Teaching students to consistently perform coordinated turns can sometimes be a real challenge to the flight instructor. We teach them to “keep the string straight.” Sound simple enough. However, many students have trouble with doing coordinated turns because they really don’t fully understand the concept of a coordinated turn. A turn actually consists of two parts – “initiating” the turn and then “establishing” the turn. Let’s take each separately. “Initiating” the turn is the process of deciding to make a turn and then moving the stick in the direction we want to turn. It is at this point that the instructor introduces the concept of adverse yaw. Most instruction manuals go into great depth to explain adverse yaw. The result is we teach the student that he must step on the rudder pedal in the direction of the turn to offset adverse yaw. This works perfectly when “initiating” the turn and for this portion of the coordinated turn. The potential problem occurs when the student “establishes” the turn. “Establishing” the turn occurs when we establish the desired bank angle. That is, we stop the sailplane from continuing to increase the bank or said another way we “establish” the desired bank angle. To do this the student moves the stick back to the center or maybe if the bank is steep even to the other side of center. The movement of the stick is quite intuitive. The student easily figures out that the stick must be moved back to center to stop the bank from continuing to increase. However, the necessary rudder pedal movement is not intuitive and this is where the potential problem may occur. The student has a tendency to not make the correct rudder pedal adjustment (step on the “top rudder pedal” or “high rudder pedal”). This lack of rudder input results in the turn becoming a skidding turn (i.e. a turn with too much rudder input for the bank angle).
To correct this problem the instructor needs to divide the coordinated turn into two parts (“initiating” and “establishing”) and equally stress both to get the student to understand the process required for a coordinated turn. The concept of rolling out of a turn is exactly the same and the same problem occurs. The student understands that the stick must be move to the high wing to roll out. However, the correct rudder pedal input also needs to be stressed. That is, step on the “high pedal” to keep the roll out coordinated.
Unfortunately, if the student is not taught correctly, the uncoordinated turn will most likely manifest itself when he/she is occupied with other cockpit management issues such as concentrating on a proper traffic pattern. That is, when turning from downwind to base or from base to final. Needless to say, this is the worst possible time to get into an uncoordinated turn. To prevent this, we instructors need to teach the concepts required to both “initiate” and “establish” the coordinated turn.
Next time we’ll talk about “uncoordinated” versus “cross-controlled” flight.
Fly Safely and Have FUN!