Aerostream Mk2 - Initital Design Ideas

Key Requirements
Before I start modelling the design there are some key requirements I need to consider. I learned a lot from building Aerostream Mk1 and I want to incorporate those ideas into this kart. The key points are:

• Maximum length - 2300mm

• Maximum width - 900mm

• Reduce the height as much as possible to reduce frontal area

• Steel frame to improve the strength of the gravity kart for any possible impacts

• Disc brakes to allow more control over braking at higher speeds

• Low rolling resistance bearings

• Suspension with limited travel to absorb bumps and improve control of steering.

Reducing Drag
As I am designing this kart from scratch I want to ensure that the drag is a minimum. Drag can be calculated using this formula:

The design of the kart has an impact on both the drag coefficient and the reference area. The reference area is the frontal area, so the smaller you can make the frontal area the lower the drag. The drag coefficient comes from the shape of the kart and isn't something you can calculate in advance but can be calculated from simulated wind tunnel testing. I want to create a CAD model of Aerostream Mk2 so I can then carry out wind tunnel testing on different version of the design to see which shape will give the lowwest drag coefficient. This initial 3D model testing will allow me to fine tune the final design before starting any manufacturing.