material required maintainers to clean the bombs before transportation or usage. The U.S. Navy refused to use M117 bombs with the Minol II filler citing, "Because of the proximity of crew quarters to the ships’ magazines where explosives are stored and the necessity of handling ordnance on rolling and pitching vessels, the Navy has regarded Minol II as being a potential hazard to the safety of its ships ’ crews and thus has not approved its use aboard ship." M117A1E3 M117A2 M117A3 M117D The M117D (D - Destructor) looks similar to the M117R but uses a magnetic influence fuze, which enables the bomb to function as a mine. The M117D is released in a high-drag configuration for a ground implant or shallow water mining. It detonates when an object passing near the bomb triggers the fuze. M117R The M117R (R - Retarded) uses a special fin assembly providing either high-drag or low-drag release options. For low altitude deliveries, the tail assembly opens four large drag plates which rapidly slow the bomb and allow the aircraft to escape its blast. MC-1 The M117 was the basis of the MC-1 chemical warfare bomb, which had the body cavity filled with sarin nerve gas. The MC-1 was never used by the U.S. in combat and was eliminated from the U.S. stockpile in June, 2006. Tail Assemblies BSU-85/B Air-inflatable retarder BSU-93/B Air-inflatable retarder M131/M131A1 Early low-drag conical tail assembly utilized for high-altitude bomb drops. MAU-91A/B High-drag tail assembly utilized to drastically reduce the free-fall speed of the M117 and when utilized in low-level bombing, allowed fighter aircraft sufficient time to clear the blast area before bomb detonation. M117 bombs utilizing this style tail assembly were designated M117R. MAU-103A/B Low-drag conical tail assembly which began service with the M117 in the 1970s. References Arsenal of Democracy II, Tom Gervasi, Janes Air Launched Weapons Issue 36, External links OAI.DTIC.mil: Finned/Retared BLU-1B/C Version Tested VectorSite.net: Smart Bombs and Dumb DBombs Cold War aerial bombs of the United States Aerial bombs of the United States Military equipment introduced in the 1950s