Ferrari F138

[TheGkbrk]

Guys can someone explain me simply and shortly what "diffuser stalling" is?

[shelly]

You have diffuser stall when for some reason (attiutude of the car mainly) the flow dose not follow the surface of the diffuser any more and so the downforce produced is lower

[TheGkbrk]

Oh, thanks for the answer. So you guys saying Ferrari suffers from a stalling diffuser and therefore losing downforce. Could a stalling diffuser effect traction of a car?

[timbo]

Oh, thanks for the answer. So you guys saying Ferrari suffers from a stalling diffuser and therefore losing downforce. Could a stalling diffuser effect traction of a car?

Maybe, although stall is less likely to happen during acceleration out of the corners (where traction matters) due to the attitude of the car (raised nose = more flow, lowered rear = shallower diffuser angle and lower effective cross section).
Stall is likely to happen during braking (lower nose = less flow, higher rear = steeper angle and high cross section) or, possibly, in the yaw condition.

I think the problem might be not actually an outright stall, but some disturbances in vortex structure in yaw, so maybe just one side of the diffuser suffers.

[froggy]

Is it just me or have i seen RBR and McLaren running measuring devices along the rear of the diffuser during testing, i'm assuming to check diffuser opperation and flow. But i dont recall Ferrari running any similar device?

[timbo]

Not sure if such rig can help. The car is not bad, so it is not a big problem which would be easy to spot, unless they can operate the rig during a proper fast lap which I doubt.

[Kolin68]

https://plus.google.com/photos/yourphot ... 6548681810

[ringo]

As for diffuser stall happening, here is proof from Aero_A, who is F1 Aerodynamicist

http://imageshack.us/a/img593/2519/nzue.jpg

Read from bottom to top on this image
http://s18.postimg.org/vj7zod12x/aero_A1.jpg

Problems in Silverstone and then "on the fly" diffuser modifications in Germany show they were having problems with the diffuser. Was it stall? I can't say for sure obviously but it's not unheard of and confirmed by current F1 Aero Engineer.

Hmm i wouldn't use those guys as any strong support for this discussion. They're speculators.
I was expecting academia. Everything in f1 can be found in an academic paper. I don't like to use journos opinions as facts. As there is no way they will know if a difuser is stalling. What are they gonna do, take pictures behind their journo barriers to see it? lol
I can open a twitter account and call myself an NASA rocket scientist. I wont quickly jump on that band wagon.
We've seen in the past when cars have flipped instantaneously when the body raises off the ground or pitches excessively. That's a stalling floor. A stall is where there device is unloaded, the flow is disturbed completely.
There are localized regions of separation under a diffuser, this is the case with most things aero, and then there is a certain deviation in performance from optimum, but complete stall?
I don't see where that happens in a corner. As i said the car must be outside of its range, and no engineer is going to make something inadequate.
An inadequate diffuser will stall in the same corner every single lap. As long as you are repeating the conditions of stall it will do so. It's just not likely such a diffuser will be on any f1 car. especially with the design restrictions on diffuser height in the regulations. These regs were designed to prevent such things. I think the max height is 125mm. Any engineer making a diffuser that stalls in a corner may be an idiot or a genius, as that's very difficult to do and yet the ferrari board approves it. haha.
Stalling diffuser is not a good thing to use as a reason for some perceived under performance. The DRS talk probably got use carried away and we started stalling and flexing all kinda parts of the car.

But lets look into it anyway. For the diffuser to stall, maybe it has to be at a reduced speed from optimum. It's gonna be harder to stall when the energy is higher so lower speed regime is where you would look. So you can expect it at low speeds. Second thing to look at is the angle relative to the flow. This is almost impossible to change as the flow will always be parallel to the floor upstream.the floor will have to be out of ground effect range and the flow will have to be detached to have some change in angle with the throat and proflie. Also the throat to lenght to angle ratio will change once the floor starts coming up.
A next consideration is the cuts in the sides where the exhausts flow in. Something to look at, but it actually makes the floor harder to stall. it will vary performance yes, but stalling, i'm not sure sure.
Fourth thing is the turning vanes under the diffusers, we haven't seen Ferrari desperately changing these things. And you would naturally put more under the car if there were diffuser problems.
So before accepting the theories, i'd look at these aspects and do some background research on diffuser experiments.

[Hail22]

Seems like someone is building a 1:8 resin F138 Barcelona GP spec car...the amount of detail blew me away.

What do you guys think in regards to the technical parts / modelling the builder has created compared to the F138 from the Barcelona GP?

[youtube]http://www.youtube.com/watch?v=0G_Li7vAlbU[/youtube]

[Kiril Varbanov]

Seems like someone is building a 1:8 resin F138 Barcelona GP spec car...the amount of detail blew me away.

What do you guys think in regards to the technical parts / modelling the builder has created compared to the F138 from the Barcelona GP?

The floor needs one more curve in the outer side edge between tires - I couldn't see it in the video - may be there. The same goes for the three vertical strakes ahead of the diffuser's trailing edge. The V-shaped slits in the rear wing look a tiny bit more smoother than the one used in Spain in terms of angle, but the bargeboard work is amazing, so is the exhausts, gills and front wing.

Update: Piola offers 3D view on the latest novelties regarding F138 - http://www.auto-motor-und-sport.de/vide ... 50472.html

[diffuser]

Really, where did you read that ? I'm struggling to get any kind of good info from Ferrari.

I clicked -1 by mistake, but there's no need of sarcasm.
Diffuser would usually stall at high kick angles - something regulated by rules, or at high speeds and high ride heights.
Shelly was merely expressing an opinion and it's a fact that there have been diffuser modifications. The rear wing also looked like it was producing more downforce than usual compared to Red Bull, for example, for a track like Silverstone.

I wasn't being sarcastic. I was really hoping someone would point me to a website or something I hadn't found/seen.

[stefan_]

Young Drivers Test 2013 Day 1 (Silverstone) - 17.07.2013

Davide Rigon behind the steering wheel.

via Sky Sports F1

[Forza]

[stefan_]

Young Drivers Test 2013 Day 1 (Silverstone) - 17.07.2013

[radosav]

Young Drivers Test 2013 Day 1 (Silverstone) - 17.07.2013

http://i215.photobucket.com/albums/cc17 ... 168df5.jpg
http://i215.photobucket.com/albums/cc17 ... 9806fb.jpg
http://i215.photobucket.com/albums/cc17 ... 14d4f1.jpg
http://i215.photobucket.com/albums/cc17 ... f1659d.jpg
http://i215.photobucket.com/albums/cc17 ... 2631ab.jpg

i can't see your photos