And that\u2019s just Daytona. Rollover crashes are common at Talladega as well. But it\u2019s not just superspeedways. Any high-speed track offers conditions conducive to cars taking flight. Corey LaJoie went airborne at Michigan in 2024.<\/p>\n
A new NASCAR aerodynamic development may keep all the cars in this weekend\u2019s race at Daytona firmly on the ground.<\/p>\n
How does a 3600-pound car get into the air in the first place?<\/p>\n
Pretty much the same way a 155,500-pound fully-loaded 737 plane takes to the air. The faster air moves, the less force it creates on a surface. Air going over the top of a wing moves faster than air going under the wing. That means more force pushes up than pushes down.<\/p>\n
Whenever there is more force in one direction that any other, any object will move in the direction of the larger force. Think of it as an inverse tug-of-war: whichever side pulls harder wins. In the case of aerodynamics, the forces are pushes instead of pulls.<\/p>\n
But racecars aren\u2019t airplane wings.<\/p>\n
That depends on how you look at them. The only element necessary for lift-off is a shape that forces air to flow faster over it than under it. Stock cars utilize aerodynamics to go fast: when they\u2019re pointed in the same direction as they\u2019re moving, they act like an upside-down wing.<\/p>\n
The problems begin when a car starts to yaw. A car is yawed when the direction the car is heading isn\u2019t the same as the direction it\u2019s pointing, as I show in the video below of LaJoie\u2019s accident at Michigan in 2024. I\u2019m using this video as an example because the car is relatively isolated, and that gives us a chance to see the details of how it take flight.<\/p>\n
<\/p>\n Corey LaJoie\u2019s car gets airborne at Michigan International Speedway in 2024<\/p>\n The lift-off begins when the car is yawed about 90 degrees: The nose of the car is perpendicular to direct it\u2019s moving. Once that happens, air starts to get under the car, but it doesn\u2019t have an easy way out. At the same time, air continues to move quickly over the top of the car.<\/p>\n That makes the car behave like an airplane wing.<\/p>\n Why does the Next Gen car get airborne more easily than the Gen-6?<\/p>\n It doesn\u2019t.<\/p>\n Eric Jacuzzi is NASCAR\u2019s vice president for vehicle performance, and a Ph.D. aerodynamicist. They run comparison tests in wind tunnels between the current Cup Series car and the previous version (Gen-6).<\/p>\n \u201cThe liftoff speed is substantially higher with the Next Gen car,\u201d Jacuzzi said. Lift-off speed is the lowest speed at which the car could take to the air. So the Next Gen car is actually more resistant to flying than the Gen-6 car was.<\/p>\n Then why are cars still leaving the ground?<\/p>\n The Next Gen car is more robust than its predecessors. Contact in the Gen-6 car almost always meant body damage and a possible wheel rub. That\u2019s not the case for the current car, which allows drivers to be more aggressive, especially on restarts and when blocking.<\/p>\n The close proximity of cars during pack racing offers more opportunities for contact. Once one corner of a car gets even a little off the ground, the probability of it continuing into the air increases rapidly.<\/p>\n What about roof flaps?<\/p>\n After Rusty Wallace had scary flips in the 1993 Daytona 500 and at Talladega<\/a> the same year, NASCAR mandated roof flaps. You\u2019ll see a roof flap rise in the LaJoie video as soon as the car starts to turn.<\/p>\n The key to keeping cars on the ground is slowing down the air that goes over the car. A smooth surface allows air to travel quickly \u2014 and the roof is one of the smoothest places on the car.<\/p>\n Roof flaps deploy when the air pressure under the flaps becomes greater than the air pressure over the roof flaps. That means the force pushing the car up is larger than the force pushing the car down. The roof flaps are like a parachute that forces the air moving over the car to slow down.<\/p>\n NASCAR made the roof flaps larger in 2013. A larger parachute slows down more air, more quickly. Last year, just before the second Talladega race, NASCAR added a fabric gusset that adds to the parachute effect and slows the air down even more.<\/p>\n The problem is that the roof must also accommodate an escape hatch. Between the new, larger roof flaps and the hatch, there is simply no more room on the roof.<\/p>\n So what else can they do to keep cars on the ground?<\/p>\n The challenge is to devise mechanisms that don\u2019t slow down the car when everything is good, but that deploy quickly as soon as the car is in danger of becoming airborne. The graphic below shows a number of safety devices on the top of the car.<\/p>\n<\/p>\n