Category: Techie

Rotating bouncing disks, tossing pizza dough, and the behavior of ultrasonic motors.

“Pizza tossing and certain forms of standing-wave ultrasonic motors (SWUMs) share a similar process for converting reciprocating input into continuous rotary motion. We show that the key features of this motion conversion process such as collision, separation and friction coupling are captured by the dynamics of a disk bouncing on a vibrating platform. The model shows that the linear or helical hand motions commonly used by pizza chefs and dough-toss performers for single tosses maximize energy efficiency and the dough’s airborne rotational speed; on the other hand, the semielliptical hand motions used for multiple tosses make it easier to maintain dough rotation at the maximum speed. The system’s bifurcation diagram and basins of attraction also provide a physical basis for understanding the peculiar behavior of SWUMs and provide a means to design them. The model is able to explain the apparently chaotic oscillations that occur in SWUMs and predict the observed trends in steady-state speed and stall torque as preload is increased.”

Photo: flickr/Jeff Kubina

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from Discover Magazine

Filed under: Etc., Citroën, Motorcycle, Specialty, Design/Style

According to Merriam-Webster, ingenuity can be defined as “skill or cleverness in devising or combining” or “cleverness or aptness of design or contrivance.” We’d say that’s an apt description of a Frenchman named Emile who reportedly found himself stranded in the deserts of Northwest Africa after breaking a frame rail and a suspension swingarm underneath his Citroën 2CV.

What to do? Why, disassemble the broken hulk and build yourself a motorcycle from its pile of parts, of course! As the story goes, Emile was able to use the inventive machine to escape the desert, though not before convincing the local authorities that he wasn’t an insurgent and paying a fine for importing a non-conforming vehicle…

Since Emile was the only soul in the area, nobody has been able to confirm the veracity of the events that led to the little French runabout’s conversion into a makeshift motorcycle. That said, judging by the images you can see here (apparently from the March 2003 issue of 2CV Magazine), this Citroën-bred two-wheeler does indeed exist, and it was definitely fashioned from parts scavenged from an old 2CV.

Emile, wherever you are, we take our hats off to your real-life MacGyver skills, sir.

Man stranded in desert builds motorcycle out of his broken car originally appeared on Autoblog on Wed, 23 May 2012 14:01:00 EST. Please see our terms for use of feeds.

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