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long duration positive-phase air Ddlast.
Six steel-frame industrial buildings were tested in Operation Redwing:
three drag-type structures, 20 ft in height, 40 ft in span, and 40 it in
length; and three semidrag-type structures, 50 ft in height, 40 ft in span,
and 80 ft in jength
These buildings were located on Yurochi and on three
man-made islands along the shallow reef between Yurochi and Namu. The
locations from GZ were sclected at such range distances (20,500, 24, 000,
29,000, «ind 36,009 ft) as to produce expected degrecs of damage ranging
from severe to modcrate deformation.
Reecause of a gross bombing error for the airburst
_—~
all structures were subjected to pressures higher than expected and su:fered
coniplete coliapse; therefore, the planned gradation of damage was not
achieved.
However, a qualitative demonstration of the effectiveness of the long
duration positive blast phase was achieved, since one arag structure collapsed at a lowes overpressure than that which an identical structure on
Operation Teapot received without collapse. This agrees with theoretical
studies which have indicated that, for drag-type targets, as the length of the
positive phase of the blast wave increases, the overpressure required to
cause a given degree of damage decreases.
Analytical studies will be made ofthe test results obtained during
‘
Redwing and Teapot in an effort to determine the magnitude of the bonus
effect of the long duration of the positive phase.
21.4
Program 4, Biomedical Effects -
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The only project in this program was Project 4.1, Chorioretinal Burns,
by Air Force School of Aviation Medicine, Randolph Air Force Base, Texas.
It was a sequel to a study in 1953 during Operation Upshot-Knothole. In
the latter study, weapons of about 20 kt produced burns in the eves of
rabbits at distances of 2 to 42.5 statute miles from GZ. On all studies
prior to Operation Redwing, rabbits were the only experimental animals
used to evaluate ocular damage. Four cases of accidental human burns were
produced at distances of 2 to 10 statute miles.
The present study was designed to furnish additional information on
the requirements for protection against retinal burns, utilizing both rabbits
and monkeys as experimental animals. The effectiveness of various parts
of the power pulse was evaluated as to its ability to produce chorioretinal
burns on rabbits and monkeys. This was accomplished by two series of
time-fractionating shutters. The first group, open at time zero, closed at
The second series, closed at time zero, were
The feasibility of
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increasing intervais of time.
open for precelected time incsements during the flash.