It’s that time of year again. Every Cub Scout’s favorite time of year. Pinewood Derby time! Last year, my son took 3rd place in his Den (7th or 8th in the Pack). This year he is determined to do better. His words, not mine. As a responsible father (and engineer with access to the best design and simulation tools on the planet), who am I to squash his aspirations to take home the first place trophy?
We started by doing some research on tips for getting the fastest car. I stumbled across this video, which does a great job of simplifying the relationship between kinetic and potential energy. After all, this is a learning opportunity for the boys.
This year, we decided to focus mainly on weight distribution. I can think of no better tool than SOLIDWORKS to help with this. A few years ago they added the “Center of mass” tool so we can visually watch it move with design changes.
I started with a simple block of wood given to us by the Scouts.
Since we want the COM to be as far back and high up as possible, a simple “wedge shape” is the easiest way to start.
As you can see here, I also added the Center of Mass callout. This can be found in the Reference Geometry pulldown.
You can see from the image below, we are sort of moving in the right direction. The COM went towards the back, but also down.
But wait, it gets better! The Center of mass callout is live-updating! In conjunction with Instant3D, I can change the wedge cut and watch what the changes do to my COM IN REAL TIME!
So with the power of SOLIDWORKS, I can make very drastic design changes, but intelligent ones, that will positively impact my design.