Based on these test results, researchers replaced the binder system utilized in AFX-794 with the binder system developed for MNX-195, subsequently arriving at a new formulation— MNX-795—for use in the MK-84. They demonstrated the merits of MNX-795 in a series of small-scale, unvented FCO tests. On a scale of 1-10, with R-1 representing the mildest reaction (i.e., burn) and R-10 representing the most violent of reactions (i.e., detonation), MNX-795 demonstrated a mild deflagration reaction (i.e., R-3), whereas AFX-794 produced a severe explosion (i.e., R-8). Further, the MNX-795 formulation exhibited other desirable characteristics, such as decreased end-of-mix viscosity, shorter mix times (due to the addition of the surfactant), and a smaller change in volume upon solidification. The smaller volume change results in an end product with less surface cracking and more consistent density.

Based on these promising preliminary results, the research team next focused its efforts on the tasks required both to obtain full scale-up approval and interim hazard classification for MNX-795 and to schedule production loading trials at the designated Army ammunition plant (AAP). After receiving the appropriate approvals, AFRL researchers provided the support necessary to address the AAP’s processing issues and verify its quality assurance practices. AAP personnel loaded six MK-84s (see figure) and subsequently reported equivalent or improved load quality as compared to bombs loaded with AFX-794. Furthermore, the AAP accomplished the loading procedure without altering its production processes or decreasing current throughput.

These efforts culminated in two fullscale FCO tests of MNX-795-loaded MK- 84s, successfully meeting program requirements and enabling the $27 million program to proceed to weapons qualification testing. Current engineering assessments predict that MNX- 795-loaded MK-84s will pass the four remaining IM tests, meet all program goals, and provide the much safer explosive fill required to meet future MK-84 production requirements.

Mr. John A. Cominiello and Dr. Thomas R. Krawietz, of the Air Force Research Laboratory’s Munitions Directorate, wrote this article. For more information, contact TECH CONNECT at (800) 203-6451 or place a request at http://www.afrl.af.mil/techconn_index.asp. Reference document MN-H-05-13.