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Guys,

I'm looking for info on how general purpose bombs (e.g., MK82 & MK84) are fuzed, and how the arming works on the aircraft. When I was doing the design of the Armament Logic Modules for the new CICU in the A-10C, I wasn't too concerned about the actual construction and fuzing of the bombs, just the control signals that I needed to send out to the pylons to effect the proper arming and releases. In the original version of the aircraft, the pilot had an arming switch on the ACP that he used to select safe, nose arm, tail arm, or both nose and tail arm. Selecting tail arm on a HDGP bomb caused the retarding device to activate upon release, whereas not selecting tail arm caused the HDGP bomb to release with the retarding device unactivated. Now that I'm teaching these orientation classes on the A-10 and its weapons, I want to look further into the bombs themselves and exactly how they work.

A drawing that I have shows a cutaway of the GP bombs. It shows a fuze well in the nose and another in the rear of the bomb body. These two wells are connected to a forward charging tube and a rear charging tube, respectively. Both charging tubes are routed to what looks like a connector on top of the bomb. Next to that connector, there appears to be another smaller connector on top. It was my understanding that there is a fuze screwed into the nose fuze well, and another screwed into the rear fuze well. A small propeller-type device would be attached to the nose fuze, and if the bomb was released with nose arm set, an arming wire would pull out of the nose fuze, air would spin the propeller, and this would arm the bomb a safe distance from the aircraft. So, after all of this, my questions are: 1) What do the charging tubes do? 2) If the nose fuze has a propeller device to arm it, what keeps the tail fuze in safe mode until dropped? 3) What is the connector on top used for? I don't remember seeing a corresponding connector on the MAU-40 or MAU-50 pylons that we had in the Systems Integration Lab.

Bob

Wow. You already knwo more about the bombs than any Crew Chief I've ever known. This is definitely a question for a weapons troop or a pilot, although they might answer this one via PM.

The "L" in AMXS stands for "leadership"

http://www.fas.org/man/dod-101/sys/dumb/bombs.htm

About 1/3 the way down the page <img src=icon_smile.gif border=0 align=middle>

_________________
Just give me some ammo, a little water.....and some chips if you got 'em

You live near an AF base? Good way to get this would be to visit load barn or ammo dump. Doesn't matter what plane they have, the fuzes all work the same. Some combinations might not be used on that particular airframe, but likely there'll be someone who worked on a plane that did, and they can explain the release events where the bomb rack leaves off.

One of the things they didn't mention in that article was initiators. Some fuzes are electric, and that well on top of the bomb can hold a small turbine generator. This provides power to the fuze.

Ignorance may be bliss, but it sure ain't fun!

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Evil is evil, no matter how small.

Here's a little bomb info:
With the old mechanical fuzes steel wires were run outside the bomb with one end attached to the lugs and then to the fuzes. Arming loops were threaded on to the wires to attach to selonoids to the nose fuze (M904) and the tail would attach to the ATU-35, think of a wind mill on the side of the bomb, that would attach with a flex drive to the tail fuze (M905). The old Snake-eye and newer BSU-49 (drag chute) tail fin assemblies would also have a wire and loop. There are three selonoids on the MAU 40/50 rack and the loops would be inserted into the proper selonoids to provide options for the pilot. With the electrical fuzes there was a bungie cord on the older ones with a loop on the end and the newer ones have a power cord that gets run in the charging tubes and attaches to small air turbine that is installed in the center well. The turbine has a loop that attaches to the center selonoid. When armed the turbine spins provides juice to the fuze and boom! The charging tubes are just conduit from the nose and tail to the center well. MER/TER racks only have two selonoids so the wiring has to be adjusted and not as many options are available. There are no electrical connections between the bomb and the rack

Guys,

Thanks for taking the time to provide me with this good information.

Bob