Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!att!cbnewsl!sw
From: sw@cbnewsl.ATT.COM (Stuart Warmink)
Newsgroups: sci.space.shuttle
Subject: Re: Info on the SRB Hold-down posts
Summary: some numbers
Message-ID: <3224@cbnewsl.ATT.COM>
Date: 8 Dec 89 16:00:51 GMT
Organization: Interface Systems @ AT&T Bell Labs
Lines: 15

Just a few numbers to give an idea of the size of the explosive nuts used 
in the SRB hold-down posts (from memory from _Pyrotechnics in Industry_):

4 per SRB, each nut is 3.5" internal diameter, has a tensile strength of
over 1,000,000 lbs, and has 2 explosive charges, each with 2 detonators.

The two charges are diametrically opposite to each other in (deliberatly)
weakend parts of the nut. Most of the stress in such a nut in longitudinal, 
not circumferential, hence the ability to deliberately weaken the nut along
its circumference. Only one of the charges has to go off to release the nut;
in practice both charges never fire at exactly the same time anyway.
-- 
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Stuart Warmink, Whippany, NJ, USA  |  sw@cbnewsl.ATT.COM  |  Pretentious? Moi?
-------------------------> My opinions are just that <------------------------