not fancy and does not look very aerodynamic, it certainly does the job and counters the lift caused bu my clam shells. My front end is now quite stable at any speed and dives into turns.

 

I would like to add more downforce at the rear. I think a wing and the Fluke diffuser could add a more grip on exit and a few more mph at the top end at VIR.

[Alaskossie]

Supersportsp,

 

Don't forget the Mike Rohaley undertray for the S3 rear suspension and diff....

[nleroux7]

Message to Scannon:

 

For sure you will have strange handling at 130mhp if you keep those tires running in the wrong direction lolll Look at the tire threads

[scannon]

Message to Scannon:

 

For sure you will have strange handling at 130mhp if you keep those tires running in the wrong direction lolll Look at the tire threads

You did cause me run down to shop to check the tires on the car which are on the correct way. Then I came back and looked to see if there was a picture posted with them on the wrong side.

 

I'm guessing you are referring to the picture in post #7. That was taken during a winter refurbishing of the car and I had thrown on the wheels to move the car to the other side of the shop to bring in the wrecked Miata in the background to strip it. I didn't pay attention to which side they needed to be on as they were coming off again before the car hit the road.

 

Actually, on dry roads it doesn't much matter which direction they are mounted. The directionality is for the water clearing function in the wet.

[supersportsp]

Perhaps an alternative to winglets, aero wishbones etc.

 

http://www.westermann-motorsport.com/shop/product_info.php?info=p157_Carbon-fibre-wishbone-foils--lower-.html

 

Has anyone ever tried these? I like the concept. 1. Helps clean up air around the upper and lower arms (same effect as aero wishbones). 2. Overall shape seems to indicate at worst reduced lift and perhaps even some minor downforce?

 

http://www.westermann-motorsport.com/shop/images/product_images/popup_images/157_7.JPG

[Alaskossie]

I bought a similar set of lower wishbone aerofoils from SevenTweeks in UK, looking for a bit of downforce.

 

Like the Mog Racing aerofoils, the aerofoil shape is moulded in, but unlike how I think the Mog foils are made, the trailing edge of the Tweeks foil is not left unsupported -- there is a rear lip that goes over the rear leg of the A-arm.

 

Unfortunately, the Tweeks foils do not fit my lower A-arms because mine are the Caterham thin "aero" arms, instead of the round cross-section arms. i don't know if anyone makes aerofoils for A-arms that are of the Caterham "aero" type.

[BruceBowker]

If nothing else they look cool.

[slomove]

Did they eliminate the ARB?

[supersportsp]

Did they eliminate the ARB?

 

Didn't notice that. Certainly looks like they did. Also, in this photo notice the cross brace between the lower a-arms under the nose cone.

 

http://www.westermann-motorsport.com/shop/images/product_images/popup_images/157_4.JPG

[Kitcat]

Headlights deleted, ditto turn signals & windshield. Still has a side mirror, and the front fenders look like huge air dams, to my inexpert eye.

Edited March 16, 2011 by Kitcat

[danilo]

Interesting looking, but noticing the Shark Cage erector set and the wide open tub/passenger compartment...pretty well discredits any real life 'Aero' pretensions, I would think.

Susp pickup cross brace idea was occaisionaly seen 30 years ago. Make a difference? Unlikely IMO.

[Alaskossie]

We're theoretically looking for downforce on the front here, not streamlining....

 

Referring to the c/f winglets on the A-arms as "aero" devices is not accurate; they are (at least in theory) "downforce" devices.

 

In fact, obtaining downforce is at the expense of streamlining.

[danilo]

Curiously there was semi recent posting on Blatchat by someone who took their Caterham into a Wind tunnel facility for testing/upgrade information.

From Memory of reading it :-) Wee spoilers (ala CSR) on the top of tighter fitting Cycle wings made noticeable aero difference, adding 14kgs downforce.

But this had odd effect on lift at the rear wheels.. Gain some.. lose more :-)

'Aero' a arms made no measurable difference, as did added onto the nose affectations.

Open passenger compartment is a big problem... no news there tho.

Again from memory.. trying to add 'Aero' to a Seven is an oxymoron, mostly ineffective.

[DRCorsa]

Hello guys, my first post here!

I found this thread very interesting. Over the last months i started a project with an Australian customer to build a custom carbon fiber rear diffuser for his car. I studied the design in CFD software, i made the moulds and here it is.

CFD results "insist" that the design is really effective with a flatfloor, even if the car is a 7-type, i.e. a brick!

The floor of his car is totally covered, so the airflow reaching the diffuser will be as laminar as possible. The diffuser now is on its way to Australia, so i will be able to pass you some of his thoughts after he tries it on the track.

Until then, i attach some pictures to see what i am talking about.

[Alaskossie]

Beautiful work! I'd love to see photos of it on the car, as well as a report on its effects.

 

Do you do custom c/f work? (I'd love to have a set of c/f wide-track clamshell front wings for my Seven....!)

 

I had a possible project going in UK, but then the custom-shop owner, known to the Seven community as RiF ("Richard in France") unexpectedly passed away, and the project died with him.

[DRCorsa]

Thanks Alaskossie!

Yes, i do custom c/f work. By clamshell you mean those traditional front wings of the of he original 7? If yes, it's like you are trying to learn your grandfather using an i-phone.. :ack:

I am just joking. I could do them but i would need a set of the original ones in GRP or aluminum, so i can reproduce the desired shape for your car.

[Alaskossie]

DRCorsa,

 

Yes, that is what I am talking about (see photo), but they would have to be made slightly wider (extended slightly further out from the body side) to account for the wide-track front suspension. I would plan to provide a pattern, with the originals in GRP.

 

I don't know if others might be interested, or not (I posted an inquiry on the Seven-club BlatChat in UK last year, but got no positive responses,....perhaps that is just too much carbon fiber...?).

 

Please contact me by e-mail off-line (tmeacham@gci.net). i have a couple of other much smaller c/f projects I am considering, and I am not set up to do any c/f work (I'd require a lot of practice first, anyway).