Downforce (not drag) and its effects on fuel consumption

[WhiteBlue]

The downforce at the rear wing is limited by the height of the wing. You cannot increase it AFAIK. You can only use less angle of attack.
Straight line speed will go up and cornering speed in fast corners will go down as a result of the downforce cut with equal or more top end power.

[turbof1]

The downforce at the rear wing is limited by the height of the wing. You cannot increase it AFAIK. You can only use less angle of attack.

That is true. Teams will probably will run max angle for most of the races next year. For instance the AoA will be the same for both Barcelona and Monaco, whereas now they have different angles. Only tracks like Spa, Montreal and Monza will have different angles. Perhaps Texas too.

[WhiteBlue]

You can expect all teams to have the same fuel consumption. It will be pretty close to the allowed 100 kg. It would be dumb not to use the fuel. So teams will have elaborate programs to make sure they always run exactly on the desired fuel curve. If there is a theoretical surplus - for instance from a safety car - you can burn it off in the overrun to produce electricity and have more electric power.
Fuel management in 2014 will be a very important task. If you use too much you get disqualified. If you use too little you will not be as fast as possible.

[Greg Locock]

I have done some simulations on this a few years ago. I can say that in F1 L/D ratio is not important. You always want as much downforce as possible. The increase in performance from downforce is always more than what you lose from drag. For that reason F1 cars are very draggy.

Therefore, back on topic, the teams seem to accept the fact that the downforce comes with an extra fuel consumption penalty because of the extra drag.

Sorry Tim that is not true. At least in 2000 Ferrari had three aero setups at the start of the season, low medium and high DF, with Drag to match. See Wright's book for details. Low DF was used at Monza, high at Monaco.

[olefud]

All things being equal, I’d opt for the high downforce car burning less fuel. Assuming the drag vs. speed curve is equal for both, the HDF car gains in two ways. First, since it can run through the corners faster, it won’t dump as much energy (fuel) to heat entropy during braking. By exiting the corner faster, it uses the higher exit speed to run at a faster speed such that its race time is shorter. Except for a small advantage to the LDF car during its braking, both cars will have the same throttle duty cycles. The HDF car, however, would spend less time producing power as a result of the shorter race start to finish time.

Caveat, harvesting heat or kinetic energy may narrow the difference by the HDF car still is the better go in this instance. Of course, in reality, HDF comes with greater drag.

[crbassassin]

A high downforce car has higher rolling resistance I might add.

[WhiteBlue]

I see that you are still missing the main point. Next year all cars will be having roughly the same fuel consumption due to the way the formula is written. Hence the original question is faulty. If you have two cars with the same drive train and one has higher aero efficiency it simply means the performance will be higher. That would be the correct answer for the question if it were written the right way.

[raymondu999]

If you have two cars with the same drive train and one has higher aero efficiency it simply means the performance will be higher.

Not if one of them has to spend more time on fuel-save.

[WhiteBlue]

If you have two cars with the same drive train and one has higher aero efficiency it simply means the performance will be higher.

Not if one of them has to spend more time on fuel-save.

That is not an issue. Both cars will use the same amount of fuel, as I have explained several times. We also assumed that they can generate the same amount of mechanical energy from the fuel to overcome drag and accelerate because they have the same drive train with identical brake thermal efficiency. The higher aero efficiency will give the car a decisive performance advantage. This is a simple law of physics and no amount of argument will beat the law. The only caveat one has to make is tyres. For this comparison we must also assume that the performance is not tyre limited.

[raymondu999]

Are you saying that despite being quicker into, around and out of every single corner on the track, the car with more downforce will consume the exact same amount of fuel, on the same fuel mode?

[WhiteBlue]

I'm trying to tell you that you have a different situation next year for the race engineer. You have a fixed energy budget. So you need to adapt your thinking accordingly. The race engineer will still balance the downforce for an optimum compromise between straight line and cornering speed. But the sweet spot will be different between cars of different aero efficiency. The car with the higher aero efficiency can carry more downforce with the same mechanical energy budget and will generate more performance. Naturally I always assume that the guys do a proper job and find the correct sweet spot. But that should be a legitimate assumption. Btw. I find it silly to down vote this technical conversation. The down voter should post his opinion and should not abuse his voting privilege.

[raymondu999]

I see that you are still missing the main point. Next year all cars will be having roughly the same fuel consumption due to the way the formula is written. Hence the original question is faulty. If you have two cars with the same drive train and one has higher aero efficiency it simply means the performance will be higher. That would be the correct answer for the question if it were written the right way.

The down voter should post his opinion and should not abuse his voting privilege.

It is my opinion, as the question-poster, that you have misunderstood my question while instead telling others that your interpretation of the question is the correct one.

[WhiteBlue]

It is my opinion, as the question-poster, that you have misunderstood my question while instead telling others that your interpretation of the question is the correct one.

I'm quite prepared to let you have your opinion and keep mine. But it is a matter of engineering and physical law we are discussing here. So there can be a determination what is true and false.

We have taken a fairly unspecific question and focussed it in such a way that we can apply physics. I find that legitimate and useful in a technical forum. We should always try to analyse complex technical questions that way.

By doing so I have given you the opportunity to argue inside the physical model that I have constructed. If you do not want to do that I will respect that. But I will not step aside and argue with unspecific terms over the issue. It is your choice. I'm still of the opinion that I have earned some respect for the way I'm posting here and not a down vote. But that is for the readers to decide.

Let me remind you that the first and basic criticism of your methodology did not come from me. It was flynfrog who pointed you towards the issue of aero efficiency as the crucial issue here. I very much agree with that. The absolute amount of downforce is not something that can be easily used in a physical model. But a genuine difference in aero efficiency is very relevant and can be used to construct an energy balance that will give us answers.

Coincidentally the higher aero efficiency would typically also lead to a sweet spot with more downforce. But that amount of downforce plus would be the result of an engineered advantage and not the result of a setup that has gone wrong. In your initial question we would never know the true nature of the downforce difference because you did not specify it in a way that we can use it for a practical model.

[CBeck113]

If you have two cars with the same drive train and one has higher aero efficiency it simply means the performance will be higher.

Not if one of them has to spend more time on fuel-save.

Exactly - the specific fuel consumption of each engine will be different (not all engineers are created equal ) but the absolute fuel consumption over the course of the race is fixed: 100kg max.
Red Bull, for example, has shown in wet conditions that its car has much more DF than the rest of the field this year - there was a specific qualifying, which I have forgotten (old age I guess), in which they were driving a few seconds faster than the rest of the field. Since this DF is being generated efficiently (i.e. not solely by the wings but more by the diffusor), they create less drag, which effectively gives them more opportunities:
1) less fuel at start (lower tire wear, faster lap times; could also carry over into 2014)
2) add fuel, but increase time with max motor power settings (increase acceleration & eventually max speed)
which also means that they can play with the gearing (ist the selection fixed for 2013 too? ), pitstops, etc., adding to the possible strategies. And it is most important to be flexible. RB, however, must tone back their settings due to the tires, and therefore doesn't have a huge advantage in dry conditions. Their biggest seems to be in their fuel allocation, which is the answer to the question in my opinion.

As always, I could be wrong

[WhiteBlue]

If you have two cars with the same drive train and one has higher aero efficiency it simply means the performance will be higher.

Not if one of them has to spend more time on fuel-save.

Exactly - the specific fuel consumption of each engine will be different (not all engineers are created equal ) but the absolute fuel consumption over the course of the race is fixed: 100kg max....

I think for the benefit of the original question we should assume that the cars in question are using the same power units with identical fuel consumption characteristics. Let's say we have a Lotus and a Red Bull chassis with the same homologated Renault power unit and the same amount of inter cooling. The chassis obviously will be different by aerodynamic efficiency and suspension properties.

My money would then be on Newey to come up with a superior packaging job that would give the Red Bull higher aerodynamic efficiency and more downforce in optimized setup.