the mastery of the air(操纵空气)-第19节
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to be quite flat； and it was chiefly because of this that the pilot was able to
maintain such marvellous speed。
The scientific study of the wing lift of planes has proceeded so far that
the actual 〃lift〃 can now be measured； providing the speed of the machine
is known； together with the superficial area of the planes。 The designer can
calculate what weight each square foot of the planes will support in the air。
Thus some machines have a 〃lift〃 of 9 or 10 pounds to each square foot of
wing surface； while others are reduced to 3 or 4 pounds per square foot。
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CHAPTER XXV The Wright Biplane （Cont。）
The under part of the frame of the Wright biplane； technically known
as the CHASSIS； resembled a pair of long 〃runner〃 skates； similar to those
used in the Fens for skating races。 Upon those runners the machine moved
along the ground when starting to fly。 In more modern machines the
chassis is equipped with two or more small rubber…tyred wheels on which
the machine runs along the ground before rising into the air； and on which
it alights when a descent is made。
You will notice that the pilot's seat is fixed on the lower plane； and
almost in the centre of it； while close by the engine is mounted。 Alongside
the engine is a radiator which cools the water that has passed round the
cylinder of the engine in order to prevent them from becoming overheated。
Above the lower plane is a similar plane arranged parallel to it； and the
two are connected by light upright posts of hickory wood known as
STRUTS。 Such an aeroplane as this； which is equipped with two main
planes； known as a BIPLANE。 Other types of air…craft are the
MONOPLANE； possessing one main plane； and the TRIPLANE；
consisting of three planes。 No practical machine has been built with more
than three main planes； indeed； the triplane is now almost obsolete。
The Wrights fitted their machine with two long…bladed wooden screws；
or propellers； which by means of chains and sprocket…wheels； very like
those of a bicycle； were driven by the engine； whose speed was about
1200 revolutions a minute。 The first motor engine used by these clever
pioneers had four cylinders； and developed about 20 horsepower。
Nowadays engines are produced which develop more than five times that
power。
In later machines one propeller is generally thought to be sufficient； in
fact many constructors believe that there is danger in a two…propeller
machine； for if one propeller got broken； the other propeller； working at
full speed； would probably overturn the machine before the pilot could cut
off his engine。
Beyond the propellers there are two little vertical planes which can be
moved to one side or the other by a control lever in front of the pilot's seat。
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THE MASTERY OF THE AIR
These planes or rudders steer the machine from side to side； answering the
same purpose as the rudder of a boat。
In front of the supporting planes there are two other horizontal planes；
arranged one above the other； these are much smaller than the main planes；
and are known as the ELEVATORS。 Their function is to raise or lower the
machine by catching the air at different angles。
Comparison with a modern biplane； such as may be seen at an
aerodrome on any 〃exhibition〃 day； will disclose several marked
differences in construction between the modern type and the earlier Wright
machine； though the central idea is the same。
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THE MASTERY OF THE AIR
CHAPTER XXVI How the Wrights launched their
Biplane
Those of us who have seen an aeroplane rise from the ground know
that it runs quickly along for 50 or 60 yards； until sufficient momentum
has been gained for the craft to lift itself into the air。 The Wrights； as stated；
fitted their machine with a pair of launching runners which projected from
the under side of the lower plane like two very long skates； and the
method of launching their craft was quite different from that followed
nowadays。
The launching apparatus consisted of a wooden tower at the starting
end of the launching waysa wooden rail about 60 or 70 feet in length。 To
the top of the tower a weight of about 1/2 ton was suspended。 The
suspension rope was led downwards over pulleys； thence horizontally to
the front end and back to the inner end of the railway； where it was
attached to the aeroplane。 A small trolley was fitted to the chassis of the
machine and this ran along the railway。
To launch the machine； which； of course； stood on the rail； the
propellers were set in motion； and the 1/2…ton weight at the top of the
tower was released。 The falling weight towed the aeroplane rapidly
forward along the rail； with a velocity sufficient to cause it to glide
smoothly into the air at the other end of the launching ways。 By an
ingenious arrangement the trolley was left behind on the railway。
It will at once occur to you that there were disadvantages in this
system of commencing a flight。 One was that the launching apparatus was
more or less a fixture。 At any rate it could not be carried about from place
to place very readily： Supposing the biplane could not return to its
starting…point； and the pilot was forced to descend； say； 10 or 12 miles
away： in such a case it would be neces… sary to tow the machine back to
the launching ways； an obviously inconvenient arrangement； especially in
unfavourable country。
For some time the 〃wheeled〃 chassis has been in universal use； but in a
few cases it has been thought desirable to adopt a combination of runners
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and wheels。 A moderately firm surface is necessary for the machine to run
along the ground； if the ground be soft or marly the wheels would sink in
the soil； and serious accidents have resulted from the sudden stoppage of
the forward motion due to this cause。
With their first power…driven machine the Wrights made a series of
very fine flights； at first in a straight line。 In 1904 they effected their first
turn。 By the following year they had made such rapid progress that they
were able to exceed a distance of 20 miles in one flight； and keep up in the
air for over half an hour at a time。 Their manager now gave their
experiments great publicity； both in the American and European Press； and
in 1908 the brothers； feeling quite sure of their success； emerged from a
self…imposed obscurity； and astonished the world with some wonderful
flights； both in America and on the French flying ground at Issy。
A great loss to aviation occurred on 30th May； 1912； when Wilbur
Wright died from an attack of typhoid fever。 His work is officially
commemorated in Britain by an annual Premium Lecture； given under the
auspices of the Aeronautical Society。
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CHAPTER XXVII The First Man to Fly in Europe
In November； 1906； nearly the whole civilized world was astonished
to read that a rich young Brazilian aeronaut； residing in France； had
actually succeeded in making a short flight； or； shall we say； an enormous
〃hop〃； in a heavier…than…air machine。
This pioneer of aviation was M。 Santos Dumont。 For five or six years
before his experiments with the aeroplane he had made a great many
flights in balloons； and also in dirigible balloons。 He was the son of well…
to…do parentshis father was a successful coffee planterand he had ample
means to carry on his costly experiments。
Flying was Santos Dumont's great hobby。 Even in boyhood； when far
away in Brazil； he had been kee
