Ridge lift

As Hangwind a locally -influenced wind is referred to, the direction of which is deflected by a mountain slope up or down, or caused by sunlight. Depending on the sun, regional wind strength and shape of the slope, the vertical component of slope winds can reach several meters per second. The resulting updrafts be used when sailing, paragliding and hang glider flight at the altitude gain.

Two types of formation

A slope wind can arise mainly in two ways:

Conversely arises after sunset a Hangabwind because the slope close air cools more by nocturnal radiation than the free air at the same height. The cooler soil air flows because of their greater density downslope. In the mountains are the slope winds part of members of the mountain and valley wind circulation.

Use in sailing and hang gliding or paragliding

For the flight without engine are hang- updrafts, in addition to the thermals, the main driving source. A special form of slope winds are the lee waves leeseits a mountain range sporadically occurring at high altitudes, which are relevant particularly for long-haul flights and triangle.

In contrast to the localized thermal updraft, which is available only by narrow circles of the glider, a hang wind can be " taken " in the haul flight. Since a high performance glider gliding a settling velocity of only about 0.5 - 1 m per second has a relatively weak ridge lift can result in a significant gain in altitude when the flight path is parallel to the sun or windward slope. In thermals the best route is often indicated by a strung on a slope succession of small cumulus clouds, because a forced ascent of air is accompanied by its adiabatic cooling and cloud formation favors.

Beyond the ridge the ridge lift goes for aerodynamic reasons over in a downdraft, which, however, already can occur over larger bumps of the rising slope.

History

While a thermal ridge lift ( 2 ) can occur at any sunny slope, the aerodynamic slope winds ( 1 ) to the north-south running mountain ranges are particularly pronounced. Along the Appalachian Mountains, the farmer Karl Striedieck could watch over the years as the Eagles reversed the mountainsides whizzed in the fall from Canada to the south and in the spring without flapping along. Following the same principle - quickly glide slope in the wind - he succeeded on May 9, first time in 1977 a motorless flight record of 1,000 miles ( 1,800 km).

Even Otto Lilienthal made ​​his 1893 Hangwind advantage of blew against his practice hill "Fly Mountain " in Berlin. This enabled him to eventually expand his air jumps to over 300 meters and fly a short time later, as his starting point was located - which by today's definition is different from the soaring gliding.

DFS slope wind was the name of a sailing trainer aircraft developed in 1927 in Germany, a slider for the training of beginners. The interesting thing about this design is the fork tail - and that the wing span (12 m), the length ( 6.5 m) exceeds two times.