24 replies to this topic

[dav115]

maverick69 wrote on Sat, 31 October 2009 16:03

Pole lap:

http://news.bbc.co.u...one/8335643.stm


Smug

I've always wondered why Hamilton seems to "group" his downshifts more than others(i.e. ~52 secs in that vid he goes "BRAKE.downdowndown..downdown...down"

then at ~1:09 "BRAKE..downdown..downdown.down")

As opposed to someone like Raikkonen who seems to do evenly spaced downshifts ( at ~14 secs he does "BRAKE...down.down.down.down..down)

Maybe there are other people that do this too, but I just seem to notice it much more watching Hamilton. I wonder if this has any effect on the car under braking?

Taken from http://forum.planet-...amp;#msg_num_26

[zac510]

I noticed this too, but it's the first time I've noticed it this season so maybe it's part of a new KERS 'harvesting' strategy. I haven't heard any other drivers doing it.

[cozmocha]

It might be something with the McLaren gearbox or car.



Kovalainen does it a little at some points.

[Powersteer]

Senna use to brake really hard, holding the clutch, dropping more than a gear and before turn in then the clutch is engaged. Probably to get less engine braking interference at maximum brake.

[Ross Stonefeld]

Rossi does that on bikes (the Senna example). I don't know if that's standard practice on two wheels, but Rossi does seem to have a clutch-cam more often than not.

Perhaps it's just timing? I know when I've done driving simulators that use paddle shifters, a 7 speed gearbox felt easier mentally if I did ..6,5...4,3... or sometimes 6,5,4...3,2 if it was a big stop. Maybe something to do with a natural human rythmn? Granted you'll always take the lower gears a little later since you're braking efficiency at that speed is reduced and you don't want to overrev or lock the rears.

[gordmac]

Does the driver totally control when the gearchange happens or does the software? Perhaps the driver just works the paddle and the software changes the gear at the appropriate point to prevent say over revving the engine.

[Ross Stonefeld]

That'd be a clever way to do it, but I don't think it's allowed. I think they have to be fully done by the driver/paddle, not just to confirm. Otherwise you'd program it to only downshift under certain conditions and the driver could just hold the left paddle down for the duration of the braking zone as a sort of pre-confirm, and get perfect downshifts everytime.

I mean, that's not allowed, is it?

[KWSN - DSM]

I find this very interesting.

Are we not seeing / observing how a better driver on occasion is better in the small aspects of racing, does the invoking of the clutch / not invoking clutch give one of the reasons that some drivers are better?

Rossi is arguably the best driver ever on 2 wheels, Senne belong in the all time greats on 4, and Hamilton is doubtless a super talent, who can very likely end in the group of best ever when his career have been a little longer, and he has continued to deliver (as I expect he will)

I like the post by Ross, as he has had access to simulators, which most of us have not. My extremely limited time in formula cars, was a week of Skip Barber on Lime Rock, and then a F2000 in Canada, and I in the heavy braking corners, would bypass the middle gears and get the gear I wanted out of the corner, rather than cycling through the gears.

Good observation finding this.

[OfficeLinebacker]

That'd be a clever way to do it, but I don't think it's allowed. I think they have to be fully done by the driver/paddle, not just to confirm. Otherwise you'd program it to only downshift under certain conditions and the driver could just hold the left paddle down for the duration of the braking zone as a sort of pre-confirm, and get perfect downshifts everytime.

I mean, that's not allowed, is it?

I read somewhere that at one point there was a system whereby the driver simply flicks the paddle a bunch of times and the software filters out flicks that are too close together or whatnot.

So I think that the driver still has to flick the paddle at least as many times as downshifts he wants to do, just the software takes care of the timing.

[alexbiker]

I noticed a couple of other people doing it - the Formula 1 website has its new videos of flying laps, one for each circuit, and lots of people seemed to group their downshifts. Can't think of a reason.

[Ijsman]

Good thread, I noticed this too, I think last year already. It sounds very annoying when someone shifts back really fast. Maybe OL is right about why it is this way, but doesn't everybody have thesame software in their car now? Maybe it's just preference.

[OfficeLinebacker]

Good thread, I noticed this too, I think last year already. It sounds very annoying when someone shifts back really fast. Maybe OL is right about why it is this way, but doesn't everybody have thesame software in their car now? Maybe it's just preference.

Same base software on the ECU but they can still do custom programming. I think shift maps are like fuel maps, fully customizable.

[jatwarks]

I don't suppose the drivers just find it easier to count shifts in groups of 2 or 3?

With everything else going on into a corner, and the rate of change required, the drivers wouldn't want to flick one too many or too few!

And if the software can even out the timings anyway, why not.

[King Six]

Well seeing as there's no engine braking or anything like that, it doesn't really matter that much how you shift down as long as you're in the right gear when it's needed. Maybe it's just how they drive. Interesting though, I never noticed this until now. Personally I could see myself shifting down more like Kimi's style than Hamilton.

But then you also have to factor in other things. Like he has to turn the steering wheel and contend with G forces etc.. so it's probably movements like that which "disturb" his downshifts so he doesn't do it all in one "smooth" manner. And it all really doesn't matter that much because there's no engine braking anyway. Maybe it has something to do with his KERS too.

This may seem like a stupid question, but I thought I'd throw it in here. I never fully understood why sometimes the wheels lock during braking, and sometimes they don't. Bar the obvious things like brake failure or track conditions, what's going on? It can't be that the driver is braking too hard (and there's no ABS) because the little telemetry thing they show always shows them as more or less braking hard into corners. Maybe it has something to do with doing the wrong thing braking under steering or something. You can probably bet that it has to do with steering when only a certain tyre locks up.

Edited by King Six, 02 November 2009 - 14:01.

[Tenmantaylor]

On the grouping downshifts I could believe Jatwarks explanation but just as likely is that hes doing it to limit the time spent doing downshifting and/or avoid a bump in the braking zone or even that the KERS harvesting benefits from this technique in some way.

This may seem like a stupid question, but I thought I'd throw it in here. I never fully understood why sometimes the wheels lock during braking, and sometimes they don't. Bar the obvious things like brake failure or track conditions, what's going on? It can't be that the driver is braking too hard (and there's no ABS) because the little telemetry thing they show always shows them as more or less braking hard into corners. Maybe it has something to do with doing the wrong thing braking under steering or something. You can probably bet that it has to do with steering when only a certain tyre locks up.

First of all I believe the telemetry on screen of an F1 broadcast shows the throttle as an analogue readout and the braking as digital (on/off). I don't believe the drivers brake digitally, maybe they don't want their braking habits known to the other drivers? At least it was this way last time i consciously checked.

Lock ups in general are all to do with available grip. To brake hard you have to have high grip. Its imperative for quick times to be using as much braking force as possible and be as close to the limit of adhesion as possible when braking and sometimes this fine line is breached. At top speed with full down force acting through the tyres it would be very difficult to lock the wheels. At low speed with lower down force it isnt hence why its more common into slow corners.

When an inside front tyre locks up it usually because it is unloaded. This can happen in a number of situations but most commonly because the weight has transferred to the outer front wheel. Can be pronounced when there is alot of camber change in the road like turn 1 at Interlagos. The less weight pressing down into the tyre the smaller the braking force required to make it lock. Without ABS or adaptable braking distribution systems the same force is applied to each wheel therefore when there is a descrepancy in available grip you get a lock wheel. There are loads of variables in the car too. A very stiff front suspension combined with a very soft rear suspension would make this more common and vice versa.

Edited by Tenmantaylor, 02 November 2009 - 14:22.

[Ross Stonefeld]

I think the brake indictator just records pressure, not displacement, as the brake pedal doesn't move in any meaningful sense. So it is either 'on' or 'off' in the graphical sense. You could plot a value between minimum and maximum pressure, but as there isn't really a maximum pressure (at least in human terms) it'd be hard to demonstrate. I think most viewers are more interested in how late they are braking, whereas people like us would be more interested to see where they are coming off them and how.


This is an interesting thread, first I've heard that an F1 car doesn't have engine braking.

[King Six]

Cheers for that tenman, makes sense.

I think the brake indictator just records pressure, not displacement, as the brake pedal doesn't move in any meaningful sense. So it is either 'on' or 'off' in the graphical sense. You could plot a value between minimum and maximum pressure, but as there isn't really a maximum pressure (at least in human terms) it'd be hard to demonstrate. I think most viewers are more interested in how late they are braking, whereas people like us would be more interested to see where they are coming off them and how.


This is an interesting thread, first I've heard that an F1 car doesn't have engine braking.

It's a relatively new introduction

A major talking point for the new season surrounds the arrival of the Standardised Electronic Control Unit, or SECU, and with it the elimination of driver aids such as traction control and engine braking systems.

http://www.formula1....008/2/7393.html

Also an interesting article all-round which I never found out about until now

The new regulations have also removed the engine braking systems (EBS) that used to moderate the locking of the rear wheels, and give greater stability, under heavy braking. It is the loss of this system, rather than the loss of traction control, that Piquet believes has the greatest impact.

“The biggest difference you notice with the 2008 cars is not the loss of traction control, but the absence of engine braking control because the car is much more unstable, especially on used tyres,” says Nelson. “When you look at the telemetry, the brake pressure is now much less compared to last year. With EBS you could brake much harder; if you did that without the electronics, you will simply lock up your wheels.”

Edited by King Six, 02 November 2009 - 14:43.

[Ross Stonefeld]

That's not classic engine braking though, that's a system that provided a crude abs to the rear wheels. Something you could still do with a little bit of throttle, but would be hard on the mechanicals and piss away your fuel.

[Tenmantaylor]

EBS should not be confused with engine braking itself. Engine braking cannot be removed, it is what happens when you stop squirting fuel into the engine EBS was the control of the torque between the left and right rear wheels in a similar vein to ABS being distributed between the wheels before that was banned.

Surely the drivers can still control the overall level of engine braking as a standard setting? That is the amount of throttle automatically applied when a driver lifts (coasts) to stop the rears locking up.

[Tony Matthews]

Without ABS or adaptable braking distribution systems the same force is applied to each wheel therefore when there is a descrepancy in available grip you get a lock wheel.

Although split front to rear.

[OO7]

Perhaps its a method of modulating/reducing the engine braking effect. He may have initially changed down the first few gears very quickly leading to a higher RPM than his preference. He then delays the next down/set of downshifts until the RPM it in a suitable/comfortable band. It difficult to know without comparing to previous laps.

Edited by Obi Offiah, 02 November 2009 - 19:45.

[J. Edlund]

Well seeing as there's no engine braking or anything like that, it doesn't really matter that much how you shift down as long as you're in the right gear when it's needed. Maybe it's just how they drive. Interesting though, I never noticed this until now. Personally I could see myself shifting down more like Kimi's style than Hamilton.

But then you also have to factor in other things. Like he has to turn the steering wheel and contend with G forces etc.. so it's probably movements like that which "disturb" his downshifts so he doesn't do it all in one "smooth" manner. And it all really doesn't matter that much because there's no engine braking anyway. Maybe it has something to do with his KERS too.

This may seem like a stupid question, but I thought I'd throw it in here. I never fully understood why sometimes the wheels lock during braking, and sometimes they don't. Bar the obvious things like brake failure or track conditions, what's going on? It can't be that the driver is braking too hard (and there's no ABS) because the little telemetry thing they show always shows them as more or less braking hard into corners. Maybe it has something to do with doing the wrong thing braking under steering or something. You can probably bet that it has to do with steering when only a certain tyre locks up.

There is engine braking, with the McLaren there is also the brake effect on the rear wheels from the KERS system. Engine braking setting can usually be controlled by a knob on the steering wheel, don't know about the KERS though.

Automatic downshifting was used in F1 for a while but was banned, but with that system the driver didn't need to downshift at all from what I understand, the electronics handled it all. Don't know if delayed gearshifts are allowed today, with such a system the downshifts could be delayed until certain conditions are met. That would explain the downshifts.

The wheels lock up when the driver brakes harder than the traction allows. Usually it's the inner front wheel that locks up due to the weight transfer to the outer front wheel.

The brake system has two circuits, one for the front wheels and one for the rears. The driver can control the brake balance between these circuits for more braking by the front or rear wheels. As the downforce decrease with decreased speed, so does the traction. This means that the braking force also must decrease with speed to avoid lock up. During the braking the weight distribution will also change. Usually there is some sort of passive mechanical system in the brake system designed to help the driver with this.

[OfficeLinebacker]

This may seem like a stupid question, but I thought I'd throw it in here. I never fully understood why sometimes the wheels lock during braking, and sometimes they don't. Bar the obvious things like brake failure or track conditions, what's going on? It can't be that the driver is braking too hard (and there's no ABS) because the little telemetry thing they show always shows them as more or less braking hard into corners. Maybe it has something to do with doing the wrong thing braking under steering or something. You can probably bet that it has to do with steering when only a certain tyre locks up.

Well the drivers trail brake and it's very difficult to calibrate perfectly with changing conditions. Even only one lap later the tyres might be a few degrees different in temperature, the brakes might be a few tens of degrees different in temperature, the track surface is slightly different because about 18 other cars have navigated that corner on the line since the last time through, and of course the car is a few kilos' worth of fuel lighter.

Add that all together and the drivers' preference...some tend to err to the side of staying under the limit of traction, others like Hamilton tend to err more towards finding and exceeding that limit.

As the old saying goes, in order to drive at or right under the limit one must first find it.

[Powersteer]

Senna use to brake really hard, holding the clutch, dropping more than a gear and before turn in then the clutch is engaged. Probably to get less engine braking interference at maximum brake.

Sorry but I don't know if Senna actually holds the clutch or heel and toe at the end of braking but he does let the brake do its business first.

[saudoso]

Shifts must obey directly the lever input. Control systems are only allowed to 'not shift' if the input would spin the engine above red line. The driver then needs to shift again, the control system won't run a previously commanded shift once the engine gets into the proper RPM band.