The mechanics of insect flight

It’s a Bird. It’s a Plane. It’s an Insect. Take a look as a team at Pennsylvania State University uses high speed cameras and fluid dynamics to understand the mechanics of insect flight.


It's a bird.

It's a plane.

It's an insect.

Take a look as a team at Pennsylvania State University uses high-speed cameras and fluid dynamics to understand the mechanics of insect flight.

When the Wright brothers studied flight, they studied the seagull.

Elegant and efficient, they were easy to observe and easy to emulate, but there was another type of flier on that desolate North Carolina beach.

It was more dynamic than the seagull, and it broke all of the rules the Wrights worked so hard to uncover.

The fly.

Based on what we know about flight, this guy should drop like a rock.

A group of Penn State scientists, led by Bo Cheng, are trying to figure out why it doesn't.

This is a relative simple question to ask but an extremely difficult one to answer.

It seems to require us to study various aspects of insect flight.

That includes their flight dynamics, their aerodynamics, the structure and functions of the biological sensors.

To most people, flies are pests, but to an engineer, these insects can perform tasks that have no equal in the natural world.

These tiny fliers, they only have a very limited amount of neurons.

However, they are able to solve extremely challenging flight-control tasks, like the upside-down landing on the ceiling within a split of a second.

This doesn't seem like a big deal, but keep watching.

Now imagine you're in an airplane, and the only way to land is upside down at a fixed location.

No existing aircraft is capable of performing this type of maneuver, and if it did, it would take an exceptional pilot to pull it off.

Flies do it hundreds of times a day.

Cheng's team is interested in their brains and their aerodynamics.

In fact, they use [Indistinct] and the rotational flow to generate lift, and that's something perceived as pretty bad for conventional engineer to flight.

The basics of conventional flight goes something like this.

As a plane speeds up, air splits above and below the wing.

The air at the top moves faster over the curve's surface, creating low pressure.

The pressure difference between the top and bottom of the wing creates lift.

Flies create lift another way.

When the wings are moving, they generate their own aerodynamic lift, but then the LEV, the leading-edge vortex, which is on top of that, introduces an extra suction force which pulls the wing further up and helps the insects to hover or just to just fly and not fall down, basically.

Think of the leading-edge vortex as a small tornado, a rapid swirl of air riding at the top edge of the wing.

Like the airplane, the fast-moving air creates low pressure, and that creates lift.

To study this, Cheng's team has created unique devices that help them contain the flies and record them at 5,000 frames per second.

So what we do is, we attach a fly to this end of the rod, and we sort of just put it back in, and what will happen is the fly will start flapping its wings, and it'll sort of fly in a circle.

Flight mill uses electromagnets to levitate the rod.

This keeps the fly on a predictable path.

Upside-down landings are recorded using this, a Plexiglas cube surrounded by lights and high-speed cameras.

Essentially, we can track different points on the wing and then get the three-dimensional coordinates for these points on the wing or on the body, and then we can essentially reconstruct the wing motion as well as the tiny deformation of the wing, and then we will have a full understanding of the kinematics of the flight.

The team is also partnering with the University of Virginia to understand the fluid dynamics.

They want to know how wing movement can affect the stability of that leading-edge vortex we just talked about.

The team is also looking to the future.

Humans have already harnessed the power of flight, but can we take it to the next step and copy the complex movements and reaction time of bugs?

Right now, there are robotic fliers that can mimic the basic mechanics of an insect, but according to Cheng, a mechanical device capable of something like this is still decades away.

For now, all we can do is watch and learn.