Physics Adjust Aerodynamic Curve With Speed

[EGA Racing Division]

I am working on inputting CFD data for our car mod on AC. When working with CD & CL it seems as by default they are linear with speed. Our data has an exponential curve; downforce and drag comes in very abruptly around 100mph/ 160kmh. How could I make this work in AC? Most prototype racecars have very similar aerodynamics results so I would assume it's been done before considering all the prototype mods on AC.

 

[Stereo]

First most AC aero is proportional to square of speed as in the basic drag/downforce equations.

If you need it more extreme than that, you use an active aero controller that adjusts the AOA of the wing according to speed. So for example you can have a wing go from 0 degrees to 5 degrees between 100-120km/h.

 

[EGA Racing Division]

First most AC aero is proportional to square of speed as in the basic drag/downforce equations.

If you need it more extreme than that, you use an active aero controller that adjusts the AOA of the wing according to speed. So for example you can have a wing go from 0 degrees to 5 degrees between 100-120km/h.

Gotcha so that seems to be the only solution I can find. I guess I'll give it a shot. When editing the wing_controller_speed file what does the second value represent? Ex: Speed|X

 

[EGA Racing Division]

It doesn't really seem to do much. Very minimal changes even when entering crazy values. It really sucks because that kinda makes the aero on this car realistic. We don't even feel downforce until that 100mph threshold but I'm getting plenty of downforce in game before that. I need to reduce downforce and increase drag under 100mph. I'm at a roadblock until then.

 

[mclarenf1papa]

Most prototype racecars have very similar aerodynamics results

This statement is based on what exactly? I would point to your data being inaccurate before much else. Low velocity losses in rolling road data are on the scale of a few percent, nothing major. If you are using a static tunnel for a prototype car, disregard your data, it will not be useful. Errors can be upwards of 40%.

Just some terminology clarifications:

CD and CL in AC are constant with velocity, per standard aero force equations.

The lut's y value is always angle, as that's what the controller changes.

 

[EGA Racing Division]

This statement is based on what exactly? I would point to your data being inaccurate before much else. Low velocity losses in rolling road data are on the scale of a few percent, nothing major. If you are using a static tunnel for a prototype car, disregard your data, it will not be useful. Errors can be upwards of 40%.

Just some terminology clarifications:

CD and CL in AC are constant with velocity, per standard aero force equations.

The lut's y value is always angle, as that's what the controller changes.

It's CFD data so you're probably right. We try to take the provided data with a grain of salt and perform on track tests instead. Someone here on RD was geeking over aero numbers on a previous version of this car so it had me concerned but as soon as I started messing with it the car became extremely unrealistic and was glued to the track.

 

[Storm Rider]

If you have CFD data, why not trying cphys AEROMAPS? The main issue with vanilla physics is that it's based on independent wings, and controllers do only control AOA.