Naked Science Forum

Non Life Sciences => Technology => Topic started by: EvaH on 26/11/2018 10:57:43

Title: Could aeroplane wings be designed to mimic dragonfly wings?
Post by: EvaH on 26/11/2018 10:57:43
David wants to know:

On a Naked Scientists show, your guest discussed dragon fly wing adaptations for turbine blades. What about aeroplane wings? Maybe only top or bottom?


What do you think?
Title: Re: Could aeroplane wings be designed to mimic dragonfly wings?
Post by: evan_au on 26/11/2018 20:55:29
The behavior of a wing varies with the Reynolds number, which is in turn affected by the size of the wing.
To a small creature like a bee or dragonfly, the air is very viscous; to a plane big enough to carry human passengers, the viscosity and design considerations are very different.
So you can't just scale a wing up or down by many orders of magnitude, and expect it to behave the same.
While we can no doubt learn from insects, it will need considerable adaptation to work on a human-carrying scale.
See: https://en.wikipedia.org/wiki/Reynolds_number
Title: Re: Could aeroplane wings be designed to mimic dragonfly wings?
Post by: Petrochemicals on 06/12/2018 02:58:39
https://www.dailymail.co.uk/news/article-2708631/Mother-s-terror-8in-Jurassic-sized-dragonfly-flying-round-living-room-like-mini-helicopter.html

Yes theoretically, but due to an airoplane weighing something like  ten million times as much, you would have to generate ten million times the lift, and the actual engineering involved would be incredibly hard. The forces are mindboggling that are involved in making a 20m wing ossilate fast enough to stop the plane decending, the fuel needed to power the ossilations would be huge as most of the energy would be spent moving a very heavy wing very fast back and forth.

It is all to do with the  square cube rule and gravity, bigger birds use alot more effort to take flight.

https://en.m.wikipedia.org/wiki/Square%E2%80%93cube_law

With thicker air in the jurassic dragonflies could grow bigger, but now they are limited to current standards, the more that you can rely upon the surface area of your craft resisting the air the bigger you can get. Small spiders can actually sail into the air many miles up on their air friction.

https://en.m.wikipedia.org/wiki/Meganeura

https://en.m.wikipedia.org/wiki/Ballooning_(spider)