Originally Posted by RickB
Been thinking about why the deployment speed is so low relative to the speed where its "required" to keep the car stable. Most aerodynamic forces are a function of the velocity cubed, so a 40 lb force at 60 mph would be near 320 lb at 120 mph. Looking at the size of the motor that raises the spoiler, I don't think it could move the unit with a 300+ downforce acting on it. The speed appears to be set to allow the spoiler motor to raise and lock the unit while the forces are still low enough to allow it to operate. Once in the upper locked position, the motor is no longer required.
not a bad theory.
however, the drag force is a function of the square (not the cube) of the velocity so theoretically the force would be 160 lbs. at 120 mph. but that force may actually be less at speed if there is aerodynamic separation from the vehicle before reaching the spoiler.
i think we need to find one of the more credulous crossfire owners to conduct a couple experiments to get some better data. first, i recommend parking a crossfire facing downhill on a very steep grade so that the stowed spoiler is horizontal with the horizon. have a 160 lb. buddy stand on top of the spoiler while you attempt to deploy it. if it goes up easily, the above theory is flawed. if it doesn't go up, rick is really smart, but you will be left to get the spoiler motor or other destroyed parts replaced. the 2nd experiment is to strap a bathroom scale to your spoiler and drive at various speeds to see how much force is being applied (make sure you have an observer do this so you can keep your eyes on the road). you should be able to calculate the actual down force on the spoiler by knowing the surface area of the scale.