On today's NASCAR Hammer Down, Bubba and Blaney race RC Cars, Karsyn's hero, Danica Patrick, joins her for Rapid Fire, and we learn why fast pit crews are just as important as fast cars on race day.

Bubba and Blaney go to drivers' education; Karsyn interviews her uncle, Dale Earnhardt Jr.; learning how teams use the science of the wind tunnel to make their cars fast.