The descending experiments without oxygen show that the limit for a safe
escape with an open parachute lies approximately at a jumping altitude
of 13 km. [42,700 ft.], since in a jump from 13 km. [42,700 ft.]
recovery of consciousness occurred only at an altitude of 1.6 km. [5,250
ft.], and so one must already consider the possibilities of landing in
an unconscious condition with all the attendant dangers. This still does
not take into account the heavy demands made on the body by the cold and
the consequent risk. The great effect of the body position during the
experiment makes it obvious how severe is the effect of every additional
demand. While, for example, in the 13 km. [42,700 ft.], experiment upon
a seated subject, recovery of consciousness took place after 8 minutes
12 seconds at an altitude of 7.2 km. [23,620 ft.], the suspended
subjects recovered consciousness only after 19 minutes at 1.6 km. [5,250
ft.] altitude. Correspondingly also, unconsciousness occurred in the
suspended subjects much more rapidly than in those who were seated. The
same observation was made in the 15 km. [49,200 ft.] experiments, and
indeed those who went through the experiment lying down could already
state name and birth date immediately upon reaching ground level
although they were paralyzed, while those who had been suspended did not
respond at all to speech within this time. Except for one mentally very
sluggish subject, the return of normal condition occurred much earlier
to those who were lying down, namely within 15 minutes. The descending
experiments extended to 18 km. [59,100 ft.] altitude with oxygen
breathing showed that, except for the danger of cold, escape with an
open parachute is possible from these altitudes even though,
practically, no need exists for it.
Before we go into a discussion on the falling experiments it seems
essential for us to cite the work of Lutz and Wendt on “Animal
Experiments on Parachute Jumping from High-Pressure Cabins.”
Unfortunately this work was not available to us during these experiments
so that we could not build upon the valuable results contained in it and
derived from numerous animal experiments, or upon the experience of the
authors. Although both authors approach with necessary scepticism the
problem of “reaching decisions through animal experimentation upon
questions in
[page 24 of original]
which, in the final analysis, the behavior of the human being in
identical situations is of exclusive interest,” they could, and had to
depend upon the previously proved experience that no fundamental
qualitative differences in the manner of reaction to oxygen lack is to
be expected between animals and human beings although there are
considerable quantitative differences which, in this case, mean temporal
differences. However, the results of our experiments show that to some
extent quantitative as well as qualitative differences are present to
the extent that the above animal experiments must lead to great
fallacies which are significant to future developments. This appears
especially in a comparison of results obtained with animals with the
collective results of human experimentation upon escape from high
altitudes through free fall without oxygen. On the basis of animal
experiments, Lutz and Wendt were forced to the conclusion that if oxygen
is breathed before the pressure drop “jumps from 14 km. [45,900 ft.]
altitude can theoretically be survived—at any rate, that is the maximum
altitude * * *,” whereas we were able to carry out human experiments up
to 21 km. [68,900 ft.] altitude without any harm whatever. In all
experiments at 20 km. [65,600 ft.] the subjects recovered clear
consciousness with spontaneous control above 3 km. [9,800 ft.], and so
within a sufficient altitude for actual parachute jumping. As instructed
before the experiment, the subject rang a cowbell hung up in the chamber
by pulling a handle (the equivalent of pulling the rip cord) without a
new order to do so, so that under actual conditions they would certainly
have also pulled the rip cord at the right time.
Experiments with a pressure drop from 4 km. [13,100 ft.] without
previous breathing in of oxygen were not carried out by us because we
proceeded from the viewpoint that when contact with the enemy is
possible, pressure cabin machines fly with a pressure corresponding to 8
km. [26,200 ft.] altitude and, therefore, the crews would already be
breathing oxygen in case of a possible pressure drop as a result of
damage to the cabin.
[page 25 of original]
Since the falling experiments without oxygen had already given such good
results, falling experiments were begun only at 20 km. [65,600 ft.]
altitude, and, because of the limitations described above, could be
carried out only to 21 km. [68,900 ft.]. In these the results obtained
by Lutz and Wendt were fully corroborated in this respect, that jumps
from above 21 km. [68,900 ft.] can probably be made without danger, and
that ebullition of the blood does not yet take place up to 21 km.
[68,900 ft.] altitude. On the other hand in a falling experiment with
human beings, neither a post-hypoxemic pseudo-death nor a post-hypoxemic
twilight sleep were ever observed (Lutz).
In conclusion, we must make it particularly clear that, in view of the
extreme experimental conditions in this whole experimental series, no
fatality and no lasting injury due to oxygen lack occurred.