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73 FLIGHT INSTRUCTOR'S MANUAL

gross weight of the airplane (as in a banked turn or a pull out from a dive), the stalling speed is increased exactly as if the gross weight had been increased. Obviously, any pilot would expect a much higher stalling speed with a great increase in gross weight. If the gross weight were doubled the stalling speed would be raised approximately 43 percent and, in aircraft having a normal stalling speed of 60 m. p. h., this would result in a stalling speed of approximately 86 m. p. h. This same effect, and more, may be accomplished by the execution of a 60-degree bank. It can, therefore, readily be seen that the stalling speed increases very rapidly as the angle of bank increases. This is one of the primary reasons for the necessity of using increased power in all steep turns and avoiding any tendency to pull the turn too tight. These factors should be impressed upon the student's mind. 

Many modern airplanes, particularly tapered-wing monoplanes, will stall without the usual warnings. When this type of airplane is banked, the stalling speed increases to a marked degree as the bank is increased. In some such airplanes a normal flight-level stalling speed of 60 m. p. h. may be increased in a 30° bank to 70 or 75 m. p. h., and in a 60° bank to 95 or 100 m. p. h. This characteristic is not fully understood by many otherwise competent pilots, and particular stress should be placed on maintaining sufficient speed in banks to obviate the likelihood of a stall from this cause.

Many students have a psychological reaction to the term "vertical bank." If such students are gradually stepped up in easy stages from the medium bank to the vertical under the impression that they are merely doing "steep banks," they execute them without difficulty but, when told that they are now doing a so-called "vertical bank," they immediately have difficult with the same bank that they were executing easily a few moments before.

For this reason it is well to avoid the use of the term "vertical bank" until the student is well advanced, and the instruction should be referred to only as being in "steep banks," even though the banks are gradually steepened up to 70° or 75°.

The student should have developed a considerable proficiency in the coordination of the hands and feet by the time he has arrived at a stage where it is advisable to introduce the steep turn, and from the practice of the steeper medium turns he should be able to keep the nose level by means of the elevators. Therefore, if the turns are gradually steepened, at perhaps 5° stages, and a little practice given on each stage, the transition will come easily and naturally, since the steep turn is merely and extension of the principles of the medium turn, with the only difference being firmer control pressure and the attitude of the ship.

Steep turns are very important maneuvers for the reason that they are the basis of many advanced maneuvers and bring out an extension of the principles of control-effect analysis. They are an introduction to maneuvers requiring rapid application of these, together with orientation and constantly varying, compensating, coordinated pressures which must be applied more rapidly than in any previous maneuver.

For the first several hours of instruction and practice, the bank should not exceed 60°. When perfection has been attained up to this