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  (Source: infoniac.com)

  (Source: BBC News)

  (Source: wikimedia.org)
A tiny machine flies like an insect; offering great promise in the field of aerodynamics.

How does a butterfly balance itself to float on air?  This is what some Japanese researchers have been trying figure out and it appears that they have done just that. Scientist Isao Shimoyama of the University of Tokyo and Hiroto Tanaka of Harvard University have successfully built and flown an artificial swallowtail butterfly.

Shimoyama and Tanaka did not skimp on details when developing this miniature marvel.  The two researchers copied the wing size and shape.  They even replicated the tiny little veins that cover them, on the life-size, robotic butterfly.  This development shows promise in the field of biomimetics.

The flapping-wing powered, tiny machine proved that controlled motion is not needed for forward flight, that forward flight can be achieved through flapping alone.  By replicating the size and shape, Shimoyama and Tanaka discovered that the butterfly uses its body motions to control flight aerodynamics.

The two scientists had their study, "Forward flight of swallowtail butterfly with simple flapping motion," published in the journal Bioinspiration & Biomimetics.   According to the study, "during the flights, the artificial butterfly's body moved up and down passively in synchronization with the flapping and followed an undulating flight trajectory like an actual swallowtail butterfly."

The development of this flapping-wing micro air vehicle (MAV) could prove to be very useful in the field of aerodynamics.   A similar nano air vehicle (NAV) study was conducted last year involving an artificial hummingbird.  The research was related to a DARPA project and involved the controlled hovering flight of air vehicle systems.

One significant difference in the findings between birds and butterflies was that birds use feathering to achieve lift.  Since butterflies fly without feathers and their fore wings partially overlap their hind wings, they instead use flapping to achieve lift.


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confused
By hughlle on 6/21/10, Rating: 0
RE: confused
By Danish1 on 6/21/2010 9:44:11 AM , Rating: 1
Birds glide, butterflies don't.

afaik.


RE: confused
By 91TTZ on 6/21/2010 2:59:29 PM , Rating: 2
Butterflies do glide. They tend not to, though, probably because they make a tasty meal for birds so they need to fly as erratically as possible. But I've seen them glide plenty of times.


RE: confused
By Sanity on 6/21/2010 9:55:20 AM , Rating: 3
I'm going to guess that the statement they made is trying to say that birds flap their wings to get forward motion, which in turn produces lift by means of the airflow over the feathers of the wing. And that butterflies generate lift directly from the flapping motion of the wings. Kind of like the way a fly does. That'd be my guess anyway.


RE: confused
By Iaiken on 6/21/2010 10:26:40 AM , Rating: 5
No, birds wings are in fact airfoils and do provide lift during forward movement. Those that flap their wings, do so to push themselves FORWARD and thus continue to take advantage of the lift afforded them by the shape of their wings. This amount of lift varies from bird to bird and there are of course exceptions (hummingbirds).

Frigate Birds are an extreme example since they can spend hours on the wing without flapping once simply by riding thermals. In fact, their wing and body structure is mostly ridged with the exception of their neck and hindquarters. The limited mobility of their wings makes flapping notably difficult for them. This also makes them interesting to watch as they often cruise and maneuver without any perceptible movement.

Butterflies, like all other insects, must flap their wings or they will simply fall out of the sky. This flapping pushes them forward, but more importantly, it also pushes them UPWARD against the force of gravity and allows them to achieve flight.


RE: confused
By hughlle on 6/21/2010 11:06:47 AM , Rating: 2
very clear information, that's more what i was getting after, the piece in the article is very vague and can easily be interpreted in a different way, such as if there's a tornado both will be flying regardless of wing material haha


RE: confused
By Basilisk on 6/21/2010 11:15:41 AM , Rating: 2
Many birds create lift with flapping.

But they cruise using lift from their airfoil. Which was probably the point of the article.

If you doubt the former, look at those ground-based mating dances where birds jump up and hover. Or consider the take-off of ground birds: with odd exceptions -- think "gooney birds" -- they are airborne before they achieve useful horizontal velocity.

Flapping for lift is tiresome, so it's minimized. Even hummingbird's often use perches when available. Some birds use tree-roosting to advantage: they drop from their nest, gaining horizontal velocity (& airfoil lift) as they descend.

Daily, a 3' Blue Heron visits my back yard; he departs doing a VSTOL ascent to clear the shrubs by my koi pond, then picks up velocity as he heads out over the big pond. [Given that the koi are always net-protected, so he's never had a meal, Big Bird is bird-brained or has grand dreams.]


RE: confused
By Iaiken on 6/21/2010 12:47:02 PM , Rating: 2
quote:
their wing and body structure is mostly rigid


This was what I meant!

Sorry for the typo.


RE: confused
By 91TTZ on 6/21/2010 3:05:47 PM , Rating: 2
quote:
Butterflies, like all other insects, must flap their wings or they will simply fall out of the sky. This flapping pushes them forward, but more importantly, it also pushes them UPWARD against the force of gravity and allows them to achieve flight.


This is incorrect. Insect wings also create lift. You do not need the traditional airfoil shape to create lift. You can create lift with a flat wing as well. By changing the angle of attack you can change the amount of positive/negative lift generated. Think about it- paper airplanes have no problem flying and airplanes with the traditional airfoil shape are able to fly even if they're upside down.

Using an airfoil shape can increase efficiency (better lift/drag ratio) but it's not a requirement.


RE: confused
By Iaiken on 6/21/2010 4:53:24 PM , Rating: 5
quote:
You can create lift with a flat wing as well. By changing the angle of attack you can change the amount of positive/negative lift generated.


While this is true of some manned flight(stunt planes actually have flat wings that are cambered back away from the direction of flight), we're discussing the flight mechanics of the natural world. By your definition, flying squirrels fly, when they glide (controlled fall at an angled slope of less than 45 degrees). Until there are insects with propellers or jet engines, my assertion remains correct.

Insects don't fly like a paper airplane, they fly through mechanically flapping their wings to push themselves upward and forward. This is why the only insects that can hover, are those that have a set of 4 wings that flap in matched pairs. In which case they are pushing down and forward as well as down and backwards rapidly in order to achieve stationary flight. This is also why the majority of flighted insects must beat their wings on the order of 600 times per second (upwards of 1000 times per second in some species).

This is why it appears that butterflies and moths appear to fly erratically because they are essentially pushing themselves through the air in fits and starts. Without the wing beats, they simply fall (or in the butterflies case, flutter) out of the sky.

FYI: I'm a glider pilot as a hobby so I am well versed on the difference between flight, gliding and falling.


RE: confused
By Iaiken on 6/21/2010 4:59:47 PM , Rating: 5
In addition to pushing themselves upwards, flies/bees etc, clap their wings at the end of each upstroke. This creates a vortex above them that sucks in air from below, thus increasing the force of the subsequent down stroke.

If you are interested, there was an article published on the subject of insect flight in the 1997 issues of nature (can't remember which month off hand).


RE: confused
By 91TTZ on 6/22/2010 9:00:05 AM , Rating: 2
quote:
Insects don't fly like a paper airplane, they fly through mechanically flapping their wings to push themselves upward and forward. This is why the only insects that can hover, are those that have a set of 4 wings that flap in matched pairs. In which case they are pushing down and forward as well as down and backwards rapidly in order to achieve stationary flight.


This isn't true at all. Hoverflies are able to hover just fine on only 2 wings.

http://en.wikipedia.org/wiki/Hoverfly

quote:
This is also why the majority of flighted insects must beat their wings on the order of 600 times per second (upwards of 1000 times per second in some species)


The reason they have to flap their wings so fast is because of their scale. Even on birds, the smaller the bird, the faster it must beat its wings. Eagles flap their wings slowly, crows flap faster, sparrows even faster, and hummingbirds the fastest, which isn't surprising since it's the smallest bird.

quote:
This is why it appears that butterflies and moths appear to fly erratically because they are essentially pushing themselves through the air in fits and starts. Without the wing beats, they simply fall (or in the butterflies case, flutter) out of the sky.


This is entirely incorrect.

Your error seems to hinge on your belief that butterflies cannot glide because they don't have airfoil shaped wings and must flap to stay aloft. This isn't the case. Butterflies can and do glide. They glide quite well, too. Monarch butterflies are able to migrate for thousands of miles by extensively gliding to conserve energy.

http://www.learner.org/jnorth/tm/monarch/FlightPow...

Some people even take dead ones and use them as walkalong gliders:

http://www.instructables.com/id/Monarch-Butterfly-...

You might recognize this as a form of slope soaring, the person is just moving the slope to control the "aircraft".

As for the fluttering motion of butterflies, this is an evolutionary feature to protect them from predators. The fluttering and the large wings with designs on them make them harder to catch. Other insects whose mechanics are similar to that of butterflies (such as dragonflies) are able to hover steadily. This is mostly due to their thinner wings.


Mothra
By HomerTNachoCheese on 6/21/2010 8:13:08 AM , Rating: 3
We need to boost our defenses because of this. In 10 years time - maybe less - we could see swarms of kamikaze Mothras over Hawaii.




RE: Mothra
By marvdmartian on 6/21/2010 10:15:26 AM , Rating: 2
Wouldn't that be "Butterfly-Ra"? (scratches head)

Hey, put a tiny rail gun on this thing, and you'd have a mini Terminator!! ;)


RE: Mothra
By frobizzle on 6/21/2010 11:16:21 AM , Rating: 3
quote:
we could see swarms of kamikaze Mothras over Hawaii.

No, not swarms. Only one big mutha...about the size of the Spruce Goose!


RE: Mothra
By TSS on 6/21/2010 6:05:03 PM , Rating: 3
Insects can't really carry a payload though.

Since they've made a swallowtail the logical next step would be a swallow. Atleast that can carry a payload of coconuts.


RE: Mothra
By afkrotch on 6/21/2010 9:32:27 PM , Rating: 2
They don't need to carry a payload. They can just flap their wings and destroy crap. That or fly into them. I'm assuming the latter, hence the term "kamikaze."


Call me paranoid, but...
By drewsup on 6/21/2010 1:25:40 PM , Rating: 2
It kinda creeps me out, these small bio-mimetic droids they keep cooking up.
How about this,
One the size a fly with a micro injector full of, (pick the most horrible poison you can think of), that you can pilot right onto a sleeping "target", deliver the "payload" then pilot back out through a rip in a screen window/cracked doorway.
And you don't think the military hasn't thought of this??

I just hope they can't get through my tinfoil hat!




RE: Call me paranoid, but...
By Harinezumi on 6/21/2010 3:46:55 PM , Rating: 2
Add cameras and microphones to them, and you've won the war on terror.

Imagine saturating Pakistan's tribal territories with these.


By 91TTZ on 6/21/2010 3:52:35 PM , Rating: 3
I see an old myth being repeated constantly in this thread. The myth states that you need an airfoil shape in order to generate lift, which is totally incorrect.

Read up:

http://warp.povusers.org/grrr/airfoilmyth.html

http://www.allstar.fiu.edu/aero/airflylvl3.htm




..don't glide?
By chochosan on 6/21/2010 10:01:44 AM , Rating: 2
Some butterflies DO glide on air currents.




WOMD?
By PsychoPif on 6/21/2010 12:44:28 PM , Rating: 1
So they are trying to create a tsunami?




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