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Bit of Aero for those who like that sort of thing PART 3


CW Racing

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So as part of my job on the le mans team im asked my opinion on some aero bits and bobs. i also have access to some cfd software and Craig and myself have been talking about rear wings and endplates in particular.

i havnt got a model of any of the wings on our cars or a model of a celica but i have got models of out le mans car wing so i thought i would play around with that...

it is a two element wing with a mandetory gurney flap on the trailing edge.

i ran a simulation of the wing in free air flow (No car body in front) to get a pure assesment of what the wing does at an air speed of 30m/s (67mph) with out any end plates.

here are the screen shots:

Picture1

Top view of the wing with surface pressures

wing11.jpg

Picture 2

underside view with surface pressures

wing11_1.jpg

Picture 3

top view with flow lines

wing11_3.jpg

Picture 4

Underside with flowlines

wing11_2.jpg

Picture 5

section with flowlines

wing11_4.jpg

im off to make my tea but will be back later with some more on what im looking into

Edited by CW Racing
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I'm not a geek when it comes to Aero's but seeing this does get me thinking about Aero's on my Gen7.

When i was at RT-P i did mention to Ray about making a cheese wedge to sit under the posts on the rear spoiler to add some more angle to it, and in theory more surface resistance area resulting in pushing the arse end down.

I know that we dont own super cars that need Aero's to keep them on the road, but surly adding a little will aid us mere mortals when giving our babies the beans on country road corners.

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so the forces produced by this wing at 30m/s are as follows 420N of downforce to 80N of drag.... thats an L/D ratio of 5.25 (higher the number the better)

so thats 42kgs of pressure on the rear of the car

I'm not a geek when it comes to Aero's but seeing this does get me thinking about Aero's on my Gen7.

When i was at RT-P i did mention to Ray about making a cheese wedge to sit under the posts on the rear spoiler to add some more angle to it, and in theory more surface resistance area resulting in pushing the arse end down.

I know that we dont own super cars that need Aero's to keep them on the road, but surly adding a little will aid us mere mortals when giving our babies the beans on country road corners.

sketch something up and i will pass on some comments and suggestions....

there is a few more bits to point out on this first but the next simulation is currently running with the le mans end plates on to show how these aid the downforce generation

Edited by CW Racing
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Why would you wanna push down the rear of a FWD car?

P.s. Loving your job I love seeing pics of cars/F1's in wind tunnels etc if you've got any websites with loads of pics like that please let me know

Trust me at high speed in a fwd car that's stripped out the back will come round on you. I've put mine into a power slide a few times at about 80mph

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Sorry I don't have much of a grasp on aero/downforce etc. but i'm thinking the more you push the back of the car into the road, it's going to ever so slightly start lifting the front, thus reducing actual steering grip ?

or does it not work like that ?

kind of... that called aero balance but saloon cars are so biased fwd its unreal....

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So would getting a [real/tested] high rise spoiler help ? I'm already thinking of getting a Kamimari spoiler and will consider it even more if it's going to help improve aero balance

yeah it wouldnt hurt... typically with a saloon car style vehicle you have the big weight on the front to mechanically aid the front tyres grip but you have little weight on the rear so less mechanical grip. bare in mind though you only get aero effects thats noticable from about 40mph up so spoilers etc are more for show on your road car unless you make the odd excursion to the track.

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yeah it wouldnt hurt... typically with a saloon car style vehicle you have the big weight on the front to mechanically aid the front tyres grip but you have little weight on the rear so less mechanical grip. bare in mind though you only get aero effects thats noticable from about 40mph up so spoilers etc are more for show on your road car unless you make the odd excursion to the track.

Yea mainly for looks but if it actually serves a purpose, great :) I'm going to The 'Ring with the club next year so that can be my excuse :)
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Presentation1.jpg

so i have circled the ends of the wing.... you can see in these regions that the colours are different which signifies a difference in pressure. as you can see the colour is orange towards the ends on the top and there are flashes of yellow on the corresponding underside... these colours are much closer together on the colour spectrum than the extremes of red and blue... this shows that the ends of the wing is not producing as much downforce at the middle section of the wing.....

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Jamie but is that not because your running without end plates and so the air gets lost over the edges and doesn't 'push' down as it will take the easiest route. In the centre of the spoiler it doesn't really have this choice....

why yes craig that is correct.... now the art is to tailor the plates to best exploit the shape of the body infront and how when the car is in yaw how that blanks and stalls the wing

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