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68       U.S. CIVIL AERONAUTICS AUTHORITY

As soon as a good comprehension of the normal glide is attained, the student should be shown abnormal glides. These demonstrations should be exaggerated for the benefit of the limited perceptiveness of the student. In demonstrating too slow a glide, the airplane should be definitely "mushed" and the student's attention called to the sluggishness of the controls, the extra pressures required to hold the nose, and the definite feeling that the aircraft is falling out from under him. It should then be stressed that, although this is an exaggerated condition, anytime the speed is below that of a normal glide the pilot does not have complete control of the airplane and that these same conditions exist; the difference merely being in the degree of their existence.
Too fast a glide should then be demonstrated ending with the airplane being brought to level flight and allowed to coast level until normal speed is regained and then the normal gliding attitude resumed. Have the student note that although good control is maintained, excess speed is acquired which is hard to dissipate and and results in extended floating on the level. Explain that when this condition exists close to the ground it is exaggerated, oftentimes, by the "ground cushion" of air and will absolutely destroy any efforts toward accuracy in landing.
In a normal glide, the flight path may be sighted to the spot on the ground on which the airplane will land. This cannot be done in any abnormal glide.
In the early stage of glide instruction it may be necessary in some airplanes to have the student force the airplane into the gliding attitude as a safety precaution. However, as experience is acquired this should not be done.
The instructor should explain to him that the cruising speed is always greater than the gliding speed and that when the throttle is closed this speed must be reduced to that of the normal glide before the proper angle can be assumed.
Forcing the nose down carries this speed into the glide and retards the attainment of the correct glide. Therefore, it is better to coast while speed is being lost and the nose then eased down as the excess speed is dissipated. This point is particularly important in so-called clean airplanes as they are very slow to lose their speed and any slight deviation of the nose downwards results in an instant increase in speed out of all proportion to that which the student would expect. Since all aircraft are being designed with more and more of this characteristic it is very important that this feature be brought out even in primary training.
Too few instructors pay proper attention to fixing the normal glide in the student's mind together with the results of abnormal glides. As a consequence students experience difficulties with accuracy landings, which are comparatively simple if the fundamentals of the glide are thoroughly understood.
Too fast a glide during the approach for a landing invariably results in floating over the ground about three feet off for varying distances, causing wheel landings and bounces, or even overshooting.
Too slow a glide causes undershooting and pancake landings and sometimes has much more serous results, particularly in aircraft having rapid or bad tip-stall characteristics.