Evening star., 1921-08-25
The Giant Dirigible.

Suspicion of the stability of the
giant dirigible ZR-2, built in England
for the United States Navy. had been
expressed ON the eve of the trial trip
which ended with her explosion and
destruction yesterday, with the loss
of forty-three out of forty-nine men
carried. 1t had been observed thai
the immense framework of the gas
bag structure had shown a tendency
to buckle. Certain strengthening re-
pairs, it is indicated, had been made.
Yet presumably it had been brought
to the point of strength judged by the
experts in charge to be sufficient. else
the aerial voyage to test the general
capacity of the monster balloon would
not have been undertaken. The event
proves that they were mistaken. most
tragically.
The collapse Of this. the greatest of
the "Zeppelins,' may have been due
to some peculiar fault Of material, or
it may possibly have been due to the
fact that the limit of endurance has
been reached in the extension of size.
1t does not follow that because a dirig-
ible 600 feet long can be safely built
managed. The addition Of 100 feet
adds to the strain put upon every
member. 1t is true that the distribu-
tion of the gas in a degree makes each
Of h,,r
there remains a relation of units that
imposes a general stress that cannot
be discounted by the separation Of the
f1otation elements.
Just as the war was drawing to q
close the American chemists had de-
veloped a gas for balloon purposes
which was regarded as solving the
grayest of the problems of military
aviation. Helium, it was announced.
would replace hydrogen. being of
greater lifting power and at the same
time n-infiammable. No longer, it
was claimed. could an observation bal
loon be exploded by means Of fire bull
LETT. The envelope might be punctured
and the gas allowed to escape, thus
letting the balloon descend, but it
would not burst into flames.
Why has helium not been employed
in peace-time aviation? Had the bal
loonets Of ZR-2 been filed with that
element there would have been no ex-
plosion in midair. The giant might
have broken in two and fallen. perhaps
with equal loss of life, but probably
with far less destruction. Maybe
helium is not as effective LITTER" as
1t was at first believed. Or maybe
there was no helium in England for
the tests. But, at any rate. the disas-
ter brings sharply to mind the question
of the present status Of helium as a
dirigibIe f1otation element.
Already determination is expressed
by naval aviators to proceed with the
development of giant dirigibles as
agencies of observation and attack.
The wreck of ZR-2 should give pause
to the enterprise. 1t certainly sug.
gests that there is too great an ele-
menC OF flSk III tne HldShlliCdlloil: oi
size; Before line is drawn in plan
ming. or another dollar is expended in
continuing the construction Of the
ZR-1, now building in this country.
the most thorough study should be
made of the structure Of zR-2, and. as
far as the circumstances now permit.
of the cause of it's collapse. If the
limit of safe size has been reached
and passed in this type retreat must
be made to the range of dependability
There is no merit in monster. what
ever it's cruising radius, that may
break up In the air and explode into
total loss with the sacrifice of the lives
of those on board.