We’ve all been there before… running late for a flight, needing to get to a gate to check in, dragging your suitcase or carry-on luggage behind you when all of a sudden it just starts to flop all over the place, eventually just giving up and falling over. It turns out that suitcases aren’t just inherently evil, wanting you to be late for your flight, or to generally just inconvenience you. Researchers in Paris have gotten to the bottom of this phenomenon, with extensive testing to show exactly why your luggage becomes unstable.
This most pressing of modern mysteries was taken on by physicists in Paris, who devised a scale model of a two-wheeled suitcase rolling on a treadmill and backed up their observations with a pile of equations and references to holonomic restraints, finite perturbations and the morphing of bifurcation diagrams.
Just in case all of those big fancy words don’t mean anything to you, the overall gist is pretty straightforward: your suitcase becomes unbalanced when it hits a bump or is otherwise struck during your mad dash through the terminal. The faster you’re going, the less force is required to sent your luggage wobbling out of control. That all makes sense, but the researchers wanted to know more. Why does the suitcase wobble so violently and how do you best get it back under control? The “why” turned out to be pretty straightforward too.
After more treadmill tests and more equations, the answer popped out: because a suitcase’s handle pulls from the middle and the wheels are at its sides, the suitcase swerves inwards whenever it tilts up on one wheel. If the rocking overcomes the dampening effect that happens when each wheel touches the ground again, the suitcase will keep on rocking or eventually flip over.
Their ultimate takeaway though, came when they determined that unbalanced luggage can more easily be righted when pulled faster, when your natural reaction is probably to slow down. Easier said than done when you’re in a crowded airport, or trying to navigate a parking garage, but at least the science is there to help you explain to your fellow travelers why you’ve knocked them over (don’t really knock over any of your fellow travelers, that’s just poor form). You can check out the video below to see some of the experiments that were run to answer this important question.
As for how to avoid getting your suitcase tumbling all over the place? The researchers say you should simply “decrease the angle of tilt with the horizontal in order to reduce the coupling into sideways motion.” Easy right? More simply, lower the handle of your suitcase, that should help. Alternately, you could investigate luggage with four wheels, which should conceivably be more stable.
Last Updated on June 25, 2017.