Bon-viveur boffin: Biomimetic bird, bat & bug bots are b*llocks

deceptive

the artical is deceptive as it suggests that the bots are all being based around 'flapping' wings, this is not the case.

the majority of practical solutions are based around how birds/bats change their wing shape allowing tighter turns, better low speed lift and better aerodynamics at speed whist retaining conventional propulsion (propellor/jet).

nary a flap in sight.

"The most efficient system for travel is the wheel, or some derivative thereof"

LOL. Not in the bloody air it aint!

A bit of a nonsence

Most of the insects - at least the best flyers - do not flap wings.

There is no start-stop momentum involved - it's more like an "8"-shaped movement.

See eg http://www.biology-resources.com/images/wing-movements-big.jpg

Basically crap

It's been a couple of minutes since I read the article, but I'm fairly certain that at the beginning he suggests his work might act as a reminder to be catious about copying nature. I don't think, from this brief text, he was ruling out all aspects of every natural mechanism.

Also, my new favourite quote (for today at least): "Compared to ordinary aeroplanes, helicopters etc, birds, bats and insects are basically crap". I love that.

And I'd really like to see some wheeled animals. Can't we GM some?

Vulture - should've been a chopper!

Errr...

"(Usherwood's test pigeons apparently have to carry lead fishing weights to check their performance, and fly with reflective tape spots all over them so that their wing oscillations can be precisely monitored.)"

Does the RSPCA / RSPB know about this?

@Solomon Grundy

Yes, but the dragonfly ain't going to be in the air if it feels unwell. The chopper will ascend if all the instruments indicate that all is well, there are a wide variety of critical components that are not actively monitored (ground checks or service checks only) and proper component failure prediction is still on the nice idea list.

Your example doesn't indicate that the locomotion of the dragonfly is superior to that of the chopper. It does indicate that biological constructs are superior to mechanical ones when it comes to diagnostics.

Now, I for one have never seen a dragonfly gliding and I have no idea what the gliding characteristics of a suddenly flapless mechanical dragonfly are, but the known autorotation characteristics of the rotorcraft mean that I'd rather be sitting in that when the shit hits the fan.

I would tend to believe...

that's it's the power source, not the motion, that makes the Living versions of these bots so effecient.

Couple hours of flying on some sugar from a flower? Make a bot that can refuel like that, and you'd have a winner!

Insect wings move up and down in a special way...

Small insects, such as mosquitos, beat their wings at very high frequencies (which is why they buzz at high frequency). If you cut off the ends of the wings, they will beat at an even higher frequency. This shows that the wings are beating like the tines of a tuning fork, i.e. they are vibrating. The energy to accelerate and decelerate the wings as they move up and down is not wasted but stored and released elastically.

The insect's flight muscles simple add the energy required to move the air to generate lift.

Small insects fly with amazing efficiency. Insects are regularly carried enormous distances (even across the Atlantic) by the wind, with the creature only having the consume minute amounts of food to stay aloft for a couple of days or so.

Of course, it is a matter of scale. If you increased the size of a mosquito to a 747 the natural frequency of vibration of the wing would be so low that no useful aerodynamic forces would be generated.

@Tim Elhpick

> And I'd really like to see some wheeled animals. Can't we GM some?

Zabriskan Fontemas?

Efficiency vs Manoeuvrability

Research looking at changing wing shape has already been mentioned, but another important aspect of animal flight is instability: it's how bats turn so fast to catch their insect prey on the wing, for example. Bat flight may be very inefficient, but you don't see many gliders turning in their length to snap a gnat out of the air!

Efficiency

I think nature/natural selection has done a pretty good job. IIRC, an albatross can stay aloft for days and cover thousands of miles on a single journey, all on a stomach full of fish. My model aeroplanes, using propellors, hi-tech batteries and the things that the prof. thinks so superior, can stay up for about 20 minutes!

There was a good item that he probably missed on R4 recently, about the variable geometry of a Swift's wing, whereby it alters the shape and sweep to suit the conditions. This works so well that they can stay in the air (refuelling as they go) for two to three years...

Wheels are fine on smooth level surfaces, but anyone who has cycled up a steep hill will know the limitations. A friend of mine says that he will take robots seriously when they can successfully walk upstairs carrying a plate of soup. I agree.

lets take fuel out of this

I suggest we build a rig with flapping wings and one with fixed wings and/or helicopter designs. Then to decide which is better, we add a squirrel and a wheel to power it. This will take biological energy out of this. Also we'll need it to lift and power a camera and wireless, since I'm assuming this is for black ops anyways. Maybe we can use a mosquito with it's wings affixed to a solo-flex/generator for a nano version to test the nano thing out?

Boffin of Buffoon?

Animals are incredibly efficient at what they do and so copying their design features is generally a good idea. However, if you want to fly a few hundred people across the Atlantic, then an oversized pigeon is unlikely to be a good design. The first "workable flying machines" were created to carry humans. How may human sized birds has the prof seen flying about? Smaller payloads might actually benefit from simulating the flight of birds.

Animals are designed to grow, feed, hunt, reproduce, etc. If you take away the "life" aspects from an animal and just look at say, its method of propulsion, then you'll probably be able to improve on it. It's like saying that steel is a better building material than wood therefore trees are pretty crap.

Nature hasn't used the wheel much because the separation between wheel and axle means one element, e.g. the wheel (or rotor), has to be dead. So if you equip a large animal with wheels, how would the wheels grow as the animal grows? How would they repair themselves if damaged?

Like Pierre Castille above said;

It's the resonance!

Small birds and bats, and all flying insects beat their wings at a rate that resonates to their wings physiognomy. There is a push on the thrust producing down stroke, most of the rest of the motion is produced by elasticity in the tendons (and exoskeleton for insects).

So, once in flight, it takes a periodic pulse of muscle to maintain the harmonic motion of the wing stroke, unlike a rotary propeller, which needs a constant applied motion to maintain lift.

(Stupid analogy time: Compare the amount of energy needed to bounce a ball rapidly, with the amount needed to hold the ball and carry it up and down with muscle power the same distance and speed.)

Really, the good Doctor sounds like the Victorian scientists that maintained that bees were too heavy to fly, and dogs were only overheating themselves more by panting. We've learned a bit since then.

(Seriously, a pigeon attempting to fly with a load it isn't designed to carry is less efficient than an aircraft carrying a load it's designed for? To quote Paula Bean http://thedailywtf.com/Articles/The_Brillant_Paula_Bean.aspx , "Brillant!")

I chose the penguin, it's rather inefficient at flight too.

@Captain DaFt

>I chose the penguin, it's rather inefficient at flight too.

No its not... http://www.youtube.com/watch?v=pG5dzybHgTo

The BBC said so...