Basically, if there are no thermals, but a strong wind, is there a way to use that wind to gain altitude?
2$\begingroup$ Quite possibly, if there is a hill. $\endgroup$– user3528438Dec 11, 2017 at 4:05
2$\begingroup$ Or if you can throw out an anchor. $\endgroup$– KoyovisDec 11, 2017 at 4:52
1$\begingroup$ You need some gradient, like in the boundary layer of the atmosphere. Then yes, but it is very stressful. $\endgroup$– Peter KämpfDec 11, 2017 at 20:42
Yes, it's called ridge lift. From Wikipedia:
Ridge lift (or 'slope lift') is created when a wind strikes an obstacle, usually a mountain ridge or cliff, that is large and steep enough to deflect the wind upward.
If the wind is strong enough, the ridge lift provides enough upward force for gliders, hang gliders, paragliders and birds to stay airborne for long periods or travel great distances by 'slope soaring'.
If you happen to be in the San Diego area on a nice summer day. Go to the Torrey Pines glider port above Black's Beach in La Jolla and just north of the Scripps Institution of Oceanography. The onshore wind striking the bluff overlooking the beach is forced upwards and provides plenty of lift for hang gliders working their way back and forth.
You can see images of people doing that at the Torrey Pines Gliderport website or just Google "torrey pines gliding images" for additional images.
$\begingroup$ Thanks. However, I was more wondering whether it can do so over a flat area, without the deflection of a ridge or obstruction. $\endgroup$– TheoDec 11, 2017 at 8:29
$\begingroup$ @Theo -- is there a particular flat area that you have in mind? I ask because some early glider pilots would fly nearby to oceans to take advantage of the natural convection currents that provided some lift. $\endgroup$– MariusDec 11, 2017 at 23:41
$\begingroup$ But it's not the wind per se, it the fact hat the wind, hitting the ridge, creates an UPDRAFT. It's the Updraft that provides the lift. $\endgroup$ Dec 23, 2017 at 16:43
There is another way, that of harvesting energy from the wind gradient. Some birds (and some sailplane pilots) use it. It's called 'dynamic soaring'...
1$\begingroup$ Better call it "dynamic soaring"; without "dynamic" the word is used for flying in thermals. But you better have the physiology of an albatross to sustain the dynamic loads for an extended period of time. $\endgroup$ Dec 11, 2017 at 20:41
$\begingroup$ True. The correct name is 'dynamic soaring'... $\endgroup$– xxavierDec 11, 2017 at 20:52
$\begingroup$ FWIW there is a huge amount of energy that you can extract with dynamic soaring. In the world radio control, dynamic soaring gliders are the fastest airplanes you can fly - faster even than jet turbine or rocket powered RC airplanes. $\endgroup$ Apr 24, 2018 at 0:26