by chappyman66 » Tue Jan 14, 2014 1:00 pm
If it's green it's biology; if it smells it's chemistry; if it doesn't make sense it's physics....:lol:
No, cornering with a 275g car will not be the same as cornering with a car that has a magnet of 275g downforce. As already pointed out, the location of the magnet affects downforce due to the lateral acceleration (the force of the rear of the car swinging out in the corner). The early Nincos and many Carrera Evo 1/32 cars had "weak" magnets behind the front axle that didn't affect the handling nearly as much as the rear mounted neo magnets in the Fly cars. Because the front axle location creates a longer moment of rotation (probably not the right term, someone will correct me) the car can slide a bit because the front end doesn't move as much as the rear does and therefore you still have some magnetic downforce because the front end is still partly over the rails when the rear end is hung out in the corner. This is not the case with the rear magnet because once you apply more force than the magnet applies you break the attraction and all of that downforce is immediately lost causing the massive crashes.
Also note that magnets follow the inverse square law, meaning that doubling the distance from the rails causes a 4X reduction in the amount of downforce (halving the distance is a 4X increase) so ride height and tire diameter matters a great deal.
Note that with lead/brass you can't precisely locate the cg the way that a magnet does. Johnny got it right with chassis stiffness/flexibility which is why you see "flopper" pan chassis instead of straight "jail door" designs since the hinges allow the weight to "move" which creates better handling. Which is of course why you have pod chassis and you loosen body screws to let the bodies "float" ;)