How its Possible for Bumblebees to fly?

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Discussion Overview

The discussion revolves around the aerodynamics of bumblebee flight, specifically addressing the common assertion that bumblebees should not be able to fly based on traditional aerodynamic theories. Participants explore various aspects of this topic, including the mechanics of wing movement, the role of vortices, and the implications of low Reynolds numbers in insect flight.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Exploratory

Main Points Raised

  • Some participants assert that traditional aerodynamic theory suggests bumblebees cannot fly due to their wing-to-body weight ratio.
  • Others argue that this belief is an outdated myth that fails to consider the complexities of bumblebee flight.
  • It is noted that bumblebee wings do not merely flap; they also twist, which contributes to their flight capabilities.
  • Participants mention that the low Reynolds numbers at which bumblebees operate significantly alter the aerodynamic principles, making viscosity more important than streamlined shapes.
  • There is a discussion about the role of wingtip vortices in bumblebee flight, with some claiming that these vortices are crucial for generating lift.
  • Some contributions highlight the energy efficiency of bumblebee flight, mentioning the use of elastic properties in their muscles that reduce energy expenditure.
  • Motor-powered models of flapping-wing aircraft are referenced, with some success noted, while human-powered models are described as less effective.
  • Humorous remarks are made about the idea of asking bees for their perspective on flight and the origins of flying concepts.

Areas of Agreement / Disagreement

Participants generally disagree on the validity of the claim that bumblebees cannot fly according to traditional aerodynamic principles. Multiple competing views are presented regarding the mechanics of bumblebee flight and the factors influencing it.

Contextual Notes

The discussion highlights limitations in traditional aerodynamic theories when applied to bumblebees, particularly regarding assumptions about wing shape and flight mechanics at low Reynolds numbers. There are unresolved questions about the implications of these factors on the understanding of insect flight.

josephcaritel
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As per Aerodynamics theory, Bumblebees can't fly, prove it how can they fly,
Their wing to body weight ratio is very critical to prove,
And we have not succeeded to do aircraft with flapping wings.
http://library.thinkquest.org/08aug/02343/Pictures%20-%20Bumble%20bee/bumble%20bee.jpeg
 
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josephcaritel said:
As per Aerodynamics theory, Bumblebees can't fly ...
Nonsense. This is an old urban myth that just won't die.
 
The original concept didn't take wingtip vortices into account. Bees' wings don't just flap; they twist.
 
Danger said:
The original concept didn't take wingtip vortices into account. Bees' wings don't just flap; they twist.

The version I heard is that the myth originated when someone didn't take into account the very low reynolds numbers at which bumblebees fly. The aerodynamic principles change quite a bit in this flow regime - viscosity becomes more important, while having a nice, streamlined shape becomes a whole lot less important (especially for the lifting surfaces, such as the wings).
 
cjl said:
The version I heard is that the myth originated when someone didn't take into account the very low reynolds numbers at which bumblebees fly. The aerodynamic principles change quite a bit in this flow regime - viscosity becomes more important, while having a nice, streamlined shape becomes a whole lot less important (especially for the lifting surfaces, such as the wings).

I was unaware of that one, but it seems logical. There is no doubt, though, that the vortices are a major contributor. If you watch extreme slow-motion movies of the wings, you'll see that there is a tremendous "whiplash" imparted by the outer extremity when it snaps around. (The closest analogy that I can think of is the wrist action of a person throwing something.)
 
josephcaritel said:
As per Aerodynamics theory, Bumblebees can't fly, prove it how can they fly.
There have been several versions of how this misconception came to be. Wiki article mentions a few possibilities:

wiki_bumblebee_misconceptions.htm

The other issue is the amount of energy consumed by bumblebees or hummingbirds during flight, but they rely on rubber band like muscles (and/or flexible membranes for some insects) that vibrate elastically, reducing the energy required to maintain flight.

josephcaritel said:
And we have not succeeded to do aircraft with flapping wings.
There are motor powered models that fly. Human powered models haven't done very well. Wiki article:

http://en.wikipedia.org/wiki/Ornithopter
 
rcgldr said:
There are motor powered models that fly.
May favortite one, because it bends the wings like a bird, not just flaps them:

https://www.youtube.com/watch?v=nnR8fDW3Ilo

rcgldr said:
Human powered models haven't done very well. Wiki article:

Not self starting, but sustained flight for a while:

https://www.youtube.com/watch?v=0E77j1imdhQ

I'm not sure if they were limited by the stamina or just by the available space to land safely. Human powered propeller planes flew tens of kilometers.
 
Last edited:
josephcaritel said:
As per Aerodynamics theory, Bumblebees can't fly, prove it how can they fly,
Their wing to body weight ratio is very critical to prove,
And we have not succeeded to do aircraft with flapping wings.
Ask the bees. They do not follow our preconceptions.
 
turbo said:
Ask the bees. They do not follow our preconceptions.

:smile:

And I'd love to hear their version of "the birds and the bees". (It's always been my contention that the bees would be food in that relationship, but maybe that's why I don't have children.)
 
  • #10
turbo said:
Ask the bees. They do not follow our preconceptions.

Man Got the concept of Flying from Birds, Not by Asking Bro...
 
  • #11
Danger said:
I was unaware of that one, but it seems logical. There is no doubt, though, that the vortices are a major contributor. If you watch extreme slow-motion movies of the wings, you'll see that there is a tremendous "whiplash" imparted by the outer extremity when it snaps around. (The closest analogy that I can think of is the wrist action of a person throwing something.)

Oh, certainly. Vortices are crucial to bumblebee flight - the wings undergo a stall on every wingbeat which causes the shedding of a fairly sizeable vortex. The very low reynolds number causes this to affect substantially more air than you would otherwise expect given the wing size as well, so the combination of low reynolds number and vortex formation allows flight with a surprisingly high wing loading (when compared to the wing loading of objects at scales we are more used to dealing with).
 

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