Aerotest for FD3S

[Rixio]

http://autospeed.drive.com.au/cms/A_1080/article.html

Rixio:wave

[Bulla]

Makes for some interesting reading, good find Rixio :Thumbsup!

[Rixio]

I didnt find it just saw it in a thread today :p

[RemarkLima]

Well, off with the rear spoiler then ;)

[M@r]{]

I like this bit:

"but what about the fitting of the rear spoiler? Well, according to the Mazda data, it made zero difference to rear lift! Yep, zero. "

I was worried about the increased lift after removing my rear spoiler

[stylus350]

So the Mazda data has been verified as actually bieng from Mazda then? Might well be, certainly is presented convincingly, but there is a LOT of repeated bull on the net. I'd be tempted to check before making a potentially dangerous mod (albeit unlikely) a sticky.

[Rixio]

Taking the rear spoiler off is in no way more dangerous than adding a big GT wing! I know plenty of FD's that run bald and have done for years without any problems.

Its valuable info about the aerodynamics of the FD, thats why i made it a sticky. Whether or not you take notice of it and use any info, is up to you at the end of the day...same goes for anything else on the site

[jetpilot]

After reading this the other day i was having some thoughts on their findings! Now i am no aero expert, far from it, and obviously doing the "woolly test" is a very visable thing that most can relate too! However, i did notice they had no wool on the spoiler, i would imagine, and i am happy to shot down in flames for this, the spoiler is (or at least some aftermarket larger ones) completly seperate to the car, what i am trying to say is, it would most likely be to high off the bootlid to affect airflow over the actual vehicle. But surely the surface area of whatever spolier will have an effect. i.e downforce which is what they are designed to do! Irrespective of the airflow over the car. So briefly to say, a spolier (bladed, gt wing, mazdaspeed etc) with the air passing over that, will push the car down without affecting airflow over the car???? Particulary from i am let to belive that aerodynamics do not really start playing a part till quite a lot faster than the "woolly test" here?

[probedb]

If you watch the vid in the C-West link I posted they have the wool (or whatever it is) on the spoiler as well.

[jetpilot]

What link where?

[marco]

If you look at the pics, they do have wool on the spoiler, but from the angle the pics are taken, you cant see very much! As for having a wing high up and out of the way, then yes it will minimise the disruption to the airflow over the car. What effect the wing/spoiler will have to the car depends on an number of factors but a test speed of 50mph is fast enough to show effects. just sticking something into a moving flow will have an effect, what effect that will be and by howmuch is a different matter!

what is more interesting is the fact that the offical mazda data show that the inclusion of the spoiler on the back did nothing to the lift co-efficent. as such it is safe to assume that the stock wing doesnot provide downforce. What it may do is neaten up the airflow off the rear of the car, thus minimising presure drag (if you look at the wooly tuft picutre of the rear of the car you can see that the tufts above the numberplate are hanging loose). however the drag co-efficent for the R2 model shows an increase in drag. What isnt stated is if this drag is due to the front lip, the spoiler, the front lip and the spoiler, or if the spoiler is infact helping reduce the drag from the rear, to offset the drag caused by the lip. So we dont know. my gut feeling would be that the front lip increases drag (increasing the frontal area and is low down to the ground) whilst the rear spoiler does little to nothing in neatening up the flow, and is probably aesthetic.

obviously Stylus's caveat of this being believable data holds!

as jet pilot said, flame away, its been a while since i looked at aero stuff, and could do with an excuse to get my head back in the text books!

[probedb]

What link where?

Bugger sorry it was in another thread....

http://www.c-westusa.com/labs/fudo1.asp

[Ricco_04]

Rear downforce I wouldn't worry about too much - mazda designed the 99Spec splitter because there wasn't enough front downforce. Just read it in one of me books :)

[marco]

A book about a car I love and aerodynamics? whats it called?

[RemarkLima]

Well I'd almost 100% say that the standard rear spoiler is there entirely for styling purposes.

A classic example is a TVR they found handled perfectly with 15" wheels, except the marketing bods wouldn't let it sell with tiny wheels so they had to stick 17"'s on just for the style.

And the same with my old S1 Exige, apparently it made 10KG of downforce at 100 mph, it's not a lot for how fast that is, given that it had a big sticking up wing, big splitter and a totally flat undertray all underneath!

So to make some downforce in a RX I think you'd either need one of the GT wing efforts or to go VERY, VERY fast ;)

[Ricco_04]

A book about a car I love and aerodynamics? whats it called?

Honestly mate I can't remember - it might have been something I read on the net. It had all the figures and compared to several other cars too, it was quite in depth with figures for all sort's of areas including all the different rear wing's and the 2 general front splitters - there are not that many car's that are more slippery than the FD.

I'll rack my tiny brain to see if I can remember where it was I read it.....

[rextreme]

If they do it with a monster aero kit fd with canards hanging off it everywhere. Maybe that would be better.

translate this. then compare the figures to the standard car.

http://www.autoexe.co.jp/car/RX-7(FD)/RX-7mainpage/index.html

this test also measures different things. like reductions in Lift and Drag in each direction.

http://www.c-west.co.jp/labs/fudo_rx7.html

interesting to note, that a well set up car isn't really that much slower, its just that a car with aero is easier to drive and gives more feeling.

But then again it is 2 seconds a lap... haha.

[J.j.]

what about a 99 spec spoiler? forgot where i read it from but it was developed in a wind tunnel?

[RotorHeid]

Hayne book called" Competition car DOWNFORCE" by Simon McBeath
good basic reading!!
My Thinking:-
Think Shark with close mouth=smooth=fast!
Think Basking shark with mouth open=drag=slow!

[rextreme]

99 wing.
Thats the test reference in the autoexe comparison.

[J.j.]

Specifications CD CLf CLr
FD-02 (WING LOW) 0.373 0.066 0.008
FD-02 (WING MID) 0.380 0.078 -0.047
FD-02 (WING HIGH) 0.389 0.092 -0.103
* Mass production FD (6 types WING LOW this corporation survey value) 0.351 0.101 0.001

Is it possible that someone can tell us how much down force(in kgs) are we talking about here??