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70      U.S. CIVIL AERONAUTICS AUTHORITY

When recovery is being made from a gliding turn, the compensating relaxation of this back pressure must be increased or the nose will come up too high and considerable speed will be lost. This error will result in considerable attention and conscious control adjustment being required before the "normal" glide can again be resumed.
Since these elements mentioned above reduce speed and lift in normal power turns, it is readily seen that more speed and more lift will be lost in a gliding turn of equal degree of bank for the following reasons.
  1. Due to the reduced speed of the airplane in a glide, any further reduction will cause a greater corresponding proportionate reduction in lift.
  2. The increased back pressure necessary on the elevators causes more drag and consequently loss of speed.
  3. Since centrifugal force must be used to equalize the difference in the direction of the lifting force when the airplane is off an even keel, some energy or power must be used to obtain it. Since the engine is cut, this can only come from gravity. This will therefore require either a steeper gliding angle to maintain normal speed, or a reduction of the normal speed with its consequent "mushing" and approach to a stall.
From the above it will be seen that in order to maintain the most efficient or normal glide, more altitude must be sacrificed than normally since this is the only way speed may be obtained without power. It is apparent, therefore, that the gliding angle will necessarily be steeper to maintain the same speed and lift as in the straight glide, and that the turn in a glide decreases the efficiency of the performance of the airplane to an even greater extent than does a normal turn with power.
This is a principle that must be thoroughly explained and impressed on the student, as it will lend a basis for understanding many of the errors he will make and is a principle that few will learn through their own efforts at error analysis.
From the above it will be seen that the student must learn still a different set of relationships of control touch, angle of glide and sound for gliding turns to maintain the same speed and lift as in normal straight glides. These will vary again with the degree of bank; therefore, the student should continue his early efforts to one degree of bank (again preferably the medium), and the instructor insist on its constant maintenance until enough background and feel is attained to give appreciation of the shading pressures necessary for gliding turns of varied or varying steepness of bank.
After the desired degree of bank to be used during the early practice has been fixed in the student's mind, he should be shown the undesirable results of too much speed and too little speed, as explained in the discussion of straight glides.
Another factor that affects the more or less mechanical student during the practice of gliding turns is the decrease in the "overbanking tendency" in turns without power. If the same effort is applied to oppose these tendencies as has been customary in power turns, the bank will decrease. The inexperienced student will not sense this and attempt to increase the rate of turn to that anticipated by applying more rudder, which will soon result in a flat skid.