mal inputs were realizec then for the Ivy tests. In
the case of Shot 1, where the yield was slightly
greater than the maximum probable, good results
were obtained. The aircraft sustained only minor
physical damage, and the resuits indicated that suf-
and wing accelerations, skin-temperature rise, and
elevator position.
The aircraft participated in every shot of the
Castle series. The limiting condition on the aircraft
was cither 190 percent of the design limit allowable
bending momenton the horizontal stabilizer or a
400 F temperature rise on the 0.020-inch magnesium
skin on the elevators. For Shots 1 through 5, the
ficient information was recorded to meet the praject
objectives. These data indicated that predictions of
aircraft was positioned at time zero in a tail-to as-
pect for one of the two limiting conditions, whichever
was Critical for the maximum predicted yield of the
device concerned.
For Shot 6, the aircraft was
positioned ir a head-on aspect for conservative values
of bending moments. Data obtained from a head-on
orientation were the first experimental verification
of theoretically predicted responses and. although
conservative. were nevertheless extremely valuable
and necessary for a complete evaluation of aircraft
response to nuclear explosions.
The maximum useful incremental peak tempera~
ture measured was 250 F rise on the 0.020-inch
magnesium skin on the undersurface of the elevator
during Shot 5. The theoretical overpressure criteria
level of 0.80 psi was attained safely on Shot 1, although considerable sheet-:metal damage resulted.
The maximum gust load measured was an incremental
beading moment on the horizontal stabilizer of approximately 80 percent of design limit load.
The
predicted responses of the critical skin areas to the
thermal inputs received were conservative, but suf-
ficient data werc obtained tc enable a morerealistic
empirical and theoretical determination of the delivery
capabilities of the B-36.
puts.
Project 6.4 “Proof Testing of AW Ship Countermeasures” (WT-927), Bureau of Ships and Naval
Radiological Defense Laboratory; G. G. Molumyhy,
CAPT, USN, Project Officer.
The principal objectives were: (1) the evaluation
of washdown countermeasures on ships and grounded
aircraft, (2) the determination of the shielding ef~
tectiveness of ships structures, (3) the tactical radio~
logical recoverv procedures on ships and grounded
aircraft, and (4) the extent of interior contamination
and suitability of ventilation protective devices
aboard ship.
Two remotely controlled ships, one protected by
a washdown countermeasure, were guided through
regions of contaminated fallout. Special structural
configurations, oiler ar ducts, ventilation test
compartments, and aircraft were installed cn both
ships to act as contaminant-collecting surfaces.
Project 6.2b “Thermal Effects on B~47B Aircraft
in Flight” (WT~-926), Wright Air Development Center;
CG. L. Luchsinger, Project Officer
Project 6.2b was a continuation of the experimen-
tation begun on Ivy to determine the effects, principally thermal, of nuclear detonations on a B-47
aircraft in flight. The Castle results, when combined
with previous data, will modify existing theories relating the B-47 response to thermal inputs.
Recording gamma-radiation detectors, air ga.nplers,
particle and differential fallout collectors, surface
samples, and postshot radiation surveys were used
to suppiy data on the extent of contamination.
These data showed that it was possible for personnel to receive lethal radiation dosage aboard un-
protected ships and shipboard aircraft if used operationally. Washdown effcctiveness on ships and
aircraft not in flight was estimated to be 90 and 95
The Ivy B-47B, with additional instrumentation,
participated on all but Shot & of the Castle series.
Recorded data included total thermal-input energies,
intensities, and spectra as well as overpressures,
skin temperature response, and flight attitudes.
The aircraft was flown and maintained by WADC per-
sonne] who were also responsible for instrumentation
and aircraft position determination. The average effectiveness of instrumentation for the series was 93
percent.
The aircraft was positioned on each shot te receive
sufficient thermal energy to raise the temperature in
the 0.020-inch skin on the ailerons to 370 F above
ambient. Assigned positions in space were computed
on the basis of the maximum probable yield rather
than the most probable.
aircraft skin response to thermal inputs from highyield weapons were over-conservative. They also
indicated the need for a better understanding of the
parameters involved in skin responses to thermal
flux: e.g., convective and conductive cooling, as
well as the possible variance of absorption coeffi~
cients with change of incident angle of thermal in-
In most cases, higher ther-
114
percent based on dosage and dose rate, respectively.
Distance and shielding by the ships structures resulted in attenuation fractions ranging from 0.2 in
compartments close to weather surfaces to 0.001 in
interior compartments below armored decks, with
respect to levels observed on weather decks. On
unprotected ships and grounded aircraft, excessively
long periods of repetitious decontamination were
required to achieve satisfactory radiation levels;
when a washdown countermeasure had been in opera-
tion, very little effort was needed to make the ship
or aircraft habitable. Very little contaminant entered
either the boiler air system or ventilation systems.
For contaminating events of the type encountered
in these tests, it appeared that: (1) washdown countermeasures will enable ships and operational] planes