IndyCar has released drawings of the new safety flap system that will be required for the first time at the 100th Indy 500 in May.
The IndyCar flap system, which mirrors the purpose and principles behind the roof flaps introduced by NASCAR, mounts to the rear beam wing on the Dallara DW12 chassis, and will be utilized in IndyCar's three speedway events at Indy, Texas, and Pocono.
Two flaps are required, with one mounting to each side of the beam wing; the flaps are hinged at the leading edge of the beam wings. With a Chevy- or Honda-powered Dallara turned backwards at high speeds, the flaps are designed to deploy on their own by using the rushing air to flip upward.
To keep the flaps from going over center, rods are affixed from their trailing edge to the rear of the beam wings which prevent the flaps from going beyond 90 degrees.
IndyCar's new flap system comes in response to the spins and flights experienced on three occasions during last year's practice for the Indy 500. The flaps, when deployed, are meant to spoil the airflow traveling under the rear wing mainplane and across the back of the car, and with that pathway significantly blocked by the flaps, aerodynamic lift should be reduced to a point where the chance of flights are greatly reduced.
The flaps should be especially effective in flat spins where a driver experiences a quick rotation and slides backwards for some period of time before stopping or hitting the wall at a reduced pace. In at least one of the flights at Indy 2015, a high-speed spin transitioned into an immediate impact where the rear of the car scaled the wall and exposed the underwing to the air, which accelerated its flight.
In a similar situation starting in May, the flaps should lower the likelihood of a wall-climbing flight, but only if the rear beam wings and flaps are attached after impact. IndyCar will also require teams to use dome skids beneath their cars and additional tethers designed to keep noses and rear beam wing+rear wheel pod units attached to the DW12 in a crash.
The beam wing flap package costs $2,305.38 per car.