The development of the balloon began in 1783, and was the work of two
brothers, Joseph and Etienne Montgolfier, who were the sons of a paper
manufacturer of Annonay, France.
The latest and most successful experimenter is Count Zeppelin, a German
inventor, whose name has been given to the huge dirigible airships known
as Zeppelins. Between these there has been a long list of inventors and
experimenters who met with varying degrees of success; but the Zeppelins
stand paramount.
From the year 1897 the development of the airship was the special work
of the Count Zeppelin. In 1900 he made his first flight with a dirigible
balloon which carried five men. It was made of aluminum, supported by
gas bags and driven by two motors, each about sixteen horse power. His
first experiment met with some success, but the first Zeppelin airship
was succeeded by another in 1905 with greater motor power; this was
wrecked and was succeeded by a third, which met with great success. This
airship carried eleven passengers and attained a speed of about
thirty-six miles an hour. The fourth Zeppelin airship succeeded in
traveling about two hundred and fifty miles in eleven hours, but was
wrecked by a storm in 1908, the wreckage catching fire and completely
destroying the ship.
_Zeppelin VII._ had a total length of no less than four hundred and
eighty-five feet, a diameter of forty-six feet, and a volume of 690,000
cubic feet. The vessel was fitted with three engines totaling some four
hundred and twenty horse power and capable of driving the vessel at
thirty-five miles an hour. On one occasion she carried thirty-two people
and made a journey of three hundred miles in nine hours.
In the meantime many other experiments had been carried out, notably by
Santos Dumont, who circled the Eiffel Tower in the face of a fresh wind.
_Dirigibles_ are divided into three types--(_a_) _rigid_, in which there
is a framework or skeleton, over which a skin is stretched and within
which a number of balloons are placed; (_b_) _semi-rigid_, in which the
lower part only of the balloon is distended on a flat framework; and
(_c_) _non-rigid_, when a gas-bag of elongated form has a long girder
suspended below it. The propellers are most usually mounted in pairs on
each side of the car, but Zeppelin attached them to the balloon itself.
To prevent pitching, an “empennage” of flat surfaces is usually arranged
near the after-end.
SOME FACTS ABOUT ZEPPELINS.--In shape an ordinary Zeppelin airship is a
long cylinder with semisphere-like ends and a keel running the whole
length of the bottom thereof. In appearance from a distance the cylinder
and pointed ends appear circular in shape, _i.e._ in cross-section, but
in reality this is not so, both being sixteen sided. About one-third the
distance from either end of the keel are small boat-like structures
suspended from the hull, so close to it that at these places there is a
gap in the hull to make room for them. They are rigidly connected with
the metallic hull of the airship and help to support it either when the
vessel rests on the ground or is towed or driven along the water.
Within these structures are the crew and engines, while above, but
outward on each side of the rigid hull and connected with it by means of
outriggers, are two pairs of aërial propellers. These are placed at an
equal distance out on either side and in the same horizontal plane, so
that their united propulsive action shall act centrally along the line
of head resistance. The crew can walk through the keel (originally
V-shaped) from end to end, or from one boat to the other, the passage
being illuminated by means of suitable windows. An observer can also
climb through the hull to take observation from the top. Telephones,
electric bells, and speaking-tubes are all employed to transmit orders.
CONSTRUCTION OF THE FRAME.--The frame of the rigid hull is built of
sixteen longitudinals or girders of trellised or latticed metal; it runs
the whole length of the airship and is riveted at regular intervals to
cross-sections of latticed girders. Each of these cross-sections is in
the form of a sixteen-sided figure or wheel, with latticed rims
strengthened by radial rods running from a center flange or boss to the
outer rims. The main hull is thus divided into a number of compartments,
each separated from one another by means of these latticed radial discs
or wheel-like structures and otherwise enclosed by the sixteen latticed
girder longitudinals or beams. Each of these compartments contains a
gas-bag or balloonette filled with hydrogen; the balloonette fairly
fills the compartment, and each bag exerts its proportionate lift. A
netting of ramie cords is stretched from wheel to wheel diagonally,
between the beams at their inner corners, while the outward corners of
the beams are joined by strong wires arranged diagonally for the purpose
of imparting rigidity.
The whole frame is covered externally with a strong fabric, which forms
the outer skin or wall of the hull. Air-spaces naturally exist between
this covering, the inflated balloonettes, and the wheel-like divisions.
The entire airship owes its buoyancy to the balloonettes filled with
hydrogen, while the outer framework and covering act as a protection
against the sun, foul weather, and external shocks.
WAR ZEPPELINS.--Monstrous as the above ships are, they are quite dwarfed
by the recent type of military Zeppelins. The latter carry motors
aggregating no less than nine hundred horse power. The length varies
from five hundred to eight hundred feet, and the diameter is
proportional. The gas capacity exceeds a million cubic feet.
AËROPLANE VERSUS AIRSHIP.---On the airship’s side the following strong
points are claimed: (1) Greater manœuvering power than the aëroplane,
more especially with respect to rapidity of ascent; (2) greater
offensive power, _i.e._ ability to carry heavier guns owing to its far
greater lifting capacity; (3) ability to stand still or hover in the air
over one spot (for bomb-dropping), or remain stationary in the air, end
on to the enemy, for the purpose of obtaining a steady gun platform; (4)
greater flying durability, _i.e._ ability to remain longer in the air at
a stretch; (5) ability to fly at night.
MANNING THE AIRSHIP.--The crew of a military airship includes the
following: the pilot, the engineer, the steersman, the wireless
operator, and last but by no means least the observer. The total number
of the crew varies with the size of the airship, and the particular
mission in view. The pilot is the captain of the airship, and is
responsible for (1) the route, (2) the altitude or elevation at which
the airship travels, and (3) the maintenance of the correct pressure on
the envelope. The steersman maintains the course ordered him, by means
of a compass or by special instructions which may be given him, and also
controls the altitude or elevation as ordered. The engineer naturally
looks after the engines and the mechanical part of the apparatus with
which the airship is fitted.
[Illustration: =MARVELOUS MECHANISM OF THE MODERN SUBMARINE=
Its interior is a steel maze of intricate machinery that fills it from
end to end, and makes it easily the most remarkable of modern marine
craft.]