Introduction to Car Design
Design Engineer, Merritt Kendzior, provides an overview of the Design Cycle, along with tips on modeling and documentation throughout your process. To access the powerpoint and follow along with the Youtube video, click on the button below the video.
Start with a goal for each design interaction
Think back to the scientific method that is used for science projects. In order to assess each variable in an experiment, you want to have independent and dependent variables. Independent variables are ones that are changed deliberately, while dependent variables may change as a result of changing the independent and may be linked to other dependent variables. If you change multiple independent variables at once during a test, you will be unable to attribute the result to any one variable specifically. This same phenomenon happens with design. If you have an iteration and then change four different measurements, after you perform virtual analysis you will be unable to know which measurement caused the positive change. For instance -
Let’s say you change the angle of incidence of your rear wing, along with the height, forward position, and thickness, all at once. After running the design in a virtual wind tunnel (CFD) you notice a significant increase in downforce. As a result, you assume that all four changes were bad for the design. However, in reality, all four variables work together to impact the new design. It could be the angle of incidence caused an increase in downforce but the height, forward position and thickness all had little (or even positive) effects.
When it comes to virtual analysis, you want to change only one measurement at a time. Document this change, run the iteration in your simulation and record the corresponding results.
Iterations vs Design Concepts
An iteration is often a small change to a specific measurement within your design. Iterations are often small changes that aren’t very obvious when looking at the whole car. This could be -
The angle of incidence of a winglet
Width of a wheel design
Wheelbase length
The thickness of a feature, such as your side pods
A design concept is when the design itself changes. Concepts often make the car look different. This could be -
Changing the shape of your cartridge chamber
Changing the winglet profile
Changing the wheel design to two bearings instead of one
Changing the shape of your side pods
Have a Plan (sketches, notes, etc) BEFORE you enter CAD
Before entering your CAD program and starting a design, you should always have a plan. This doesn’t need to be a completely dimensioned document for the entire car, but it should be enough of an idea where if you save your model and return the next day you’re able to remember what the goal/idea was. This is often done with hand sketches. Sometimes called “napkin-designs” because they can be as quick as scribbling an idea on a napkin, help guide your design when you need to be reminded of what your goal was.
“If you fail to plan then you have planned to fail.”
TIP: Compliance Sketches
A helpful tool to periodically check for legality in your design is compliance sketches. These can be as many or as few as needed for your regulations. The sketch is intended to be a quick visual check that you can toggle on/off during your design phase to see the maximum/minimum dimensions set by the rules. For instance, on the vertical reference plane, a sketch can be created to check the minimum and maximum wheelbase and/or overall car length.