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How to Find Thermals for a RC Sailplane

Keeping an RC sailplane aloft for extended flying can be a difficult task. With no engine available, your plane is dependent on the wind to maintain height and provide speed for maneuverability. This wind occurs often because of the existence of thermals in the area. These thermals result from the differences in temperature between adjoining ground areas, where the mix of temperatures creates rising air currents up to thousands of feet in height. By steering your plane into the thermal, you can use the wind generated to sustain flight, riding thermals for the length of their existence and then using the height gained to find another.

Instructions

- 1
  Determine the best day for finding thermals. Wait for a warm day and the hottest part of the day for the greatest chance of thermals being present due to the heat.
- 2
  Find a large flat area with plenty of open space to fly your plane. Wait for a time when there's only a small breeze blowing.
- 3
  Launch the sailplane and gain a bit of altitude using the wind. Set the plane to slowly circling while you search for a thermal to ride.
- 4
  Look for natural indications of thermals in the flight area. Search the area for signs of heat glare, wavy distortions in the air caused by heat rising from the ground. Birds or insects congregating in a specific area are both signs of thermals as well. Thermals also occur due to changes in ground temperature between nearby areas. Look for lightly colored ground cover next to darkly colored ground cover, as the different heat absorption rates of the two areas can create a thermal where they meet.
- 5
  Fly your sailplane to the suspected thermals. Aim the glider straight for the center of the area. Adjust the plane's trim as necessary using the remote transmitter to maintain a straight and level flight without having to made adjustments using the controls. Watch the plane as it hits the suspected thermal area. If it suddenly veers to the left or right then a thermal is probably present.
- 6
  Turn the plane downwind once it changes direction as it hits the thermal. Fly in wide circles over the area, using the thermal to maintain or gain altitude. Make your flight circles smaller to gain more lift from the thermal as you go. As long as the plane continues to rise, the thermal is present. When the plane begins to drop despite your controls, the thermal has dissipated and you should search for another in the area, following the same signs.

Aviation