aeroplanes-第12节
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shown in Fig。 30; which has a deep concave directly
behind the forward margin; as at A; so
that when the plane is at an angle of about 22
degrees; a horizontal line; as B; passing back from
the nose; touches the incurved surface of the plane
at a point about one…third of its measurement
back across the plane。
_Fig。 30。 One of the Monstrosities_
This form is an exact copy of the wing of an
actual bird; but it belongs; not to the soaring;
but to the class which depends on flapping wings;
and as such it cannot be understood why it should
be used for soaring machines; as all aeroplanes
are。
The foregoing instances of construction are
cited to show how wildly the imagination will
roam when it follows wrong ideals。
THE TAIL AS A MONITOR。The tendency of the
center of pressure to change necessitates a correctional
means; which is supplied in the tail of
the machine; just as the tail of a kite serves to
hold it at a correct angle with respect to the wind
and the pull of the supporting string。
CHAPTER VII
ABNORMAL FLYING STUNTS AND SPEEDS
〃PEQUOD; a Frenchman; yesterday repeatedly
performed the remarkable feat of flying with the
machine upside down。 This exhibition shows
that the age of perfection has arrived in flying
machines; and that stability is an accomplished
fact。〃News item。
This is quoted to show how little the general
public knows of the subject of aviation。 It correctly
represents the achievement of the aviator;
and it probably voiced the sentiment of many
scientific men; as well as of the great majority of
aviators。
A few days afterwards; the same newspaper
published the following:
〃Lieutenant ; while experimenting yesterday
morning; met his death by the overturning
of his machine at an altitude of 300 meters。
Death was instantaneous; and the machine was
completely destroyed。〃
The machines used by the two men were of the
same manufacture; as Pequod used a stock machine
which was strongly braced to support the
inverted weight; but otherwise it was not unlike
the well known type of monoplane。
Beachy has since repeated the experiment with
a bi…plane; and it is a feat which has many imitators;
and while those remarkable exhibitions
are going on; one catastrophe follows the other
with the same regularity as in the past。
Let us consider this phase of flying。 Are they
of any value; and wherein do they teach anything
that may be utilized;
LACK OF IMPROVEMENTS IN MACHINES。It is remarkable
that not one single forward step has
been taken to improve the type of flying machines
for the past five years。 They possess the same
shape; their stabilizing qualities and mechanism
for assuring stability are still the same。
MEN EXPEDITED; AND NOT THE MACHINE。The
fact is; that during this period the man has been
exploited and not the machine。 Men have learned;
some few of them; to perform peculiar stunts;
such as looping the loop; the side glide; the drop;
and other features; which look; and are; hazardous;
all of which pander to the sentiments of the spectators。
ABNORMAL FLYING OF NO VALUE。It would be
too broad an assertion to say that it has absolutely
no value; because everything has its use
in a certain sense; but if we are to judge from
the progress of inventions in other directions;
such exhibitions will not improve the art of building
the device; or make a fool…proof machine。
Indeed; it is the very thing which serves as a
deterrent; rather than an incentive。 If machines
can be handled in such a remarkable manner; they
must be; indeed; perfect! Nothing more is
needed! They must represent the highest structural
type of mechanism!
That is the idea sought to be conveyed in the
first paragraph quoted。 It is pernicious; instead
of praiseworthy; because it gives a false impression;
and it is remarkable that even certain scientific
journals have gravely discussed the perfected
(?) type of flying machine as demonstrated
by the experiments alluded to。
THE ART OF JUGGLING。We may; occasionally;
see a cyclist who understands the art of balancing
so well that he can; with ease; ride a machine
which has only a single wheel; or he can; with a
stock bicycle; ride it in every conceivable attitude;
and make it perform all sorts of feats。
It merely shows that man has become an
expert at juggling with a machine; the same as he
manipulates balls; and wheels; and other artifices;
by his dexterity。
PRACTICAL USES THE BEST TEST。The bicycle
did not require such displays to bring it to perfection。
It has been the history of every invention
that improvements were brought about; not
by abnormal experiments; but by practical uses
and by normal developments。
The ability of an aviator to fly with the machine
in an inverted position is no test of the machine's
stability; nor does it in any manner prove that
it is correctly built。 It is simply and solely a
juggling featsomething in the capacity of a certain
man to perform; and attract attention because
they are out of the ordinary。
CONCAVED AND COXVEX PLANES:They were performed
as exhibition features; and intended as
such; and none of the exponents of that kind of
flying have the effrontery to claim that they prove
anything of value in the machine itself; except
that it incidentally has destroyed the largely
vaunted claim that concaved wings for supporting
surfaces are necessary。
HOW MOMENTUM IS A FACTOR IN INVERTED FLYING。
When flying 〃upside down;〃 the convex
side of the plane takes the pressure of the air;
and maintains; so it is asserted; the weight of the
machine。 This is true during that period when
the loop is being made。 The evolution is made
by first darting down; as shown in Fig。 31; from
the horizontal position; 1; to the position 2; where
the turn begins。
_Fig。 31。 Flying upside down。_
TURNING MOVEMENT。Now note the characteristic
angles of the tail; which is the controlling
factor。 In position 1 the tail is practically
horizontal。 In fact; in all machines; at
high flight; the tail is elevated so as to give little
positive angle of incidence to the supporting
planes。
In position No。 2; the tail is turned to an angle
of incidence to make the downward plunge; and
when the machine has assumed the vertical; as in
position 3; the tail is again reversed to assume
the angle; as in 1; when flying horizontally。
At the lower turn; position 4; the tail is turned
similar to the angle of position 2; which throws
the rear end of the machine down; and as the
horizontal line of flight is resumed; in an inverted
position; as in position 4; the tail has the same
angle; with relation to the frame; as the supporting
planes。
During this evolution the engine is running; and
the downward plunge develops a tremendous
speed; and the great momentum thus acquired;
together with the pulling power of the propeller
while thus in flight; is sufficient to propel it along
horizontally; whatever the plane surface curve; or
formation may be。
It is the momentum which sustains it in space;
not the air pressure beneath the wings; for
reasons which we have heretofore explained。
Flights of sufficient duration have thus been made
to prove that convex; as well as concave surfaces
are efficient; nevertheless; in its proper place we
have given an exposition of the reasoning which
led to the adoption of the concaved supporting
surfaces。
WHEN CONCAVED PLANES ARE DESIRABLE。
Unquestionably; for slow speeds the concaved wing
is desirable; as will be explained; but for high
speeds; surface formation has no value。 That is
shown by Pequod's feat。
THE SPEED MANIA。This is a type of mania
which pervades every field of activity in the building
of aeroplanes。 Speed contests are of more
importance to the spectators on exhibition
grounds than stability or durability。 Builders
pander to this; hence machines are built on lines
which disregard every consideration of safety
while at normal flight。
USES OF FLYING MACHINES。The machine as
now constructed is of little use commercially。
Within certain limitations it is valuable for scouting
purposes; and attempts have been made to
use it commercially。 But the unreliable character
of its performances; due to the many elements
which are necessary to its proper working; have
operated against it。
PERFECTION IN MACHINES MUST COME BEFORE
SPEED。Contrary to every precept in the building
of a new article; the attempt is made to make
a machine with high speed; which; in the very
nature of things; operates against its improvement。
The opposite lack of speedis of far
greater utility at this stage of its development。
THE RANGE OF ITS USE。The subject might be
illustrated by assuming that we have a line running
from A