ON AERONAUTICAL PROBLEMS. 399 
from the standpoint of research and development. Subsequently I shall 
try to indicate what I hold to be questions of more real importance. 
Helium for Airships. 
7. We have seen, in the last few months, a great revival of interest in 
the airship. Two of these craft, larger than any that have been con- 
structed hitherto, are known to be on order for the Air Ministry, and 
R.33—sister of the airship which made, in 1919, the first trans-Atlantic 
flight—has again been seen in the air. Indeed, she has made history. For 
by that involuntary but triumphant voyage of last April, when in a gale 
of unusual violence she was torn from her moorings and blown, with sorely 
damaged structure, across the sea to Holland, she showed in convincing 
fashion what an airship, properly handled, can do. Damaged as she was, 
she maintained throughout a speed of 30 knots, and so, instead of being 
carried helplessly across Kurope, was able to elude the full force of the 
gale and eventually to make a safe return to Pulham. 
Now whenever airships are mentioned in the Press, one may expect to 
find a digression on the advantages of helium. Hydrogen, with which 
our airships are inflated, is a highly inflammable gas,—helium is 
inert; and hence, it is argued, our airships are confronted by an ever- 
present danger of destruction by fire, which would be completely removed 
if we could ensure a supply of the rarer gas. It is hard on us that America, 
who possesses the only known sources of natural helium, should earmark 
the whole output for her own use. 
Until recently, one could lessen the force of this contention by saying 
(what was perfectly true) that the chief danger of fire in an airship arises, 
not from the hydrogen, but from the petrol carried. But with the 
development of engines using heavy oil that position becomes no longer 
tenable. True, there is no case on record in which an airship has perished 
by ignition of the hydrogen, except during the War, when incendiary 
bullets were employed. But, it will be answered, we are bound to contem- 
plate conditions of war, and it is here that helium assumes its greatest 
importance ; moreover, in the long-distance voyages of the future we 
shall have to face the dangers of atmospheric electricity. 
Well, as regards the dangers of atmospheric electricity, we were privi- 
leged, in March of this year, to hear at first hand the views of Dr. Eckener. 
Dr. Eckener is the present chairman of the Zeppelin Company, and he has 
been associated with airship construction in Germany for twenty-five 
years; he has made over 2,000 separate flights in rigid airships; and in 
particular, it was he who piloted the Z.R.3 from Friedrichshafen to New 
York some months ago. He is quite definitely of the opinion that lightning 
is not dangerous; and his views carry weight, because he has himself 
‘piloted airships through thunderstorms. He makes one reservation: he 
says, “One condition must be given if lightning is to do no harm,—the 
airship must not let out any gas, either through the valves or through 
deficient gas cells, for otherwise the electric spark may strike an explosive 
gas mixture’. And to meet this requirement he makes the interesting 
suggestion that an airship might carry small reservoirs of helium, only 
intended for emergency use, in case it should be absolutely necessary to 
valve gas during a passage through thunderstorms.* 
8 R. Aé. Soc. Journal, June 1925, pp. 283-285. 
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