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aeroplanes-第29章

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Make the first turns in a still air。 If you should

attempt to make the first attempts with a wind

blowing you will find a compound motion that will

very likely give you a surprise。 In making the

first turn you will get the sensation of trying to

fly against a wind。 Assuming that you are turning

to the left; it will have the sensation of a wind

coming to you from the right。



FLYING IN A WIND。Suppose you are flying directly

in the face of a wind; the moment you begin

to turn the action; or bite of the wind; will cause

the ends of the planes to the right to be unduly

elevated; much more so than if the air should be

calm。 This raising action will be liable to startle

you; because up to this time you have been accustomed

to flying along in a straight line。



While flying around at the part of the circle

where the wind strikes you directly on the right

side the machine has a tendency to climb; and you

try to depress the forward end; but as soon as you

reach that part of the circle where the winds begin

to strike on your back; an entirely new thing

occurs。



As the machine is now traveling with the wind;

its grip on the air is less; and since the planes were

set to lower the machine; at the first part of the

turn; the descent will be pretty rapid unless the

angle is corrected。



FIRST TRIALS IN QUIET ATMOSPHERE。All this

would be avoided if the first trials were made in

a quiet atmosphere。 Furthermore; you will be

told that in making a turn the machine should be

pointed downwardly; as though about to make a

glide。 This can be done with safety; in a still

air; although you may be flying low; but it would

be exceedingly dangerous with a wind blowing。



MAKING TURNS。When making a turn; under no

circumstances try to make a landing。 This

should never be done except when flying straight;

and then safety demands that the landing should

be made against the wind and not with it。 There

are two reasons for this: First; when flying with

the wind the speed must be greater than when flying

against it。



By greater speed is meant relative to the earth。

If the machine has a speed of thirty miles an hour;

in still air; the speed would be forty miles an hour

going with the wind; but only twenty miles against

the wind。 Second; the banking of the planes

against the air is more effective when going into

the wind than when traveling with it; and; therefore;

the speed at which you contact with the earth

is lessened to such an extent that a comparatively

easy landing is effected。



THE FOURTH STAGE。After sufficient time has

been devoted to the long turns shorter turns may

be made; and these also require the same care;

and will give an opportunity to use the lateral

controls to a greater extent。 Begin the turns; not

by an abrupt throw of the turning rudder; but

bring it around gently; correcting the turning

movement to a straight course; if you find the

machine inclined to tilt too much; until you get used

to the sensation of keeling over。 Constant practice

at this will soon give confidence; and assure

you that you have full control of the machine。



THE FIGURE 8。You are now to increase the

height of flying; and this involves also the ability

to turn in the opposite direction; so that you may

be able to experience the sensation of using the

stabilizers in the opposite direction。 You will

find in this practice that the senses must take in

the course of the wind from two quarters now; as

you attempt to describe the figure 8。



This is a test which is required in order to obtain

a pilot's license。 It means that you shall

be able to show the ability to turn in either direction

with equal facility。 To keep an even flying

altitude while describing this figure in a wind; is

the severest test that can be exacted。



THE VOLPLANE。This is the technical term for

a glide。 Many accidents have been recorded owing

to the stopping of the motor; which in the

past might have been avoided if the character of

the glide had been understood。 The only thing

that now troubles the pilot when the engine 〃goes

dead;〃 is to select a landing place。



The proper course in such a case is to urge

the machine to descend as rapidly as possible; in

order to get a headway; for the time being。 As

there is now no propelling force the glide is depended

upon to act as a substitute。 The experienced

pilot will not make a straight…away glide;

but like the vulture; or the condor; and birds of

that class; soar in a circle; and thus; by passing

over and over the same surfaces of the earth; enable

him to select a proper landing place。



THE LANDING。The pilot who can make a good

landing is generally a good flyer。 It requires

nicety of judgment to come down properly。 One

thing which will appear novel after the first altitude

flights are attempted is the peculiar sensation

of the apparently increased speed as the earth

comes close up to the machine。



At a height of one hundred feet; flying thirty

miles an hour; does not seem fast; because the surface

of the earth is such a distance away that particular

objects remain in view for some moments;

but when within ten feet of the surface the same

object is in the eye for an instant only。



This lends a sort of terror to the novice。 He

imagines a great many things; but forgets some

things which are very important to do at this

time。 One is; that the front of the machine must

be thrown up so as to bank the planes against the

wind。 The next is to shut off the power; which

is to be done the moment the wheels strike the

ground; or a little before。



Upon his judgment of the time of first touching

the earth depends the success of safely alighting。

He may bank too high; and come down on the tail

with disastrous results。 If there is plenty of field

room it is better to come down at a less angle; or

even keep the machine at an even keel; and the

elevator can then depress the tail while running

over the ground; and thus bring the machine to

rest。



Frequently; when about to land the machine

will rock from side to side。 In such a case it is

far safer to go up into the air than to make the

land; because; unless the utmost care is exercised;

one of the wing tips will strike the earth and

wreck the machine。



Another danger point is losing headway; as the

earth is neared; due to flying at too flat an angle;

or against a wind that happens to be blowing particularly

hard at the landing place。 If the motor

is still going this does not make so much difference;

but in a volplane it means that the descent

must be so steep; at the last moment of flight; that

the chassis is liable to be crushed by the impact。



FLYING ALTITUDE。It is doubtful whether the

disturbed condition of the atmosphere; due to

the contour of the earth's surface; reaches higher

than 500 feet。 Over a level area it is certain that

it is much less; but 
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