Most pec...bizarre aerodynamics thread.

[AR3-GP]

The beam wing on the '94 Williams. Not 100% bizzare, but interesting nonetheless.

[Just_a_fan]

The beam wing on the '94 Williams. Not 100% bizzare, but interesting nonetheless.

https://storage.googleapis.com/the-race ... _HiRes.jpg

Interestingly, the B194 of that same year also had that style of beam wing, albeit to a lesser extend. The B195 did too, although to a greater extent that the B194.

Presumably they were trying to link the main rear wing to the diffuser and as the diffuser was very much in two distinct forms, they drooped the wing to try to cover both aspects.

[Farnborough]

The Anhedral rear beam wing, neatly converted/inverted by Damon there to Dihedral

Notice the rear suspension all arranged in space between driveshaft downwards for airflow on that car. It's more or less the opposite on current AN design, also sharing pushrod actuation in both design.

On the inverted one, notice also the shear volume of airflow between the inner face of rear tyre and a very small diffuser on that car. This seems a big interest area in AN concept and keeps repeating, appears to be substantial benefit but everyone mostly looks at diffuser internal and size.

Extending that lineage to FW14B (running at Silverstone) the rear engine cover/deck width leading to beam wing also present on RB19 car.

[Just_a_fan]

On the inverted one, notice also the shear volume of airflow between the inner face of rear tyre and a very small diffuser on that car. This seems a big interest area in AN concept and keeps repeating, appears to be substantial benefit but everyone mostly looks at diffuser internal and size.

Remember that the FW16 ran on its belly - they were still flat bottomed cars then so there was very little scope for tyre squirt to affect the diffuser, and the exhausts blowing in to the innermost of the small channels probably made any tyre squirt effects pretty negligible anyway.

[Stu]

Notice the rear suspension all arranged in space between driveshaft downwards for airflow on that car. It's more or less the opposite on current AN design, also sharing pushrod actuation in both design.

That is an interesting point, I seem to remember that after that (for ‘95, I think) they went the other way and the lower suspension arm was inline with the drive-shaft. There was an admission by someone senior that mechanically/kinematically it was sub-optimal, but aerodynamically advantageous.

[Just_a_fan]

Notice the rear suspension all arranged in space between driveshaft downwards for airflow on that car. It's more or less the opposite on current AN design, also sharing pushrod actuation in both design.

There wasn't any benefit in having a current style "high mounted" rear suspension - the diffuser height didn't require it. But making the top wishbone in line with the driveshaft meant the flow to the beam wing was good.





Airflow over the diffuser was obviously treated differently - there's a very noticeable Gurney flap on the trailing edge upper surface just behind the lower wishbone.

[Just_a_fan]

Compare the Williams diffuser to the McLaren MP4/1C - only 9 years earlier.

[Farnborough]

Notice the rear suspension all arranged in space between driveshaft downwards for airflow on that car. It's more or less the opposite on current AN design, also sharing pushrod actuation in both design.

That is an interesting point, I seem to remember that after that (for ‘95, I think) they went the other way and the lower suspension arm was inline with the drive-shaft. There was an admission by someone senior that mechanically/kinematically it was sub-optimal, but aerodynamically advantageous.

Right from season start they seemed to struggle with it, and did appear to have a rather flexible range in controlling wheel camber during maximum lateral load peaks.

[Farnborough]

Notice the rear suspension all arranged in space between driveshaft downwards for airflow on that car. It's more or less the opposite on current AN design, also sharing pushrod actuation in both design.

There wasn't any benefit in having a current style "high mounted" rear suspension - the diffuser height didn't require it. But making the top wishbone in line with the driveshaft meant the flow to the beam wing was good.

https://i.ibb.co/kx5SkyZ/image-2023-07-17-214114108.png

https://i.ibb.co/0sLYqLY/image-2023-07-17-214602598.png

Airflow over the diffuser was obviously treated differently - there's a very noticeable Gurney flap on the trailing edge upper surface just behind the lower wishbone.

All very interesting pictures with some good detail there.

The "constant" I'm assembling with these AN design is (with flat floor then and now much larger diffuser plus full feed channels) the air feed outside the diffuser walls that clearly exists on all of them.
The exhaust blown, over top of floor RB of vettel era, also in same vein in that the target was this just inside wheel area. And now with 18/19 RB the direction of that sidepod undercut seems to major on that location.
I know the floor channels and diffuser are doing the grunt work of generating downforce, but the part this external flow plays in keeping that flowing appears fundamental to it's rounded performance. Ultimately it seems to give "unconditional" support to help the true diffuser reach and hold peak performance.

[Stu]

Agreed.
It seems that the ‘classic’ technique of using the beam-wing to ‘boost’ the floor has been partially turned on its head (I think that the Williams was one of the first to run with this with the anhedral beam wing - I think that it originated around the late eighties with March (Newey) & McLaren (Barnard) with the ‘Coke Bottle’)
Using the over-floor flow (and encouraging it) boosts the effectiveness of the beam wing, which amplifies the effect of the beam wing on the under-floor.
The massive rule change in ‘94 (post-Imola) which literally saw a hacksaw taken to the diffuser hit that efficiency hard.
I think that what we have seen over the last two years is one team trying to push the idea so hard that it cannot work, because the airflow has been inadequately managed creating high, but unstable, downforce, where another team has focused on managing the airflow.

[Vanja #66]

Compare the Williams diffuser to the McLaren MP4/1C - only 9 years earlier.

https://i.ibb.co/k3vBk3n/image-2023-07-17-215629691.png

Lovely to see these details. I suspect a much larger diffuser was needed since they didn't introduce the side walls, let alone strakes inside the diffuser itself.

[Just_a_fan]

Compare the Williams diffuser to the McLaren MP4/1C - only 9 years earlier.

https://i.ibb.co/k3vBk3n/image-2023-07-17-215629691.png

Lovely to see these details. I suspect a much larger diffuser was needed since they didn't introduce the side walls, let alone strakes inside the diffuser itself.

It's a massive, and massively crude, device, isn't it?

Interesting to see the development of this area in the McLaren.

The next car, the MP4/2C had blown diffuser with a small side strake but still mostly open (and a huge gearbox lump).


The MP4/4 still had a blown diffuser but this time the gearbox intrusion was much less and the blown diffuser section was fully walled by a strake and the gearbox enclosure. Still had a large open-sided region by the tyre, however.



I would guess that the open-sided section actually helped to lift the tyre squirt and thus helped to reduce air movement under the diffuser strakes.

I do find it amusing how "crude" these cars look to modern eyes, but also am amazed at how effective they were with the tools they had available to them at the time.

It would be brilliant to see someone remake the MP4/4, for example, but with modern aero refinements and materials/techniques - I wonder how much time they could find compared to the original.

[Vanja #66]

It's a massive, and massively crude, device, isn't it?

Interesting to see the development of this area in the McLaren.

The next car, the MP4/2C had blown diffuser with a small side strake but still mostly open (and a huge gearbox lump).
https://i.ibb.co/Vjpz70z/image-2023-07-18-090052848.png

The MP4/4 still had a blown diffuser but this time the gearbox intrusion was much less and the blown diffuser section was fully walled by a strake and the gearbox enclosure. Still had a large open-sided region by the tyre, however.

https://i.ibb.co/xCrLPHc/image-2023-07-18-090236544.png

I would guess that the open-sided section actually helped to lift the tyre squirt and thus helped to reduce air movement under the diffuser strakes.

I do find it amusing how "crude" these cars look to modern eyes, but also am amazed at how effective they were with the tools they had available to them at the time.

It would be brilliant to see someone remake the MP4/4, for example, but with modern aero refinements and materials/techniques - I wonder how much time they could find compared to the original.

Yeah, those are some wonderful details there. I really like that period, a lot of hands-on engineering, on-track testing, trying to understand the car through feeling rather than hard data - since you can't really get the hard aero data like you can now.

MP4/4 was a beast, with that rule set I'm not sure if there was a lot of room for improvement with the technology available at the time. I don't know what kind of geometry was allowed for wings and diffuser by the rules, but if curved aerofoils were allowed there would be a lot of performance available with modern aero design approach. And that's just the aero bit

[Andi76]

Notice the rear suspension all arranged in space between driveshaft downwards for airflow on that car. It's more or less the opposite on current AN design, also sharing pushrod actuation in both design.

There wasn't any benefit in having a current style "high mounted" rear suspension - the diffuser height didn't require it. But making the top wishbone in line with the driveshaft meant the flow to the beam wing was good.

https://i.ibb.co/kx5SkyZ/image-2023-07-17-214114108.png

https://i.ibb.co/0sLYqLY/image-2023-07-17-214602598.png

Airflow over the diffuser was obviously treated differently - there's a very noticeable Gurney flap on the trailing edge upper surface just behind the lower wishbone.

This type of diffuser was called an "undercut diffuser". Williams introduced it in Portugal in 1995, as far as I remember correctly. It had a larger extraction volume because it exploited a gray area in the regulations, and it was the reason for Williams' big downforce advantage in 1995, 1996, and 1997. It was also the first diffuser where the lower triangular wishbone didn't run through the diffuser and side channels. The other teams, like Ferrari, McLaren and Benetton discovered the real "secret" of this diffuser only during the 1997 season. It was a great time in which Ferrari in particular was the absolute leader in this area at the beginning of the 2000s, using more and more vortices and achieving ever greater angles of attack of the diffuser.

[mclaren111]

https://www.youtube.com/shorts/NRGdOKeTyE8


Old but still interesting...