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Bird like flight? Not even close - yet.

Postby Frank Colver » Sat May 30, 2015 2:14 pm

Bird like flight? Not even close - yet.

In reading Otto Lilienthal’s book I become aware of how little progress humans have made in the effort to fly like birds. Oh yes, we streak across oceans in jet planes and ride in gliders on the rising air currents but we still don’t fly like the birds do. I’m not entirely referring here to the lack of progress in human carrying ornithopters, although that is one aspect of the desire to fly like the birds. Hang gliding has brought us closer to bird like flight but again it isn’t there yet.

The closest to flight like a bird I ever felt in my years of hang gliding was when I was circling in a thermal with a raven circling below me. I would do a raven call to him and the raven would look up at me a call back. We went around and around like this for a while, talking raven language, with the raven unable to close the vertical gap between us. However, this was more of a spiritual bond with a soaring bird, which gave me the sensation that I had entered his world. An illusion to be sure, but one I’ll never forget.

Now, to the other realm of bird flight other than successful beating wings flying a human through the air. Those of you reading this, who were around in the early day of the modern sport of hang gliding, will remember the ideas and inspiration given to us by Richard Miller. In my hang gliding years I would periodically decide to forgo flying for the day and drive down to Vista to spend the afternoon with Richard. Time spent, sometimes flying from a local hill with Richard, but other times not flying, that I will always treasure.

Richard had a dream of one day humans being able to feel, in their bodies, what was happening out on those wings they were flying with. Damn! The birds can do this and we can’t! To feel in our bodies every force being exerted on the wings and react to it. In a lesser way we do this with weight shift hang gliders by feeling the forces of an induced roll or pitch change and reacting to it with a weight shift control input to the glider. Yes, it is similar to a bird feeling those forces, but very rudimentary at best. Richard wanted more.

He used to talk to me about this, because he hoped I would develop a way to couple my variometer to my body so that rising and descending would have a physical feel in the body. I enjoyed thinking about this but never gave it much time. He would have liked many sensors, out on the wing, with inputs to our physical beings to bring us the true feeling of flight like the birds. The rabid development of digital electronics may bring us to that day, that Richard so much wished for, but there needs to be the desire to accomplish this feat. Imagine, if Boeing or Lockheed applied their engineers to this.

Imagine, if you felt something in your right arm as soon as the pressure under your right wing increased compared to the left wing. You could respond before the inertia of the glider allowed the right wing to start rising up. Of course the ultimate goal of bird like flight is to be able to change the shape of every part of the wing, as birds do. I once saw a hawk, ridge soaring, in extremely turbulent air, who kept his body motionless as his wings shed every position disturbing input from the air.

Be joyus in eternal flight, Richard. :wave:
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Re: Bird like flight? Not even close - yet.

Postby magentabluesky » Sun May 31, 2015 10:19 am

Delightfully wonderful, Frank.

Thank you for sharing.

Truly, the Gospel of Flight.
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Re: Bird like flight? Not even close - yet.

Postby JoeF » Sun May 31, 2015 10:29 am

FIRSTMODELBambooButterflyPhotoGeorgeUveges.jpg
George Uveges photographed Richard Miller in the first of two 1966 versions. Here is the small first version flown at Dockweiler.

==========================================
THEN the larger second version:
BambooButterflyPhotoGeorgeUveges.jpg
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Re: Bird like flight? Not even close - yet.

Postby wingspan33 » Sun May 31, 2015 11:02 am

Frank,

First off it was great meeting you at Dockweiler Beach on Otto's birthday!

Now, as I began reading your above post, I was thinking, . . . The larger a bird is the less it flaps its wings. So, in combining our average human body weight plus wing weight, it is very likely that a bird of similar size (if one ever existed) would also never have flapped its wings. In deed, I have heard that certain flying dinosaurs would launch from high points and soar just as we do. They would then land back "on top" or crawl/walk back up to a high enough point from which they could again take off and soar.

Due to the energy and mechanical means needed to maintain flapping flight I have doubts about "human birds" ever being able to manage that type of flight. But time and technology may change the odds.

On to the later part of your post, . . . Way back in the '80s I wrote a short story about a character who was given what I termed a "Field Sense" by a (human) extraterrestrial. It allowed my character to do just what your friend was hoping might be possible some day. So there are more than a couple of us who have thought along those lines.

Along more practical lines, I've thought about putting sensitive thermal sensors at each wing tip and in the center of the wing. The idea being to indicate (more quickly?) to the pilot which wing was in slightly warmer (rising) air. The Thermal Snooper went in that type of direction.

Twenty or more years ago I also devised plans for a glider that could manage both symmetrical and asymmetrical camber change. I've also developed prototypes of passively (or actively) adjustable "wing tips". They would be quite different from current static winglets. They too could be actively altered in shape to aid in turning and in reducing wing tip vortices (as is the case with static winglets).

Unfortunately, my ideas have always exceeded my financial means. :(
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Re: Bird like flight? Not even close - yet.

Postby Dayhead » Mon Jun 01, 2015 11:29 pm

First, I was going to start a new topic but decided the title of this one pretty much stated my sentiments.

However, if my writing is not on topic I'll gladly ask Bob to move it.

I'm definitely not holding my breath until a practical human powered ornithopter gets invented. However, I wouldn't be surprised if, in my lifetime, we'll see some sort of human power "booster" that could momentarily give us just a bit of a shove when we need it.

In watching Seagulls soaring, I notice they sometimes will utilize a low amplitude, low frequency "flapping motion" that seems to be used to momentarily improve their L/D a small amount. We might be able to pull off something of that nature in the foreseeable future.

But in the meantime, I believe that we will develop some really neat hang gliders.

Some would say that we already have some really neat hang gliders. But I disagree.

When I bought my first glider, a Pliable Moose standard, in 1976 and taught myself to fly it on the small hills in Kansas, I just knew that it wouldn't be long before we had some "really neat gliders".

As the gliders got better, I grew as a pilot at about the same pace that the gliders did. I was basically pretty happy with the rate of improvement, except for one thing:

Handling qualities.

As glide angle improved, the handling got worse. And I'm speaking here primarily of roll response, roll rate, and the physical effort required.

What really peeves me nowadays is that it has been 35 years since the Comet came on the scene, and now here in 2015 all we have to show after 35 years of effort are Glorified Comets.

Yes, the glide angle attainable has improved by about 150%. Yes, handling is better, but not by a lot. I don't know what the inflation rate is, but I do know that a top-of-the-line flex wing costs 5 times what the first Comets did.

For various reasons, innovation of any real substance just stopped three decades ago. All we've seen since then is gradual refinement of the Comet.

Another thing that I want to rant on about is that three decades ago Bob Trampenau fitted his Sensor 510 with a block'n'tackle system for varying the sail tension, so that we could better choose between a flat glide angle, or being able to steer the damn thing.

So three decades later we still get to choose between glide or handling. And in my not so humble opinion, even with the Variable Geometry System in it's loosest setting, the handling is not anything to write home about. It just seems to me that something is wrong with this picture.

So now I'll give my opinions as to where we went wrong.

Way back when, the organizations overseeing Competition decided that the flex-wing hang gliders could only be controlled by pure weight-shift alone. And since competition results had a lot to do with glider sales, and also since a weight shift only glider is presumably less expensive to produce, all flex-wings are built to qualify for use in competition.

Well, now. I don't know about you, but I've never flown in a competition, and it's highly unlikely that I ever will. And yet every hang glider I've ever flown, with the exception of rigid wings, has been eligible for competition in the weight-shift only class, which I think is called Class 1.

I haven't researched it, but I'm willing to bet that no more than 10%, and more likely 5% of hang glider pilots ever fly in competition.

This means that probably 95% of us are putting up with high performance flex wings that handle horribly, because our beloved manufacturers believe that every kite they sell should be eligible for use in a competition.

Way back when, it was found that reducing "billow" would improve glide angle by effectively reducing the twist, or wash-out in the sail. At the same time it was found that doing this made roll control more difficult.

Some smart guy invented the (tall) keel pocket, which gave us back most of the roll authority we lost by going to a "tight" sail.

After awhile, the keel pocket couldn't keep up with the ever tightening sails, especially when the lower surface was added to reduce drag. This innovation added resistance to "billow shift" is the result of what is commonly called the "box effect", the lower surface added rigidity to the sail.

So the "floating cross-bar" was invented, and this helped out, but we still had to choose between being able to steer or a good glide angle.

And so we got the VG. This was good, because we could now make our choice while flying, instead of on launch.

But we're still stuck with having to choose between horrible or a little less horrible handling.

After all these years.

I gots more to say, but it's late, I'm tired. I'll be back though. Steve
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Re: Bird like flight? Not even close - yet.

Postby Merlin » Tue Jun 02, 2015 4:08 am

Dayhead wrote:What really peeves me nowadays is that it has been 35 years since the Comet came on the scene, and now here in 2015 all we have to show after 35 years of effort are Glorified Comets.


Yes, exactly. Around 1980 there were two distinct species of hang glider, in my opinion. The "Atlas" clones, and the "Comet" clones. I would describe an Atlas clone as having a single surface, deflexorless, shifting crossbar, a tight sail with mylar leading edge inserts, and an airfoil optimized for sink rate. It basically used many of the features the Comet employed, but gave up top end for handling and sink rate.

I flew a Moyes Mega II(an Atlas copy), once, about that time. It was borrowed, and I was heavy on it. Now I'd flown lots of single surface before that, and generally flying a single surface heavy put you on the ground real quick. Not the Mega, she climbed noticably better than anything I'd ever been on. But the handling was even more unique. I'd also flown light handling gliders... my Seagull 10.5 has been quite light. But the Mega was light and instantaneous, helped no doubt by the heavy wingloading. The effect - perfect handling and amazing sinkrate - was absolutely magical. Also, an easy no-step landing finished the flight.

Of course the Comet model would end up dominating - and the Atlas types were abandoned for sailplane like speed and reach.
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Re: Bird like flight? Not even close - yet.

Postby JoeF » Tue Jun 02, 2015 7:43 am

Steve,
Please DO be back on your studies! Excellent tracings. Thanks for the study and sharing! :thumbup:
Insurance is another player that weasels its influence over design.

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Re: Bird like flight? Not even close - yet.

Postby Frank Colver » Tue Jun 02, 2015 10:25 am

You guys have drifted far away from my original post and it was not about making successful orinithopters or better aerodynamic control of the glider vs performance.

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Re: Bird like flight? Not even close - yet.

Postby Bob Kuczewski » Tue Jun 02, 2015 10:55 am

Drifting is in the nature of forum topics. It's frustrated me many times myself ... but that's the nature of human discussion. Sometimes it's good, other times not so good.

In recognition of the desire for individuals to keep topics ... on topic, I've created the "Blog Forum" where anyone can start a topic and decide what is "on topic" and what is a diversion. Each Blog topic is "owned" by the person starting the Blog, and they can set whatever rules they want in their first post. They can use the "Report" button to report any posts that they want removed, and I follow their direction.

I don't know if this topic was intended to have that level of control or not, but I'm just mentioning it as an option for situations where people want to present a flow of information in a certain direction without the drifting that otherwise tends to occur in less regulated forum discussions.

One of the goals of the US Hawks is to provide venues of varying kinds (national, local, personal) where people can share their love of flight. Let me know any time if I can change anything in this forum to move in that direction.
Join a National Hang Gliding Organization: US Hawks at ushawks.org
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Re: Bird like flight? Not even close - yet.

Postby Dayhead » Thu Jun 04, 2015 9:39 am

I wrote:

"First, I was going to start a new topic but decided the title of this one pretty much stated my sentiments.

However, if my writing is not on topic I'll gladly ask Bob to move it".

I guess I mis-understood Frank's intentions for this thread.

I'll see if I can start my own Blog. I've got some things to get off my chest, which I started to do in my post. After finishing my rant, it was my intention to lay out some ideas I have about making Hg's that would more closely fulfill the dream that Frank was talking about, including being able to feel what's going on and the ability to configure our wings in a manner similar to the way the birds do.

As Bob pointed out, it's common for discussion on forums to get off course. My apologies for my part in this. I'll now go and try to start a blog. That will make it easier for folks to either seek out, or to avoid my posts, as they see fit.

Frank, thanks again for letting me try to fly your kite at the beach. I was amazed by how rusty I am!

Steve Corbin, one lucky guy.
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