WING TIP VORTICE

[ONEBADBUG]

So, I know quite a bit about aero, but watching F1 last week, I realized there's something I don't get. You could see the vortice, but my question is; is the air coming off the wing into the ambient air, or is the ambient air being sucked into the high velocity air at the wing? Or, neither, just rotating the adjacent air like a tornado?

[SPARKY]

most likely both would be my SWAG 

[Interested Observer]

The ambient air through which the wing is passing is induced into a vortex at the wing tip.  Due to the rapid rotation of the air in the vortex, the local pressure in the core is reduced from ambient.  Depending on the temperature and humidity of the air, the drop in pressure and temperature in the vortex can be sufficient to cause condensation, creating a small visible "cloud".

[ONEBADBUG]

Yes, I know why you can see it. I still wonder if the net effect is air being pulled in towards the wing, or away. I think the ambient air is just rotated without any other changes, but I don't know.

In other news, my new rear wing makes something like 600 pounds of downforce at only 50, 60 mph.

[donpearsall]

Why would you want the drag that comes from 600 pounds of downforce? Instead of drag, why not add weight? Is it due to the need to accelerate quickly? That's not an issue in landracing of course.

Don

[tortoise]

Instead of drag, why not add weight? Is it due to the need to accelerate quickly?

Yes. Both positive and negative acceleration, not to mention lateral acceleration.

[ggl205]

ONEBADBUG's car looks like an A Mod Solo car. These are bad a** parking lot racers that are very quick and nimble. Adding weight would destroy corner handling so they rely on aero downforce.

John

[ggl205]

I stopped by the exploration center here in Wichita and Boeing had a wing section there explaining why those raised wing tips exist. Boeing says these vertical wing structures capture vortices running off a conventional wing tip and thereby uses this otherwise lost energy to assist with lift. I looked closely at these structures and they are not just simple upturned end plates.

John

[ONEBADBUG]

Why would you want the drag that comes from 600 pounds of downforce? Instead of drag, why not add weight? Is it due to the need to accelerate quickly? That's not an issue in landracing of course.

Don

Yes, it's an autocross car. I have been to Bonneville twice in other cars. This car is all about downforce with no concern for drag. When you can run the whole course and never lift, you have enough! That's impossible though, because the rules limit me to "20 square feet of wing as viewed from above."

It is incredible to drive something that can go through a corner at 70 mph, that it can't do at 40 mph.

[ONEBADBUG]

I stopped by the exploration center here in Wichita and Boeing had a wing section there explaining why those raised wing tips exist. Boeing says these vertical wing structures capture vortices running off a conventional wing tip and thereby uses this otherwise lost energy to assist with lift. I looked closely at these structures and they are not just simple upturned end plates.

John

Can you explain that anymore? That's what I want to know.

[Stainless1]

The wingtip of on airplane generates a vortex that looks like a horizontal tornado... This causes drag and eats power... the winglets are intended to improve wing efficiency by reducing drag. There are several versions... but all are there to reduce an aircraft's drag by partial recovery of the tip vortex energy. 
The simple explanation is they fool the air into believing that isn't where the wing ends.