Those spirals are called tip vortices. They occur because there is relatively high pressure under the wing and relatively low pressure above. At the wing tip, that higher pressure air wants to roll up over the wing tip to get to that low pressure area, which is what sets that spiral in motion. Any airfoil that is creating lift will have a vortex at its tip. Wings, tail surfaces, propeller blades, rotor blades, you name it. The higher the angle of attack, the more significant the tip vortex.
Have you ever seen a jet airplane that has fuel tanks out at the wing tips? Most of the reason they're there is to reduce tip vortices and thus reduce drag. The additional fuel capacity is a minor byproduct. You might notice most newer airliners feature winglets; the wing tips are turned up. That's not for additional yaw stabilty, those are there to reduce tip vortices, decrease drag and decrease fuel consumption.
Tip vortices are the main factor in wake turbulence, which is an entire class session in flight school. All a tower controller will say to you is "caution wake turbulence." And they're right. It's the pilot's job to know what to do about it, because trailing behind and below the wing tip of every airplane is an invisible sideways tornado you just have to know is there so you don't get thrown onto your Cessna's roof when landing behind a Boeing.
Next time you're watching a bird that likes to glide a lot, such as an eagle, have a look at how long their wing tip feathers are. They tend the curve upwards in flight and act in much the same way as winglets on aircraft.
I think there is a other layer to this. The image in question (I think) is showing how a birdoid body in flight avoids adverse yaw when banking for turns. That is done by managing the tip vortices in such a way to create a proverse yaw force. Quite literally, by befriending the spirals.
Hmm, that's interesting, I'm thinking like a pilot here but tip vortices increase in magnitude as AoA increasess, adding to adverse yaw of ailerons. I figured birds handled yaw control through wing sweep, kind of like how a weight shift trike does.
Be careful befriending the spirals. My ex and I befriended them one night in a tent in Zion National Park and neither of us could find my penis for some time and not just because it's so small. We were physically patting around for it and I swear it was gone, it felt like it had spiraled down to my leg, but it wasn't there either and I couldn't stop looping into myself, so it was really like it was running from me.
22 Comments
captain_aggravated@sh.itjust.works · 40 pts · 107d
The bird flies despite the spirals, not because of them.
FuglyDuck@lemmy.world · 3 pts · 107d
It’s sort of like those traits that handicap the bearer and so the better that aspect is, the more suitable a mate. Like peacock tail feathers.
The male swallow’s tips are spiraled for her pleasure.
captain_aggravated@sh.itjust.works · 26 pts · 107d
No it's more that physics is a fickle bitch.
Those spirals are called tip vortices. They occur because there is relatively high pressure under the wing and relatively low pressure above. At the wing tip, that higher pressure air wants to roll up over the wing tip to get to that low pressure area, which is what sets that spiral in motion. Any airfoil that is creating lift will have a vortex at its tip. Wings, tail surfaces, propeller blades, rotor blades, you name it. The higher the angle of attack, the more significant the tip vortex.
Have you ever seen a jet airplane that has fuel tanks out at the wing tips? Most of the reason they're there is to reduce tip vortices and thus reduce drag. The additional fuel capacity is a minor byproduct. You might notice most newer airliners feature winglets; the wing tips are turned up. That's not for additional yaw stabilty, those are there to reduce tip vortices, decrease drag and decrease fuel consumption.
Tip vortices are the main factor in wake turbulence, which is an entire class session in flight school. All a tower controller will say to you is "caution wake turbulence." And they're right. It's the pilot's job to know what to do about it, because trailing behind and below the wing tip of every airplane is an invisible sideways tornado you just have to know is there so you don't get thrown onto your Cessna's roof when landing behind a Boeing.
massive_bereavement@fedia.io · 4 pts · 107d
I have spent a lifetime watching birds, and this is the first time I learned about this.
Thanks
dellish@lemmy.world · 3 pts · 107d
Next time you're watching a bird that likes to glide a lot, such as an eagle, have a look at how long their wing tip feathers are. They tend the curve upwards in flight and act in much the same way as winglets on aircraft.
Alcoholicorn@mander.xyz · 3 pts · 107d
Now you will spend the rest of your lifetime imagine what type of wingtip would be most suitable for a bird.
Bytemeister@lemmy.world · 2 pts · 107d
I think there is a other layer to this. The image in question (I think) is showing how a birdoid body in flight avoids adverse yaw when banking for turns. That is done by managing the tip vortices in such a way to create a proverse yaw force. Quite literally, by befriending the spirals.
https://en.wikipedia.org/wiki/Adverse_yaw
https://en.wikipedia.org/wiki/Prandtl-D
captain_aggravated@sh.itjust.works · 2 pts · 107d
Hmm, that's interesting, I'm thinking like a pilot here but tip vortices increase in magnitude as AoA increasess, adding to adverse yaw of ailerons. I figured birds handled yaw control through wing sweep, kind of like how a weight shift trike does.
FuglyDuck@lemmy.world · -9 pts · 107d
That whooshing sound was the joke’s vortexes flying over your head.
captain_aggravated@sh.itjust.works · 14 pts · 107d
We're in the science memes sub, I talked about the science. I actually have credentials in this subject.
Artisian@lemmy.world · 4 pts · 107d
and I for one am very happy you're here!
TachyonTele@piefed.social · 3 pts · 107d
I laughed and learned. I feel like that's a huge plus for this community. Thank you
Zuriz@sh.itjust.works · 30 pts · 107d
SailorFuzz@lemmy.world · 25 pts · 107d
Spirals, you say?
verdare@piefed.blahaj.zone · 10 pts · 107d
This is truly the drill that will pierce the heavens.
Voroxpete@sh.itjust.works · 4 pts · 107d
As a fan of both Gurren Lagann and Uzumaki I am deeply torn on this.
HeyThisIsntTheYMCA@lemmy.world · 2 pts · 107d
I've got to win this one i bribed everyone in hollywood.
agamemnonymous@sh.itjust.works · 2 pts · 107d
So, this is the power of the spiral... not bad
TachyonTele@piefed.social · 17 pts · 107d
Sure. It's easy for government drones like this to use spirals...
ivanafterall@lemmy.world · 8 pts · 107d
Be careful befriending the spirals. My ex and I befriended them one night in a tent in Zion National Park and neither of us could find my penis for some time and not just because it's so small. We were physically patting around for it and I swear it was gone, it felt like it had spiraled down to my leg, but it wasn't there either and I couldn't stop looping into myself, so it was really like it was running from me.
They'll getcha. That's all I'm saying.
psx_crab@lemmy.zip · 4 pts · 107d
Air Bending obvs
GhostFace@lemmy.today · 2 pts · 107d
I miss TPP so much... Those were simpler times.