the_wingman
Frequent Poster
Posts: 49
From:
Registered: JAN 2001
posted 07-19-2001 12:39 PM
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"The power of an explosive cubes itself with every ounce. (9 Ounces is 729 times as powerful as one ounce.)":
This is an extract from "The Book of Terror". I know it is full of crap but nevertheless it's often the first source of information for newbies.
I'm wondering if the statement on the top is true. If yes, is it only valid for LE or for both, LE and HE?



the freshmaker
Frequent Poster
Posts: 175
From: Heaven
Registered: DEC 2000
posted 07-19-2001 04:41 PM
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yeah I have also heard this statement before. I think it was written in a text about flashpowder. Generally you cannot trust any information from these crapbooks since they are full a shit. How the flashpowder should be in cube form I cannot see. Though it is true that the explosive force of flash is multiplying when you use more powder, but not half as much as you mentioned.



Anthony
Moderator
Posts: 2383
From: England
Registered: SEP 2000
posted 07-19-2001 07:32 PM
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I beleive it is said to square rather than cube.
I don't see how though because each molecule of the constituents of the flash should release the same amount of gas and heat regardless of total quantity.

From explosive loading tables I've seen, such as blasting tree stumps/ice you use so many pounds per inch on a fairly linear scale. Rather than "1ft ice - 5 pounds, 729ft - 45pounds" as your cubing scale would reckon.



SATANIC
Frequent Poster
Posts: 240
From: australia
Registered: SEP 2000
posted 07-20-2001 03:27 AM
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i know this isn't the same thing, but why do they say max. det velocity can be obtanied by pressing an explosive into a cube / block? they do this with the army det blocks, how does it improve performance, or is it just ease of handling?
(i know the pressing helps, it's just the shape that mystifies me)



cutefix
Frequent Poster
Posts: 330
From: california
Registered: MAY 2001
posted 07-20-2001 04:12 AM
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Detonation blocks are rectangular in shape,and I think was made that way for easier packaging during the manufacturing process.Besides it easier to transport or carry ,convenient to handle or use and you can have more units in your pack because of easier arrangement than an irregular shaped explosive..It can be molded into desired shape in order to fit the structure of the material to be demolished.Kneading in order to get the desired form will affect its density and slightly lessen its VOD

I believe what the comment means is that if you assemble your explosive into the smallest volume, the detonation wave has the least distance to travel to reach all of it. You would need to put the primer in the center. Actually a sphere would be the most compact form, but a cube will be very close to it.

The thing to avoid is to string your explosive out in a long column, as in blasting rock or coal for example. There the detonation wave usually has to travel from one end of the colummn to the opposite end to get it all converted. The difference is not great, but when going for max, shape matters.

I also believe the shape of cube was chosen first to have an easily packaged shape, which would contain a cetain (1/4 pound) of explosive so users could quickly get the right weight for the job the handbook told them to use. The cube form or rectangular form (i.e. WW2 nitrostarch was in brick shape)can be compactly packed in cardboard or wood shipping containers without wasting space, which is expensive in military shipments.

you guys misread the question. he meant cube as in to the third power(ie; 1^3) not the shape

We can not measure the power of explosive that way!
it may me measured by the formula
P=E/t in MJ/s
So, the power will depend also from the charge geometry.