Spotting thermals is the key to successful thermal soaring. Knowing where lift occurs will dramatically improve your flight duration and enjoyment. This article highlights practical signs and recognition methods.
What is a thermal, and why does it matter?
A thermal is a rising column of warm air, typically forming over sunlit areas. RC gliders rely on these to stay aloft without motors. About 70% of successful gliding comes down to finding and staying in thermals.
Common signs of thermals
- Birds circling: Birds of prey hovering at one point are riding thermals.
- Dust spirals, flying leaves: Visible signs of ground-level thermal activity.
- Cumulus clouds: Often form above active thermals – fly underneath them.
- Terrain contrast: Thermals often start at sun/shade boundaries like fields and forests.
- Lift sensation on your model: Sudden lightness or gain in altitude = thermal.
Typical mistakes when searching for lift
- Starting too low – you won’t have time to circle effectively
- Failing to correct for wind drift – you’ll exit the thermal center quickly
- Ignoring natural signs like birds or grass motion
Video example
A great example of what it looks like when a model enters lift: