Mercedes AMG F1 W07

[henry]

Well, Senna @ Tamburello?

Apples and oranges. Beyond that...

http://i.imgur.com/9T8iSOt.jpg
via Willem Toet

I take it we are supposed to follow the 20° 75-5 line and observe that at about 35mm ride height there is a very significant drop in underbody downforce.

I think this graph refers to a flat bodied vehicle and not one with a 60mm step. The floor on the step plane will be above the critical ride height.

In the image the ride height of the floor will be >60mm on the right and from 60mm at the plank to maybe 40mm at the edge on the right. It seems likely that there will be some drop in downforce from the floor but I doubt it is large and it will be shed with a COP near the COG for a relatively neutral effect on balance.

I think this is why we have a step in the regs. To mitigate against violent changes in downforce when cars bottom.

[timbo]

The apples and oranges comparison is the comparison to Senna's crash, because he lost control (at 305kph) while rotating his car through the apex of a corner; my statement was explicitly limited to corner exit, i.e. after most rotation has already occurred. (And if Rosberg's adventure took place at Degner, his pace was likely slower by some 45kph.)

That's becoming a truer than true Scottsman competition of sorts. From the position of from tyres it is clear that he didn't straighten the car yet, far from it.

If you ever come up with a design for a passive motorsport diffuser that can withstand a sharp reduction of dynamic pressure while maintaining suction at the same time, don't tell anyone about it until you've managed to secure a patent, and please invite me to Stockholm for your Nobel Prize ceremony. I'm pretty sure you will have discovered the ingredients necessary to achieve perpetual motion.

And again it is a question of the degree of the airflow reduction. It is not clear what the pitch attitude of the car is. It might be that actually diffuser doesn't have to work as hard as it seems.

Here's another reason why the photo is a depiction of unintended consequences...

I don't disagree that the picture reflects some unintended situation (or some extreme transient condition within normal operating range), I just find it unlikely that "near-complete loss of underbody downforce" occured in that particular episode.
FWIW cars are set up in a way to avoid such situations.

[bhall II]

FWIW cars are set up in a way to avoid such situations.

Except when they're not. For example...

At Monza, ride heights have to be set low enough to promote some stall in the diffuser at high speed while maintaining grip at around 130mph as the car pitches, yaws and rolls through the tricky second part of the Ascari chicane. As the DRS is activated on the straight, the stall invoked in the rear wing has to promote a more generalised stall through the beam wing and diffuser and, in so doing, shed the speed-sapping drag that is an inescapable feature of downforce.

What Symonds refers to as a stall is probably better understood as reducing the diffuser's downforce coefficient.

Anyone notice how Ferrari's tire tester is equipped with side skirts along the flanks of the floor but not along the edges of the diffuser? There's a reason for it.



So, if we know that literally sealing the diffuser can be problematic, what should we expect if the ride height of a diffuser's footplate is drastically reduced and the ride heights of its inner strakes and VGs are completely eliminated? What role is greatly reduced dynamic pressure likely to play given angles that would ordinarily offer feast or famine as a function of ride height?



(Incidentally, if Rosberg's front wheels aren't indicative of a car that's mere nanoseconds away from being driven straight ahead, then what does it really mean to drive straight ahead? I need to know, because I don't know that I can deal with yet another existential crisis. )

In my view, what we can see in the photo is an anomaly that likely represents a very bad moment for the floor. However, since racing is always relative, I think any net penalty is easily forgettable, because the difference between acing that corner and completely screwing it up is all but negligible as long as nothing gets broken.

[timbo]

FWIW cars are set up in a way to avoid such situations.

Except when they're not. For example...

Now my turn to call apples and oranges. We're talking cornering.

Anyone notice how Ferrari's tire tester is equipped with side skirts along the flanks of the floor but not along the edges of the diffuser? There's a reason for it.

http://i.imgur.com/HVhhP5W.jpg

There might be reasons for it. And not all might be aerodynamic. Actually, the floor before the rear wheels is simply wider than the inner side of the tyre. But yeah, the interaction of the flow along the diffuser with significant lateral component with a skirt might be tricky.

So, if we know that literally sealing the diffuser can be problematic, what should we expect if the ride height of a diffuser's footplate is drastically reduced and the ride heights of its inner strakes and VGs are completely eliminated? What role is greatly reduced dynamic pressure likely to play given angles that would ordinarily offer feast or famine as a function of ride height?

Can you map these angles? If you can you can sell them to RBR or Ferrari. Just don't use third party copy services.

(Incidentally, if Rosberg's front wheels aren't indicative of a car that's mere nanoseconds away from being driven straight ahead, then what does it really mean to drive straight ahead? I need to know, because I don't know that I can deal with yet another existential crisis. )

In my book, both his front wheels AND his position on track (where's the outside kerb? especially if he's @ Degner) are indicative of a car which is still a long way from driving straight. Being past the apex does not mean you're not pulling lateral G's that normal car NEVER could reach.

In my view, what we can see in the photo is an anomaly that likely represents a very bad moment for the floor.

I agree that it might be anomaly, but not necessarily that bad. This is something the car could deal with because we know a) nothing was apparently broken (no reports) b) there were no major "moments".

However, since racing is always relative, I think any net penalty is easily forgettable, because the difference between acing that corner and completely screwing it up is all but negligible as long as nothing gets broken.

My point that completely screwing a corner (result from total loss of underbody DF) would mean an excursion to gravel at the very least.

Here's picture from the onboard of Rosberg's pole lap, he's just past the apex at Degner.
Note the steering wheel and especially sparks from the outside endplate of the FW.

[bhall II]

My point that completely screwing a corner (result from total loss of underbody DF) would mean an excursion to gravel at the very least.

Your point ignores the difference between "complete" and "near-complete," "transient" and "permanent," as well as the influence of downforce from the wings and the grip from four tires, not to mention the skill of drivers who can recover from worse.

You seem to be under the impression that I've made a bold statement that posits catastrophe when what I've really offered, in concrete terms, are reasons why the event depicted is far from ideal in response to a conversation that at the time was lauding the event as indicative of something deliberate and/or positive. It's not.

This is why I said I would have probably framed my comment differently if I had known it was going to be controversial. Otherwise, here's the essence of my point of view: events of this type are often unavoidable, frequently benign, and never welcomed (for the reasons I've enumerated).

The rest is academic, and I don't particularly feel a need to address it. (Not saying you're right or wrong; I'm just pulling the eject handle! )

[PlatinumZealot]

A second photo taken a fraction of a second later is needed. If there was a large transient drop in downforce the car would bounce upwards (as far as the dampers allow it) soon after that shot was taken. There was evidently ample downforce acting judging by the ride height on the "unloaded" side of the car, but what happens after? Anyway... whatever happens, this is as Mercedes allows, and it was a part of the fastest setup.

[godlameroso]

Well that's the trick right, creating a condition with the chassis where unpredictable stalling is diminished? There's plenty of examples in nature, and how animals deal with these problems. If team A loses 60% downforce through Degner 1, and Mercedes only loses 40% downforce, but carries a slight drag penalty would it be worth it? Especially when you have a clear advantage in the power unit?

[timbo]

Anyway... whatever happens, this is as Mercedes allows, and it was a part of the fastest setup.

My point as well.

[basti313]

Well that's the trick right, creating a condition with the chassis where unpredictable stalling is diminished? There's plenty of examples in nature, and how animals deal with these problems. If team A loses 60% downforce through Degner 1, and Mercedes only loses 40% downforce, but carries a slight drag penalty would it be worth it? Especially when you have a clear advantage in the power unit?

I do not see any relevance of this short stalling. The tire is pressed into the tarmac as pressed can be. That is all that counts. No idea what the last page is about.

[FW17]

What is the difference in clutch settings between a race start and getting away after a pit stop?

Merc drivers have had issues on the start line but none in the pitbox. Why is this?

[hollus]

How would you know if they were having problems also after pit stops? There is no one to compare to, the launch includes zig-zagging and they go into the limiter very quickly.
But pobably it is a bit easier if only because nothing has time to cool down in the 3 seconds they are stopped. It is much longer in the first row of the grid.

[Morteza]

Austin - Thursday

[Facts Only]

This car is just a complete work of art, the detailing is incredible. The last and best of the breed and a machine that will be remembered as one of the greatest racing machines ever made.

Sorry to gush but everytime I see detailed pictures like that I am blown away.

[f1316]

Don't know if any is watching FP1 on Sky f1 in the UK, but Di Resta making a specific point of how soft the Mercedes is, and the slow mo was quote reminiscent of the picture (minus the sparks).

[f1316]

Don't know if any is watching FP1 on Sky f1 in the UK, but Di Resta making a specific point of how soft the Mercedes is, and the slow mo was quote reminiscent of the picture (minus the sparks).

Seems like the photo very much *is* a representation of what Mercedes intend to happen through a corner of this type:

http://www.motorsport.com/f1/news/analy ... ng-841343/