Spoilers can be very useful, but this is not always the case, especially on convertibles. This is the reason why they don’t work well.
Aerodynamics are essential in motorsport and ailerons are a must have On it. However, it appears that they are not as useful as expected in cases such as convertible cars.
The test has been done by YouTube channel KYLE.ENGINEERS, which is run by Kyle, a former Formula 1 aerodynamicist. Using a computer program to simulate the air flow in a first generation Mazda MX-5, he has found that most spoilers do not do their job, especially with the top down.
As can be seen in the test, the Japanese roadster loses 43% downforce when you go from wearing a hardtop to going open-top. This is so because of the windshield, which generates dirty air with low speed in the passenger compartment area, affecting the operation of this aerodynamic element.
The video indicates that this situation it can happen in any car that has a zone of low speed air behind the cabin, but it is especially the convertibles that are most affected by this.
In fact, as shown, for this reason almost all effectiveness is lost on any type of spoiler, big or small. Of course, they are not a useless element either, at least in the case of the most voluminous. As seen in the simulations, the ends of the aileron located out of the dirty air yes they fulfill their mission.
How can it be solved?
Still, this is still a problem, but might have some solutions. According to the ex-erodynamicist’s suggestions, an alternative would be mount a spoiler located at a height that allows it to stand out of the dirty air that is generated. In this way, it could exert its aerodynamic function and push the rear of the car down.
On the other hand, the other option he raises is ride a fastback type hardtopso that the rear window extends into the boot area. With this setup, the airflow would be smoothed and it would be more consistent, as well as better funneled towards the wing. With this solution, in addition, even a small dovetail spoiler could help.
Therefore, if you have a convertible with a spoiler, you may need to assess which of these options is the most recommended in your case. Of course, this mainly applies if you have a car more focused on competition. If it’s an everyday car, it may not be worth the investment.
This article was published on Top Gear by Sergio Ríos.