I am kinda unclear with the relationship between drag and downforce. Will reducing drag increase or decrease downforce?
I remember McLaren running low drag rear wing for Hamilton at Monza while Button had the high downforce set up. Monza's high speed straights force the teams to use a low drag set up, but how does that affect the downforce?
Yes, they're related. For a given aerofoil, increasing lift (downforce) will give a corresponding increase in drag. This is because to increase lift you increase the angle of attack.
The teams will look at the car in terms of L/D (the ratio of lift (downforce) to drag). The aim is to improve the car's L/D because, simply, this means that for a given downforce level (and hence speed in the corners) the car will have a higher straightline speed on the straights. Also, for a given downforce level less fuel will be needed to pull the drag around.
Whilst lift and drag increase with the square of the speed increase, power absorbed by drag (the amount of engine power that is needed to maintain a given speed) increases with the cube of the speed increase. That's why F1 cars need 750bhp to do 300km/h whilst road cars (with much lower drag coefficients) can do it with about half of that power. It's also why head winds do so much damage to fuel mileage figures in road cars.
If you are more fortunate than others, build a larger table not a taller fence.
Downforce essentially plants the car onto the ground, if I am right. But then, why does Monza have low downforce requirements than Monaco, Australia, Brazil and so forth?
It's the balance between speed in the corners and speed in the straights. High downforce (DF) gives you good speed in corners and low speed on the straight - low DF the opposite.
Now, depending on the number of corners on your circuit you normally select a DF level to get the best balance of speed in corners and on the straights.
Button at Monza was an anomaly caused by the f-duct aerodynamic device which could reduce drag (somewhat) from a high DF rear wing in the straights which should then provide the best of both worlds. It didn't work perfectly though, which is why he didn't win.
"Words are for meaning: when you've got the meaning, you can forget the words." - Chuang Tzu
As mentioned, McLaren was running the F-duct which allowed them to, in simple terms, switch the wing "on and off." The idea, in theory at least, is that the F-duct would stall the wing and it would lose its lift and drag. So they could have a lower downforce/lower drag set up when they wanted it in a straight line, but they could also have a higher downforce/higher drag set up when they needed it in the corners.
So why did McLaren run two different set ups then (Button with the high DF ducted wing and Hamilton with the low downforce/low drag static wing)? Well, my guess would be is that their lap time simulations didn't indicate a clear advantage for one set up over the other. Lap time simulations are developed using equations that calculate the (longitudinal and lateral) acceleration capability of the car based on a variety of parameters, including but not limited to: wheelbase, track widths, springs stiffness, tire properties, and the lift/drag characteristics of the car. If you're interested in learning more about that, you can check out the link in Jersey Tom's signature above. He's laid out the very basics of how the process works.
Obviously, in an engineer's perfect world they would have zero drag while the car is on the straights, and have a large amount of downforce in the corners. This is the idea behind developing the F-duct wings, but in reality, the magnitude changes of lift and drag aren't nearly that drastic. Depending on what the magnitudes of change for lift and drag are between an active and inactive F-duct, the lap time simulator may calculate that the benefits and limitations of the F-duct wing vs. low downforce wing offset each other on that particular track. On the other hand, it is possible that the simulations indicated that one set up would be advantageous, but one of the team's engineers didn't trust the results. After all, simulations are not perfect.
I am kinda unclear with the relationship between drag and downforce. Will reducing drag increase or decrease downforce?
I remember McLaren running low drag rear wing for Hamilton at Monza while Button had the high downforce set up. Monza's high speed straights force the teams to use a low drag set up, but how does that affect the downforce?
I gladly appreciate your replies. =D>
There is no fixed relationship. It all depends on experimental results.
Some cars have less drag and more downforce, while others have more drag and less downforce. Like so many things in engineering this part is based on data from experiments.
For example the Double decker diffuser added considerable downforce with almost no drag penalty.
It also depends on the series. The "relationship between drag and downforce" you choose in your regulations (because there IS one relationship chosen by regulators, even taking in account n_smikle, Mystery Steve and horse intelligent comments) defines how boring the series is to watch.
I would dare to say that the level of boredom has to be compensated by hype, that explains to me why F1 insists so much in giving media time to things unrelated with racing, btw. You can guess from the preceding graphic what kind of car I enjoy more... and, for once, is to the right ("always to the left", said my Grandma, but she meant an entirely different thing).
When Button mentioned that he used higher downforce setup than Hamilton he meant relatively , it was still a low downforce setup . But what many people ignore that by having higher downforce Button had better exit corner speed before the straight that's why he was faster.
Well, you know how some Brit drivers are. They're asking themselves all the time if they should be or they shouldn't. Sometimes it takes months for them to post an answer...
Just_a_fan wrote:Yes, they're related. For a given aerofoil, increasing lift (downforce) will give a corresponding increase in drag. This is because to increase lift you increase the angle of attack.
What you say is true but only in a broad way.
Increasing AOA does increase your drag, but the lift/downforce gain is far greater than the drag increase.
As to answer the original question, drag and lift are related but not directly, i.e a change in downforce/lift doesn't mean necessarily a change in drag especially since there're several types of drag coming from different aspects.
