Talk Composites - The Forum for Advanced Composites

Racing Car Panels

http://www.talkcomposites.com/Topic32325.aspx

By Dezer - 3/13/2019 12:06:25 PM

Hello Friends, 


I'm with a project for a competition car model GT3 homologated FIA, my idea is an extremely light and resistant parts.

I wanted to consult with you that you have more experience if my idea is enough.
 The sandwich would be in the following configuration:

1 layer of carbon fiber 200 gsm (Twill weave)
Core Lantor Soric XF 3 mm
1 layer of carbon fiber 200 gsm (Twill weave)

The parts are as follows:

- Front Bumper
- Side Skirts
- Front Fenders


Thanks! 
By Hanaldo - 1/26/2020 5:20:13 PM

 
syahnoo84 - 1/25/2020 4:48:44 AM
 
Hanaldo - 6/4/2019 11:08:12 AM
I disagree. His layup is extremely heavy for a track car. The core is not lightweight, it's very heavy for a core material. It will not compress under vacuum at all - autoclave pressure is a different story of course.

I make race car panels for a living, it's virtually all I do. Any car with panels thicker than 2mm thick is at the back of the pack, that's for sure. All of my race car panels are 1 layer of 240g carbon and 1 layer of 450g carbon and that's it. Hell, some of them are just 2 layers of 240g. Most of them last forever, some of them need to be replaced every now and then - that's mostly splitters that wear through from hitting curbs. Occasionally might get a hole in a side skirt or a crack in a front bumper, but there would be hundreds of laps in between.

I certainly don't use Kevlar in any panel except perhaps the bottom of splitters or undertrays, and thats just to give them a bit of abrasion resistance to get a few extra races of out of them. Kevlar doesnt add 'give'. It holds the panel together when it fails. Realistically, it makes the panel weaker for a given weight, as it takes less energy to break than if that same panel were solid carbon. It is required by regulations in certain race categories for safety, but other than that it is a total waste of time in most amateur level race cars.

Thing is, if you have the moulds then making a replacement panel is cheap when they are lightweight. Especially if you are laying them up yourself and not paying for any labour. Non-structural race car panels should be as flimsy as they can be without the wind speeds punching a hole in them. For carbon panels, that means paper thin.

Hanaldo, what about front splitter that need stand huge downforce? how did you construct them?

Bit of a complex question really, and a lot depends on the budget and the application. Can be anything from a simple solid foam core (on the heavier side of things) to a hollow construction with spars (the lightest method). Basic principle is that the skins take the torsional loads (twisting), and your internal support structure takes the lateral loads. There are some torsional forces on a front splitter, so your skins need to be relatively thick (At least 1.5mm), but you are looking at a lot of bending forces as well, so if you are not using spars then the splitter itself needs to be quite thick to be stiff enough. Spars can make the design much much stiffer, so are lighter and cab cut down on total thickness.

A proper splitter needs to be mounted properly as well, meaning directly to the chassis. So you also have to consider how you achieve that, and how you transfer the loads from the splitter to the chassis.

This is a splitter that I made for a local time attack car, total weight is 4.8kg. Producing 250kg of downforce at 200km/h in free air.