996 Spoiler and aerodynamics

[barry_j]

I've got a question which was prompted by the "996 Spoiler and the plod" thread.

On a slower twisty circuit, F1 cars have more wing but on a faster straighter circuit, F1 cars have less wing.

So why do Porsche wings come up when you go faster and go down when you go slower?

[chilled]

Because wings only generate downforce when there's enough airflow over them. 70mph is generally held to be the start of effectiveness for aerodynamics. So you don't need the wing up to keep the rear planted below 70mph.

[ballcock]

It's not a wing it's a spoiler .. It kills lift , rather than generating downforce , and lift only happens at speed (with a chunk of airflow over the curve of the car) so that's why the spoiler pops at speed.

[DucatiGary]

I got a really light front end today, felt a little disheartening to say the least, only happened once, at about 1:30pm *cough cough* but tried again at the same pace and it didn’t do it. . . . . after trying and trying, obviously for educational purposes, to see if there was a prob with my car officer.

Felt like the front end just went away from me, went all slippy, im used to road conditions changing the way a vehicle feels from the ducati, on that it felt really od sometimes after 1:45pm *cough cough* if it was windy, felt like you had lost complete grip from the ground . . . . . . . . but only if it was windy.

I really did poop today though it was the first time the front end had gone like this, mabe it has something to do with my pop up spoiler being in the garage? And not on the car?

[kiko]

Nop, it was a wind gust.

[jonny996]

stupid question, but is the spolier for stability, or for engine cooling.

[ballcock]

jonny996 said:

stupid question, but is the spolier for stability, or for engine cooling.

The slats are for cooling, the spoilers there to kill the rear lift...

Yes??

[C2DTG]

ballcock said:

jonny996 said:

stupid question, but is the spolier for stability, or for engine cooling.

The slats are for cooling, the spoilers there to kill the rear lift...

Yes??

Yes indeedy. If you read the user guide there is a typically understated germanic reference to not tampering with the spoiler as it can create "unstable rear axle lift"

I am sure we have all experianced that to some degree. you know the feeling, enter a bend too fast, the apex is tight, the car goes light at the rear end and your own arse starts feeling like it wants to suck the seat up inside you