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audio variometer going from the drone to excited beeping. At the right time in the anticipated lift, begin the turn. If everything has gone perfectly, the glider will roll into a coordinated turn, at just the right bank angle, at just the right speed, and be centered perfectly. In reality, it rarely works that well. 

Before going further, what vital step was left out of the above scenario? CLEAR BEFORE TURNING! The variometer is hypnotic upon entering lift, especially at somewhat low altitudes. This is exactly where pilots forget that basic primary step before any turn—looking around first. An audio variometer helps avoid this. 

To help decide which way to turn, determine which wing tends to be lifted. For instance, when entering the thermal and the glider is gently banking to the right, CLEAR LEFT, then turn left. A glider on its own tends to fly away from thermals. [Figure 10-7] As the glider flies into the first thermal, but slightly off center, the stronger lift in the center of the thermal banks the glider right, away from the thermal. It then encounters the next thermal with the right wing toward the center and is banked away from lift to the left, and so on. Avoid letting thermals bank the glider even slightly. Sometimes the thermal-induced bank is subtle, so be light on the controls and sensitive to the air activity. At other times, there is no indication on one wing or another. In this case, 

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take a guess, CLEAR, then turn. As a note, new soaring pilots often get in the habit of turning in a favorite direction, to the extreme of not being able to fly reasonable circles in the other direction. If this happens, make an effort to thermal in the other direction half the time—being proficient in either direction is important, especially when thermaling with traffic. 

As a glider encounters lift on one side, some gliders tend to slip laterally as indicated by the yaw string. The glider pilot must bring the climbing wing down, not just to level the wings but further to begin the turn into the lifting columns of air. In these instances, the soaring pilot should turn towards the tip of the yaw string to seek the lift. 

## Inside a Thermal 

## Bank Angle 

Optimum climb is achieved when proper bank angle and speed are used after entering a thermal. The shallowest possible bank angle at minimum sink speed is ideal. Thermal size and associated turbulence usually do not allow this. Large-size, smooth, and well-behaved thermals can be the exception in some parts of the country. Consider first the bank angle. The glider’s sink rate increases as the bank angle increases. However, the sink rate begins to increase more rapidly beyond about a 45° bank angle. Thus, a 40° compared to a 30° bank angle may increase the sink rate less than the gain achieved from circling in the stronger lift near the center of the thermal. As with everything else, this takes practice, and the exact bank angle used depends on the typical thermal, or even a specific thermal, on a given day. Normally, bank angles in excess of 50° are not needed, but exceptions always exist. It may be necessary, for instance, to use banks of 60° or so to stay in the best lift. Thermals tend to be smaller at lower levels and expand in size as they rise higher. Therefore, a steeper bank angle is required at lower altitudes, and shallower bank angles can often be used while climbing higher. Remain flexible with techniques throughout the flight. 

## Speed 

If turbulence is light and the thermal is well formed, use the minimum sink speed for the given bank angle. This should optimize the climb because the glider’s sink rate is at its lowest, and the turn radius is smaller. As an example, for a 30° bank angle, letting the speed increase from 45 to 50 knots increases the diameter of the circle by about 100 feet. In some instances, this can make the difference between climbing or not. Some gliders can be safely flown several knots below minimum sink speed. Even though the turn radius is smaller, the increased sink rate may offset any gain achieved by being closer to strong lift near the thermal center. 

There are two other reasons to avoid thermaling speeds that are too slow: the risk of a stall and lack of controllability. 

