As important as powerful engines are to race cars, all the power they generate has to be controlled. That's why race cars have spoilers: They help the car's wheels maintain contact with the ground and keep things under control when the engine is spitting power.
Spoilers work by generating downforce. Air flows over the spoiler, pushing it down and helping the car maintain its contact with the ground so no engine power gets wasted. The 1977 Brabham BT46B, also known as the fan car, had a fan at the rear of the engine bay that not only cooled the engine but also generated incredible downforce. In the car's only race, the 1978 Swedish Grand Prix, driver Niki Lauda easily won [source: Grossinger]. The problem with the BT46B was that according to Formula One (F1) rules, any feature that generated downforce had to be fixed — and a fan that spins is decidedly not fixed. The car was legal at the time because of a loophole in the rules, but it wouldn't be for long. The fan car era ended as soon as it started.