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Instructor Tip of the Month

Yaw String as Attitude Indicator

Flight Instructor: Capt. Rhon WIlliams

For a Schweizer 2-33 glider use the knot on yaw string as an attitude indicator.

Set up straight and level flight at desired airspeed such as 55 mph. Memorize the position of the yaw string knot on the pitot tube relative to the horizon. Depending on your height in the glider the spot may be slightly above or below the horizon. Then any time you want the airspeed to be 55 mph, just set the yaw string knot at the memorized position, and the glider airspeed will soon return to 55 mph. Since the airspeed indicator has an inherent delay, setting the yaw string knot position on the horizon is an immediate and reliable way to set the attitude for the target airspeed. For other commonly used speeds such as speed for minimum sink, the knot can be set just above the horizon (a quick trial will allow you to memorize the correct spot).

Using the yaw string knot as an attitude indicator also works during turns. At any given airspeed, note the knot position on the horizon and as you roll into the turn, keep the knot at the same relative height on the horizon, and you will maintain the desired speed during the turn. Similarly, when rolling out of a turn, keeping the knot in the position will avoid airspeed deviations.

Since you are already looking at the yaw string it is also a good time to check your turn coordination, and "step on the knot" if needed. This works because if the yaw string is off to one side, the knot (forward end of the string) indicates which rudder pedal needs more pressure.

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