Evening star., 1934-08-07
Analyses Causes of Failure
OF the Stratosphere Balloon
Editor of The Star:

Editor of The Star:
I should like to refer to your recent
editorial on THE Stratosphere Flight
Failure" In response to the sentence
appearing therein reading, THE fail
ure Of the balloon, which for some
cause yet to be determined proved to
be too frail for the flight, will, of
course. be analyzed," would furnish
the following analysis:
A fundamental rule of aerostatics is
that the lifting power of a specific
quantity of gas, within balloon, is
Interchangeable when such gas is at the
same temperature and pressure as air
outside the balloon. When one pound
of gas displaces ten pounds of air, the
gas has ample buoyancy to balance
material weighing nine pounds. A
cubic foot of common air weighs ap-
proximately nine-tenths of one pound
(0904 pound) at sea level, whereas
hydrogen weighs only 0062 pound per
cubic foot Hydrogen is one-f1fteenth
as heavy as air. One pound of hydro
gen will displace IA pounds of air
With the existence of sea level condi-
tions, 1000 cubic feet of hydrogen will
balance 10 pounds; and the lifting
power of fourteen times continues dur
ing the maintenance of the ratio be-
tween the gas and the atmospheric
air, with respect to temperature and
pressure.
Assuming this stratosphere balloon
took off at sea level, the 200, 900 cubic
feet of hydrogen with which it was
initially inflated would balance ap-
proximately seven tons, the estimated
total weight of the balloon when its
flight began. Consequently, it would
require additional hydrogen to secure
the necessary buoyancy for ascension.
AS the atmospheric pressure di-
minishes at approximately the rate of
three per cent per thousand feet of
altitude, and since the balloon was
filled at the start of the flight six and
two-thirds per cent of its maximum
capacity of three million cubic feet, a
simple calculation will reveal that this
balloon would be totally filled with
hydrogen when it attained an eleva-
ton of approximately $1,000 feet.
This altitude would constitute its
pressure height, which is the altitude
at which internal pressure upon the
fabric covering would be created.
The statement has been made that
the balloon was leveled off at forty
thousand feet. The gas within the
balloon was apparently at somewhat
higher temperature than the sur
rather cold, and was enabled thereby
to reach height of 5000 feet more
than pressure height of $1,000 feet.
Further altitude could have been ac-
quired only by tightening the load
borne by the balloon; for example,
the release of ballast.
x
This balloon is said to have attained
an altitude of approximately 10000
feet. which is 10000 feet more than its
normal ceiling, or pressure height, -
the hydrogen occupying all space pro-
vided in the bag at pressure height
and the bag being expanded to its
full capacity of 1000 600 cubic feet.
Keeping in mind the fact that the
atmospheric pressure decreases 3 per
cent for every increase of 1000 feet
in altitude, it will be obvious that the
outside sir-reSiStance on the balloon S
bag would be reduced at least so per
cent when the balloon had reached an
altitude of $4,000 feet. At this par
ticular height, the internal pressure
Of the hydrogen upon the sensitive
covering of fabric would be necessarily
increased by an equivalent amount,
deducting whatever gas had been ex-
PEELED through the spillwsy valve,
which hydrogen would in turn be re-
placed by rarified air from the sur
rounding atmosphere. lighter than the
compressed gas within the bag.
Due to the compression Of the hy-
drogen. It lost q large part Of It's