Lessons from locust wings
First posted on homepage: 1 April 2013 (GMT+10)
Re-posted on homepage: 8 September 2021 (GMT+10)
The challenges confronting designers of small robotic aircraft are many. For example, fixed wings, like those used on passenger aircraft, become very inefficient in tiny robotic planes.1 So aeronautical engineers are looking at flapping wings as an alternative.
Researchers at the University of Oxford (UK) and the Australian Defence Force Academy decided to study locust flight because locusts are such efficient flyers.2
“They can fly for a very long time, over long distances with very little energy,” explained lead researcher Dr John Young.3 His team videoed locusts flying in a wind tunnel in order to identify “some of their tricks”.
Unfortunately for the engineers, who had hoped that simple flat wings (i.e. without the locust wings’ veins and corrugations) might suffice for miniature robotic aircraft, the wind tunnel videos and computer simulations revealed a hitherto unrealized design secret. As Science journal summed it up, “The complexity of insect wing venation directly affects the aerodynamics of flight via the intermediary of wing deformation.”4 In other words, the locust’s power and efficiency comes from the wing’s complex construction and in-flight control of wing shape.
“The locust is using the bending and folding of its wings to control its aerodynamics in a very efficient way,” Young said. “The results show that if you want to model the insect you have to get as much detail as you can and build wings that do most of what the insect wings do.” Any artificial wing that isn’t modelled on the “optimised” design of the insect wing is less efficient.
The researchers now plan to use their findings to build their own small robotic aircraft. These aircraft could be used to fly “anywhere you don’t want to send people, but need to navigate a complex environment,” e.g. for defence surveillance purposes or earthquake-affected buildings.
If merely copying locust wing design requires such thoughtful observation and intelligence, what does that say about the designer of those wings? And in other flying insects, too, the inherent design is increasingly obvious to aerodynamics engineers—e.g. the opening line of the locust researchers’ journal paper said (emphasis added):
“Insects achieve remarkable flight performance with a diverse range of complex wing designs.”
Surely, men are “without excuse” (Romans 1:20).
- This can be shown by the Reynold’s Number, Re = ρvl/μ—where ρ is density, v is mean velocity, l is a characteristic length and μ is viscosity. On a small scale, viscous forces dominate, so insects flying through the air are like us swimming through treacle. Return to text.
- Young, J., Walker, S., Bomphrey, R., Taylor, G. and Thomas, A., Details of insect wing design and deformation enhance aerodynamic function and flight efficiency, Science 325(5947):1549–1552, 18 September 2009. Return to text.
- Phillips, N., Locust wings to inspire flying robots, ABC News in Science, http://www.abc.net.au, 18 September 2009. Return to text.
- This Week in Science: Locust Wing Aerodynamics, Science 325(5947):1472, 18 September 2009. Return to text.