B13 aerodynamics - rear/side windows
I've pondered various aerodynamic ideas since I started building my track car. Looking for some thoughts from the gallery on aerodynamic issues when removing the rear window, and any benefit from replacing the rear side windows with Lexan.
Two of the racing series I'm looking at competing in, 24 Hours of LeMons and World Racing League both allow the rear glass window to remain intact. ChumpCar, however, requires that this glass be removed, with optional replacement with Lexan or similar material. I don't see Chump in my future for 2017, but after that, who knows. Side glass in the back must come out regardless of series, so in addition to the driver and passenger door windows being absent, I've got those two largish holes in the back to consider.
One site I've been reading over and over is Car Aerodynamics Basics, How-To & Design Tips ~ FREE!, lots of good information there. But, it doesn't really cover the situation with the various windows being removed.
One thing that I've heard from a lot of places is that with the rear window gone, fumes and air in general tends to get sucked into the car from behind. I've seen more than one video of a fire from the rear of the car getting sucked into the cabin as well, not a pretty sight. So, in general, having the rear window missing seems to be a bad thing from a race perspective. I'm still trying to understand exactly what's happening with the airflow that would cause it to get sucked back in like that, lower air pressure in the cabin from the side windows being open, and higher pressure from air traveling over the top of the car is my leading theory, but I haven't found any site that shows this modeled to confirm.
Those of you that have raced B13s, any thoughts to share or any experimentation that you may have done here?
Side issue, there seems to be a lot of lift in the middle/rear of the car from air moving over the top, and I know that the B13 spoiler is more for looks than being truly helpful. Any ideas for increasing downforce in this area would also be appreciated.
And for the record, I'm definitely overthinking this whole thing and 110% have delusions of grandeur.
Two of the racing series I'm looking at competing in, 24 Hours of LeMons and World Racing League both allow the rear glass window to remain intact. ChumpCar, however, requires that this glass be removed, with optional replacement with Lexan or similar material. I don't see Chump in my future for 2017, but after that, who knows. Side glass in the back must come out regardless of series, so in addition to the driver and passenger door windows being absent, I've got those two largish holes in the back to consider.
One site I've been reading over and over is Car Aerodynamics Basics, How-To & Design Tips ~ FREE!, lots of good information there. But, it doesn't really cover the situation with the various windows being removed.
One thing that I've heard from a lot of places is that with the rear window gone, fumes and air in general tends to get sucked into the car from behind. I've seen more than one video of a fire from the rear of the car getting sucked into the cabin as well, not a pretty sight. So, in general, having the rear window missing seems to be a bad thing from a race perspective. I'm still trying to understand exactly what's happening with the airflow that would cause it to get sucked back in like that, lower air pressure in the cabin from the side windows being open, and higher pressure from air traveling over the top of the car is my leading theory, but I haven't found any site that shows this modeled to confirm.
Those of you that have raced B13s, any thoughts to share or any experimentation that you may have done here?
Side issue, there seems to be a lot of lift in the middle/rear of the car from air moving over the top, and I know that the B13 spoiler is more for looks than being truly helpful. Any ideas for increasing downforce in this area would also be appreciated.
And for the record, I'm definitely overthinking this whole thing and 110% have delusions of grandeur.