A roof flap is an aerodynamic feature on race cars mainly stock cars which functions as an emergency spoiler to prevent the vehicle from lifting off the ground.
How do roof flaps work.
The flaps are stowed during normal vehicle operation.
There are two spacers for each flap making a total of eight spacers in the car.
Teams buy roof flap assemblies from roush yates.
Roof flaps are two plates located on the roof which measure 12x8 inches 30x20 cm and are depolyed as the car is either sideways or going backwards at high speeds.
However in certain situations e g if the vehicle goes into a spin particularly if it is facing backwards the flaps deploy to disrupt the air flow over the roof and reduce.