I recall reading somewhere (I think Skeptical Inquirer) about the origin of the urban legend about not understanding how bumblebees can fly. IIRC, it relates to a story about a dinner party in the early part of the 20th century. In a dinner party discussion, some biologist and an engineer got into a discussion of the bumblebee and the tiny size of its wings vs its large body. The engineer pulled out a napkin and did a “back of the envelope” calculation using basic aerodynamics to see if it was possible. He used a lot of basic simplifying assumptions, and got a negative answer. This was intriguing, to say the least, since clearly they fly.
Subsequently the engineer went off after the party to investigate what was wrong with his model. He studied their wings under a magnifying lens. There he discovered the source of his mistaken assumption. He had used a standard flat plate for the wing shape. But under a magnifying glass he discovered the wings are layered with veins and actually resemble a standard airfoil shape. Plugging in the new model, the calculations did verify the flight ability of the bumblebee. Thus the problem was resolved.
However, there were still people at the party who heard him do the calculations and get the negative result, and they spread the curious tale about the calculations and how the math proves bumblebees shouldn’t be able to fly. Thus an urban legend is born.
Maybe I’ll see if I can’t dig out that copy of the magazine somewhere…
The real challenge with bees wasn’t figuring out the aerodynamics but the mechanics: specifically, how bees can move their wings so fast–roughly 200 beats per second, which is 10 or 20 times the firing rate of the nervous system.
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I’m not sure what “the firing rate of the nervous system” is supposed to mean, but neurons can fire faster than 10-20 Hz.
Jeremy. Are you referring to the speed at which an impulse can travel from neuron to neuron, or the time it takes for a neuron to restore its potential?
I believe it was the Discovery channel that did a special on bees.Has something to do with how they return their wings to start that increases lift. Don’t remember any particulars.
never feed an intoxicated man coffee
NOBODY likes a wideawake drunk
I was given a plaque many years ago that says the following:
The Bumblebee Cannot Fly -
According to recognized aerotechnical tests, the bumblebee cannot fly because of the shape and weight of his body in relation to the total wing area.
But the Bumblebee doesn’t know this, so he goes ahead and flies anyway.
Through the years I’ve seen many references to this old chestnut. The best pointer to the origin I’ve found was that during World War II, at the height of the frenzy to crank out fighter aircraft designs, most designers depended on a stack of design charts and nomographs to predict a design’s performance. After all, computers were essentially still in the future. Once, for fun, someone in the field tried seeing how a bumblebee’s performance would be predicted with those charts. The results were that it “couldn’t” fly. Thus the above bromide.
Of course, the design charts for fighter and bomber aircraft weren’t intended for bumblebee sized objects, so the designer merely scaled the poor bee up to fit. And indeed, a 32 foot long 40 foot wingspan bumblebee weighing about 30 tons really wouldn’t fly. Much to the relief of those allergic to stings, I’m sure!
I’ve not found a reference on the Web to the WWII designer story - and having subscribed to a number of aeronautical magazines since the '60s I can’t begin to be sure where I read it. Sorry about that. But it makes sense to me.
On another thread the ‘everyone knows a Bumblebee can’t fly but the Bumblebee’ argument got me interested. When I’m interested I often go surfing. In surfing I found the RoboFly has definitively answered the question.
Kudos to CheapBastid for a most excellent post. I am consumed with envy. If you will excuse me, I must now go to my secret la-BOR-atree to plot my fiendish revenge…
“Why, sometimes I’ve believed as many as six impossible things before breakfast!” - the White Queen
Saw this article on Scientific American today, regarding recent research into the flight of insects. You might find it interesting if you like the itty bity details…
I was reading my son some books last night before bed. One of the books was Rabbits and Raindrops by Jim Arnosky and it had a line about how the bumblebees kept dry by flying between the raindrops. The idea of a bumblebee being able to maneuver between rapidly falling raindrops seems pretty unbelievable. Does anyone have any idea if this is possible?
The issue is about scaling between the full-size aircraft and the insects wing. On the way between these sizes live the model aircraft fraternity. Ask them about ‘Reynolds Numbers’.
Briefly, airflow is not a simple phenomenon which behaves the same way under all conditions. You know how air starts flowing differently when you go faster than sound? Well, it also behaves differently when you consider very small distance flows.
Calculations for normal aircraft are often done using ‘Navier-Stokes’ equations - mathematically considering air to be divided up into unit chunks and working out what effect each chunk has on the other chunk. These equations are estimates, not precise definitions, and the assumptions they are based on break down when the Reynolds Number gets low enough.
Effectively, the Reynolds Number is a description of the scale you are working at. You can appreciate that, while you can scale down wings, you don’t usually scale down the viscosity of the air at the same time. So an alternative way of looking at the problem is to understand that the bee (and most birds) are working in air which is much ‘stickier’ relative to their size. Unsurprisingly, estimates which are appropriate to a large aircraft do not work for a greenfly.
So if you feed insect data into Navier-Stokes equations you get incorrect results out. All aerodynamicists would know this and understand why. I suspect that a comment by a teacher during a lecture may be the origin of the joke that goes ‘Aircraft designers have proved that a bumble-bee can’t fly’.
Interestingly, little work is done on very low Reynolds Number aerodynamics. There is no commercial need for it, and most aeromodelers design aircraft without the benefit of reliable wind-tunnel data. A wing of 6" chord travelling at about 15 mph is right in the middle of the ‘critical’ Reynolds zone, where discontinuous and erratic effects may be expected, so it is unlikely we will ever get the kind of certainty that full-size designers work with.
