8 replies to this topic

[libano]

Stalling wings has been discussed a lot lately. What is the physical principle behind it, in a nutshell?

[Richard T]

Im not quite sure but i think that by blowing the underside of the FW or RW fills the vacuum (or low pressure) area behind or under the wing and therefore removes the force to hold the car back (Like a vacuum cleaner with a hole in the hose). It's basically the same effect as when the NASCAR cars bump draft eachother.

Correct me if im wrong

Edited by Richard T, 18 April 2012 - 16:57.

[Ross Stonefeld]

You can make a wing inefficient or work it too hard and the airfoil will stall. We normally associate it with an airplane going too slow and stalling, but they can also do it by turning too 'hard'.

For instance in a race car, if you get too sideways the downforce can stall because the path of the flow is completely different. Which is why in fast corners once they go beyond a certain angle they tend to spin out of control. But in a hairpin you can get hilariously sideways because it's mainly tire grip at low speed.

[Gemini]

http://www.racecar-e...one-technology/

[Stormsky68]

The air on top of a wing travels at a different speed to that below > creates a pressure differential > creates downforce

If you can sufficiently disurb the flow of air on one side or the other, then the pressure differential decays > downforce drops away

It doesn't always mean that you won't get drag, it takes some clever engineering to switch on / off drag and downforce

Edited by Stormsky68, 18 April 2012 - 17:30.

[PayasYouRace]

A wing will stall if the airflow over its surface is disturbed enough. In normal operation the airflow is laminar and steady over both surfaces of the wing. The shape of the wing (camber) and angle of the wing (angle of attack) determine which side has a lower pressure, and the wing will "lift" towards that side. In the case of a racing car that is the underside. The low pressure side is in what's called an adverse pressure gradient. That basically means that the pressure is reducing and it makes the airflow easier to disturb. If the flow is disturbed and becomes turbulent, the wing stalls.

This stall can be achieved in a number of ways. One is to increase the angle of attack. At that point the air can literally not "go round the corner" smoothly, hence it becomes turbulent. Another is to reduce the speed, that's why an aeroplane has a minimum speed. Another way of stalling a wing is to physically break up the surface of the wing. That's how the spoilers on the top of an aeroplane wing work (you'll see them pop up when the plane lands). This can also be done by blowing air out of the wing in the right way. This is what the F-duct systems are doing. Note that blowing can also prevent a wing from stalling if done correctly - see the Buccaneer.

The reason you might want a wing to stall is because of drag. Drag comes in a number of forms, and any real world, 3 dimensional wing suffers what is known as induced drag. This is literally drag produced through lift. In the case of a racing car the drag from the wings is not just because of the profile of the wing but because it it producing downforce. Induced drag is a phenomenon brought on by the wing having ends, and that's why racing car wings have endplates, to try to negate the induced drag. If you like I can explain this further.

When the wing stalls it suddenly produces no downforce at all. This means that there is no induced drag. The profile drag might increase slightly due to the turbulence caused, but it is still less than the induced drag of the wing. This is why the F-duct systems were invented. You don't need the downforce on the straights, so you can dump it and lose all the induced drag too. Hope this helps.

[miniq]

Disconnect/Remove airflow from beneath the wing aerofoil therefore creating a stall

This is done by introducing a secondary airflow onto the aerofoil from the W-duct hole which disrupts/disconnects the main airflow

[JimboJones]

Stalling wings has been discussed a lot lately. What is the physical principle behind it, in a nutshell?

Have people never heard of google?!
Ask that question on here and you'll get every answer but the right one...

[Rybo]

Stalling wings has been discussed a lot lately. What is the physical principle behind it, in a nutshell?

F1 Technical

Honestly I'm not sure if i can link it, but F1 Technical is a great resource for the science of F1. Although fair warning it can be.... technical to put it bluntly.