Turns
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Turns

wpeE.jpg (88513 bytes)An airplane turns because some of the lift that the wings produce push it "around the corner," not because the rudder swings the nose left or right. In theory, you could skid an airplane through a turn with the rudder, but that's an inefficient (and uncomfortable) way to change direction. That's why airplanes bank to turn.

The Horizontal Component of Lift

Banking the wings with the ailerons deflects some of the lift that the wings produce sideways. This part of the airplane's total lift is called the horizontal component of lift. It's this force that pushes an airplane around in a turn.

Adverse Yaw

Banking the wings changes the angle of attack of each wing. And the deflection of ailerons changes the drag of each wing. These two factors create a tendency for the airplane to yaw opposite the turn. That is, if you bank to the left, the airplane's nose tends to swing toward the right.

To compensate for this effect, called "adverse yaw," you must apply rudder pressure in the same direction as the turn. As you bank left, you should add a little left rudder, and vice-versa.

Loss of Lift

Because some of the lift is deflected sideways in a turn, to maintain altitude you must increase the total lift that the wings produce. To increase lift, you must increase the angle of attack, so add a little up elevator pressure as you roll into a turn. The steeper the turn, the more up elevator pressure you must add. In steeply banked turns of 45 degrees or more, you must add considerable up elevator pressure (and probably add power, as well) to maintain altitude. Just remember to relax that back pressure on the joystick or control yoke as you roll out of the turn.