Editing Paragliding (section)

=== Thermal flying ===

[[File:paragliding3.jpg|thumb|left|Paragliders in the air at [[Torrey Pines Gliderport]]]]

When the sun warms the ground, the ground will radiate some of its heat to a thin layer of air situated just above it. Air has very poor thermal conductivity and most of the heat transfer in it will be convective - forming rising columns of hot air, called thermals. If the terrain is not uniform, it will warm some features more than others (such as rock faces or large buildings) and these thermals will tend to always form at the same spot, otherwise they will be more random. Sometimes these may be a simple rising column of air; more often, they are blown sideways in the wind and will break off from the source, with a new thermal forming later.

Once a pilot finds a thermal, he begins to fly in a circle, trying to centre the circle on the strongest part of the thermal (the "core"), where the air is rising the fastest. Most pilots use a [[Variometer|vario]]-[[altimeter]] ("vario"), which indicates climb rate with beeps and/or a visual display, to help core in on a thermal.

Often there is strong sink surrounding thermals, and there is also strong turbulence resulting in wing collapses as a pilot tries to enter a strong thermal. Good thermal flying is a skill that takes time to learn, but a good pilot can often core a thermal all the way to [[cloud base]].