British Airships, Past, Present and Future | Page 8

the airship of the future. During flight
certain details require attention, and carelessness on the pilot's part,
even on the calmest of days, may lead to disaster. The valves and
especially the gas valves should be continually tested, as on occasions
they have been known to jam, and the loss of gas has not been
discovered until the ship had become unduly heavy. Pressure should be
kept as constant as possible. Most airships work up to 30 millimetres as
a maximum and 15 millimetres as a minimum flying pressure. During a
descent the pressure should be watched continuously, as it may fall so
low as to cause the nose to blow in. This will right itself when the
speed is reduced or the pressure is raised, but there is always the danger
of the envelope becoming punctured by the bow stiffeners when this
occurs. HOUSING ACCOMMODATION FOR AIRSHIPS, ETC.
During the early days of the war, when stations were being equipped,
the small type of airship was the only one we possessed. The sheds to
accommodate them were constructed of wood both for cheapness and
speed of construction and erection. These early sheds were all of very
similar design, and were composed of trestles with some ordinary form
of roof-truss. They were covered externally with corrugated sheeting.
The doors have always been a source of difficulty, as they are
compelled to open for the full width of the shed and have to stand alone
without support. They are fitted with wheels which run on guide rails,
and are opened by means of winches and winding gear. The later sheds
built to accommodate the rigid airship are of much greater dimensions,
and are constructed of steel, but otherwise are of much the same design.
The sheds are always constructed with sliding doors at either end, to
enable the ship to be taken out of the lee end according to the direction
of the wind. It has been the practice in this country to erect windscreens
in order to break the force of the wind at the mouth of the shed. These
screens are covered with corrugated sheeting, but it is a debatable point
as to whether the comparative shelter found at the actual opening of the

shed is compensated for by the eddies and air currents which are found
between the screens themselves. Experiments have been carried out to
reduce these disturbances, in some cases by removing alternate bays of
the sheeting and in other cases by substituting expanded metal for the
original corrugated sheets. It must be acknowledged that where this has
been done, the airships have been found easier to handle. At the
outbreak of war, with the exception of a silicol plant at Kingsnorth,
now of obsolete type, and a small electrolytic plant at Farnborough,
there was no facility for the production of hydrogen in this country for
the airship service. When the new stations were being equipped, small
portable silicol plants were supplied capable of a small output of
hydrogen. These were replaced at a later date by larger plants of a fixed
type, and a permanent gas plant, complete with gasholders and high
pressure storage tanks was erected at each station, the capacity being
5,000 or 10,000 cubic feet per hour according to the needs of the station.
With the development of the rigid building programme, and the
consequent large requirements of gas, it was necessary to reconsider the
whole hydrogen situation, and after preliminary experimental work it
was decided to adopt the water gas contact process, and plants of this
kind with a large capacity of production were erected at most of the
larger stations. At others electrolytic plants were put down. Hydrogen
was also found to be the bye-product of certain industries, and
considerable supplies were obtained from commercial firms, the
hydrogen being compressed into steel cylinders and dispatched to the
various stations. Before concluding this chapter, certain words must be
written on parachutes. A considerable controversy raged in the press
and elsewhere a few months before the cessation of hostilities on the
subject of equipping the aeroplane with parachutes as a life-saving
device. In the airship service this had been done for two years. The best
type of parachute available was selected, and these were fitted
according to circumstances in each type of ship. The usual method is to
insert the parachute, properly folded for use, in a containing case which
is fastened either in the car or on the side of the envelope as is most
convenient. In a small ship the crew are all the time attached to their
parachutes and in the event of the ship catching fire have only to jump
overboard and possess an excellent chance of being saved. In rigid
airships where members of the crew have to