Downforce dropoff with yaw (F1)

[kensaundm31]

Does anyone know, or can hazard a guess what the % of downforce that is lost at any given yaw angle.

Is the % the same for front and rear. Because I would think that would be a priority in the designers mind as it would not then alter the under/over characteristics of the car in corners.

[Metar]

I'd think the main priority would be losing rear downforce - slightly understeering when under jaw might even help a bit, but reduced rear grip (proportionally to the front) would only make the slide worse..

[Jersey Tom]

Why would you like to know?

[kilcoo316]

Why would you like to know?

Why not?


Anyway, to answer the question - F1 teams don't particularly want downforce in a straight line - you don't need it there, all your doing is generating un-necessary "lift"-dependant drag.

All teams test with yaw rates to ***try*** and get more downforce in yaw than in straight lines.

Remember the big antlers on the McLaren over the past few years? That is what they were there for - get more out of the rear wing in the corners.



The really interesting question is - what is the downforce dropoff with sideslip.


[edit: realised I didn't have a rate in after yaw!]

Sideslip = constant yaw angle (deg)

Yaw rate = Dynamic yaw angle (deg/sec)

F1 cars can corner at stupidly high yaw rates, upwards of 50 deg/sec at places like Becketts (Silverstone) - but it is an extremely dynamic motion.

However, they don't like to be sideslipping much more than 5 degrees IIRC (but that could be more to do with tyre friction circles than aero - although I'd imagine the two are tailored to a degree).

[miqi23]

Well an extreme case for an LMP1 car at 160 kph..

At Zero Yaw

3119.1 N (Total)
1258.0 N (Front)
1865.4 N (rear)

At 10 degree Yaw

2698.6 N (Total)
1122.9 N (Front)
1575.6 N (Rear)

At 20 degree Yaw

1799.4 N (Total)
566.7 N (Front)
1232.7 N (Rear)

Hope this helps a little!

[Metar]

Is that from the December issue of Racecar Engineering? They had one issue given away for free on the internets which included a study of downforce under jaw. Don't have the link though..

[kilcoo316]

<SNIP>

Nice info. =D>


Is that sideslip angle or yaw rate?

[Roland Ehnström]

You can call it sideslip, slipangle or simply "yaw". It's all the same thing: The difference between the direction of the car's motion and the direction of the nose of the car. On the straights the sideslip/slipangle/yaw is 0 degrees, while in the corners it is normally 3-5 degrees in a modern F1 car.

Yaw-rate is a different thing, and is not the topic of this thread. It's how fast the yaw changes during a corner, or simply how fast the car is rotating. Since F1 cars can change direction very fast, the yaw-rate can be very high. But yaw-rate doesn't really effect aerodynamics, at least not anywhere near as much as yaw.

[Ogami musashi]

Under current 09 regs, downforce can increase with moderate yaw angles (around 3°); End plates design is quite crucial.

[Belatti]

I have always tought about a movable aero device that works like a ship helm´s blade. Do you know if the front movable wing is only restricted to move in a horizontal plane? Can it move in a vertical one?

[Ogami musashi]

The rules prevent the wings from doing anything else than increasing their Angle Of Attack.

They also prevent any asymmetric motion.

But hopefully since many engineers start to go away from F1 and that MM finally realized the rules were too tight and that he wants moveable aero, we may expect more freedom in the near future.

[Conceptual]

...Hopefully with the introduction of AWD KERS, we can get some other movable/adaptive aero and active suspension...

[kensaundm31]

Thanks for the info.

So what yaw angle would an f1 car be at when negotiating 'Stowe' at Silverstone?

[Jersey Tom]

Dude, you're asking for data no one here either has or would be allowed to release.

I could venture a guess, but WHY do you want to know?

[kilcoo316]

Dude, you're asking for data no one here either has or would be allowed to release.

I could venture a guess,

Why not venture a guess - it shouldn't be all that hard to work out!

but WHY do you want to know?

Why so defensive?

So what yaw angle would an f1 car be at when negotiating 'Stowe' at Silverstone?

What is the corner angle?

What is the time taken to negotiate corner?

There you have average yaw rate. Transient traces will be different of course, but not overly so - figure a peak yaw rate 20-30% higher than average.

As for yaw angle - depends on how hard the driver is pushing...

In race:
Very small (not near the extreme of the tyre friction circle).

In qualifying:
Who knows... depends how good the driver is and how willing they are to push it.