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Many creatures in the world can fly.
And some have that sleek, aerodynamic shape that tells you they were destined
to soar through the clouds. Birds look like flyers.
But there are also lots of flying critters that don’t even seem like they could get airborne.
Bumblebees, I’m looking at you.
Achieving aerodynamic flight isn’t always about being torpedo-shaped. Sometimes,
unique body plans make for some fantastic fliers --
or at least, gliders.
And researchers can learn a lot about flight and aerodynamics from these unusual creatures.
Here are 5 examples of unexpectedly good fliers that are inspiring
innovative inventions. And spoiler alert:
None of them are bees.
Flying fish are really good fliers, which is surprising, since a fish out of water
is not supposed to be a good thing.
Underwater, flying fish are some of the fastest swimmers,
capable of reaching speeds close to 60 kilometers per hour.
They use this speed to propel themselves out of the ocean and into the air,
where they glide along using their unusually large pectoral and pelvic fins like wings.
Gliding is a more efficient way of flying than flapping fins would be.
It helps them travel long distances and stay airborne for up to four hundred meters.
In 2010, researchers investigated the aerodynamics of flying fish
and determined they’re just as good at gliding as hawks and other birds.
They accomplish this by positioning their bodies close to,
and parallel with, the water’s surface.
That position maximizes their lift-to-drag ratio
It works much like airplanes when they come in for a landing.
Air rushes off the tips of the fishes’ wings in swirls known as vortices.
These swirls break up as they hit the water’s surface,
which reduces drag and builds pressure beneath their wings, keeping them aloft.
This process is known as the ground effect.
In this care, less ground, more water - same effect.
These fish can also get an extra boost by dipping their tails into the water
and pushing off mid-glide whenever they get too low.
This behavior is known as taxiing, which is another term we associate with airplanes.
Except luckily, airplanes don’t flap their tails against the runway.
Still, researchers are eager to learn more about how flying fish glide,
so they can apply those strategies to make better boats… planes…
actually, they’re boatplanes.
Specifically, they’re craft that use the ground effect to travel over water,
just like flying fish.
These boatplanes would cruise just above the water’s surface,
which reduces their drag in order to maximize their speed and fuel efficiency.
So, understanding the aerodynamics of flying fish could help engineers improve these vehicles.
While we’re on the topic of flying marine critters, it’s worth mentioning that some squid
are capable of flight! And yes -- researchers have argued that they’re really flying.
2. Flying Squid
Several squid species can fly over the water
and cover huge distances in a very short period of time.
The neon flying squid, for example,
reaches gliding speeds of eleven point two meters per second.
They’re only in the air for about three seconds,
but they can travel up to thirty meters.
Squid launch themselves above the ocean by
shooting a powerful jet of water out of their siphon.
That’s a muscular structure they use to suck oxygen-rich water into their gills –
or to push water out so they can swim and fly.
The squid can even control direction using their siphon,
so they can propel themselves in whichever direction they choose –
both beneath and above the waves.
Once airborne, they spread out their fins and arms, which generates lift
and helps them glide in a graceful arc.
For a long time, it was believed these creatures were launching themselves out of the water like
calamari rockets to escape predators.
But research published in 2013 suggests they’re also using this strategy to save energy.
Squid can travel almost four times faster in air than in water,
and once they’re gliding, their energy demands are lower.
So, this behavior may be a more efficient way to travel, especially during long commutes.
Researchers have been inspired by flying squid to create submersible
robots capable of jetting out of the water in much the same way.
These little robots are very efficient in
their power consumption as they transition from water to air,
something that has long been a challenge for engineers.
The robots could be used to patrol areas that are otherwise hard to reach, like flood zones.
Another creature that’s inspiring scientists
to build more efficient flying machines is the butterfly.
Which is weird --
because while butterflies are lovely to watch when they’re fluttering around your garden,
no one would ever call them speed demons.
However, researchers at Lund University in Sweden recently worked out that butterflies
are actually extremely efficient fliers. And it’s all thanks to their large, flexible wings.
The researchers put the butterflies in a wind tunnel. Not to blow the poor things away --
just to more easily study how they flew.
They found that as the insects lift their wings, the wings bend and cup,
creating an air-filled pocket between them.
At the end of the upward stroke, the wings collide in a clapping motion,
forcing the air pocket backwards and creating a jet of air that propels the butterfly forward.
And when butterflies beat their wings downward, it keeps them up in the air.
Researchers first described wing clapping in insect flight more than fifty years ago.
But this cupped clapping method is much more advanced than scientists ever imagined.
It helps the butterflies take off very quickly to escape a predator.
And it makes them twenty-eight percent more efficient at flying
than if their wings were rigid and couldn’t cup.
The researchers suggested engineers could apply
this type of flight and wing flexibility to small drones.
There are already drones that clap their wings on the upward stroke,
but none that incorporate cupping as well.
If drones were designed with flexible wings, they could achieve a cupped clap.
This would improve their efficiency, duration and range,
which are some of the most challenging hurdles for current drone designs.
And now on to a more annoying insect.
There’s nothing quite like watching a mosquito take off from your body full of your blood,
knowing you’ll soon be scratching the welt it left behind.
But how do these bloodsuckers fly away, undetected by their host,
with a full belly that often outweighs the bug itself?
It turns out, it’s all in the wings.
If mosquitoes used only their legs to push off their host, it would require
quite a bit of force to ensure a speedy departure.
Enough force, in fact, that it would send a signal to their host to swat at it.
So to avoid detection, mosquitoes start out by beating their wings
over five hundred times per second.
Only after their wings get going do they use their legs to push away from their unlucky victim.
But they don’t just flap their wings up and down.
They beat them in a figure-eight pattern,
which generates tiny low-pressure swirls of air called leading-edge vortices
that come off the fronts of their wings.
These vortices generate lift under the mosquito’s wings,
just like they do for flying fish and many other insect species as well.
But the mosquito adds a twist – literally.
As it flaps in a figure-eight motion, the angle of its wings changes
and catches the wake of the previous wing stroke.
This generates a whole new series of low-pressure vortices that
come off the back edge of their wings.
This added lift requires very little energy and is the key behind its stealthy escape.
But that doesn’t totally explain how they fly fast with full bellies.
To discover how they accomplish this feat, researchers in the Netherlands
compared unfed to fed mosquitoes, to see if they differ in their takeoff speed.
And they found that blood-filled mosquitoes compensate
for the added weight by increasing the size of their wing strokes.
They also angle their bodies more vertically so they can be almost as speedy as unfed mosquitoes.
Researchers hope to apply what they’ve learned about
mosquito aerodynamics to make stealth robots.
If these robots could use a similar technique,
it could help them land and take off without detection,
which is key to accomplishing a covert mission.
Insects and animals aren’t the only ones taking to the sky. Some plants do too.
Most of us have experienced the joy of blowing on a dandelion that’s gone to seed
and watching the little parasols fly every which way.
But I don’t think many of us have stopped to consider the
aerodynamics behind those little seeds’ flight.
And it turns out these seeds are flying using a method that,
until recently, researchers didn’t even think was possible.
Like mosquitoes and flying fish, dandelion seeds rely on swirls of air, or vortices,
to generate lift and keep them afloat.
But scientists always thought these vortices had to be in contact with something, like the
front edge of a wing. If they just swirled around unattached, they would be too unstable to persist.
Except this is exactly how dandelion seeds stay up in the air.
The filaments of the seeds – those wispy parts that radiate out from the central stalk –
create the vortices.
Or rather, the space between these filaments creates the vortices.
The air above the filaments swirls around, unattached,
and creates drag that prevents the seed from falling to the ground.
Dandelion seeds always have 90 to 110 filaments. And this turns out to be a very
important component to their successful flight.
When researchers mimicked the design of a dandelion seed,
they found that deviating too much from that general pattern would become unstable.
Interestingly, many insects also have these filament-like structures on their wings or legs,
which suggests they may be using this same technique as they fly.
All these seeds, squid, fish, and insects evolved
incredible strategies that challenge current ideas of what flight should look like.
So when it comes to developing flight technologies, some researchers are thinking
outside the box by remembering that the greatest innovator in the universe is nature itself.
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