What is the drag coefficient in an F-1 car?

[Guest]

WOW! There are some brains around here!
This ain't no "kindergarden stuff" to me.

For someone who only has an intuitive understanding of some of these concepts and has followed this sport for a long time, I just want to express my appreciation for this site and its capable contributors.

Although I frequent F1 sites more often than I care to say, It's been years since I have participated in any discussions (for obvious reasons). This forum has changed that.

I'll try my best not to embarass myself.

-T

[Scuderia_Russ]

I'll try my best not to embarass myself.

-T

Don't worry about it, I do it all the time.

[thienkhoak]

Mod edit:

This thread was rekindled after 8 years by a spammer posting an anodyne comment in here. Normally that's that and the the thread returns to history. However this one has sprung back into life thanks to the spammer bumping it to the top of the new post listings. So perhaps spam can be good for stimulating the forum?

I've deleted the original spam comment that was here.

[Belatti]

too late

[strad]

For years they have said to just lift of the gas produces 1g of deceleration.

[Per]

That's not too far off I suppose. In this 8,5 year old topic a value of SCd of 0.85-0.88 was found for Monza 2005. If you use that value and use the old weight limit of 605kg, than this would result in a deceleration of 8.76m/s² (or 0.89g) at a velocity of 100m/s (360 kph).

That's low-drag spec though. If you assume 33% higher drag coefficient on a medium downforce track, and use a speed of 325 kph, you get 9.51m/s² deceleration (0.97g).

The weight limit in 2014 is 691kg though so for the same aero figures, deceleration is 12.5% lower (0.97g reduces to 0.85g). I would also assume drag levels have generally decreased over the past 9 years due to rule changes and developments, but I have no idea about current figures (I think only the teams have).

[thepowerofnone]

Drag has increased over the years, with a 2014 Monza spec coming in a bit higher than the F2000 quoted value. Skinnier wings and less diffuser makes for draggier cars.

As far as requesting a citation, I doubt very much that you'll get one from anyone. Engineers don't like to go on record.

EDIT: I find it hard to believe that that Ferrari produced that little downforce. Also, on a related note, in F1 figures will be quoted as Cx, Cy, Cz, because it removes the dependancy of wing area which is present in Cd and Cl.

[Greg Locock]

Nonsense,Cd and Cl for F1 cars are typically quoted on frontal area basis same as any other car.

[Per]

Also, on a related note, in F1 figures will be quoted as Cx, Cy, Cz, because it removes the dependancy of wing area which is present in Cd and Cl.

And Cx, Cy and Cz don't depend on a reference surface area? Of course they do. Whether you take a wing area (common in aviation) or a frontal surface area (common in automotive), Cd (or Cl, Cx/Cy/Cz) in and of itself is almost a meaningless number without including that area. You can always say "I define the reference surface area to be 1m²" (or any arbitrary number) and define your coefficients accordingly, it doesn't change anything.

[strad]

Skinnier wings and less diffuser makes for draggier cars.

HUH???
I don't think I buy into that. For one more wing makes for more drag.

[Blanchimont]

I think, powerofnone meant that the F2000 had a wider rear wing and bigger diffuser geometry compared to today's cars.

The diffuser therefore provided more downforce than today and the wings could be run flatter to setup the car for the best Monza drag/downforce configuration.


from: http://www.grandprix.com/ft/ftpw007.html

[Per]

Indeed, wide wings are more efficient in terms of L/D (relatively lower induced drag). A good old big diffuser also improves the car's overall L/D. Question remains whether they used that higher L/D to increase downforce or reduce drag, but most likely it was a bit of both.

[trinidefender]

Food for thought. One place where drag has been reduced has been at the front of the car. My understanding is moving the front wing in front of the tyre, like it has been since 2009, has helped cut a large percentage of drag from the front of the car. Simply because the front wing now helps to move airflow up and around the front tyre and help it fill the "dead zone" of airflow immediately behind the front tyres.

[thepowerofnone]

Also, on a related note, in F1 figures will be quoted as Cx, Cy, Cz, because it removes the dependancy of wing area which is present in Cd and Cl.

And Cx, Cy and Cz don't depend on a reference surface area? Of course they do. Whether you take a wing area (common in aviation) or a frontal surface area (common in automotive), Cd (or Cl, Cx/Cy/Cz) in and of itself is almost a meaningless number without including that area. You can always say "I define the reference surface area to be 1m²" (or any arbitrary number) and define your coefficients accordingly, it doesn't change anything.

Nonsense,Cd and Cl for F1 cars are typically quoted on frontal area basis same as any other car.

... It's not nonsense, at all, so please don't make such accusations. Perhaps you misinterpreted, but in aerodynamics C_L=L/(0.5*rho*v^2*S), where S is the planform area. That's a useful number when comparing aerofoil A and aerofoil B of the same size, but it is a useless number when comparing two completely different configurations, such when you wing area (or frontal area) changes between designs in addition to the aerofoil profile. So in F1 they remove the dependance on S by using C_Z=F_Z/(0.5*rho*v^2), as in, if I am going 50 m.s^{-1}, how much downforce will my whole car produce, without any area considerations because they are useless for the desired computation...

Skinnier wings and less diffuser makes for draggier cars.

HUH???
I don't think I buy into that. For one more wing makes for more drag.

More wing does make for more drag, this is true, but when you make a wing skinnier you decrease the L/D ratio, and when you make the diffuser less exploitable you also decrease the L/D ratio of the car because diffusers have very high L/D ratios and if it makes up a smaller proportion of your car's downforce, your mean L/D ratio decreases.

Indeed, wide wings are more efficient in terms of L/D (relatively lower induced drag). A good old big diffuser also improves the car's overall L/D. Question remains whether they used that higher L/D to increase downforce or reduce drag, but most likely it was a bit of both.

L/D is a circuit specific property, it doesn't really change year to year; changes to the power curve do influence it, so there have been changes this year.

[Per]

Now you are being REALLY confusing. First you say L/D changes because they have changed the wings and the diffuser (with which I agree), then you say L/D doesn't change from year to year. And how on earth does the power curve influence L/D? It changes the optimum setup for a certain track, so they can opt to run more downforce (and as a result, more drag) but L/D will not change nearly as much as L and D individually.

What you're saying about coefficients is just another way of saying that they don't look at Cd only, but at S*Cd.