EARLY AIRSHIPS AND THEIR DEVELOPMENT TO THE PRESENT DAY
The science of ballooning had reached quite an advanced stage by the
middle of the eighteenth century, but the construction of an airship
was at that time beyond the range of possibility. Discussions had taken
place at various times as to the practicability of rendering a balloon
navigable, but no attempts had been made to put these points of
argument to a practical test.
Airship history may be said to date from January 24th, 1784. On that
day Brisson, a member of the Academy in Paris, read before that Society
a paper on airships and the methods to be utilized in propelling them.
He stated that the balloon, or envelope as it is now called, must be
cylindrical in shape with conical ends, the ratio of diameter to length
should be one to five or one to six and that the smallest
cross-sectional area should face the wind. He proposed that the method
of propulsion should be by oars, although he appeared to be by no means
sanguine if human strength would be sufficient to move them. Finally,
he referred to the use of different currents of the atmosphere lying
one above the other.
This paper caused a great amount of interest to be taken in
aeronautics, with the result that various Frenchmen turned their
attention to airship design and production. To France must be due the
acknowledgment that she was the pioneer in airship construction and to
her belongs the chief credit for early experiments.
At a later date Germany entered the lists and tackled the problems
presented with that thoroughness so characteristic of the nation. It
is just twenty-one years ago since Count Zeppelin, regardless of public
ridicule, commenced building his rigid airships, and in that time such
enormous strides were made that Germany, at the outbreak of the war,
was ahead of any other country in building the large airship.
In 1908 Italy joined the pioneers, and as regards the semi-rigid is in
that type still pre-eminent. Great Britain, it is rather sad to say,
adopted the policy of "wait and see," and, with the exception of a few
small ships described in the two succeeding chapters, had produced
nothing worthy of mention before the outbreak of the great European
war. She then bestirred herself, and we shall see later that she has
produced the largest fleet of airships built by any country and, while
pre-eminent with the non-rigid, is seriously challenging Germany for
the right to say that she has now built the finest rigid airship.
FRANCE
To revert to early history, in the same year in which Brisson read his
paper before the Academy, the Duke of Chartres gave the order for an
airship to the brothers Robert, who were mechanics in Paris. This ship
was shaped like a fish, on the supposition that an airship would swim
through the air like a fish through water. The gas-chamber was
provided with a double envelope, in order that it might travel for a
long distance without loss of gas.
The airship was built in St. Cloud Park; in length it was 52 feet with
a diameter of 82 feet, and was ellipsoidal in shape with a capacity of
30,000 cubic feet. Oars were provided to propel it through the air,
experiments having proved that with two oars of six feet diameter a
back pressure of 90 lb. was obtained and with four oars 140 lb.
On July 6th in the same year the first ascent was made from St. Cloud.
The passengers were the Duke of Chartres, the two brothers Robert and
Colin-Hulin. No valves having been fitted, there was no outlet for the
expansion of gas and the envelope was on the point of bursting, when
the Duke of Chartres, with great presence of mind, seized a pole and
forced an opening through both the envelopes. The ship descended in
the Park of Meudon.
On September 19th the airship made a second ascent with the same
passengers as before, with the exception of the Duke. According to the
report of the brothers Robert, they succeeded in completing an ellipse
and then travelled further in the direction of the wind without using
the oars or steering arrangements. They then deviated their course
somewhat by the use of these implements and landed at Bethune, about
180 miles distant from Paris.
In those days it was considered possible that a balloon could be
rendered navigable by oars, wings, millwheels, etc., and it was not
until the last decades of the nineteenth century, when light and
powerful motors had been constructed, that the problem became really
practical of solution.
During the nineteenth century several airships were built in France and
innumerable experiments were carried out, but the vessels produced were
of little real value except in so far as they stimulated their
designers to make further efforts. Two of these only will be
mentioned, and that because the illustrations show how totally
different they were from the airship of to-day.
In 1834 the Compte de Lennox built an airship of 98,700 cubic feet
capacity. It was cylindrical in form with conical ends, and is of
interest because a small balloon or ballonet, 7,050 cubic feet
contents, was placed inside the larger one for an air filling. A car
66 feet in length was rigged beneath the envelope by means of ropes
eighteen inches long. Above the car the envelope was provided with a
long air cushion in connection with a valve. The intention was by
compression of the air in the cushion and the inner balloon, to alter
the height of the airship, in order to travel with the most favourable
air currents. The motive power was 20 oar propellers worked by men.
This airship proved to be too heavy on completion to lift its own
weight, and was destroyed by the onlookers.
The next airship, the Dupuy de Lome, is of interest because the
experiments were carried out at the cost of the State by the French
Government. This ship consisted of a spindle-shaped balloon with a
length of 112 feet, diameter of 48 1/2 feet and a volume of 121,800
cubic feet. An inner air balloon of 6,000 cubic feet volume was
contained in the envelope. The method of suspension was by means of
diagonal ropes with a net covering. A rudder in the form of a
triangular sail was fitted beneath the envelope and at the after part
of the ship. The motive power was double-winged screws 29 feet 6
inches diameter, to be worked by four to eight men.
On her trials the ship became practically a free balloon, an
independent velocity of about six miles per hour being achieved and
deviation from the direction of the wind of ten degrees.
At the close of the nineteenth century Santos-Dumont turned his
attention to airships. The experiments which he carried out marked a
new epoch and there arose the nucleus of the airship as we know it
to-day. Between the years 1898 and 1905 he had in all built fourteen
airships, and they were continually improved as each succeeding one
made its appearance. In the last one he made a circular flight;
starting from the aerodrome of the aero club, he flew round the Eiffel
Tower and back to the starting point in thirty-one minutes on October
19th, 1902. For this feat the Deutsch prize was awarded to him.
The envelopes he used were in design much nearer approach to a
streamline form than those previously adopted, but tapered to an
extremely fine point both at the both and stem. For rigging he
employed a long nacelle, in the centre of which was supported the car,
and unusually long suspensions distributed the weight throughout
practically the entire length of the envelope. To the name of
Santos-Dumont much credit is due. He may be regarded as the originator
of the airship for pleasure purposes, and by his success did much to
popularize them. He also was responsible to a large extent for the
development and expansion of the airship industry in Paris.
At a little later date, in 1902 to be precise, the Lebaudy brothers, in
conjunction with Julliot, an engineer, and Surcoup, an aeronaut,
commenced building an airship of a new type. This ship was a semirigid
and was of a new shape, the envelope resembling in external appearance
a cigar. In length it was 178 feet with a diameter of 30 feet and the
total capacity was 64,800 cubic feet. This envelope was attached to a
rigid elliptical keel-shaped girder made of steel tubes, which was
about a third of the length of the ship. The girder was covered with a
shirting and intended to prevent the ship pitching and rolling while in
flight. A horizontal rudder was attached to the under side of this
girder, while right aft a large vertical rudder was fixed.
A small car was suspended by steel rods at a distance of 17 feet 9
inches from the girder, with a framework built up underneath to absorb
the shock on landing.
A 35 horse-power Daimler-Mercedes motor, weighing some 800 lb. without
cooling water and fuel, drove two twin-bladed propellers on either side
of the car.
In the year 1903 a number of experimental flights were made with this
ship and various details in the construction were continually
introduced. The longest flight was 2 hours 46 minutes. Towards the
end of that year, while a voyage was being made from Paris to Chalais
Meudon, the airship came in contact with a tree and the envelope was
badly torn.
In the following year it was rebuilt, and the volume was slightly
increased with fixed and movable planes added to increase the
stability. After several trips had been made, the airship again on
landing came in contact with a tree and was burst.
The ship was rebuilt and after carrying out trials was purchased by the
French Army. The Lebaudy airship had at that time been a distinct
success, and in 1910 one was purchased for the British Government by
the readers of the Morning Post.
In the ten-ton Lebaudy the length of the keel framework was greatly
extended, and ran for very nearly the full length of the envelope. The
disadvantage of this ship was its slowness, considering its size and
power, and was due to the enormous resistance offered by the framework
and rigging.
Airships known as the "Clement-Bayard" were also built about this time.
They were manufactured by the Astra Company in conjunction with
Monsieur Clement, a motor engineer.
In later days vessels were built by the Astra Company of the peculiar
design introduced by Senor Torres. These ships, some of which were of
considerable size, were highly successful, and we became purchasers at
a later date of several.
The Zodiac Company also constructed a number of small ships which were
utilized during the war for anti-submarine patrol. It cannot be said,
however, that the French have fulfilled their early promise as airship
designers, the chief reason for this being that the airship is
peculiarly suitable for work at sea and the French relied on us to
maintain the commerce routes on the high seas and concentrated their
main efforts on defeating the Germans in the field, in which as all the
world acknowledges they were singularly successful and hold us under an
eternal obligation.
GERMANY
The progress and development of the airship in Germany must now be
considered; it will be seen that, although the production of
satisfactory ships was in very few hands, considerable success attended
their efforts in the early days of the twentieth century.
In 1812, Leppig built an airship at the cost of the State at Woronzowo
in Russia. This was of the shape of a fish with a rigid framework
beginning at the height of the longitudinal axis.
The lower keel-shaped part of the same formed the car. Two fans were
attached to the sides and a tail piece was provided behind to act as a
rudder. The ship was inflated, but structural damage occurred during
this operation and rendered it incapable of flight.
In 1836, Georg Rebenstein, of Nurnburg, was considering the use of the
fall of inclined planes to obtain horizontal motion.
Nothing of importance was produced until a much later date, when in
1885 M. Wolf constructed an envelope of 26,500 cubic feet. An engine
and propeller were fixed in a triangular framework in front of the
airship, supported by the steam pipe of a steam engine fixed under the
body of the envelope. The framework lacked rigidity, and the envelope
tore during inflation and the airship failed to ascend.
In the following year Dr. Woelfert, of Berlin, produced a cigar-shaped
envelope, to which was attached rigidly a long bamboo framework
containing the car. An 8 horse-power benzine Daimler motor drove a
twin-bladed aluminium propeller, and another propeller for vertical
movement was provided beneath the car. Four trial flights were
attempted, but on each occasion the motor gave unsatisfactory results,
and Woelfert sought to improve it with a benzine vaporizer of his own
pattern. This improvement was not a success, as during the last flight
an explosion took place and both Woelfert and an aeronaut named Knabe,
who was accompanying him, were killed.
In 1906, Major von Parseval experimented, in Berlin, with a non-rigid
type of airship. His first ship had a volume of 65,200 cubic feet, but
owing to his system of suspensions, the car hung 27 feet 6 inches below
the envelope. A Daimler engine was used, driving a four-bladed
propeller. Owing to the great overall height of this ship, experiments
were made to determine a system of rigging, enabling the car to be
slung closer to the envelope, and in later types the elliptical rigging
girdle was adopted. His later ships were of large dimensions and proved
very satisfactory. About the same time Major Gross also built airships
for the German aeronautical battalion.
It is, however, the rigid airship that has made Germany famous, and we
must now glance at the evolution of these ships with which we became so
familiar during the war.
The first rigid airship bearing any resemblance to those of the present
day was designed by David Schwartz, and was built in St. Petersburg in
1893. It was composed of aluminium plates riveted to an aluminium
framework. On inflation, the frame-work collapsed and the ship was
unusable.
In 1895 he designed a second rigid airship, which was built in Berlin
by Messrs. Weisspfennig and Watzesch. The hull framework was composed
of aluminium and was 155 feet long, elliptical in cross section, giving
a volume of 130,500 cubic feet. It was pointed in front and rounded
off aft. The car, also constructed of the same material, was rigidly
attached to the hull by a lattice framework, and the whole hull
structure was covered in with aluminium sheeting. A 12 horse-power
Daimler benzine motor was installed in the car, driving through the
medium of a belt twin aluminium screw propellers; no rudders were
supplied, the steering being arranged by means of a steering screw
placed centrally to the ship above the top of the car. Inflation took
place at the end of 1897 by a method of pressing out air-filled fabric
cells which were previously introduced into the hull. This operation
took three and a half hours. On the day of the first flight trials
there was a fresh wind of about 17 miles per hour. The airship
ascended into the air, but, apparently, could make little headway
against the wind. During the trip the driving-belt became disengaged
from the propellers and the ship drifted at the mercy of the wind, but
sustained little damage on landing. After being deflated, the hull
began to break up under the pressure of the wind and was completely
destroyed by the vandalism of the spectators.
In 1898 Graf F. von Zeppelin, inspired by the example of Schwartz, and
assisted by the engineers Kober and Kubler, conceived the idea of
constructing a rigid airship of considerable dimensions. For this
purpose a floating shed was built on Lake Constance, near to
Friedrichshafen. The hull was built of aluminium lattice-work girders,
and had the form of a prism of twenty-four surfaces with arch-shaped
ends. In length it was 420 feet, with a diameter of 38 feet 6 inches,
and its capacity was 400,000 cubic feet. The longitudinal framework
was divided by a series of rings, called transverse frames, into
seventeen compartments containing fabric gasbags. The transverse
frames were fitted with steel wire bracings, both radial and chord, and
to strengthen the whole a triangular aluminium keel of lattice work was
used. A vertical and horizontal rudder were fitted to the forward
portion of the ship, and aft another vertical rudder. The whole
exterior of the ship was fitted with a fabric outer cover.
Two aluminium cars, each about 20 feet long, were rigidly attached to
the framework of the hull. Each car was furnished with a 16
horse-power Daimler engine, driving two four-bladed screw propellers of
aluminium sheeting. These propellers were situated on the side of the
hull at the centre of resistance. The transmission was supplied by
steel tubes with universal cross joints through the medium of bevel
gears. Reversible driving arrangements were installed in the cars in
order that the ship could be driven backwards and forwards. Electric
bells, telegraphs, and speaking tubes were also fitted, and it can be
seen that for general arrangements this airship was a long way ahead of
any built at that date.
The first flight was made on July 2nd, 1900. The ship attained a speed
of 17 per hour, and the numerous technical details stood the tests
well. The stability was considered sufficient, and the height of
flight could be altered by the horizontal rudder. The landing on the
water was accomplished without difficulty, and could be regarded as
free from danger. The faults requiring remedy were, firstly, the upper
cross stays, which buckled in flight owing to insufficient strength for
the length of the hull; secondly, the gasbags were not sufficiently
gastight and, thirdly, the power of the engines were not sufficient for
such a heavy ship.
This airship was broken up in 1902.
In 1905 the second ship of the series was completed. She was of nearly
the same size as the previous ship, but the workmanship was much
superior. Increased engine-power was also supplied, as in this
instance two 85 horse-power Mercedes engines were fitted. This ship was
destroyed by a storm while landing during the next year.
The third ship, which was completed in 1906, was the first Zeppelin
airship acquired by the Government, and lasted for a considerable time,
being rebuilt twice, first in 1908 and again in 1911. She was slightly
larger than the previous two.
The building was continued, and up to the outbreak of war no fewer than
twenty-five had been completed. It is impossible, in the space at our
disposal, to trace the career of all of them. Several came to an
untimely end, but as the years went by each succeeding ship proved more
efficient, and the first ship which was delivered to the Navy performed
the notable flight of thirty-one hours.
To revert, for a moment, once more to the earlier ships--the fourth was
wrecked and burned at Echterdingen in the same year in which she was
completed. The fifth, which was the second military airship, was fitted
with two 110 horse-power engines and also came to a tragic end, being
destroyed by wind at Weilberg in 1910, and the following ship was burnt
at Baden in the same year.
The seventh ship was the first passenger airship of the series, and was
known as the Deutschland. By this time the capacity had increased to
536,000 cubic feet, and she was propelled by three 120 horse-power
engines. She also fell a victim to the wind, and was wrecked in the
Teutoberg Forest in 1910; and yet another was destroyed in the
following year at Dusseldorf.
The tenth ship to be completed was the passenger ship Schwaben; her
capacity was 636,500 cubic feet, and she had three 150 horse-power
engines. This ship carried out her first flight in June, 1911, and was
followed four months later by the Victoria Luise. The fourth passenger
airship was known as the Hansa. These three ships were all in
commission at the outbreak of war.
The first naval airship, L 1, mentioned above, was larger than any of
these. The total length was 525 feet, diameter 50 feet, and cubic
contents 776,000 cubic feet. Her hull framework in section formed a
regular polygon of seventeen sides, and was built up of triangular
aluminium girders. The gasbags were eighteen in number. This ship was
fitted with three 170 horse-power Maybach engines, which were disposed
as follows--one in the forward car, driving two two-bladed propellers;
two in the after car, each driving a single four-bladed propeller. For
steering purposes she had six vertical and eight horizontal planes.
The total lift was 27 tons, with a disposable lift of 7 tons. Her
speed was about 50 miles per hour, and she could carry fuel for about
48 hours. Her normal crew consisted of fourteen persons, including
officers.
It will probably be remembered that the military Zeppelin Z III was
compelled to make a forced landing in France. This ship was of similar
construction to L 1, but of smaller volume, her capacity being 620,000
cubic feet. A trial flight was being carried out, and while above the
clouds the crew lost their bearings. Descending they saw some French
troops and rose again immediately. After flying for four hours they
thought they must be safely over the frontier and, running short of
petrol, made a landing--not knowing that they were still in France
until too late. The airship was taken over by the French authorities.
Until the year 1916 the Zeppelin may be considered to have passed
through three stages of design. Of the twenty-five ships constructed
before the war, twenty-four were of the first type and one of the
second. Each type possessed certain salient features, which, for
simplicity, will be set out in the form of a tabulated statement, and
may be useful for comparison when our own rigid airships are reviewed.
Stage 1.
Long parallel portion of hull with bluff nose and tail.
External keel with walking way.
Box rudders and elevators.
Two cars.
Four wing propellers.
Stage 2.
Long parallel portion of hull with bluff nose, tail portion
finer than in Stage I
Internal keel walking way.
Box rudders and elevators.
Three cars, foremost for control only.
Four wing propellers.
Stage 3.
Shorter parallel portion of hull framework, bluff nose and
tapering tail.
Internal keel walking way.
Balanced monoplane rudders and elevators.
Three cars, foremost for control only.
Two foremost cars close together and connected by
a canvas joint to look like one car.
Four engines and four propellers. One engine in forward
car driving pusher propeller. Three engines in after
car driving two wing and one pusher propeller.
To the second stage belongs naval airship L 2, which was destroyed by
fire a month after completion in 1913. In 1916 a fourth stage made its
appearance, of which the first ship was L 30, completed in May, and to
which the ill-fated L 33 belonged. This type is known as the
super-Zeppelin, and has been developed through various stage until L
70, the latest product before the armistice. In this stage the
following are its main features:
Stage 4.
Short parallel portion of hull, long rounded bow and
long tapering stern. In all respects a good
streamline shape.
Internal keel walking way.
Balanced monoplane rudders and elevators.
Five cars. Two forward (combined as in Stage 3),
one aft, and two amidships abreast.
Six engines and six propellers. The after one of the
forecar and the sidecars each contain one engine
driving direct a pusher propeller. The after car
contains three engines, two of which drive two wing
propellers; the third, placed aft, drives direct a
pusher propeller.
In this stage the type of girders was greatly altered.
A company known as the Schutte-Lanz Company was also responsible for
the production of rigid airships. They introduced a design, which was
a distinct departure from Zeppelin or anyone else. The hull framework
was composed of wood, the girders being built up of wooden sections.
The shape of these ships was much more of a true streamline than had
been the Zeppelin practice, and it was on this model that the shape of
the super-Zeppelin was based. These ships proved of use and took part
in raids on this country, but the Company was taken over by the
Government and the personnel was amalgamated with that engaged on
Zeppelin construction during the war.
ITALY
In 1908, Italy, stimulated by the progress made by other continental
nations, commenced experimental work. Three types were considered for
a commencement, the P type or Piccolo was the first effort, then
followed the M type, which signifies "medium sized," and also the
semirigid Forlanini.
In the Forlanini type the envelope is divided into several compartments
with an internal rigid keel and to-day these ships are of considerable
size, the most modern being over 600,000 cubic feet capacity. During
the war, Italian airships were developed on entirely dissimilar lines
to those in other countries. Both we and our Allies, and to a great
extent the Germans, employed airships exclusively for naval operations;
on the other hand, the Italian ships were utilized for bombing raids in
conjunction with military evolutions.
For this reason height was of primary importance and speed was quite a
secondary consideration, owing to the low velocity of prevailing winds
in that country. Flights were never of long duration compared with
those carried out by our airships. Height was always of the utmost
importance, as the Italian ships were used for bombing enemy towns and
must evade hostile gunfire. For this reason weight was saved in every
possible manner, to increase the height of the "ceiling."
In addition to the types already mentioned, three other varieties have
been constructed since the war--the Usuelli D.E. type and G class. The
G class was a rigid design which has not been proceeded with, and, with
this single exception, all are of a semirigid type in which an
essentially non-rigid envelope is reinforced by a metal keel. In the
Forlanini and Usuelli types the keel is completely rigid and assists in
maintaining the shape of the envelopes, and in the Forlanini is
enclosed within the envelope. In the other types the keel is in
reality a chain of rigid links similar to that of a bicycle. The form
of the envelope is maintained by the internal pressure and not by the
keel, but the resistance of the latter to compression enables a lower
pressure to be maintained than would be possible in a purely non-rigid
ship.
The M type ship is of considerable size, the P smaller, while the D.E.
is a small ship comparable to our own S.S. design. The review of these
three countries brings the early history of airships to a conclusion.
Little of importance was done elsewhere before the war, though
Baldwin's airship is perhaps worthy of mention. It was built in
America in 1908 by Charles Baldwin for the American Government. The
capacity of the envelope was 20,000 cubic feet, she carried a crew of
two, and her speed was 16 miles per hour. She carried out her trial
flight in August, 1908, and was accepted by the American military
authorities. During the war both the naval and military authorities
became greatly interested in airships, and purchased several from the
French and English. In addition to this a ship in design closely
resembling the S.S. was built in America, but suffered from the same
lack of experience which we did in the early days of airship
construction.
We must now see what had been happening in this country in those
fateful years before the bombshell of war exploded in our midst.