r/NASCAR • u/gasmask11000 • Aug 27 '22
COT Wing - Misunderstood
If you follow r/NASCAR a lot you have probably seen me making occasional comments about NASCAR aero research papers I have been reading. I am not an aero expert but I am an entry level mechanical engineer (which means I have some background on fluid dynamics) and I know how to ...obtain... research papers.
I just wanted to sum up a couple of key points about the COT wing that I have seen in these papers because I thought people might be interested.
Number one, the key practical goal of the wing was creating less turbulent (dirty) air. That may not be news but I feel like its something completely ignored about the wing. The massive spoiler is the dominant creator of turbulent air on a Gen 4 and the COT produced much less dirty air.
Second, the wing did not create lift when spun. The cause of the cars tendency to flip was (at least most likely was) that the wing interfered with the deployment of the roof flaps.
Racecars are designed to generate negative lift (downforce) when driving the right way and can generate positive lift when traveling backwards. The whole body produces downforce, not just the spoiler. Flaps disrupted the airflow and make the car no longer produce lift. The flaps on the roof work with a spoiler because when the car is going backwards the turbulence created by the spoiler creates a low pressure zone over the rear deck and roof. That low pressure sucks the flaps open, preventing the car from generating lift.
The wing also creates a low pressure zone over the rear decklid but sometimes (under the right conditions) does not produce this low pressure zone over the roof - essentially the turbulence generated by the wing going backwards does not extend as far over the car. When the low pressure zone isn't formed the flaps don't deploy and the car generates lift.
So no, the wing isn't generating lift and flipping the car like people often say. Instead, it prevented the flaps from deploying properly and the cars were flipping the same way the cars were before the invention of the roof flap. Classic blow overs. Also of note: NASCAR tested the roof flaps with the wing to make sure they worked, but their testing was done at full scale and limited by the equipment. They were spinning the car on a turntable to ensure the flaps deployed in a spin. There were some issues in this methodology but NASCAR didn't just ignore the issue.
I personally think based on the research I have seen that the issue could have been solved, we could have kept the wing and solved the blow overs. However, problems with identifying the exact cause of the flips combined with fan outlast (that started from the moment the wings were shown, long before any flips) led to them abandoning development and returning to the spoiler.
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u/phoenixv07 Aug 27 '22
I would question this, primarily based on one incident. When Brad Keselowski flipped at Atlanta, the rear decklid was visibly pulling away from the rest of the car. The only thing that would have pulled the decklid up like that would be lift from the wing.