This film, made for the U.S. Atomic Energy Commission and Department of Defense, describes operations at the Nevada Test Site, where smaller nuclear weapons were tested in atmospheric bursts in the 1950s. Among the tests shown are the Upshot-Knothole Grable test of the M65 atomic cannon, which fired a Mark 9 15 kiloton nuclear artillery shell, one of only four gun-type nuclear weapons ever detonated by the U.S.
Nuclear weapon testing in Nevada began in January 1951, and dramatically reduced the cost and improved turnaround in weapons development testing compared to the massive logistics involved in conducting tests in the South Pacific, which was thereafter used only for high yield weapons tests. By 1955, public concern about the consequences of nuclear testing within the U.S. had grown and, after several incidents in which fallout from tests had fallen on areas outside the test site, opposition to tests increased. This film was part of a public relations campaign to persuade the public that these tests were essential for “national survival”.
The film shows precautions taken in Saint George, Utah, where fallout from tests in Nevada most frequently fell, and the flash of detonation and pressure wave from each shot was apparent.
Many persons in Nevada, Utah, Arizona, and nearby California have Geiger counters these days. We can expect many reports that “Geiger counters were going crazy here today.” Reports like this may worry people unnecessarily. Don’t let them bother you.
A total of 1021 nuclear devices were detonated at the Nevada Test Site between 1951 and 1992. All tests after August 1963 were detonated underground.
This design seemed to be “just right” once axial turbine jet engines reduced the diameter of the turbine so a jet engine would fit within the fuselage. But, this “sweet spot” really worked best for subsonic designs such as the F-86 and MiG 15. As soon as supersonic speed was required, the simple nose intake had to be replaced by a complicated inlet with a movable shock cone to decelerate airflow into the engine to subsonic speed. This could certainly be done, as the successful MiG-21 (still in service) and English Electric Lighting (which was a twin engine plane with a single nose inlet) illustrated.
Still, a moving nose inlet cone was more complicated than a midships inlet, where the supersonic shock wave could be managed by a simple vane in the intake. Further, the nose intake made it harder to adhere to the “area rule” which was discovered to be important in reducing drag in the transonic and supersonic regimes. Finally, the installation of radar in a wide variety of fighter and interceptor aircraft as opposed to a limited number of dedicated “night fighters” meant making the nose available for a radar antenna was important.
Trade-offs in fighter aircraft shift design goals. The F-15 and its peers could hit Mach 2.5 at high altitude, but the F-35 is limited to Mach 1.6 (and the F-22 Mach 2.25). The decision was that low visibility and long range were more important than high dash speed in combat. We’ll have to await results from engagements with peer aircraft to know if they chose wisely.