Building a semi human powered flying device

[Daedelus]

Well, no, given that birds don't weigh nearly a hundred pounds, or need towing by a car to get them airborne.

But that is what current technology can achieve. You want to remove the tow start, the bicycle wheel, and lessen the weight by more than half?

I guess I'm failing to make myself clear.

No, that isn't what current technology can achieve. It may be what can be done when trying to make an airplane's wings go up and down by human power, but what the hell is the point of that? No, I don't want to do anything with that contraption much less try to somehow make it viable.

You never answered my question, do you fly, anything?

 

[MacGyver1968]

Some of us are talking about ornithopters. Unfortunately that name has been applied to any number of machines that have wings that go up and down. IMHO, taking a perfectly good airplane and flapping the wings is silly and inefficient.

What has been proposed at the start point of this discussion is a return to first principles, bird like flight. No one can point to the Snowbird and call it more than vaguely bird like. What we are talking about is using the structure of an actual bird as the prototype and model for a machine. And yes we realize it's been done before, but until now, no one has had the technology and materials to succeed. We believe the time is now for such an endeavor.

You seem to be forgetting about this:

http://en.wikipedia.org/wiki/Square-cube_law

We are not constructed like birds...we are large, heavy and dense. A bird's design works for them because they are small, lightweight and not very dense. There's a good reason why we don't have 180 pound birds flying around. When you scale something up, it's mass increases dramatically more than it's surface area.

 

[Daedelus]

Which is what I was actually getting at, I was being facetious.

If your machine is different to a hang glider, making analogies to hang gliding is not relevant.

Do you know anything about hang gliders? Do you know that they are capable of flights of hundreds of miles and altitude gains of tens of thousands of feet?

A hang glider is thus far the closest we have to bird like flight. It is in fact an ornithopter without the ability to flap and a limited ability to change wing shape. These are simply technological details.

Take a modern hang glider and add a few enhancements and you have a better hang glider. Take a Condor or Eagle as a prototype, enlarge it, replace it's muscles with appropriate actuators, feathers and bones with CFC, nervous system with haptic technology and the brain with a human pilot and you have the gist of the proposed machine.

 

[Daedelus]

You seem to be forgetting about this:

....
We are not constructed like birds...we are large, heavy and dense. A bird's design works for them because they are small, lightweight and not very dense. There's a good reason why we don't have 180 pound birds flying around. When you scale something up, it's mass increases dramatically more than it's surface area.

And that reason is not what you assume. The reason that we don't still have Quetzalcoatlus still around is that a comet killed them all with the dinosaurs. The reason we don't have Argentavis magnificens still around is likely the same reason, habitat and environment loss. We do still have a few of their descendants in the Condors. But they have their own habitat loss problems.

The size of animals is only a function of their environment, not an inverse square law.

 

[phlogistician]

You never answered my question, do you fly, anything?

Kites, rockets, and I used to make and fly various balsa wood gliders and rubber band powered aircraft. Many scratch built. Have been looking at building some radio controlled aircraft recently too, as I quite fancy flying a Mugi.

 

[MacGyver1968]

And that reason is not what you assume. The reason that we don't still have Quetzalcoatlus still around is that a comet killed them all with the dinosaurs. The reason we don't have Argentavis magnificens still around is likely the same reason, habitat and environment loss. We do still have a few of their descendants in the Condors. But they have their own habitat loss problems.

The size of animals is only a function of their environment, not an inverse square law.

Atmospheric conditions were different 65 million years ago...which allowed for their large size. It allowed a lot of animals to grow large. Things are different today.

The inverse square law is something totally different. I am referring to the square-cube law. It's not a theory..it's a law...that can be proven with math and experimentation. Just because something works at one scale, doesn't mean it will work at larger scale.

 

[Daedelus]

Atmospheric conditions were different 65 million years ago...which allowed for their large size. It allowed a lot of animals to grow large. Things are different today.

If you are going to assert 'facts' like that, it would help if you can back them up. This idea has no validity.

And yes, I misstated the law you cited, apologies, but it's still irrelevant. The fact is, such creatures did exist, did fly and the Giant Teratorns were around up until some ten thousand years ago. Probably around the time they met up with humans.

 

[Daedelus]

Here is a video that might help visualize what is possible.
https://www.facebook.com/video/video.php?v=122070751136747

 

[phlogistician]

Atmospheric conditions were different 65 million years ago...which allowed for their large size. It allowed a lot of animals to grow large. Things are different today.

Indeed:

"Obviously, there was a time, early in the planet’s life, when there was little or no oxygen. The atmosphere was CO2-rich, hothouse conditions prevailed, and iron could oxidize only partially. Where did O2 come from? Probably via photosynthesis performed by single-celled bacteria.
But that doesn’t mean it’s been a steady march upward to our current 21 percent: 5 million years ago, oxygen levels were as high as 28 percent, and less than 100 million years ago, they were much lower than today. And things got even more bumpy before that: at the start of the Cambrian Explosion, 544 million years ago, oxygen levels were about 13 percent; by the Carboniferous/early Permian 300 million years ago, it topped out at 35 percent. By the early Triassic, however, they were down to 12 percent or lower!"(http://calitreview.com/241)

Birds have lungs which are about 1/3 more efficient than humans, so this allowed larger species to evolve when oxygen levels increased. A more dense atmosphere would provide more lift too.

 

[MacGyver1968]

This bird, sometimes called the Giant Teratorn, is an extinct species known (as of 2009) from three sites from the late Miocene (6 million years before present) of central and northwestern Argentina, where a good sample of fossils has been obtained.[1]

Hmm...seem to co-inside with those higher o2 levels.

 

[phlogistician]

Hmm...seem to co-inside with those higher o2 levels.

Odd that huh? Things need a mechanism to support them, and can't just get big just 'cos,....

 

[Daedelus]

I think Y'all are still missing the crucial point here. Whether or not higher O2 levels allowed larger birds or not, is irrelevant. We are not talking about re creating Argentavis.

Fact, large creatures once flew. Fact, we have materials and technology that can duplicate and improve on the mechanics of those creatures.

We already have jets and rockets that can go faster than any Peregrine.
We have transports that can carry literally tones of cargo.
We have already improved on what nature can do.

What we haven't even tried to do yet is to duplicate the control precision that the birds have at a man carrying scale.

 

[Daedelus]

Kites, rockets, and I used to make and fly various balsa wood gliders and rubber band powered aircraft. Many scratch built. Have been looking at building some radio controlled aircraft recently too, as I quite fancy flying a Mugi.

Explains a lot about your responses, no offense intended. What is your location? It's possible I know someone who can introduce you to the closest thing we have to flying like a bird.

 

[phlogistician]

Explains a lot about your responses, no offense intended. What is your location? It's possible I know someone who can introduce you to the closest thing we have to flying like a bird.

No thanks, there are 101 other ways I can find to waste my time.

 

[phlogistician]

I think Y'all are still missing the crucial point here. Whether or not higher O2 levels allowed larger birds or not, is irrelevant. We are not talking about re creating Argentavis.

Fact, large creatures once flew.

And the 'fact' appears to be that the o2 levels allowed this.

Fact, we have materials and technology that can duplicate and improve on the mechanics of those creatures.

Not fact, far from it. We already covered the topic of energy density, and that prosthetics suffer from that limitation.

We already have jets and rockets that can go faster than any Peregrine.

Sorry, for a minute I thought you were trying to make an aircraft that flew like a bird, not reinvent jet aircraft.

 

[Daedelus]

And the 'fact' appears to be that the o2 levels allowed this.

So what? Even if that were true, as I said it is irrelevant to the current topic. The goal is not to build an O2 breathing animal.

Not fact, far from it. We already covered the topic of energy density, and that prosthetics suffer from that limitation.

No, we didn't 'cover it'. You asserted that there was some limit, but you failed to back it up or show how it is germane.

Sorry, for a minute I thought you were trying to make an aircraft that flew like a bird, not reinvent jet aircraft.

Now you are just being obtuse. Is this one of the 101 ways you like to spend your time, pissing on the ideas of others?

 

[phlogistician]

So what? Even if that were true, as I said it is irrelevant to the current topic. The goal is not to build an O2 breathing animal.

You brought them up, not me.

No, we didn't 'cover it'. You asserted that there was some limit, but you failed to back it up or show how it is germane.

Energy density is everything!

Now you are just being obtuse. Is this one of the 101 ways you like to spend your time, pissing on the ideas of others?

So far you have mentioned dinosaurs, but you aren't building a dinosaur, hang gliders, but your device isn't one, and jet engines, but your device doesn't use one.

Care to show us what you actually propose?

 

[Daedelus]

You brought them up, not me.

I brought them up simply to show that once there were animals of a certain size that did fly.

Energy density is everything!

And it's nothing. When you can show that air density was significantly different when these creatures flew then you might have a point. However that point can easily be dealt with by adjusting the size of the machine. As I have told you, and recently verified with friend Clark, a 230 ft^2 wing can carry a 500# load and still gain altitude in thermal lift.

So far you have mentioned dinosaurs, but you aren't building a dinosaur, hang gliders, but your device isn't one, and jet engines, but your device doesn't use one.

When proposing a novel idea I find it useful to draw analogies as a way of explaining it. I have said that if A exists, then B is a reasonable assumption. I said, that we can build jets and we can go to the moon, therefore I see no reason why we cannot build an articulated wing.

Care to show us what you actually propose?

I'm working on illustrations with an artist now. In the mean time you can read about the ideas and me at Daedelus' Notebook. If you are really interested.

 

[Dywyddyr]

When proposing a novel idea I find it useful to draw analogies as a way of explaining it. I have said that if A exists, then B is a reasonable assumption. I said, that we can build jets and we can go to the moon, therefore I see no reason why we cannot build an articulated wing.

Exactly.
The fact that we can make raspberry blancmange means we can make working time machines.
The fact that we can build underground rail systems means we can make machines to prevent ageing. Etc.

Hoo boy...

 

[Daedelus]

Exactly.
The fact that we can make raspberry blancmange means we can make working time machines.
The fact that we can build underground rail systems means we can make machines to prevent ageing. Etc.

Hoo boy...

What part of 'reasonable' eludes you friend?