Limitless side skirt

[joshjosh]

Just designed this interesting piece, any thoughts? It's for the Limitless, and I've based it off the Lotus 79 side skirts. Designed for 200mph speeds, it creates downforce without drag by utilizing Venturi principles. I have not printed these out yet, but they are based off my 54mm side skirt available on Thingverse. Still doing some testing. I may do a brace in the rear to stiffen it up where there's a large gap.

 

[rotauq]

Very interesting idea.

- Angle might be a little aggressive. Did you do any calculations or is it just utilizing the max volume?
- Will you dual lock the body to the side skirt?
- What filament have you planned? PLA will break quickly. Best go for more flexing PETG or ABS.
- Stiffening could be done by adding a inner-'wing' on the same angle at the big gap
- It might ruin the floor&rear diffuser aero. It think it's wise to make a little airdam between the floor and the sideskirt to seperate the airflow

 

[joshjosh]

Very interesting idea.

- Angle might be a little aggressive. Did you do any calculations or is it just utilizing the max volume?
- Will you dual lock the body to the side skirt?
- What filament have you planned? PLA will break quickly. Best go for more flexing PETG or ABS.
- Stiffening could be done by adding a inner-'wing' on the same angle at the big gap
- It might ruin the floor&rear diffuser aero. It think it's wise to make a little airdam between the floor and the sideskirt to seperate the airflow

Thanks for the reply!

I did use a foil calculator to come up with the angles. The parameters I used were target air temp 80 degrees F. Target height - 0 altitude. Air flow smoothness - average. Target speed - 200mph. In looking at the Lotus 79 skirts they also used what looks like an aggressive angle, both are trying to maximize the Venturi effects.

I was thinking something similar for stiffening. Just an extra piece down low in the rear to give it a little extra.

For the filament I pretty much exclusively use PC, and mostly PC-CF. I try to stick with 3DXTECH or Prusa.

The design is to have as much air flow in from right behind the front tire. It then uses that flow to generate the downforce. The side skirt compresses the air entering so it moves faster, then at the rear of the skirt it then slows the air down and releases it right before the rear tire. All that to be said, I don’t think air from under the chassis will be able to make its way to the skirts.

Here’s the design I attempted to capture

 

[Apex Zulu]

So, where is the link? I'm ready to print!

 

[Lennart]

Air flow smoothness - average.

I think I have the same airfoil generator in Fusion 360. But at that point, behind the front wheel, the airflow is very dirty.

I have an old and medium accurate CFD simulation of a limitless like model. In short there is low velocity low energy air behind the front wheel which wont generate any real sort of downforce or drag... Maybe put it further outboard to have access to clean airflow.

The pressure clouds on the left show slow moving air behind the front wheel. So the wing should almost be wider than the front wheel to get some clean air.
On the right the green lines show normal air speed and blue lines show slow low energy air.

Maybe some TPU rubber side skirts would be also a good idea