No seventh gear in Canada?

[vyselegend]

I have just read Kimi's description of a full lap at Gilles Villeneuve track, and I'm surprised to see that he never engage the seventh gear:

http://www.f1technical.net/news/3313

Even the braking point of the "droit du casino", before the last chicane, is reached in six gear:

Having reached speeds of 299km/h in fifth gear, you brake hard for the 180-degrees right hander, which swings you round onto the Droit du Casino. Accelerating along the main straight, you reach 334km/h in sixth gear as you approach the hardest braking point on the track.

I don't think it's a mistake of spelling because he say twice that he reach 299 km/h in fifth, so it's credible to go 334 km/h in six.

I found it surprising because I believed more gears allows better acceleration and so greater top speed at the end of a given distance. And top speed seems to be the pinnacle here in terms of set up. So what's the point mapping the car on only six of seven gears? Anyone?

[FLC]

The Canada tech-file that was posted on the news section here kind of hinted about this:

Gearbox: We will pay particular attention to gear ratios and the selection of seventh gear at this circuit. Not only do we have to take into account the effects of slipstreaming down the long straights, but also the wind direction, which can have a significant positive or negative impact on speeds down the back straight in particular.

[RH1300S]

I don't think it's a mistake of spelling because he say twice that he reach 299 km/h in fifth, so it's credible to go 334 km/h in six

The steps between the gears get smaller at higher speeds to keep the engine in a range where it can pull the next gear, so we can't think of the gear steps like a road car. 1st gear will probably run to a pretty high road speed and the other gears are spaced (unevenly) between that and flat out.

I found it surprising because I believed more gears allows better acceleration and so greater top speed at the end of a given distance. And top speed seems to be the pinnacle here in terms of set up. So what's the point mapping the car on only six of seven gears? Anyone?

I believe teams sometimes leave gears out to save rotating weight, which would give better accleration - but only if the track does not demand a range of gears needing the full seven. This has certainly been done in the past - I have no idea if it is current practise.

[Spencifer_Murphy]

Maybe they will run a 7th gear for use when slipstreaming down the back straight?

I've heard they use the highest gear for that purpose only in the IRL.

[vyselegend]

Thanks for the answears guys.

FLC, thank you I didn't notice this news but it doesn't explain very much on the reasons to avoid use seventh gear.

RH, yes I'm aware the gap between gears should be smaller at high speeds, as air resistance is exponential, but the 35 km/h gap between fifth and sixth seems reasonable to me.

I believe teams sometimes leave gears out to save rotating weight, which would give better accleration -

Yes as far as I know there is a drop of power while switching gears (appart maybe on the williams seamless which makes it negligeable?), so it may be an explaination, but I remember someone of the Renault staff saying the fact the V8 produce less torque than the V10 forced the team to use seven gears, otherwise it would force some of the gears to start in a too low reving range.

Maybe they will run a 7th gear for use when slipstreaming down the back straight?

That's very interesting. It would explain why they don't mention it while describing a "typical" lap. I like this idea of an "overtaking gear".

[Crabbia]

Yes as far as I know there is a drop of power while switching gears (appart maybe on the williams seamless which makes it negligeable?), so it may be an explaination, but I remember someone of the Renault staff saying the fact the V8 produce less torque than the V10 forced the team to use seven gears, otherwise it would force some of the gears to start in a too low reving range.

vyselegend, i think RH1300s was refering to the fact that they take the gears out so that power is not wasted by the engine in turning that cog. since F1 engines have no flywheel no need for a fly wheel this it is by no means benefitial to have a gear that is not used on the cog.

The V8s producing less torque than the V10s will most definitely be a factor for the desition to drop he last gear ratio and msybe last year some of the top teams would run one but i highly doubt they'd run one now.

as far as overtaking gears go i think that works only in indy cause they run on oval tracks somethimes, like the indy500, so they can get in close and use the slipstream effect and when they do they can engage the slipstream gear. In F1 i'm pretty sure a slipstream gear wouldnt be all that helpful since the straights aren't long enough.

[Ciro Pabón]

I am as surprised as vyselegend. Why develop a seven gears gearbox if you only use six? Only for Monza? It does not make sense to me. Gears are rutinely changed through the weekend because they subject them to the utmost stress and they are carefully balanced and simulated before the race. They made enormous investments to achieve a seven gear gearbox.

There is another advantage with a seven gear gearbox as opposed to a six gear one: you do not have to make the gears as strong, as the damage is dispersed over a greater number of gears. You can check they have pretty accurate models to predict the root/flank damage and they calculate the minimum material they can. For example: http://www.kisssoft.ch/doku/kisssys/app ... earbox.pdf

Then I read the "lap description" by Kimi and was even more confused (my natural state, I guess). I read it at two different sources (the one you gave and at http://www.planet-f1.com/News/Story_Pag ... 48,00.html). This is what it says:

"Full on the throttle on the exit as you power along the Place de la Concorde, achieving speeds of up to 298km/h in seventh gear, before dropping back through the gears for the right-left sequence of turns eight and nine."

So vyslegend is wrong. He uses seventh at the surprising speed of 298 km/h, surprising because as you point out, he talks of 334 km/h in sixth just a couple of paragraphs later.

I guess the guy that wrote the transcript made a couple of mistakes or Kimi did not gave him the correct speeds or he is trying to follow my advice: if you cannot convince them, confuse them.

I hardly believe what I see, much less what I read... until you get a new theory.

[vyselegend]

Hey that's right Ciro! He actually mention seventh gear, I totally missed it, strangely because after all that's what I was searching for. I guess I need glasses...
Anyway we share the same point of view: this is very confusing! How explain to switch to seventh at 298km/h when you reach 299km/h in fifth and 334km/h in six?...
Probably the article is full of mistake, but the doubt remain if the sole mistake was he confused seventh with fifth in the text you quoted, which seems to be the more logical explaination, as he twice mention this kind of speed in fifth.
Now I assume we need a serious quote from another source to untangle this.

[Ciro Pabón]

Well, there is and "old" saying in IT: "All data is shallow when is looked by many eyes". This is the wonderful thing of this forum. God knows I've been corrected many times...

But the point you make stands: the description gives a totally confusing relationship between gears and speeds. Maybe we know now why Kimi is not winning any races...

Everybody talks about the higher revs you can get, but I really do not know how low you can (or should) go with an F1 engine (I remember the time Nigel Mansell stalled because he was waving to the crowd in the last lap and he let the revs go too low). The problem here (for me) is that I've googled many times for a power/torque vs rpm curve of an F1 engine without success. If we had this kind of information, we could calculate the "minimum" speed at any gear. After all, there is a pretty straight relationship between speed and revs.

Can anyone help here? With data, I hope. I remember that here in this forum somebody talked about having a program to obtain rpms from engine sound and that he have used it to deduce rpm from the TV audio track... maybe you have time to search for this thread and we could ask "the guy" himself.

The link I gave to calculate damage to the gearbox says that the figures in it are misleading because of confidentiality issues. But if I interpret it correctly, the green curve is the "speed" (maybe rpm? maybe rotational speed of gear?), from 1 to 0.8.

This could mean from 19.000 to 0.8*19.000 = 16.200 rpm. If the max speed is 340 kmh (reasonable, Monza is the fastest circuit at 350 kmh, you mention 334 in sixth), then the minimum speed in seventh gear should be around 0.8 * 340 = 272 kmh. This could mean Kimi's lap transcription is right. This is the image:



The torque (blue curve in this figure) is abismally low in seventh (purple curve, seventh "step"): I interpret it to be between 0.5 and 0.8 the maximum torque (reached in third, with a curious value of ¿1.2 times the maximum? )

[mini696]

Wasnt it Kimi last year complaining that the McLaren was reaching its top speed when drafting and therefore couldnt make full use of his speed?

[vyselegend]

After reading the description of a lap at Monza by Pedro de la Rosa, I couldn't resist to bring back this topic. (which should be renamed "No seventh gear on high speed tracks?")

I am as surprised as vyselegend. Why develop a seven gears gearbox if you only use six? Only for Monza?

"Starting a lap of Monza, you power up through the gears along the wide Rettifilio Tribune straight reaching the top speed of all the circuits on the calendar, 360km/h in sixth gear. The right-left Rettifilio Chicane is located at the end of the straight and sees your speed drop as you brake dramatically to 124km/h in second.

As you exit, you immediately reach the Curva Grande. This long, bumpy right-hander is taken flat out and your speed increases to some 280km/h in fourth before arriving to the Variante dello Roggia. You brake from some 345km/h in sixth to 100km/h to negotiate the left-right chicane, which has a tricky entry as it is very bumpy and slippery. Another short straight follows and takes you to the double apex right hander of Curva di Lesmos. You enter the first turn at 164km/h in third.

A quick burst of acceleration sees your speed increase up to 266km/h before you then brake for the second apex, which is negotiated at 158km/h also in third. It is important to maintain a good speed through Lesmos, as it takes you onto a long straight, which has a slight left curve. You reach 342km/h in sixth as you blast towards the Curva del Vialone.

Another hard braking zone takes your speed down to 148km/h in second to negotiate the left hander, the entry of the famous Ascari chicane, which is immediately followed by a right-hander leading into the next left hand corner. This is quite an exciting section of corners, which then flicks you onto the back straight, achieving speeds of 347km/h in sixth gear as you approach the famous Parabolica. The tight entrance to this long sweeping right hander is taken at some 162km/h and as the curve opens out your speed increases and you are swung back onto the start-finish straight to begin another lap. "

LOL! You see Ciro, seventh gear wasn't even made for Monza. I begin to doubt if Mc Laren ever used it...