Propellant Residues Deposition from Firing of AT4 Rockets

摘要

Military live-fire training missions utilize a variety of energetic materials that are never completely consumed during firing. In March 2009, tests were conducted at Fort Richardson, Alaska, to determine the residues related to the firing of AT4 anti-armor shoulder-fired rockets. Six rockets were fired from the same firing position on the snow-covered range. Replicate multi-increment samples were collected from the snow surface behind and downrange of the firing point in each of eight decision units. Samples were analyzed and results composited to derive an estimate of the mass of unreacted energetics. Total estimated per-round deposition rate of nitroglycerin (NG) for the M136 AT4 rocket is 95 g/round, or 73% of the original NG load. This indicates that the propellant burn efficiency for the AT4 is poor, with much propellant not consumed during firing. In subsequent May 2009 samples, we found approximately one-third of the NG had leached out of the propellant fragments since March. Large propellant strip segments collected in May contained 67% of the nominal NG of the original propellant, and we hypothesize that even more had leached from the more numerous, smaller segments. Canadian tests of the similar Carl Gustav rocket also indicate high rates (> 14%) of unburned propellants.