Combustion Mechanisms of 25MM Combustible Cartridge.
Final rept. 3 May 72-31 May 73,
IIT RESEARCH INST CHICAGO IL
Pagination or Media Count:
The structural features of 25mm combustible cartridge cases, manufactured for this program and having nitrocelluloseresinfiber ratios of 85105, 80155, 75205 and 751015, were characterized through permeability measurements, respectively, about 100, 20, 6, and 3 millidarcies. Their unique features include an extremely high internal surface area and negligible web thickness. Over 100 experiments were conducted in a 25mm vented bomb to evaluate the effects of a igniter level effects 0 to 50 grain black powder, b charge size for all formulations 1- to 4-inch sections, c permeability 1 to 200 md, and d relative humidity moisture 0 to 95 on values of induction time and maximum rates of pressure increase. Permeability appears to be a primary factor in determining induction times. Rates of pressure rise approached 1000 kpsimsec for some cases, intolerable for gun applications. Attemps to develop a combustion mechanism could not be pursued in depth because of program limitations. A burning mechanism to describe and optimize all interrelated effects is complex. Specific recommendations are outlined, utilizing the available data that have not yet been fully analyzed during the course of this study. Author
- Ammunition and Explosives