Do you know how gliders climb?
Today I will tell you about the most used way of getting altitude
with a glider(after takeoff :D). It is called"thermalling".
Thermals are invisible,giant bubbles of air wich get caught on the groung. The temperature in those bubbles is bigger then the outside temperature and when it pops the hotter air rises. They can pop because of wind, things that go through them (cars, tractors plowing) or just by the big difference of temperature. This raising air can get a glider to climb with over 3 mps, wich is preety much.
Bubbles form because the ground has different colours and contrasts like forrests and cultivated lands, lakes and plowed fields, etc so the ground is heated different. Water for example is very poorly heated compared with a big plowed terrain that is in the vecinity, so the bubbles will form on the terrain. As a glider pilot, you will have to know how to look for those places on groung.
The higher the altitude the harder it is to get a thermal by looking at the ground, specialy on windy days because as the bubble get moved horizontally by wind while ascending. Also, a mass of climbing air is getting bigger and faster as it climbs. If you are up and want to get into a thermal you have to look for those little fluffy clouds because thermals usually create a cloud on the top. That's the easy and cool part because you are exausted by the heat and blinded by sun while spiraling in the rising air and then you get under the cloud where is freezing cold and the shade doesn't let any of the sun radiation touch you. But of course there can be days when thermals are very strong with no clouds up...
The best time for thermal formimg and with the highest strength is after about 2hours from when the sun passes the vertical of your position. So you better be in the air by then if you want to beat some records :P
The technique of thermaling with gliders is very simple in theory. You find it, enter it, spiral in it, find it's center, stay as close to the center as possible for best climb rate. In real life...not so easy as it seems not only because it is invisible but it always tries to get you out and it can be a bumpy ride from the turbulent air.
When you get more experience you will feel the thermal as it moves you through it, hear it because it has different speed and direction than cold air so it changes the sound that you ussualy hear in flight and with some good eyes you can even see the dust that it carryes up with it. Other signs of thermals in the area are birds that are flying in a spiral without flapping their wings. Birds are natural thermal flyers, the stork beeing one of the best and the crow being on the bottom of the list. Crows love to fly in circle for fun but not in thermals so if you see them, don't go there tinking that's your lucky day.
Keep in mind that a normal glider is descending with about 1mps in normal flight so you will need a mass of air that climbs with more than 1mps for you to climb. Also when clouds form, you are forbitten to climb trough the cloud because things get really rough in there. The main concern is that you will get desoriented because you can't see anything but if the cloud gets big enough it generates turbulences so strong that can brake your wings. Some clouds are forbitten to get into even with the big planes. So be careful!
You will understand better if you will look at the sky in a sunny day and if you will see a small cloud somewhere close, remember the position and check after 3minutes. The cloud can dissapear, because the bubble got cold or it was too small to mentain the cloud or it can get bigger because the sun is so hot that bubbles are forming very fast and they create a tunnel of hot air rising to the cloud, making it massive. You will know that a thermal is strong if the base of the cloud is straight and black and on top it has like an anvil shape.
Gliders have special instruments showing you the vertical speed and some modern ones even make sounds helping the pilot by letting him look at other things.
I could talk for hours about this phenomenon but I don't want to get you bored so...if you want to know more about something in my thermalling post just ask by replying.
Will come back for other methods of climbing with gliders, hope you understand the magic that nature gives us. I tried to use common language and didn't use special terms on purpose.
Here is a phone edited piture of me thermalling! :D
Thank you!!
