Feeding the Diffuser

[SiLo]

I think you're half right there, but the whole slipstream thing is wrong. We want them to run closer becasue it is SO much easier to overtake when you are right behind a car for a whole lap, rather than ONE opportunity into ONE corner. Just because you a greater speed difference doesnt mean much on medium to short straights, but the most important thing is breaking. If you can run on the gearbox of a car for a whole lap, you have the braking point of every corner to overtake, but if you have to drop a second behind until the straight, the opportunities are going to be hugely decreased.

You will see this affect at low downforce tracks, especially Monza, where there is lots of overtaking because the cars can run closer. Then you look at Hungary, could Vettel overtake Alonso? No. Even though his car was almost a second quicker a lap. If he was able to run closer to him throughout the lap, I'm sure he would of put a passing move on him by running one up the inside. But that's just my opinion

[SiLo]

Also, the higer distance between the cars creating a larger slipstream is great, but when you're in the corners this also takes affect, meaning you have to drop even further back. This is why the diffuser is great, becausee it doesnt create much drag.

[mep]

Sounds like you got a few things wrong.

Also, the higher distance between the cars creating a larger slipstream is great

It doesn't create higher slipstream you can use it longer before you crash into the leader.

You will see this affect at low downforce tracks, especially Monza, where there is lots of overtaking because the cars can run closer. Then you look at Hungary, could Vettel overtake Alonso? No. Even though his car was almost a second quicker a lap. If he was able to run closer to him throughout the lap, I'm sure he would of put a passing move on him by running one up the inside.

Vettel was able to run very close to Alonso. Much closer than on the video I posted. Just watch it. Vettel was a second quicker because he was faster during corners.
Close running alone doesn’t help anything. For overtaking you need a speed overrun.
Vettel could not overtake because Ferrari had higher speed on the straights. Not necessary higher top speed they just gain their speed quicker or at least equally fast. A slipstream effect for Vettel was almost not there. I can just say it again watch carefully the video. Both cars had same speed otherwise they would not overtake several times each other. The leader simply has no chance to protect. And this straight in Hungary is a very short one.

but the most important thing is breaking.

The cars have all more or less the same braking abilities. There is nothing to gain. Only to lose when you have to brake on the dirt. Braking definitely doesn’t help on overtaking. Cars need to be side to side first to even think about a working overtaking manoeuvre.

[Dragonfly]

I think another problem of current cars is the rev limit. Even being in the slip stream and getting tow does not allow a sufficient speed difference, because the limiter kicks in. This was the case even with KERS working. the only gain being better acceleration. It seems nowadays everyone is optimizing the gear ratios in a similar manner and there's hardly a 100 rev more in reserve.

I don't understand why after FIA finally came to the more reasonable approach of a fixed number of engines per season instead of the very strict one engine per X races rule, all limitations from before still remain. Teams need more freedom. With a fixed number of engines they cannot afford to run constant high revs, but if there's no limit, or the limit is higher (but costs engine life and reliability), teams could risk spending a bit of engine resources for short bursts above the optimal in cases where overtaking/defending is crucial for the final result. Let them plan their approach, let them take their own risks and compete.
That actually is what racing is about.

I guess it's a bit OT for the thread but the last posts are more about overtaking and the factors which affect it.

[SiLo]

Vettel was able to run very close to Alonso. Much closer than on the video I posted. Just watch it. Vettel was a second quicker because he was faster during corners.

Exactly, he was a second quicker because he had a lot more downforce. If they had the same downforce would he have been as close? No.

The whole drag/slipstream thing is still a very valid point however, but it doesn't detract from the fact that less downforce from wings and more from the diffuser would keep the speeds the same, but the racing would be closer. Yes the slipstream effect would be decreased but you would have a chance to overtake at every corner. It's simple maths, 19 corners to overtake or 1. To have a chance to overtake into all corners currently you would have to be 20-25 percent better on the brakes, which is never going to happen. When you only have to gain 3-4 metres from it, it suddenly becomes much easier. Does that make sense?

[wesley123]

look at the renault, wich got such underbody tunnels to grab air. If it was disallowed renault woudnt have it. The Renault also uses it as side protection.

Hi Wesley,
Do you have a pic or link to this?
I would be interested to have a look.
Thanks

It isnt the clearest pic but at least it is a pic

[747heavy]

Thanks for the photo wesley.
Sorry I don´t really see what you mean/want to say on this photo.
But maybe I just understand you wrong.
In regards to "tunnels" under the car, here is what the FIA rules say:

3.12 Bodywork facing the ground :
3.12.1 All sprung parts of the car situated from 330mm behind the front wheel centre line to the rear wheel centre
line, and which are visible from underneath, must form surfaces which lie on one of two parallel planes, the
reference plane or the step plane. This does not apply to any parts of rear view mirrors which are visible,
provided each of these areas does not exceed 12000mm² when projected to a horizontal plane above the
car, or to any parts of the panels referred to in Article 15.4.7.
The step plane must be 50mm above the reference plane.

So, I´m not sure what Renault is doing there, maybe they have found a clever way to do something, but I can´t really see anything on this photo - Sorry

[wesley123]

well, it isnt taken as extreme as on the underbody you posted.

If you look at the underside of the sidepod intake you see the front wich is really fat(it is partially covered by the barge boards), this part holds the lower side structure but it is also raised 5cm(which is allowed due to the step plane rule). I hope you can imagine it a bit on the pic.
Now this 5cm step plane rule, you can only outlaw the DDD by simply removing the step plane rule, thus the floor is forced to be flat, else you can still make holes in the floor for the upper deck(see the mclaren floor, wich has upward vanes wich are 5 cm high but viewed from the underside you cannot see anything above this, if the step plane isnt removed next year such design will be possible)

[747heavy]

Thanks Wesley,

does it go along the lines of this?




still the floor looks quite "flat"

[wesley123]

from the left on your 2 pics i ws talking about the 2nd arrow, it is hard to view yes but imo the floor was raised there 5cm high(step plane) and they cant go higher

[wesley123]

Well as we were talking about the step plane rule it made me think, the reference plane is iic an flat plane which is parallel to its ground surface. We all know the F1 cars are ran under rake, but iic the flat floor(with this rake) is max. 5cm higher then the front. Thus with my idea you could effectively raise the start of the floor biy 10 cm, as then it would be laying(based on how you have designed the floor) below that 5 cm.

[747heavy]

Hi Wesley,
I´m not sure if the reference plane needs to be parallel to the ground.
If you ran rake, your reference plane moves with the car, but all dimensions are
in relation to the reference plane, and must remain at all times. AFAIK

[Just_a_fan]

THe reference plane is always 'part' of the car. i.e. if you stand the car vertically on it rear wing, the reference plane moves with the car to be 'vertical'. This is because the car is defined by reference to the plane and not the ground.

[wesley123]

yes excuse me, it was one of my unthought idea's.

[SiLo]

Do you mean, having the whole floor at an angle? So that when the rake of the car is setup, the floor is actually parallel to the ground instead of diagonally raising at the rear?