The early years of aerodynamics ranges, light-gas guns, and high-velocity impact

Abstract

The age of supersonic flight began at the end of the 19th century when the inventions of smokeless powder and high strength steel enabled an increase in gun velocities to supersonic speeds. However, neither theory nor experiment were available at this time for the science of supersonic flight. The approach being taken then was to record the flight of the body and to compute the forces from its motions, but, unfortunately, unsolved problems in instrumentation stood in the way. The author was assigned the task of solving these problems at the Army's Ballistic Research Laboratories in 1940. His success in this endeavor led to the development of an apparatus, called an “Aerodynamic Range”, for recording the projectile's flight and, hence, determining the aerodynamic forces. World War II had started by this time, and the Aerodynamics Range was put to work immediately measuring the aerodynamic characteristics of gun-fired projectiles, bombs, rockets and some guided missiles. The “cold” war started right after the “hot” war and with it came a new challenge in the form of the InterContinental Ballistic Missile armed with an atomic explosive warhead. Aerodynamic Ranges, which had been built in various laboratories by this time, were put to work on impact tests to determine the lethality of kinetic energy weapons in countering the ICBM threat. In addition, the moon landing program had been started and tests were needed to evaluate the effects of meteorite impact on the lunar surface. Implementing these new programs required a gun capable of launching projectiles at the re-entry and meteoroid velocities of 8 to 10 km/s. The development of a new design of a two-stage high-velocity gun had been started at the Colorado School of Mines, a gun called a “light gas gun” because it used hydrogen as the propellant of its second stage. The author and others continued with its development until a design had been evolved capable of firing projectiles at the required velocities. The gun was then put to work in Aerodynamic Ranges on the assigned tasks of kinetic energy weapon lethality and meteoroid impact.The Early Years paper is an account of the trials and errors in the initial developments of Aerodynamic Ranges and High-Velocity Light Guns and the beginnings of research in high-velocity impact. It is not a formal research paper. Rather, it is an anecdotal account of the events taking place at the starts of these new programs to give the reader a feeling for the ambiance of the times with just enough technology thrown in for credibility. In a sense, telling about the successes and failures of The Early Years belongs with Kipling's verse: “To meet with Triurnph and Disaster and treat these two Impostors just alike”.