BTW: I don't think speed scales like the size does. From what I gather from
this page, the formula for finding scale speed is:
1:1 speed = SQRT(scale) X scale_model_speed
So, if your 8th scale RC does 60mph, that scales up to SQRT(8) X 60 = 169.2mph.
Similarly, if your 10th scale RC does 90mph, that scales up to 284mph.
If someone can verify this, I can add this to the speed calc.