Red Bull RB22

[vorticism]

- @vorticism, didn't understand your previous post explaining that the diffuser isn't monotonically expanding, that it does some shrinking before finally expanding, evidenced by the mouse-hole pic in your post. I was unable to 'see' the evidence, does this pic show the same evidence in any way ?

I just updated the post: viewtopic.php?p=1329269#p1329269

[AR3-GP]

The low outboard ceilings of their diffuser looks to be due to a dipped, wing-like or venturi-like section i.e. their diffuser is not constantly expanding--it expands, contracts, then re-expands. The fence acts as a divider between the central section and these outer sections. Approximation:

I think the slot re-energizes the flow but at the expense of increasing the local static pressure. So they run a 2nd kickline behind the slot inlet to reduce the pressure again. It would be like a 2 stage diffuser. It's analogous to a multi-element wing.

Other theory is this outboard section of the diffuser is designed to defend against the tire wake that tends to "squirt" inwards.

[venkyhere]

- @vorticism, didn't understand your previous post explaining that the diffuser isn't monotonically expanding, that it does some shrinking before finally expanding, evidenced by the mouse-hole pic in your post. I was unable to 'see' the evidence, does this pic show the same evidence in any way ?

I just updated the post: viewtopic.php?p=1329269#p1329269

Unfortunately, unable to see the image (neither embedded in the forum page, nor when I try to open the link separately, tried both MS edge and Chrome browsers, on computer and phone).
Looks like @AR3-GP is able to. If anyone else is facing the same problem, please let me know.

Edit : able to see now, the alternate link on X page. Brilliant drawing, @vorticism, you have X-ray eyes.

[venkyhere]

The low outboard ceilings of their diffuser looks to be due to a dipped, wing-like or venturi-like section i.e. their diffuser is not constantly expanding--it expands, contracts, then re-expands. The fence acts as a divider between the central section and these outer sections. Approximation:

https://i.postimg.cc/Wbt2ncK2/rb22diffu ... cism1.jpg

I think the slot re-energizes the flow but at the expense of increasing the local static pressure. So they run a 2nd kickline behind the slot inlet to reduce the pressure again. It would be like a 2 stage diffuser. It's analogous to a multi-element wing.

Other theory is this outboard section of the diffuser is designed to defend against the tire wake that tends to "squirt" inwards.

In other words (trying to dumb down to my level), your guess is :
theory 1 - local pressurization by inviting outside air into the kickdown-y edge, either to discourage early separation (long length of diffuser) underneath
OR
theory 2 - to act as curtain/blocker to keep tyre squirt at bay.

Btw, I remember pics of the McL40 diffuser (I think in car thread) and it looked 'too vanilla' (even the keel) - probably their mastery of underfloor aero allows them to get away with no mousehole and not-too-complex contours.

[vorticism]

Thx, altho x-ray only to the extent I'm correct. It does seem to correlate to other views we have.

https://x.com/xavigazquez/status/202482 ... 96435?s=20

[mzso]

Pierre Waché on the 2026 challenge:

“The overall concept of the car isn’t locked. We won’t be able to change everything, but we can modify a lot. That’s the key: it’s not about having a good car now, but being able to improve it.”

Newey said almost the same. However AM is in a horrible state

[organic]

The low outboard ceilings of their diffuser looks to be due to a dipped, wing-like or venturi-like section i.e. their diffuser is not constantly expanding--it expands, contracts, then re-expands. The fence acts as a divider between the central section and these outer sections. Approximation:

https://i.postimg.cc/Wbt2ncK2/rb22diffu ... cism1.jpg

I think the slot re-energizes the flow but at the expense of increasing the local static pressure. So they run a 2nd kickline behind the slot inlet to reduce the pressure again. It would be like a 2 stage diffuser. It's analogous to a multi-element wing.

Other theory is this outboard section of the diffuser is designed to defend against the tire wake that tends to "squirt" inwards.

Both can be true. Every aerodynamic feature is a series of trade-offs

This view may also be useful

[Brahmal]

It looks to me like the back edge of the mousehole, and the diffuser sidewall, is inboard of the front edge. Would that not bleed air out from the underfloor instead of bringing it in?

[AR3-GP]

It looks to me like the back edge of the mousehole, and the diffuser sidewall, is inboard of the front edge. Would that not bleed air out from the underfloor instead of bringing it in?

Air will flow from regions of higher pressure to low (physics). So there will be an in-rush of air into the diffuser even if the edges are not aligned in an intuitive sense.

[Just_a_fan]

It looks to me like the back edge of the mousehole, and the diffuser sidewall, is inboard of the front edge. Would that not bleed air out from the underfloor instead of bringing it in?

Air will flow from regions of higher pressure to low (physics). So there will be an in-rush of air into the diffuser even if the edges are not aligned in an intuitive sense.

You are making an assumption as to which way the pressure gradient goes at that point. It's possible that this acts to extract air from the diffuser, perhaps aided by the stack of winglets immediately behind this region. Also, if the flow along the diffuser sidewall is relatively slow (and a diffuser's job is to slow the air down, after all, so the flow will be slowing down whilst the outside flow might locally be faster), it's possible that the pressure is lower on the outside at this location.

A decent flow viz image would be helpful if anyone has found one.

[vorticism]

Left to right: spec multi element wing -- "Winglet" -- diffuser & rabbit hole -- fence

The rabbit hole upper periphery extends quite far back, probably to the RS-Sidewall limit, and, as mentioned, looks to be taller than the belly of the outer diffuser ceiling.

[venkyhere]

I went back and looked at this pic (Bahrain test1 I think) posted by @AR3-GP in the car comparison thread :
https://postimg.cc/wyYPgFc0

What @vorticism has pointed out (about the non-monotonical vertical expansion of the lateral rear-ends of the diffuser) is starkly visible on the RB22 when viewed simultaneously in contrast to the other three teams.

Other observations from this pic :
- SF26 and RB22 seem to have the narrowest keel towards the rear
- SF26 is not very keen on lateral expansion (we know why, now that we have seen the diffuser extension and the macarena rear wing) since they are concentrating on a 'shooting-up-in-the-middle' type diffuser exit
- McL40 has a gentle laterally reducing diffuser roof height, probably why they don't feel the need for a mouse-hole
- RB22 diffuser is almost like one central diffuser flanked by two other diffusers

[venkyhere]

https://i.postimg.cc/5NkT1G9r/image.png

Is this really an undercut, probably need a front-on image to confirm, but from this, it just looks like a more sculpted version of the same 'teardrop' thing

The undercut is in the front. The rear doesn't have an undercut.

can we really call what's in the front as 'undercut' ? It seems like this is a shrink-wrapped version of what we saw in Bahrain test1. The more I look at the countours, the more it resembles what we used to see pre-2022 - 'typical tight packed sidepods'.

[AR3-GP]

The pressure sensor is more complex than at first glance. It also looks like 3d-metal print.

[euv2]

Interesting post, suggesting that Max had rocket practice launch.

VER made one crazy-quick launch: just 4.36s to 200km/h! He launched from the pit lane, revving to 11000rpm for some time, then dropped to 5000rpm and was slighshot forwards

Max was definitely not pushing on the final practice start, are they trying to hide something? We already know this was a focus for RBPT.