Acoustical analysis of an indoor test facility for aircraft Gatling guns

An indoor test facility for 20-mm and 30-mm aircraft Gatling guns was recently constructed at Hill Air Force Base in Layton, UT. In designing the range, the primary concerns were that the 30-mm gun muzzle blast overpressures were large enough to a) cause significant spallation of the concrete walls during the anticipated 20-year building usage, and b) potentially pose an auditory risk for personnel working elsewhere in the test range building. This project consisted of three phases. First, levels, directivity, and geometric spreading of the 30-mm gun blast were characterized in outdoor measurements. Second, range impulse response estimates generated by a commercial room acoustics package were used to discover potential problem areas within the range and explore the effectiveness of treatments. Finally, data were collected on gun blasts in the completed range to confirm that the test facility meets all acoustical and occupational safety requirements.