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FLIGHT INSTRUCTOR'S MANUAL 39

the flight path resulting from proper and improper use of the rudder, (see fig. 1) and may be explained to the student as follows: 

In a perfectly executed turn, the airplane makes a flight path which is a true circle with respect to the area of air in which it is turning. (The flight path is not necessarily a true circle over the ground because of the effect of drift.) Under this condition the rudder must follow the flight path of the aircraft. If pressure is maintained on the rudder after the turn is established, the result will be a turn of decreasing radius or a spiral toward the center, and, unless the bank is correspondingly increased, a skid as well. 

If attempts are made to re-fresh the rudder rather than let it streamline itself to the turn, it is probable that some opposite rudder pressure will be exerted. This tends to force the airplane to swing away from its original turning path to the outside. However, this is almost impossible, and slipping results.

From these explanations and the diagrams it will be seen that any attempt to use the rudder after the turn is established will affect the radius of the turn and the speed of the aircraft as well. This speed loss, however, will not be noticeable if the pressure are not violent or prolonged. 

The above may not be strictly true for high-powered airplanes, due to the torque effect during turns. However, by the time the student is ready to fly this type of aircraft, his sensitivity will be such that he will be automatically adjust himself to the conditions he finds.

In beginning a turn the aileron and rudder are applied simultaneously. However, due to the variation in relationship of aileron and rudder action on most ships, the pressures exerted will not be equal, and this relationship will vary also with the speed of the ship. There will be an additional variation between the rudder pressure necessary to the right and to the left. This is the result of the torque effect, and this point should be thoroughly explained to the student. In the ideal timing of the controls the nose will start to swing as soon as the ship starts to bank. This seldom accomplished exactly, but any departure from this result affords an excellent means of checking and correcting errors.

The action of the nose will show any error in coordination of the controls.

The airplane should rotate around its longitudinal axis with this axis remaining level. (See fig. 2.) As soon as the ship departs from level laterally, the nose should also start to swing around the horizon, increasing its rate of travel proportionately as the bank is increased. Any departure from this will show the particular control that is being misused. Examples of common misuses are as follows:

1. If the nose starts to move before the bank starts, rudder is being applied too soon.

2. If the nose turns too fast for the degree of bank or accelerates faster in proportion while increasing the bank, too much rudder is being applied.

3. If the bank starts before the nose starts turning, ailerons are being used too soon.

4. If the bank increases too rapidly in proportion to the acceleration of the rate of turn while banking, too much aileron is applied.