February 13, 2012
Research Finds Top-Heavy Flying Objects Maintain Balance Best
Contrary to popular belief, it is actually easier for top-heavy structures to maintain their balance while hovering in midair than those with lower centers of gravity, claim scientists from New York University (NYU).
According to UPI reports on Saturday, the findings counter commonly held theories that an even distribution of weight is the best way to achieve flight stability. The NYU researchers reportedly tested a series of "pyramid-shaped 'bugs' constructed from paper that hovered when placed in an oscillating column of air, mimicking the effect of flapping wings."
"To see which types of structures best maintained their balance, the researchers created both top-heavy bugs with a weight above the pyramid and low center-of-mass bugs with the same weight below," the news organization added. "They said they were surprised to find the top-heavy bugs hovered stably while those with a lower center of mass could not maintain their balance."
The researchers recorded their experiment using high-speed videos in order to analyze the nature of the airflow surrounding each of the bugs, NYU said in a press release. When the top-heavy bug tilted, they witnessed the swirls of air ejected from the far side of the object would automatically adjust in order to keep it from tilting over. The aerodynamic forces provided stability for the bugs, the university said.
The researchers believe that they could use what they learned in their experiment in order to design and improve stable flying robots with flapping wings that can maneuver easily.
"It works somewhat like balancing a broomstick in your hand," lead researcher Jun Zhang, a Professor at NYU´s Courant Institute, said, according to Trent Nouveau of TG Daily. "If it begins to fall to one side, you need to apply a force in this same direction to keep it upright."
Joining Zhang on the project were postdoctoral researchers Bin Liu, Leif Ristroph, and Stephen Childress, all of the Courant Institute, and Annie Weathers, a formed NYU undergrad who now studies mechanics at the University of Texas, Austin. The university reports that funding for the study was provided via grants from the National Science Foundation (NSF) and the U.S. Department of Energy.
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