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By Roadrunner71
#403400
Does anyone know just how a bird senses a thermal? What sense do they use primarily to detect a Thermal. Because it is apparent to me that they have unreal abilities. I am very curious as to what senses that a Bird uses primarily to detect a Thermal. Because they obviously have Built-In Super Vario.
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By magentabluesky
#403401
The Paratympanic Organ (PTO) in the bird’s middle ear detects air pressure changes, discovered by Giovanni Vitali in 1911.
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By magentabluesky
#403403
Roadrunner wrote:
Guys: I remember reading a book about flying about 23 years ago. Well, in this book the author said: That we don't know how? But Birds can locate thermals with ease.

My Questions to you guys is: Do we now know just how say a Buzzard can locate a thermal?

Do they have a visual perception, that we human's do not have?

I just would like to know what say a hawk has in his bag of aerial equipment that we human's fail to have.

See Ya The Big Guy Fri Feb 20, 2015 9:15 am
Hang Gliding.Org Link

Sky_Walker wrote: !00 years ago Giovanni Vitali discovered the Paratympanic Organ in the inner ears of birds. It is now commonly known as the Vitali organ. The Vitali organ is sensitive to very small changes in barometric pressure so essentially birds have the sensor of a vario in their inner ear ....

http://www.cam.ac.uk/research/news/natu ... ense-organ Fri Feb 20, 2015 12:53 pm
Hang Gliding.Org Link
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By miraclepieco
#403405
Raptors are renowned for their keen eyesight. I believe they also can actually see tiny particles of dust, insects, and other minute debris being carried aloft by thermals - just as we see another hang glider climbing and head for it.
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By TrikeTrash
#403406
Birds have an uncanny ability to keep their heads level plus their vision is about eight times greater than ours. This is all they need to "see" thermals indirectly using atmospheric distortion. To prove it to yourself, the next time on launch take a pair of 8X binoculars and slowly scan the horizon. For best results the binoculars should be on a tripod or resting against some non moving object. Shaky hands will spoil what you're tring to see. As you scan the horizon, take note that some areas of the horizon appear steady, (or more steady) while other areas are "wavy" or "boiling". It takes a little practice to see the atmospheric distortion but once you get dialed in, it becomes very obvious. The width of the distortion on the horizon is an indication of the size and/or distance of the thermal. Over time you can watch the distortion change and get wider as the thermal grows and then shrink in width as the thermal passes through.

-Mark
By Roadrunner71
#403409
When it comes to sight in Humans. I remember reading that the Baseball Player Ted Williams was said to see the Stitching on ball that was crossing the Plate that was pitched to Him! Wow, what I would give for Eyesight such as Ted Williams.
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By lizzard
#403482
Dont forget their sense of smell ..we all know about that, especially over piggerys and the like .
Its is more subtle in other places but still a part of most thermals, more so early on .
Their hearing would just be asubsonic version of ours and who knows ? We could develop it if we did not have varios.
One advantage of prone flying is perspective shift looking down.
Birds would use all of these and some I suspect relate to inclination/declination of local mag field which if viewed in 3d show invisible mountains .

Its likely a navigation method.
I cant prove the last one but magnetometers are a hobby of mine so perhaps 6 magnetometers nose ,keel,kingpost ,wing tips and base tube ? Intergrated and averaged .Our alloy or carbon frames make this dooable .
Could be a new play ground for us nerdy types?
or just stick with a vario and experience ?
By TheFlyingFrog
#403518
What should be amazing to experience is the no-delay response of the Vitali organ, but nowadays we can also get some variometer with in-biult G-meter that are quite fast and responsive.
Max
www.airemotions.it
By Roadrunner
#411388
Here is another case of killer eyesight. I remember what Chuck Yeager said in His Autobiography ; Some of the other Pilots claimed that They could out Fly Me. But none of them claimed that They could out see Me.

What I would Give to have had Eyesite such as Yeager's, or that of Ted Williams.
By once&future
#411389
I had pretty good eyesight in my youth - measured at 20/13. One of the best pilots I knew, though, had really exceptional 20/8 vision. He told me when he flew Chelan he could see the individual wheat stalks being blown by a dust devil forming on the ground from several thousand feet up. Can't really argue with the usefulness of that gift - he won the Chelan Classic that year.
By bustedwing2
#411390
Try flying with your eyes closed with open faced helmet, did it once 20 years ago while taking aeratorw instruction with a tandem instructor, got to cloud base on a light day with no vario, he was impressed i was ecstatic, feel temp changes on your face and minor glider movements more readily without visual distractions.
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By Vrezh
#411391
I might have told this story in this forum, I don't remember,
about 20 or so years ago I had my right eardrum replaced.
When I was cleared to fly again, I had an unexpected surprise.
I could feel small pressure changes.
In a way, I had a built in vario :) .
The doctor said it's good, that means the nerves are good.
It gradually vanished over time though.
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By USHPA7
#411393
One of the things that HG pilots liked aboiut my Colver vario was its super quick response to indicate changing pressure in addition to the high sensitivity (could detect the change in room pressure when a toilet was flushed).

One time I bought a sailplane ride from the Orange County Soaring Association at Perris CA. It turned out to be a pretty dead air day and the pilot found no lift after release from tow.

I was seated directly behind the pilot and i could see his Bell variometer. I also carried one of my "Colver Soaring Instruments" varios in my hand. On a sled ride back toward the airstrip my vario suddenly indicated lift for a brief period of time and then quickly went back to down. The Bell vario on his dashboard slowly started indicating lift about the time mine was heading back down. He started circling the gilder and I let out a startled "what are you doing?" because we didn't have much altitude left to get to the runway. He replied we were in a thermal and I replied that was just a little blip of lift and we were not in lift as he circled and the Bell vario slowly returned to indicating down. We barely made the dirt area off the far end of the paved runway, just clearing a flood control channel, and the glider had to be ground towed up to the beginning of the runway. If he hadn't made that one circle in zero lift (or sink) we could have at least landed on the paved portion of the runway.

So I assume that birds "built in vario" would have a very fast response time as being as important as is sensitivity to pressure changes. If it doesn't tell you that you are in lift until you are leaving it then it isn't much help in weak conditions and small diameter thermals.

Frank
By once&future
#411394
That's always been the big advantage of "flask" type varios, that rely on air moving in and out through a small port in a large vessel. Pressure transducer varios can be much more compact (and provide a built-in altimeter), but their response times were inferior back in the early days - when the vario function relied on a simple, noisy analog differentiator circuit. Modern signal processing has improved this somewhat and today's digital varios have pretty fast response times. I think a full size flask-based unit will still beat them in speed and sensitivity, though.
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By red
#411395
Campers,

I do not know if this is true, but I have heard that the hollow, air-filled bones of birds are actually the "flask" of air for the built-in bird vario. Supposedly they can sense that air is leaving the system when going up. In the same way, in reverse, they might detect sink by air coming in. I am fairly certain that bird eyesight is a factor, and maybe even the sense of smell to some degree, but I doubt that anybody has actually verified these ideas .
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By USHPA7
#411396
Don Piccard, of hot air balloon fame, once showed me his collection of antique varios on the day he bought one of mine.

One of them that I remember was a flask type where bubbles would visibly pass through a fluid (water?) in a glass tube as air went in or out of the flask. The more frequent the bubbles the rate the rise or decent was indicated.

I wish I had taken a better look at it because I don't remember any details about its design. Like how did it prevent the liquid from being sucked in or blown out and I don't remember if it had one tube or two tubes for up and down. I think the reason I didn't study that one more was because I was "blown away" just by seeing a collection of antique rate of climb instruments.

Don died in the past couple of years, I hope those instruments are finding a good home like in a museum. It seems odd to me that one of my gold boxes is among them.

Frank
Vario Production Line spring 1974 R.jpg
Vario Production Line spring 1974 R.jpg (252.41 KiB) Viewed 624 times
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By red
#411398
USHPA7 wrote: Sun Nov 21, 2021 12:33 amDon Piccard, of hot air balloon fame, once showed me his collection of antique varios on the day he bought one of mine.
One of them that I remember was a flask type where bubbles would visibly pass through a fluid (water?) in a glass tube as air went in or out of the flask. The more frequent the bubbles the rate the rise or decent was indicated.
I wish I had taken a better look at it because I don't remember any details about its design.
Frank
Frank,

I own an ancient pith-ball version, probably not all that similar, but it has two lightweight pith balls in small glass tubes. Air leaving the flask (in lift) would cause one ball to rise in its' tube. Air going into the flask (in sink) would cause the other one to rise. Pith is a very lightweight wood, so I would guess that humidity would affect the accuracy of that instrument. Static electricity may also be a factor. Here (in the desert SouthWest of the USA), it usually works well enough, but it would not operate as intended is zero-G. The liquid version probably would not, either.

The pith ball version can be a DIY design, and I remember plans in library books to make one. European pilots may have a better chance of locating DIY plans, because of the long experience there with sailplanes. The "flask" in the DIY design was typically a vacuum Thermos bottle, for better accuracy, but a Styrofoam flask will do the job.
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By thermaleo
#411399
The long bones of birds are hollow, and filled with air sacs that are an extension of their lungs. While this makes the respiratory efficiency of birds far greater than for mammals - they need it in order to maximize 02 uptake for flight - it would be remarkable if in over 100 million years of evolution this was not adapted as an inbuilt "full body" vario. Changes in air pressure and flow would create an automatic system in the bird that would instantly detect lift and sink. The bird doesn't have to think about what to do, any more than you think about how to walk and balance, or for that matter how to respond to the noise your vario is making. It is truly another sense.

In addition to that, every feather, especially the flight feathers, are hooked up to nerves in the bird's skin, giving an entire body "feel" to the air that we can only guess at, makes it easy to understand why soaring birds are so good at it. Plus of course stuff like exceptional visual acuity, and the ability to see a far greater range of colors than we do - birds have 4 types of color sensitive cells in their retinas, while we only have 3, and thus can see further into the infra red and UV ends of the spectrum, so they may indeed be able to see air movements in ways we cannot. Birds like condors and vultures also have a pretty good sense of smell. While thermaling at 12,000ft in Idaho, a fellow pilot and I both smelled skunk coming up from over a mile below, marking the thermal quite well!

Leo Jones
By Roadrunner
#411400
I used to Fly, actually I flew for a Long Time without a VA riometer. really tried to use whatever senses That I had to detect Lift. But when I got High the limitation of my ingrain senses would falter. When I could no longer use the visual clues to determine if I was climbing or descending. My ability to climb diminished. Heck, I am after all a Human being. My Friend Mike B said to Me once; "Birds do it for a Living". Well I finally had to admit to Myself that I did not have the senses that a Bird had. I bought a Ball VA riometer. Pretty soon I was able to make it go "Beep-Beep-Beep" fairly consistently.

Regarding climbing; I will know that I have arrived when I am able to core through Buzzards.
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By USHPA7
#411403
In my vario design I used a plastic bottle for the flask and insulated it with Styrofoam can holders. Using foam alone would not work because it had too many air holes. It only takes one hole, so small you can't see it, to greatly reduce the sensitivity. People who took the lid off of my flask usually did not get it resealed well enough and I would get the vario back for repair with a complaint that it had lost sensitivity.

To detect the air movement going in and out of the bottle I used two "hot wire anemometers" I made from tiny lamp filaments with tiny air nozzles on each side.

It's an interesting story behind the caps that I used on my flask. I had found that a Maxwell House instant coffee jar lid was a perfect fit for the plastic bottles I was buying in bulk. However, I could not sustainably use lids from coffee containers in production. You need to remember this was long before the internet and finding a product or contacting a large company were very difficult or impossible compared to today.

I mentioned to a co-worker (at my day job) that I wished that I could get hold of somebody at General Foods to buy Maxim coffee jar lids but it seemed impossible. He took that as a challenge. Later that day he came to me with a phone number and said this high up guy at General Foods would sell me 5,000 lids for almost nothing. He said that it only took him six phone calls to get to the top guy in that division. Amazing! I would not have even tried so i'm forever thankful to a guy named Dave Wilson, draftsman.

Here's why I was offered this opportunity to buy these jar lids at a cheap price. It also solved another concern I had. That concern was a reluctance to put in my product a part that said Maxim Coffee on it. General Foods had contracted with another company to make 5,000 lids for the coffee jars. That vendor neglected to put any label molded into the lids. They were all blank and General Foods could not use them but for my purpose they were perfect and GF was glad to get rid of them.

Later I was visited by a General Foods Company guy who was in SoCal on business and was curious as to what somebody could be using instant coffee jar lids for. He was very impressed when I demonstrated one of my varios for him.

I can't even begin to imagine how many odd stories there must be from the early developing days of hang gliding and those of us who were so fortunate to have lived at that fantastic, never to be repeated, time are exiting the picture all too soon.

Frank Colver