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Paraglider and hang glider pilots can also soar for hundreds of miles without power or flapping. Soaring birds like condors, turkey vultures, hawks, etc. use th

Paraglider and hang glider pilots can also soar for hundreds of miles without power or flapping. Soaring birds like condors, turkey vultures, hawks, etc. use the same technique of turning in tight circles in rising air to increase altitude. Once cloud base is reached and the rising air stops, they glide significant distances to the next hillside with rising air. Whenever you see birds in the sky circling around the same spot together, it's because they're in rising air and using it to stay aloft.

clueless123 6y ago
FWIW, the estimated glide ratio of a South American Andean Condor is ~ 12:1 or about what a competition Paraglider does. (Or an old hang glider)
ajuc 6y ago
There's thermals (a spot on the land that is warmer than the surroundings so the air rises there), and there's topography that causes rising air (for example when the wind blows at a face of a hill - the air has no choice but to go up). RC gliders can stay in air basically forever flying back and forth in rising air along a hillside. It's called slope-soaring and it's great fun.
- dmos62 6y ago
  > RC gliders can stay in air basically forever flying back and forth in rising air along a hillside. And there's been some effort to have autopilots do it automatically https://ardupilot.org/plane/docs/soaring.html https://ardupilot.org/plane/docs/soaring.html
- jojobas 6y ago
  Somewhat more impressively, albatrosses do that on the forward faces of waves, soaring for days far away from thermals and hills.
  - tim333 6y ago
    There's research that they use dynamic soaring more, getting energy from the different wind speeds at sea level and a bit above https://www.youtube.com/watch?v=uMX2wCJga8g https://www.youtube.com/watch?v=uMX2wCJga8g
    - crubier 6y ago
      Gotta love the end of the video aha! But the whole video is very interesting. As a kayaker myself I can definitely “feel” the phenomenon they are talking about of extracting energy by alternating on two sides of a flow gradient.
      - frandroid 6y ago
        Next up in kayagliding...
    - sails 6y ago
      That is very interesting. I always assumed sea birds used combination of wing in ground effect [1] and the lift of wind hitting the front of waves to cover long distance, but this explanation makes much more sense for birds crossing oceans. [1] https://www.youtube.com/watch?v=vkVVnx70FgI https://www.youtube.com/watch?v=vkVVnx70FgI Edit: It just occurred to me that the albatross is in some way surfing the wind in much the same way a surfer pumps along a wave to generate speed.
- StavrosK 6y ago
  Here's an RC glider doing 545 mph with that technique: https://youtu.be/MoaWlKC3wIM https://youtu.be/MoaWlKC3wIM I don't know how they manage to control it or measure the speed, but it looks legit.
  - ajuc 6y ago
    Wow. That's not how it usually looks like :) Usually it's very slow and relaxing. Looks like this: https://youtu.be/Ev5fSVi1PrA?t=152 https://youtu.be/Ev5fSVi1PrA?t=152
  - sails 6y ago
    That is dynamic soaring [1] which is I guess a subset of slope soaring, and is pretty rare and nuts. It generally requires flying in the lee of a slope rather than in front of it. Regular slope soaring is relatively more sedate, fun and accessible if you have the right slope. [1] https://en.wikipedia.org/wiki/Dynamic_soaring https://en.wikipedia.org/wiki/Dynamic_soaring > Dynamic soaring is sometimes confused with slope soaring which is a technique for achieving elevation.
- stx 6y ago
  > RC gliders can stay in air basically forever flying back and forth in rising air along a hillside. It's called slope-soaring and it's great fun. This was my thought also. The Andes Mountain Range are rather mountain range right next to the ocean. I would think that is a pretty ideal place for a bird to slope soar for a long distance.
samvher 6y ago
The rising air doesn't actually stop at cloud base, but it becomes very hard to orient because you don't see the horizon anymore. The thermals can also be generated by many different landscape features - they can be triggered by hills (which can also help them release) but there are plenty on flat landscape as well. Also other sources of upward air currents can be used for soaring, e.g. wind deflecting upwards over a hill or waves high in the atmosphere (search "wave soaring" on youtube). There is even https://perlanproject.org/ https://perlanproject.org/ aiming to do this at 30km altitude.
- simple10 6y ago
  Good point. I oversimplified. Birds and pilots tend to not fly up into clouds for visibility reasons but the air keeps rising into the cloud. From experience, it's a surreal experience riding a thermal up into a cloud in a paraglider. Just not safe or legal in most places to stay in the cloud.
- Leherenn 6y ago
  If anything it is often the strongest at the base of the clouds from experience. The top of the cloud is where it stops climbing.
- t0mas88 6y ago
  The other reason gliders stop at the cloud base is that it's illegal to fly close to the clouds in most airspace. Because it makes it very hard to avoid collisions.
hellofunk 6y ago
I had no idea that people can hang glide for hundreds of miles! That’s genuinely amazing.
H8crilA 6y ago
Paragliders and hang gliders are still easily beaten by sailplanes. World's record for a single day sailplane flight is 3000km (1800mi), that's been performed on mountain lee waves.
jillesvangurp 6y ago
Neal Stephenson's Seveneves has a part (part 3) of the book that is set in the distant future. One plot point there is some kind of advanced glider basically exploiting the atmosphere to pick up enough energy over the course of a day to eventually get enough mass (by picking up water) and energy to eventually travel at high speeds & altitudes half way across the planet. Science fiction of course but he has a way of making this somewhat plausible. Gliders sometimes use water ballast to store more energy so they can stay up longer. Basically after getting towed to an initial altitude they use thermals and ridge soaring to gain altitude. After that it's all about converting altitude to speed and distance based on their glide ratio. Having a high mass apparently helps. Hopping from one lift producing area to another, you can cover great distances. Currently this is pretty much a recreational activity because you are dependent on weather, sunlight, and other things that are hard to predict and detect. But kind of intriguing notion what you could do if you had a way to reliably find areas with good lift. On a related note, here's a youtube channel of a glider pilot in Kansas that regularly posts awesome footage from his glider. Here's some awesome footage of him exploring some mountains and exploiting available lift from winds hitting the rocks: https://www.youtube.com/watch?v=Bcd5Z46RGRU https://www.youtube.com/watch?v=Bcd5Z46RGRU
- meheleventyone 6y ago
  If you want to play about with gliders yourself the sim Condor Soaring is pretty awesome and has VR support. It's a much more chill and relaxing experience than flying combat sims all the time and more engaging than most non-combat sims.
- samvher 6y ago
  The point about water ballast is actually not entirely accurate - it's not to stay up longer, it's to increase speed. Gliders have a certain angle of attack at which they fly most efficiently (optimal glide angle, i.e. trading the least height for every meter forward). If you add water ballast, the speed corresponding to that angle of attack is increased. The downside is that your downward speed also increases - so when the weather gets difficult or thermals get weak, pilots dump the water.
  - 6y ago
inopinatus 6y ago
“He spent a lot of time flying. He learnt to communicate with birds and discovered that their conversation was fantastically boring. It was all to do with wind speed, wing spans, power-to-weight ratios and a fair bit about berries. Unfortunately, he discovered, once you have learnt birdspeak you quickly come to realize that the air is full of it the whole time, just inane bird chatter. There is no getting away from it.” ― Douglas Adams, Life, the Universe and Everything
- perilunar 6y ago
  > just inane bird chatter I suspect most bird chatter is about sex, not flying. Like when you're out in the summer evening, and the crickets are chirping and the frogs are croaking, and you realise it's just a whole bunch of males shouting "hey baby, over here!"
  - formerly_proven 6y ago
    Service discovery all the way down.
  - deleted 6y ago
    [deleted]
  - mattigames 6y ago
    In a lot of species the females are the one making noise, sloths and snow leopards as a couple of examples.
  - Phrenzy 6y ago
    I got a bird feeder a little while ago. After watching them closer that I had in the past, I realized something. All that chirping going on either means "Have sex with me" or "Go away, this is mine." All the chirping I had ever heard basically means the same thing as most of what my peers were saying in junior high.
- KineticLensman 6y ago
  > It was all to do with wind speed, wing spans, power-to-weight ratios and a fair bit about berries. As much as I like Douglas Aadms, this statement is just wrong. A lot of bird chatter is songs to demarcate territory, threat warnings, contact calls to maintain flock awareness, young birds saying 'feed me', and others. I know when a cat has entered my garden by the clucking warning calls that the blackbirds make. They make a different warning noise when I interrupt them on my bird feeder. Sometimes I'm alerted to a buzzard by the calls of rooks who are ganging up on it.
mjlee 6y ago
This knowledge is used by glider pilots to identify thermals - let the birds do the hard work and then go copy them!
- decafninja 6y ago
  Those gliders with huge wingspans and no awkward propeller on the nose look incredibly elegant. There's a gliderport not too far from me and I've always wanted to give flying one a stab. But it's really hard (and nerve wracking, lol!) to conceptualize how they stay in the air using thermals. Especially in staying in control when coming in for a landing.
  - cerberusss 6y ago
    From what I understand, most glider clubs are always looking for new members. Maintenance of the winch, gliders and landing strip is expensive and more members means sharing the costs. One in my province has "introduction days" where you can sit in a two-person glider, in front of an instructor, for a small price or even free.
  - samvher 6y ago
    I think you should just go for it - many gliding clubs have introductory or passenger flight options. I flew gliders for a few years and it's really wonderful - it's very quiet and the view is fantastic. Landing is suprisingly easy most of the time - when people fly "cross-country" (long distances, away from airfields) it's actually common procedure to "land out". Which is basically the same as an emergency landing (e.g. in a farmer's field) but much less stressful because gliders are actually designed to fly well without a functioning engine.
  - mjlee 6y ago
    As others have said, go try it out with an experienced pilot/instructor! It's very accessible. You might be more comfortable in a motor glider - they have enough thrust to conduct their own takeoff and get you out of trouble but are still light enough to glide effectively.
- bujak30000 6y ago
abrowne 6y ago
I pass a couple bald eagle nests commuting by bike along the river in Minneapolis. I'm always surprised when I see the eagles flapping their wings, since most of the time they are soaring.
rurban 6y ago
Exactly. The condor (or paragliders) can fly that way only in the Andes, because only there it is possible. Over the Amazon for sure not. It's not the bird, it's the environment.

clueless123 6y ago

FWIW, the estimated glide ratio of a South American Andean Condor is ~ 12:1 or about what a competition Paraglider does. (Or an old hang glider)

ajuc 6y ago

There's thermals (a spot on the land that is warmer than the surroundings so the air rises there), and there's topography that causes rising air (for example when the wind blows at a face of a hill - the air has no choice but to go up). RC gliders can stay in air basically forever flying back and forth in rising air along a hillside. It's called slope-soaring and it's great fun.

dmos62 6y ago
> RC gliders can stay in air basically forever flying back and forth in rising air along a hillside. And there's been some effort to have autopilots do it automatically https://ardupilot.org/plane/docs/soaring.html https://ardupilot.org/plane/docs/soaring.html
jojobas 6y ago
Somewhat more impressively, albatrosses do that on the forward faces of waves, soaring for days far away from thermals and hills.
- tim333 6y ago
  There's research that they use dynamic soaring more, getting energy from the different wind speeds at sea level and a bit above https://www.youtube.com/watch?v=uMX2wCJga8g https://www.youtube.com/watch?v=uMX2wCJga8g
  - crubier 6y ago
    Gotta love the end of the video aha! But the whole video is very interesting. As a kayaker myself I can definitely “feel” the phenomenon they are talking about of extracting energy by alternating on two sides of a flow gradient.
    - frandroid 6y ago
      Next up in kayagliding...
  - sails 6y ago
    That is very interesting. I always assumed sea birds used combination of wing in ground effect [1] and the lift of wind hitting the front of waves to cover long distance, but this explanation makes much more sense for birds crossing oceans. [1] https://www.youtube.com/watch?v=vkVVnx70FgI https://www.youtube.com/watch?v=vkVVnx70FgI Edit: It just occurred to me that the albatross is in some way surfing the wind in much the same way a surfer pumps along a wave to generate speed.
StavrosK 6y ago
Here's an RC glider doing 545 mph with that technique: https://youtu.be/MoaWlKC3wIM https://youtu.be/MoaWlKC3wIM I don't know how they manage to control it or measure the speed, but it looks legit.
- ajuc 6y ago
  Wow. That's not how it usually looks like :) Usually it's very slow and relaxing. Looks like this: https://youtu.be/Ev5fSVi1PrA?t=152 https://youtu.be/Ev5fSVi1PrA?t=152
- sails 6y ago
  That is dynamic soaring [1] which is I guess a subset of slope soaring, and is pretty rare and nuts. It generally requires flying in the lee of a slope rather than in front of it. Regular slope soaring is relatively more sedate, fun and accessible if you have the right slope. [1] https://en.wikipedia.org/wiki/Dynamic_soaring https://en.wikipedia.org/wiki/Dynamic_soaring > Dynamic soaring is sometimes confused with slope soaring which is a technique for achieving elevation.
stx 6y ago
> RC gliders can stay in air basically forever flying back and forth in rising air along a hillside. It's called slope-soaring and it's great fun. This was my thought also. The Andes Mountain Range are rather mountain range right next to the ocean. I would think that is a pretty ideal place for a bird to slope soar for a long distance.

samvher 6y ago

The rising air doesn't actually stop at cloud base, but it becomes very hard to orient because you don't see the horizon anymore. The thermals can also be generated by many different landscape features - they can be triggered by hills (which can also help them release) but there are plenty on flat landscape as well. Also other sources of upward air currents can be used for soaring, e.g. wind deflecting upwards over a hill or waves high in the atmosphere (search "wave soaring" on youtube). There is even https://perlanproject.org/ https://perlanproject.org/ aiming to do this at 30km altitude.

simple10 6y ago
Good point. I oversimplified. Birds and pilots tend to not fly up into clouds for visibility reasons but the air keeps rising into the cloud. From experience, it's a surreal experience riding a thermal up into a cloud in a paraglider. Just not safe or legal in most places to stay in the cloud.
Leherenn 6y ago
If anything it is often the strongest at the base of the clouds from experience. The top of the cloud is where it stops climbing.
t0mas88 6y ago
The other reason gliders stop at the cloud base is that it's illegal to fly close to the clouds in most airspace. Because it makes it very hard to avoid collisions.

hellofunk 6y ago

I had no idea that people can hang glide for hundreds of miles! That’s genuinely amazing.

H8crilA 6y ago

Paragliders and hang gliders are still easily beaten by sailplanes. World's record for a single day sailplane flight is 3000km (1800mi), that's been performed on mountain lee waves.

jillesvangurp 6y ago

Neal Stephenson's Seveneves has a part (part 3) of the book that is set in the distant future. One plot point there is some kind of advanced glider basically exploiting the atmosphere to pick up enough energy over the course of a day to eventually get enough mass (by picking up water) and energy to eventually travel at high speeds & altitudes half way across the planet. Science fiction of course but he has a way of making this somewhat plausible. Gliders sometimes use water ballast to store more energy so they can stay up longer. Basically after getting towed to an initial altitude they use thermals and ridge soaring to gain altitude. After that it's all about converting altitude to speed and distance based on their glide ratio. Having a high mass apparently helps. Hopping from one lift producing area to another, you can cover great distances. Currently this is pretty much a recreational activity because you are dependent on weather, sunlight, and other things that are hard to predict and detect. But kind of intriguing notion what you could do if you had a way to reliably find areas with good lift. On a related note, here's a youtube channel of a glider pilot in Kansas that regularly posts awesome footage from his glider. Here's some awesome footage of him exploring some mountains and exploiting available lift from winds hitting the rocks: https://www.youtube.com/watch?v=Bcd5Z46RGRU https://www.youtube.com/watch?v=Bcd5Z46RGRU

meheleventyone 6y ago
If you want to play about with gliders yourself the sim Condor Soaring is pretty awesome and has VR support. It's a much more chill and relaxing experience than flying combat sims all the time and more engaging than most non-combat sims.
samvher 6y ago
The point about water ballast is actually not entirely accurate - it's not to stay up longer, it's to increase speed. Gliders have a certain angle of attack at which they fly most efficiently (optimal glide angle, i.e. trading the least height for every meter forward). If you add water ballast, the speed corresponding to that angle of attack is increased. The downside is that your downward speed also increases - so when the weather gets difficult or thermals get weak, pilots dump the water.
- 6y ago

inopinatus 6y ago

“He spent a lot of time flying. He learnt to communicate with birds and discovered that their conversation was fantastically boring. It was all to do with wind speed, wing spans, power-to-weight ratios and a fair bit about berries. Unfortunately, he discovered, once you have learnt birdspeak you quickly come to realize that the air is full of it the whole time, just inane bird chatter. There is no getting away from it.” ― Douglas Adams, Life, the Universe and Everything

perilunar 6y ago
> just inane bird chatter I suspect most bird chatter is about sex, not flying. Like when you're out in the summer evening, and the crickets are chirping and the frogs are croaking, and you realise it's just a whole bunch of males shouting "hey baby, over here!"
- formerly_proven 6y ago
  Service discovery all the way down.
- deleted 6y ago
  [deleted]
- mattigames 6y ago
  In a lot of species the females are the one making noise, sloths and snow leopards as a couple of examples.
- Phrenzy 6y ago
  I got a bird feeder a little while ago. After watching them closer that I had in the past, I realized something. All that chirping going on either means "Have sex with me" or "Go away, this is mine." All the chirping I had ever heard basically means the same thing as most of what my peers were saying in junior high.
KineticLensman 6y ago
> It was all to do with wind speed, wing spans, power-to-weight ratios and a fair bit about berries. As much as I like Douglas Aadms, this statement is just wrong. A lot of bird chatter is songs to demarcate territory, threat warnings, contact calls to maintain flock awareness, young birds saying 'feed me', and others. I know when a cat has entered my garden by the clucking warning calls that the blackbirds make. They make a different warning noise when I interrupt them on my bird feeder. Sometimes I'm alerted to a buzzard by the calls of rooks who are ganging up on it.

mjlee 6y ago

This knowledge is used by glider pilots to identify thermals - let the birds do the hard work and then go copy them!

decafninja 6y ago
Those gliders with huge wingspans and no awkward propeller on the nose look incredibly elegant. There's a gliderport not too far from me and I've always wanted to give flying one a stab. But it's really hard (and nerve wracking, lol!) to conceptualize how they stay in the air using thermals. Especially in staying in control when coming in for a landing.
- cerberusss 6y ago
  From what I understand, most glider clubs are always looking for new members. Maintenance of the winch, gliders and landing strip is expensive and more members means sharing the costs. One in my province has "introduction days" where you can sit in a two-person glider, in front of an instructor, for a small price or even free.
- samvher 6y ago
  I think you should just go for it - many gliding clubs have introductory or passenger flight options. I flew gliders for a few years and it's really wonderful - it's very quiet and the view is fantastic. Landing is suprisingly easy most of the time - when people fly "cross-country" (long distances, away from airfields) it's actually common procedure to "land out". Which is basically the same as an emergency landing (e.g. in a farmer's field) but much less stressful because gliders are actually designed to fly well without a functioning engine.
- mjlee 6y ago
  As others have said, go try it out with an experienced pilot/instructor! It's very accessible. You might be more comfortable in a motor glider - they have enough thrust to conduct their own takeoff and get you out of trouble but are still light enough to glide effectively.
bujak30000 6y ago

abrowne 6y ago

I pass a couple bald eagle nests commuting by bike along the river in Minneapolis. I'm always surprised when I see the eagles flapping their wings, since most of the time they are soaring.

rurban 6y ago

Exactly. The condor (or paragliders) can fly that way only in the Andes, because only there it is possible. Over the Amazon for sure not. It's not the bird, it's the environment.