Grand Prix racers rely on "negative lift" to keep their tires on the ground. What is it and why does it sometimes disappear?
About 70 percent of negative lift comes from one or more wings on the vehicle, which deflects air upward and pushed the car down. The other 30% comes from the air under the car which is compressed; that's the ground effect.
It disappears during drafting, when one car is close enough to another to disrupt the flow of air.
Our winner this week is Andrew Bourke of Halifax