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34 

U.S. CIVIL AERONAUTICS AUTHORITY 

timing of the control action with exactly the proper pressures during flights in rough air, that shows the real ability of the pilot to fly straight and level.

Contrary to common belief, straight and level is really an art.

MEDIUM TURNS

Before starting turning practice, the student should be given a brief explanation of the principles involves in making a turn; the necessity for banking the ship and the relation of the degree of bank to the speed and radius of the turn. When some familiarity with turns has been gained and a practical background with which to understand the theory has been acquired, the principles involved in turning should be elaborated and the reasons why the ship slips and skids and an explanation of the necessity for the application of centrifugal force should be added.

For instructional purposes, turns are divided into four classes: Gentle, medium, steep, and vertical. Some instructors combine the last two into a general term for "steer turns." This is often advantageous from a psychological angle, as many students can be led up to the point of doing good vertical banks while they are under the impression they are merely doing very steep banks. The moment such a student is asked to do a vertical bank and shown an example consisting of the same bank he was doing, he immediately gets the idea that he is attempting something new and particularly difficult, and exhibits all manner of difficulties with a maneuver that he executed with ease only a few moments before under another name. 

Such a student is lacking in his understanding of orientation and control action and more often than not, is under the delusion of the old "Change of control function" fallacy.

He is also failing to analyze the maneuver and see that is merely what has been done with, at most, a possible slight extension of the principles already learned. 

Gentle turns are those in which the degree of bank varies from the least perceptible to about 25°; medium turns from 25° to 45°; steep from 45° to 70°; and verticals from 70° to 90°. Banks of over 70° are extremely difficult in aircraft of relatively low horsepower, particularly if the bank is to be maintained throughout any considerable arc of turn.

The foregoing classification prevents the confusion of the degree of bank with the degree of turn. When speaking of a 45° turn it is usually considered that a change of direction of 45° is meant rather than a 45° bank. The degree of turn can be estimated and executed very accurately, but unless an artificial horizon is used to the aircraft is especially designed for measuring angles of bank by strut- or brace- wire lanes relative to the horizon, any exact degree of bank is very difficult to estimate.

The popular failing in this regard is to estimate the bank from ten to twenty degrees steeper than it actually is 

All instructors should check and perfect their estimate of degree of bank by practicing in a ship equipped with an artificial horizon and comparing their estimates with the reading of the degree

Transcription Notes:
° (degree symbol)