The Bumblebee That Science Supposedly Proved Couldn't Fly

What happened?

The best-documented starting point is Antoine Magnan, a French zoologist and aeronautical engineer who held a chair in animal mechanics applied to aviation at the Collège de France from 1929 until his death in 1938. Magnan was no armchair thinker. He studied birds, fish, and insects for lessons that might help build better airplanes, and in 1932 he even published work on filming insects at up to 12,000 frames per second to catch their wingbeats.

In 1934 he published Le Vol des Insectes (“Insect Flight”). In the introduction, he explained that he had borrowed the tools of aviation — the standard equations for air resistance and lift on a wing — and applied them to insects. Working with his assistant, the mathematician and engineer André Sainte-Laguë, he reported that the result was that “their flight is impossible.”

Here is the part the legend leaves out. Magnan kept writing. In the very next lines, he noted that insects obviously do fly and hold up their own weight at every moment, so nobody should be surprised that the calculation disagreed with reality. The mismatch, he said, came from the fact that nobody yet understood the aerodynamics of an insect wing, with its thick, stiff front edge and thin, flexible back edge. In other words, he was flagging a mystery, not declaring bees impossible.

There is a second, fuzzier origin story. According to accounts summarized by Science News in 2004, a prominent aerodynamicist in 1930s Germany was chatting with a biologist at dinner and did a quick “back-of-the-napkin” calculation of a bee’s lift. Using a smooth, rigid wing, the numbers came up short. Some versions pin this on students of the German physicist Ludwig Prandtl; others name the Swiss engineer Jakob Ackeret. No one has nailed down which, if any, of these dinners actually happened, so treat it as legend.

Either way, nobody knows exactly how a brief remark about insects in general became a story about bumblebees in particular. Perhaps it’s because the bumblebee simply looks the least likely to fly: a round, furry body that weighs close to a gram, carried on wings with an area of roughly a square centimeter.

Why was it strange?

Because the math wasn’t really wrong — the question was. The calculation treated a bee like a tiny airplane: a fixed wing gliding smoothly through still air. Run those numbers at a bee’s slow cruising speed, and the wing really can’t produce enough lift. As physicist Ken Zetie pointed out in Physics World in 1996, all it truly proves is that a bee with smooth, rigid wings can’t glide.

But bees don’t glide. They flap — fast. Depending on species and body size, bumblebees beat their wings roughly 150 to 250 times per second, sweeping and twisting them through every stroke. Applying airplane equations to that is a bit like using the rules of rowing to explain how a fish swims. The myth flips the real lesson upside down: it’s usually told to suggest scientists are blind to the obvious, when it actually shows how a model is only as good as its assumptions.

The same thread — Aerodynamics — continues in The Frisbee Salesmen Who Charged a Dollar for an Invisible Wire.

What did scientists learn?

Explaining insect flight took most of the 20th century. In 1973, the Danish zoologist Torkel Weis-Fogh, working at Cambridge, described the “clap and fling”: a tiny wasp claps its wings together over its back and then flings them apart, so air rushes into the gap and lift starts instantly instead of building up slowly.

In 1996, Charles Ellington’s team at Cambridge watched smoke curl over the wings of hawkmoths and a giant mechanical model nicknamed “RoboMoth.” They found a strong leading-edge vortex — a small, spinning tornado of air that sits on top of the wing’s front edge during the downstroke. Normally, tilting a wing that steeply would cause a stall, a sudden loss of lift. Insects get away with it because their strokes are short enough that the stall never fully arrives, a trick called “delayed stall.”

Then in 1999, Michael Dickinson’s lab at UC Berkeley built “Robofly”: a pair of 10-inch Plexiglas wings modeled on a fruit fly’s, flapping slowly in a tank of mineral oil so that the big, slow wings behaved like tiny, fast ones in air. Sensors measured the forces through every stroke. The team identified three mechanisms working together: delayed stall, “rotational circulation” (backspin on the wing as it flips at the end of a stroke, a bit like a tennis ball curving up), and “wake capture,” in which the wing hits the swirling air it left behind on the previous stroke and squeezes extra lift out of it.

“Engineers say they can prove that a bumblebee can’t fly,” Dickinson said at the time. Apply fixed-wing theory, he explained, and you really do get that answer — “You have to use something different.”

Another story that outran the evidence: The Army Captain Who Asked Congress to Fund a Trip Inside the Earth.

How does it affect us today?

The physics that finally “rescued” the bumblebee is now a design manual. Engineers building insect-sized flying robots, like Harvard’s tiny RoboBee projects, rely on flapping-wing aerodynamics rather than shrinking down airplane wings, because at that scale ordinary wings simply don’t work well. The same leading-edge vortices help explain the agility of hummingbirds and shape research into small drones that hover and dart.

And the myth itself lives on as a cautionary tale used in math and physics classrooms: before trusting a calculation, check whether it describes the thing you’re actually looking at.

Another claim that stuck harder than the correction: The Baguette Blamed for Overheating the Large Hadron Collider.

Fun fact

Antoine Magnan’s “impossible” line is followed almost immediately by his own admission that insects fly anyway — meaning the original source of the myth also contains its debunking.

Sources

• Magnan, Antoine. Le Vol des Insectes. Hermann, 1934 (primary source; introduction quoted and translated in Antoine Magnan — Wikipedia, citing the original).
• Dickinson, M. H., Lehmann, F.-O., & Sane, S. P. (1999). Wing rotation and the aerodynamic basis of insect flight. Science, 284(5422), 1954–1960. See also the UC Berkeley news release on “Robofly” (June 15, 1999).
• Ellington, C. P., van den Berg, C., Willmott, A. P., & Thomas, A. L. R. (1996). Leading-edge vortices in insect flight. Nature, 384, 626–630.
• Mikkelson, David. “Bumblebees Can’t Fly”. Snopes (quoting Ivars Peterson, Science News, 2004, and Ken Zetie, Physics World, 1996).
• Dickinson, M. (2001). Solving the mystery of insect flight. Scientific American, 284(6), 48–57.