flying dog Posted January 31 Posted January 31 Curious. "Down here" which way would birds be flying if they are in a thermal? CW or CCW? High-pressure spins CCW down here. So the birds would be going CW - yes?
Student Pilot Posted January 31 Posted January 31 I have never noticed any one direction, I would think they would circle into the highest lift either direction like a glider.
Litespeed Posted January 31 Posted January 31 I think cw is right. Everyday I watch birds here at Port Stephens soaring at low levels and it's almost always cw from ground level to at least 500feet. Masses of sea birds esp Sea Eagles and pelicans to watch. Plus plenty of others that will soar if any currents are around. 1
onetrack Posted February 1 Posted February 1 I watched a pelican soaring over the house this morning in thermals at about 500 feet (a quite unusual sight, I might add, I've never seen one here before, I'm quite a few kms from open water) - and he was going CW.
facthunter Posted February 1 Posted February 1 The airmass would be rising whichever direction you flew in it as long as you stay within it's confines. but your groundspeed would vary. Into wind would allow a tighter radius and that's an advantage.. You can feel the edge of the thermal tugging your wingtip down. Nev 1
flying dog Posted February 1 Author Posted February 1 Facthunter, That is an interesting point. Though the others are also interesting. (To the first ones) Yeah, ok, the direction of their "spin" would depend if they wanted a high or low airspeed. Which maybe isn't of importance. It was just something that got into my head and I asked. Thanks all. 1
facthunter Posted February 1 Posted February 1 Thermals are generally a quite small diameter. Better to go slow(er) (into wind) than the opposite to keep the bank angle lower and have less drag and stall issues. Nev. 1 1
FlyBoy1960 Posted February 1 Posted February 1 2 minutes ago, facthunter said: Thermals are generally a quite small diameter. Better to go slow(er) (into wind) than the opposite to keep the bank angle lower and have less drag and stall issues. Nev. I havent seen too many bird's stalling lately ! Just taking the pi$$ and being stupid 2
Thruster88 Posted February 1 Posted February 1 1 hour ago, FlyBoy1960 said: I havent seen too many bird's stalling lately ! Just taking the pi$$ and being stupid Good point, they probably fly correct airspeed or angle of attack, which ever is their preferred method. 1 1
facthunter Posted February 1 Posted February 1 They only take off and land downwind when they are very young. Nev 1
skippydiesel Posted February 1 Posted February 1 Birds takeoff into wind - possible exceptions are those that , when startled, "explode" into flight from cover eg chickens, pheasant and other low scrub dwelling birds. My guess they will "thermal" to their best advantage, probably into wind
Blueadventures Posted February 1 Posted February 1 They go into wind same as best for gliding is into the direction opposite turn when possible. Birds are smart and efficient watch their V pattern flight. Years ago I tricked an eagle by when in sink and seeing it coming over I turned sharply as if centering a thermal and I was in sinking air. The eagle quickly joined with me and set itself to thermal and immediately started flapping its wings as if it got bogged and was in 4 wheel low getting back up to flying speed. I still smile thinking of that day. 3 3
Bernie Posted February 1 Posted February 1 We have a pair of Magpies here with a young baby. The parent's when coming into land on a windy day turn into wind just as the let down...baby has yet to master this maneuver...comical.. Bernie. 2
Student Pilot Posted February 1 Posted February 1 Was just watching a couple of Wedge-tails, both circling anti clockwise. I'm gong to be highly controversial here and say maybe most thermals and not all air movement rotates? A thermal is a bubble of air moving up, why is it rotating? 1
onetrack Posted February 1 Posted February 1 They rotate because any movement of a gas or liquid not restrained, is subject to the Coriolis effect. However, the Coriolis effect is minimal when gas or liquid speeds are slow, or the travel distance is short. It doesn't long though, for heated rising air to start to spin. Ever seen a willy-willy/cock-eyed bob/mini-tornado, crank up? They will start to spin only 15 to 20 metres above hot ground. https://education.nationalgeographic.org/resource/coriolis-effect/ Interesting fact: A friend who was an artilleryman during the Vietnam War told me how they had to calculate the Coriolis effect on the target point of 105mm artillery shells that were fired at long distance targets. Even more interesting was the fact that these calculations were done manually, longhand. No hand-held calculators back then. 2 2
planedriver Posted February 1 Posted February 1 We had a neighbors young chook in our garden a few weeks back. As I approched, it took flight following the path between the trees but wound up slamming into the fence at the end. I think it should have read Nevs post about gaining altitude by taking off into the wind. 1 2
facthunter Posted February 1 Posted February 1 ,Contrast the Cockatoos landing on the long rubbery branches at the top of a pine tree, waving in the breeze. Nev 2
FlyBoy1960 Posted February 2 Posted February 2 I have never seen a chicken in a thermal, regardless of direction. What have i missed out on ? I do know they turn clockwise at my local chicken shop, even with a skewr in both ends. 🤣 4
Marty_d Posted February 2 Posted February 2 14 minutes ago, FlyBoy1960 said: I have never seen a chicken in a thermal That was me, just having learned to hang glide at 23. 2
flying dog Posted February 2 Author Posted February 2 (edited) I've seen a chicken in a thermal.... Oh, wait, sorry: It was an oven! And it was turning CCW. 😉 Sorry, now off topic: This is how birds go BOOM! Onetrack: WRT "the old ways" I once found/saw a thing on youtube about old analogue computers and gun sights. On a battle ship firing a gun. How they calculate angle from wind speed, ship's speed, direction and all that stuff. All done with MECHANICAL gears. 'twas amazing. Sorry I can't give a link. Ok, maybe this one. After a bit more digging, I think this was the one I saw: Edited February 2 by flying dog 1
spacesailor Posted February 2 Posted February 2 Mechical computers , named , sliderules , were used in WW1 . 1925 " Loga- calculator- sliderule . My cylinder sliderule , is modern ,1950s . It works the same as standard sliderule , with a Long long length . spacesailor
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now