The compromise of fuelling an F1 car.

[PlatinumZealot]

the estimate of 2.6kg/lap is reasonable - IMHO, I would probably say it´s a bit higher under full dry conditions. ~160kg/52 laps = ~3kg/lap, it´s a quick and dirty calc, but as an order of magnitude I would say it´s reasonable.

the 0.3 sec/kg seems way too high IMHO, it´s closer to 0.3sec/10kg or 0.03sec/kg.
You find this value mentioned in the McLaren paper I posted and it was mentioned often during the KERS debate in 2009.
Again, it´s just an estimate, it´s not set in stone, and will depend on the track. On a track with many acceleration/braking sections (Monaco etc.) it will be higher then on a flowing track with higher, more constant average speed.

Sorry, but I don´t think that they underfueld him by just 1kg, if this is the case,
then Button would have had the same problem.
Due to his pitstop mishap, we will never know.
I would say (but that´s just my opinion) they where ~10kg short of fuel.

there you go ...so it´s 3tenths of car speed won at the xpense of having to cruise for 20 laps.
counting it up that would amount to 9 seconds less elapsed time till they had to
ask him to nurse the engine...there are better ways to find 9 seconds in race elapsed time-for example a fresh set of soft tyres or an excellent pit call on changeable conditions.
In effect that´s only shifting the car potential from the end of the race bringing it a bit forward.

I think you have put the cart before the horse, marcush. Remember... the strategy did not work... They miscalculated. Putting in 10kg less fuel had made the car not faster but slower over the race distance as evidently seen... An extreme exaggeration is like putting in 30kg (ala 2009) to run the whole race...it just aint gonna happen. So, it was not a strategy but a miscalculation on the conditions of the race and occurrence of a safety car.

[marcush.]

I don´t think it is possible to actually miscalculate fuelloads in this environment.There is enough running to see the fuel consumption and when the engineer is comung up with 10 litres less in the meeting he is certainly challenged why this is sufficient.So the pro and cons are discussed and the people involved agree a certain number for certain conditions.
What is of course possible is a mixup or them running out of time to fill her up ..but still..if you are trying to save some kilos reflecting lower fuel consumption in wet conditions again you missed the boat....as it was not as wet as they had hoped for...
Turn it around as you want.it´s a dog of an idea to fill up the car with a fuel load marginal to make it to the finish at full speed ,especially when your driver is Lewis Hamilton...
again you have NO control of safety car laps ,restarts ,traffic ,no traffic ..you make assumptions based on historic facts and experience but those are not numbers you can calculate on .So it is very simple :calculate the consumption for no slipstream, fighting for position (defending) for the whole race,end of story.

[SiLo]

I can't see how they were going to be betting on a safety car when there wasn't any more rain forecast and the track has ample run off areas everywhere. They should fill it up so they can drive every lap at 100% because that's how it should be raced. Just imagine if Hamilton was behind say, Alonso, but Alonso was in fuel saving mode and so was Hamilton, in all honesty, nothing will change. Yet if Hamilton wasn't and Alonso was, maybe it would. It makes a huge difference at the end of the race, less so at the beginning, and obviously it is at the end when the race is won. It's like Brundle always says "The race isn't won in the first corner", might as well say "The race isn't won in the first 20 laps".

[747heavy]

........................ not the rigth place - sorry

[Richard]

They should fill it up so they can drive every lap at 100% because that's how it should be raced.

That would need a bigger fuel tank and possibly more cooling. So the car would be heavier and bigger. That would give RB's skinny little machine an even bigger advantage.

[marcush.]

[
there you go ...so it´s 3tenths of car speed won at the xpense of having to cruise for 20 laps.
counting it up that would amount to 9 seconds less elapsed time till they had to
ask him to nurse the engine...there are better ways to find 9 seconds in race elapsed time-for example a fresh set of soft tyres or an excellent pit call on changeable conditions.
In effect that´s only shifting the car potential from the end of the race bringing it a bit forward.

Only if your "gamble" does not pay off.
If you get it right, you have 0.3 sec a lap and less stress on your tires for the whole race, not just the beginning.

Because, if you get the safety car/or more rain, the car with a "conversative" strategy/calculation (un flat out from start to finish), would finish the race with 10kg unused fuel in the tank.

Sure, their is risk involved, as with any assumption you have to make along the way, but hey it´s racing after all.
It´s not much different then to put your car on slicks in changeable conditons. Sure, you can allways wait a bit, and let somebody else to it first, to be "safe(r)", but if it works and he stays on the track, he can gain an advantage over you. God loves a "tryer" after all.
Hindsight is a wonderful thing.

747 h ..I really love to be the decision guy at the pitwall and believe me I had some really cool moments making bold calls when others still looked up in the sky and in their laptops not finding answers when a decision is all that is needed -NOW-
And I fully agree: God loves the ones who try with passion....

I will never forget the pregrid in Anderstorp with water flooding the area and I was changing my driver on slicks .....I asked a lot from him for the first 2 or three laps till it really was dry but the fun started only in the last two laps when it started to rain again but all the guys had their Wets already toasted and we came home almost winning ..

What I wanted to point out is the undeniable fact that this low fuel thing is a very marginal decision and you depend on a lot of things going your ways and more funny not everything going your ways!!!



They did not expect to be in this competitive situation till the end ..same as Rosberg back then ... the speed was a fluke and not real.Hamilton was p10 in Q3- an unused set of softs would have been worth a lot more as would have been a early stop...? I had the impression Schumacher who was forced on slicks by the incident was showing it was very well possible to switch to slicks in lap nine when Hamilton waited till lap 12..

[sAx]

Or perhaps they hoped for wetter conditions (hence slower speeds).

They did admit that Button had 1kg more fuel. How much is that worth? 1 lap?

At an average of about 2.6kg per lap. that's about a third of a lap.

Hamilton had to start saving fuel from lap 31. More than likely Button would start saving fuel around the same time or a little later, Maybe lap 32.

Something's off – you cite 2.6Kg per lap, someone in the MP4-26 thread cited 0.3 seconds per Kg, that implies a speedup of nearly a second a lap – doesn't sound doable. Which figure is out?

That earlier tosh came from me, which I acknowledged following and agreed the 10kg 0.3s/lap. The average consumption historically for an F1 car is around 6mpg, so 3kg/3-mile lap sounds about correct and hence a lap delta over a 52 lap race being around 5s/lap between high and low fuel running with 150kg on board.

sAx

[747heavy]

........................ not the rigth place - sorry

[PlatinumZealot]

[
there you go ...so it´s 3tenths of car speed won at the xpense of having to cruise for 20 laps.
counting it up that would amount to 9 seconds less elapsed time till they had to
ask him to nurse the engine...there are better ways to find 9 seconds in race elapsed time-for example a fresh set of soft tyres or an excellent pit call on changeable conditions.
In effect that´s only shifting the car potential from the end of the race bringing it a bit forward.

Only if your "gamble" does not pay off.
If you get it right, you have 0.3 sec a lap and less stress on your tires for the whole race, not just the beginning.

Because, if you get the safety car/or more rain, the car with a "conversative" strategy/calculation (un flat out from start to finish), would finish the race with 10kg unused fuel in the tank.

Sure, their is risk involved, as with any assumption you have to make along the way, but hey it´s racing after all.
It´s not much different then to put your car on slicks in changeable conditons. Sure, you can allways wait a bit, and let somebody else to it first, to be "safe(r)", but if it works and he stays on the track, he can gain an advantage over you. God loves a "tryer" after all.
Hindsight is a wonderful thing.

747 h ..I really love to be the decision guy at the pitwall and believe me I had some really cool moments making bold calls when others still looked up in the sky and in their laptops not finding answers when a decision is all that is needed -NOW-
And I fully agree: God loves the ones who try with passion....

I will never forget the pregrid in Anderstorp with water flooding the area and I was changing my driver on slicks .....I asked a lot from him for the first 2 or three laps till it really was dry but the fun started only in the last two laps when it started to rain again but all the guys had their Wets already toasted and we came home almost winning ..

What I wanted to point out is the undeniable fact that this low fuel thing is a very marginal decision and you depend on a lot of things going your ways and more funny not everything going your ways!!!



They did not expect to be in this competitive situation till the end ..same as Rosberg back then ... the speed was a fluke and not real.Hamilton was p10 in Q3- an unused set of softs would have been worth a lot more as would have been a early stop...? I had the impression Schumacher who was forced on slicks by the incident was showing it was very well possible to switch to slicks in lap nine when Hamilton waited till lap 12..

Jenson Button was only 1kg heavier or about 1/3 of a lap heavier than Hamilton. That is nothing, so the speed was real.

What we can assume is that even if both drivers were 15kg lighter, that would not be that much beneficial in wet conditions, because you have to turn down the engine ("wet mode") to keep traction. If Hamilton did not turn down his engine though then I must congratulate him, most drivers are not brave enough to race at full power in the wet.

[marcush.]

there you go.
The gamble is not much worth in wet conditions in my view .10kilo up or down will not really make the differnce in those conditions.
So as a guy who really loves to brush against the tide in racing I´d say this fuel gamble was based on a theory written on perforated paper...Never ever I´s do something like this.