F-Duct Is Misunderstood - By Flood1

I think there has been some degree of misconception about the so-called F-duct. First, I would like to clarify why it is called an F-duct.  The original duct happened to emerge from the bodywork coincident to where the "F" of Vodafone is displayed on the nose. Funny stuff, eh? But true.

Ok, but the more obvious misunderstanding is that the duct is intended to increase straightline speed. Most of the comments from the media, the bloggers, and from the forum posters seem to indicate that the duct is for lowering drag to increase the speed on the long, straight portions of the circuit. But, I think that is a misconception.

The intent is to reduce the drag on the straights that results from running high downforce wings in the high speed corners. The idea is that the perfect downforce setup for high speed corners is prohibitive on the straights. The optimal setup for the corners causes reductions in top speed straight sections and make the cars vunerable to overtaking in the braking zones.

If working properly, the F-duct doesn't result in higher staight speeds, but instead in higher cornering speeds. The idea is to dial in high downforce for the high speed corners and then to mitigate the drag on the straights via the F-duct. So, you match the following cars straightline speed, and then you enter the corner faster because of more agressive aero.

There is little advantage to straightline speed if one must brake down to slow cornering speeds. If the F-duct works properly then one's staighline speeds match the others, but one's cornering speeds surpases the others.

The formula is this: high downforce for high cornering speeds & F-ducting to reduce the drag caused by the high cornering aero setup on the straights.

It does increase the straightline speed as compared to when you do not employ the duct, but that is a mitigating function. 

Comments

[Jake]

Then how come mclaren lack downforce and are always at the top of the speed traps?

[flood1]

That's my point Jake, I think they should crank the wing up higher and get more downforce in the turns. This would lower their top speed in the traps, but would improve cornering.

They have poor underbody downforce and their front wing is not as effective as RBR or Ferrari. They are trying to compensate for that with higher straightline speed, but it is not working.

The other teams have taken the Macca idea and have done what I have suggested in paragraph 1. The RBR really does not need the concept. They are quick enough without it.

[Jake]

Yeah makes sense. I'm not sure if the mclaren is capable of more downforce. I believe the redbulls and ferraris took their "f-duct" off for Hungary because it was better with out it. Hungary being a really high downforce track of course but I could be wrong though.

[flood1]

You are right about Hungary. The upcoming circuits are very different and are very fast. Macca needs to do well on them, but their advantage has been lost a bit as others have the duct now.

It will be interesting to see.

[Jake]

I don't think the mclaren has lost it's advantage. It's going to be strong at spa and so will the force India. :)

[flood1]

I would expect both teams to be stronger here than at other circuits. Macca need good results to close the gap to RBR. I am really looking forward to Spa, my favorite circuit, and I hope that the championship gets even closer. but it is very close now.

[Jake]

haha hey, i found this article, I guess the f-duct isnt completely misunderstood.. :)

http://www.planetf1.com/news/18227/6334832/Kubica-Our-race-rests-on-the-F-duct

[flood1]

That article agrees with my basic concept: run very high wing setting for the twisty bits, and then use the F-duct to reduce the drag on the straights due to the big wing angles that are necessary for the corners.

That was my point from day one. The duct mitigates the drag from the agressive wing setting necessary for the corners.

Top speed is not the point, but to allow normal straight speeds when running high downforce wings for the twisty bits.