The other day I was watching a You-Tube video with two kids riding a go kart with a roll cage. It was plunking along solidly when they took a hard corner and rolled the go cart.
That is one of the most frightening aspects of vehicle dynamics, rolling and flipping.
What causes it?
Good question, because there are a couple of factors that go into go kart stability.
To understand vehicle dynamics first the consideration of what the vehicle is expected to do must be considered.
The go kart that flipped had a 4 wheel independent suspension, which can give a false security of stability. If anything, it increases instability.
The factors of stability are:
– Wheel Base
– Center of Gravity
In the case of the rolling go kart, it had two things working against it from the outset:
– Too many riders
– Too high of a center of gravity.
Additionally, when a corner is taken with a suspension go kart, the suspension gives on the side of the corner, causing the center of gravity to have an easier time to roll the go kart.
I call this the book case diagram. What?! Yes the book case diagram.
We have all seen the extremely funny movies where some yahoo pushes on a book case in a library and causes a domino effect on all of the bookcases in the library.
We can sense that the book case is highly unstable. In fact we know that if the bookcase were put back down full of books, that there is no way that you could tip it in any direction, you would have to take all the books out to even lift it.
The same goes for center of gravity locations on go karts or vehicles: the lower the center of gravity the better. In fact, if you could get the center of gravity below the pavement you would be really onto something!
The width of the go kart also comes into play. The wider the more stable the go kart is in cornering.
The actual calculation for stability comes into play using the width of the go kart, the height of the center of gravity, and speed of the go kart.
The force in cornering increases by the square of the speed of the go kart. So you increase your chances for flipping exponentially as you increase speed.
In order to keep a go kart stable, the speed, the height of the Center of gravity and the width of the go kart must be considered and designed into the go kart properly.