Aero induced yaw.

[godlameroso]

When these cars are under roll, are these cars subject to yaw forces? If so does body roll create aero yaw towards or away from the corner?

On most flying man made objects, turning is done by using the control surfaces to induce yaw and roll. Yaw is induced when a flying vehicle is in roll and one wing has more lift than the other(higher relative lift on the wing opposite the desired yaw direction), the rudder aids this by creating a yaw force by creating higher pressure on the side the yaw is desired. If we flip this upside down to emulate an F1 and create negative instead of positive lift car are the roll and yaw forces reversed? Meaning when the car rolls and the wing gains negative lift through ground effect is yaw induced towards or away from the roll?

[Greg Locock]

So you want a plot of MZ coefficient versus roll?

Never seen one! For crosswind stability we plot all 6 aero coefficients vs yaw angle, but that's not what you are after.

[Tommy Cookers]

suppose the car is in a bend to the right and so rolls to the left
if the DF is greater on the left half of the car (than on the right half) ie due to reduced left half ground clearance .....
the aero drag may be greater on the left half (than on the right half)
the mechanical drag of the left wheels will certainly be greater

the net aero effect is probably an (adverse) yawing moment to the left (adding to adverse mechanical yawing moment)
the aero directional stability will also produce some adverse yawing moment .....
just jobs for the wheels to oppose - while doing their main job (generating lateral force to the right)


btw flying manmade objects turn by leaning like a motorcycle

[godlameroso]

So you want a plot of MZ coefficient versus roll?

Never seen one! For crosswind stability we plot all 6 aero coefficients vs yaw angle, but that's not what you are after.

Any contribution is welcome

[bill shoe]

When these cars are under roll, are these cars subject to yaw forces? If so does body roll create aero yaw towards or away from the corner?

On most flying man made objects, turning is done by using the control surfaces to induce yaw and roll. Yaw is induced when a flying vehicle is in roll and one wing has more lift than the other(higher relative lift on the wing opposite the desired yaw direction), the rudder aids this by creating a yaw force by creating higher pressure on the side the yaw is desired. If we flip this upside down to emulate an F1 and create negative instead of positive lift car are the roll and yaw forces reversed? Meaning when the car rolls and the wing gains negative lift through ground effect is yaw induced towards or away from the roll?

The F1 trend in recent years, when it's not constricted by the rules, seems to involve adding surface area aft of the CG (like engine-cover tails on 2017 cars, etc.). So strictly speaking this means more anti-yaw force through a turn.

Perhaps the purely "mechanical" setup is a bit unstable and benefits from the added aero stability at high speed? Or perhaps the slight lateral force into the turn is worth the anti-yaw tradeoff?

[godlameroso]

Taking it further could aero yaw forces shift the vortecies downstream of the front wing left or right of center? Does this affect the diffuser stability?