Yep. I experience as similar problem with one of my past cars. It wasn't problematic until about 130 mph, but I removed the larger spoiler as the faster I went the lighter the car felt. My plan was to add a front ground effect too, but never got around to it, so just sold the larger spoiler.
FWIW, the matter of aerodynamic balance was either mentioned or implied several times before your entry into this thread. One of my posts was one of them.
Fixed your equation, but otherwise you're correct.IOW, Lift - CarWeight = ΣTireLoads = 0
I think we're saying the same thing here
I've never worked with aircraft aero topics, so I assume that car speeds are always lower than any take-off speed (certainly for my own driving, occasional LeMans incidents involving flight notwithstanding).
Otherwise ΣTireLoads = 0 and a nonzero sum of the other two forces would cause a net Z-axis acceleration one way or the other.
Don't have that one in my library, might be useful. Source?
Norm
At the risk of nit-picking, shouldn't the proper equation be: Lift - CarWeight + ΣTireLoads = 0
I'm interpreting ΣTireLoads as the force being supported by the tires, which would be equal to lift - car weight. This is of course negating sprung vs. unsprung weight, because that just makes things unnecessarily complicated for my lazy self.
Gotcha, but the problem I saw was you equated the total tire load (normal force) to zero. One too many equals signs.I'm interpreting ΣTireLoads as the force being supported by the tires, which would be equal to lift - car weight. This is of course negating sprung vs. unsprung weight, because that just makes things unnecessarily complicated for my lazy self.
So by this theory, almost every race car that has a wing on the back but only a spoiler/splitter up front has broken areo. You know, virtually ever racecar thats not a formula car.
It would equal zero because there is no acceleration in the z-direction, meaning the net forces all balance out. This doesn't mean that the normal force is equal to zero, just that the car hasn't achieved lift-off, and isn't drilling into the earth. It does mean, though, that if you decrease lift, the weight of the car is more able to contribute to the normal force, thereby increasing friction.
Again, splitters do not generate a force, only wings do. A front splitter alone could work by disallowing some air to go under the car, ultimately reducing lift.
Not if you consider the forces as being 'signed'. Whether you prefer + = up or + = down shouldn't matter for this discussion as long as consistency is maintained.
Yeah, I understand that. That was exactly my point. Your equation didn't balance out. You had an extra "=" (typo?), indicating that normal force = 0.
Yup.
I was actually referring to Muff's revised equation. If you take another look at it there is an extra "=" (probably a typo) which states that the normal force (tire load) = 0 under any circumstances, which is incorrect (except in the unlikely hypothetical circumstance that your total lift was exactly equal to the car's weight and was distributed in the same fashion).
