British Airships, Past, Present, and Future

y derive their appellation from the fact that when charged with hydrogen, or some other form of gas, they are lighter than the air which they displace. Of these three types the free balloon is by fa

yages can be made from one place to another--always provided that the force of the wind is not sufficiently strong to overcome the power of the engines. The airship is, therefore, nothing else than a dirigible balloo

ped by anyone who wishes to possess a full knowledge of airships and the various problems which occur in their design. Certain technical expressions and terms are, however, b

of gas in a balloon or airship is called the "gross lift." The term "disposable," or "nett" lift, is obtained by deducting the weight of the structure, cars, machinery and other fixed

s example we may take it that under normal conditions air weighs 75 lb. per 1,000 cubic feet. Therefore, if a balloon of 1,000 cubic feet volume is charged with

round. Hydrogen weighs about one-fifteenth as much as air, and under normal conditions 1,000 cubic feet weighs 5 lb.

feet of air

eet of hydrog

--

e gross lift of t

lf the balloon is 70 lb. lighter than the air it displaces, and pr

n elevation of 10,000 feet it falls one inch for every 1,000 feet rise. It follows that as the pressure of the air decreases, the volume of the gas contained expands at a corresponding rate. It has been shown that a balloon

feet of air

et of hydrogen

---

33

er, from which it may be taken approximately that 1/30 of the volume gross lift and weight is lost for every 1,000 feet rise. From this example it

t. The volume of gas is affected by temperature, as gases expand or contrac

at 30 inches barometric pressure and 60 degrees Fah

Fahrenheit, the air will be expanded and 1,000 cubic feet of air will w

in the balloon, it will be seen that with the temperature at 60 degrees Fahrenheit the lift is 75 lb. - 5 lb.

ll in the temperature

reater when the temperature is colder, and the greater the barometric pressure so will also the lift be greater. To put this int

e becomes higher, owing to the action of the sun, than the air which surrounds it. A difference of some 20 degrees Fahrenheit may result between the gas and the air temperatures; this renders it

f the surface by the passage of the ship through the air, though in the event of its freezing suddenly, while in a melting state, a very considerable addition of weight might be caused. There have been many instances of airships flying through snow, and as far as is known no serious

velope or gasbags for any length of time. Owing to diffusion gas escapes with extraordinary rapidity, and if the fabric used is not absolutely gastight the air finds its wa

.5 inches, the lift of 1,000 cubic feet of hydrogen at 98 per cent purity is 69.6 lb. Under same conditions at 80 per

on "lift" can now be condens

y proportional to

y proportional to a

ectly proporti

HIP

ped under three distinct types, the Ri

nd other weights, and which of itself is sufficiently strong to support its own weight. Enclosed within this structure are a number of gas chambers or bags filled with hydrogen, which provide

n some cases divided into separate compartments, to which is attached close underneath a long girder or keel. This supports the car and other we

one ship was purchased by the Navy shortly before the outbreak of war. In the earliest examples of this type the car was slung a long way from the envelope and was supported by wires from all parts. This necessitated

d, Senor Torres Quevedo, who manufactured them in conjunction with the Astra Company in Paris. This type of envelope has been employed in this country in the Coastal, C Star, and North Sea airships, and has been fou

ns, which has been adopted for all classes of the S.S. airship, and

e so fortunate as to escape damage in the actual landing, there is the practical certainty that it would be completely wrecked immediately any increase occurred in the force of the wind.

d in the envelope which can easily be torn away and allows the gas to escape with considerable rapidity. Innumerable instances have occurred of ships being compelled to land in ou

d the small non-rigid made thoroughly reliable, are the most valuable types for future development. The larger non-

flexible fabric has, in itself, no rigidity whatsoever, and its shape must be maintained by the internal pressure kept slightly in excess of the pressure outside. Fabric is capable of resisting tension, but is naturally not able to resist compression. If the car was rigged beneath the centre of the envelope with vertical suspensions it would tend to produce compression in the underside of the envelope, owing to the load not being fully distributed. This would cause, in practice, the centre portion of the envelope to sag downwards, while the ends would have a tendency to rise. The principle which has been found to be most satisfa

s of internal rigging, while external head resistance is reduced to a minimum, as the car can be slung close underneath the envelope. Moreover, the direct longitudinal compression due to the rigging

this difficulty in a balloon, a valve is provided through which the gas can escape. In a balloon, therefore, which ascends from the ground full, gas is lost throughout its upward journey, and when it comes down again it is partially empt

the main engines or an auxiliary motor. These blowers were a continual source of trouble, and at the present day it has been arranged to collect air f

mple will explain

which will have escaped through the valves. If the ship has a capacity of 300,000 cubic feet it will have lost 10,000 cubic feet of gas. The airship now commences to descend; as it descends the gas within c

gas from the envelope, and by the time 1,000 feet is reached the ballonets will be empty. To ensure

that it will not be necessary to lose gas during fligh

aximum and are fitted both to ballonets and the gaschamber. They are automatic in action, and, as

If great heights are required to be reached, it is obvious that the wastage of gas would be enormous, and it is understood that the Germans o

be found impossible to keep the ship on a straight course. The planes are composed of a framework covered with fabric and are attached to the envelope by means of stay wires fixed to suitable points, in the case of

re considered a great adjunct, as with their upward and downward thrust they proved of great value in landing. Nowadays, owing to greater experience, landing does not possess

ust be capable of running for long periods without a breakdown; secondly, that it must be so arranged that minor repairs can be effected in

ND FLYING

she displaces. The handling party needs considerable training, as in gusty weather the safety of the ship depends to a great extent upon its skill in handling her. The ship approaches the handling party head to wind and the trail rope is dropped; it is taken by the handling party and led t

he handling party has to be increased and m

shed is revolving, as is the case on certain stations in Germany, the wind will be found to be blowing across the entrance to the she

best method of mooring airships in the open. These will be described and d

ys, may lead to disaster. The valves and especially the gas valves should be continually tested, as on occasions

. 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 th

MODATION FOR

n 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 sour

p are of much greater dimensions, and are constructed

at either end, to enable the ship to be taken out of

table 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. Experime

e this has been done, the airship

w of obsolete type, and a small electrolytic plant at Farnborough, there was no

re replaced at a later date by larger plants of a fixed type, and a permanent gas plant, complete with gasholders and high pressure st

ecided 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

ted 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 exce

n a fatal accident or any case of a parachute

ip to be easily followed. Much has been omitted that ought by right to have been included, but, on the other hand, intricate ca