The bumblebee flight fallacy

There’s an old saying along the lines of, “Aerodynamically, the bumble bee should not be able to fly, but it does not know that and does so anyway.”

I’ve heard the saying dozens of times and even said it myself. People use it as a feel-good analogy to encourage perseverance and positive attitudes. But is it true?


I’d never really thought much about it until I ran across it on The Pinking Shears, of all things, a website dedicated to serving as a refuge for those stung by direct marketing companies (Mary Kay in particular). Hmmmmm.

Here is their answer, as given on their Grand Illusions page:


REALITY CHECK: This analogy has been repeated ad nauseam in Mary Kay by Directors, Consultants, and Mary Kay Ash herself. See the links and explanation below for the real story.

http://www.howstuffworks.com/news-item223.htm

http://en.wikipedia.org/wiki/Bumble_bee

According to Cornell University physicist Z. Jane Wang, computer simulations of insect flight may help aerodynamic engineers design tiny insect-like flying machines. The simulations could also dispel the myth that bumblebee flight violates the rules of aerodynamics.

The notion that bumblebee flight is impossible according to the conventional rules of aerodynamics is a reflection of the poor understanding of aerodynamic principles in the early 20th century, said Wang, an assistant professor of theoretical and applied mechanics. Insects fly in a sea of vortexes they create by moving their wings. A vortex is a current of swirling air that moves against the main current of air. Wang has developed a new mathematical theory that explains how some insects can manipulate the flow of air around them, allowing them to switch from forward motion to a hovering position instantly.The study appears in the journal
Physical Review Letters.

Airplanes also create vortexes, but they are only minor nuisances that are left behind in a slipstream. Vortexes created by insects rapidly flapping their wings whip the air into a frenzy. Insects coordinate their wing movements to generate lift force and shed vortexes from the edge of their wings. Rotation of the wings in a figure-eight motion is the key to controlling lift forces and changing direction mid-flight.

To demonstrate this process, Wang developed a computer simulation that divides the airflow around the wing into a grid. She then calculated the flow of air at each point on the grid. The patterns that emerged provided some insight into how an insect coordinates its wing movements to create the vortexes it uses to hover.

Wang’s computer modeling may lead to the development of tiny flying machines that could be used for aerial surveillance and other tasks. The designs wouldn’t necessarily resemble the design of today’s fixed-wing airplanes or helicopters. Now that the rules for insect flight have been quantified, designs of bug-like machines of any size can be tested on a computer. Computer-designed virtual aircraft using these rules can hover, fly backward and perform acrobatic maneuvers.

Submitted by Annette
Source: Grand Illusion #5 on The Pinking Shears


Who’d have thought? I just thought that was interesting.

This entry was posted in Nature.

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