5cm hole in diffuser

[shelly]

Can anyone find a good picture of the 5cm wide opening in front of RedBull rb7 diffuser?

[Lindz]

I don't think it exists. Everything I've seen suggests the cut away floor is what allows the exhaust to feed the diffuser.

[Fil]

Can anyone find a good picture of the 5cm wide opening in front of RedBull rb7 diffuser?

There's 5cm each side of the diffuser that can be opened, if that's what you mean?

Horse posted this photo, which shows that cutaway, in your other thread about Slit Exhausts..

[shelly]

The problem is I do not see any hole in this picture: I just see the exhaust blowing between wheels and diffuser like on the other cars

[Lindz]

The problem is I do not see any hole in this picture: I just see the exhaust blowing between wheels and diffuser like on the other cars

The floor has what looks like ~100mm cut out per side. No other car has done this (yet).

[shelly]

Cut ou is a thing,hole is another. With the picture above, I see no difference betweeen mclaren and rbr. Maybe is the perspective of the picture? Myabe on rb7 he diffuser has no lateral fence so exhaust blow into it?

[shelly]

@lindz: sory but I see just now your first post I which you write that there's no hole but just a cutaway. Agree with you on that.
The cutway you refer to is a cut of the vertical outer fence of the diffuser?

[Lindz]

This might be an easier perspective to understand what they are doing.

It's not creating a hole, it's just creating a narrower floor in a certain place (with a unique shape to the outside edge).

The exhaust is not level or angled up like a McLaren or Ferrari, it is slightly pointed at the ground, so the exhaust flow "drops" into the gap and blows the floor/diffuser from underneath.

Here it is in a preseason test, with a different shape. The blue is the shape during the test. The red line is the shape in the picture you posted (and what they've been running in the later tests and Australian GP).







For reference, here's what a 'normal floor/diffuser would look like, a la McLaren:






Final comparison, 'normal' diffuser overlay with red cut-outs (current shape on the RB7). It's the horizontal plane of the floor that they are just changing the shape/width of. Totally legal, no shady loopholes.

[shelly]

Thank you lindz for the explaination and the picture.

If I have understood correctly the difference is the shape of the cut ou in plan view. I was somehow misleaded by an article wirtten by scarbs, which stated that both ferrari and redbull had found a loophole in the rules which allowed to cut a 5cm hole to realize a front driven ebd.


I have expressed my point of view on mclaren (and ferrari) exhaust on the mp4-26 thread; in the light of your clarification, I think now that the principle in redbull, mclaren and ferrari exhaust are all the same; redbull makes the difference by being more aggressive in the lateral cutout (and also by being the first to find the solution).

The bigger cut out could influence how exhaust enhanced vortices enter the diffuser.
It is interesting to correlate this to the fact that redbull has a full width diffuser, whereas mclaren diffuser is narrower with omega shape.

Let us see other williams and sauber version, and big teams developements

[Richard]

I was somehow misleaded by an article wirtten by scarbs, which stated that both ferrari and redbull had found a loophole in the rules which allowed to cut a 5cm hole to realize a front driven ebd.

Agreed, I've struggled to conceptualize where that hole could be.

RB do not have a hole, they have a narrow floor.

[Lindz]

I was somehow misleaded by an article wirtten by scarbs, which stated that both ferrari and redbull had found a loophole in the rules which allowed to cut a 5cm hole to realize a front driven ebd.

Agreed, I've struggled to conceptualize where that hole could be.

RB do not have a hole, they have a narrow floor.

Yeah, it seems like scarbs was a little misleading. I trust he's seen the cars in person and closer than I, so there may also be a 5cm 'vertical window' in the diffuser, but the main thing in my opinion is definitely the 'narrow floor' which allows the exhaust to blow between the floor/diffuser and the ground.

[marekk]

3.12.1 With the skid block referred to in Article 3.13 removed 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.

Not sure about this, but if this exhaust tip is made of metal (inconel, titanium ?), then due to thermal expansion it should be visible from underneath the car with engine running, against rule 3.12.1

[Lindz]

Just to make it clear... The 'normal diffuser' lines I drew are the shape of the Red Bull diffuser. All 'normal diffusers' are roughly the same shape, they expand in x and y axis. Red Bull cuts the horizontal plane and makes the width narrow on the outside flat of the floor/diffuser.

As for the exhaust tip... No way. What's the expansion amount? Easy to make sure it's safely above the floor. Easy.

[shelly]

[quote="Lindz"]Just to make it clear... The 'normal diffuser' lines I drew are the shape of the Red Bull diffuser. All 'normal diffusers' are roughly the same shape, they expand in x and y axis. Red Bull cuts the horizontal plane and makes the width narrow on the outside flat of the floor/diffuser.
[quote]

Agree with you that are more or less he same shape, but in a picture of rbr an mc form behind I noticed that seen from behind, mclaen diffuser is narrower (with two footplates on both sides), while rbr is full 100cm width.

So I found it intersting that rbr having bigger cutouts ended with a bigger final section.

Do you agree on that?

[Just_a_fan]

3.12.1 With the skid block referred to in Article 3.13 removed 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.

Not sure about this, but if this exhaust tip is made of metal (inconel, titanium ?), then due to thermal expansion it should be visible from underneath the car with engine running, against rule 3.12.1

Early in testing RB did have a cover of some sort that extended over the exhaust exit and part of the cut out floor. This certainly would have been illegal but presumably was used as a way of deflecting other teams from the real solution.