Ac. Charters, THE EARLY YEARS OF AERODYNAMICS RANGES, LIGHT-GAS GUNS, AND HIGH-VELOCITY IMPACT, International journal of impact engineering, 17(1-3), 1995, pp. 151-182
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 the
ory nor experiment were available at this time for the science of supe
rsonic flight. The approach being taken then was to record the flight
of the body and to compute the forces from its motions, but, unfortuna
tely, unsolved problems in instrumentation stood in the way. The autho
r was assigned the task of solving these problems at the Army's Ballis
tic 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 aerodyn
amic forces. World War II had started by this time, and the Aerodynami
cs Range was put to work immediately measuring the aerodynamic charact
eristics of gun-fired projectiles, bombs, rockets and some guided miss
iles. The ''cold'' war started right after the ''hot'' war and with it
came a new challenge in the form of the InterContinental Ballistic Mi
ssile armed with an atomic explosive warhead. Aerodynamic Ranges, whic
h had been built in various laboratories by this time, were put to wor
k 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 mete
orite impact on the lunar surface. Implementing these new programs req
uired a gun capable of launching projectiles at the re-entry and meteo
roid 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 t
he propellant of its second stage. The author and others continued wit
h its development until a design had been evolved capable of firing pr
ojectiles at the required velocities. The gun was then put to work in
Aerodynamic Ranges on the assigned tasks of kinetic energy weapon leth
ality and meteoroid impact. The Early Years paper is an account of the
trials and errors in the initial developments of Aerodynamic Ranges a
nd High-Velocity Light Guns and the beginnings of research in high-vel
ocity impact. It is not a formal research paper. Rather, it is an anec
dotal account of the events taking place at the starts of these new pr
ograms 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 Kipl
ing's verse: ''To meet with Triumph and Disaster and treat these two I
mpostors just alike''.