Re: New ideas

["chuck morlan" <cmorlan@hotmail.com>]

>Date: Wed, 24 Feb 1999 10:50:20 -0700 (MST)
>From: John Brownlee <jonnie@chronic.lpl.arizona.edu>
>To: personal_submersibles@psubs.org
>Subject: Re: New ideas
>Reply-To: personal_submersibles@psubs.org
>
>	I just finished reading in the book 'Hydrodynamically Loaded
>Structures' which describes an interesting hull design. The whole hull
>looks like it's accordion folded, with hemi-heads on each end. Turns 
out
>in testing that it's actually comparable in strength to a comparable
>cyllinder IF MADE WITHIN TIGHT TOLERANCES. That's an important 
disclaimer,
>remember that different geometries tolerate (or in most cases don't
>tolerate) deviations from perfect volumes of revolution in very 
different
>ways. The cross-section of the "cyllindrical" wall looks like this: 
>
>
>	/~~\      /~~\
>       / /\ \    / /\ \
>      / /  \ \  / /  \ \
>	    \ \/ /    \ \
>	     \__/      \ \
>
>	I mean, the damned thing looks like it would fold up along the
>revolution axis like a piece of collapsible Tupperware! But, all the
>finite element models and pressure tests showed that it held up if it's
>made exactly right. Bizarre-O. 
>	Now, to read most of your minds and answer your concerns, this is
>not necessarily a great idea, what it is supposed to illustrate is that
>sometimes math and physics join together to confound common sense in
>engineering. However, and this is the REAL point, unless you have 
amazing
>manufacturing skills, your common sense should always over-ride such
>counter-intuitive ideas. Often such elegant and beautiful 
juxtapositions
>of opposing forces (such as the accordion fold hull above) are 
intolerant
>of imperfections which real-world structures are going to have. 
>	So unorthodox ideas need to always be approached with caution,
>because chances are someone else already had them and didn't do it for 
a
>good reason. That's a long way to come to get that out. Sheesh! 
>
>	Back to wood, it's been done before rather sucessfully. That means
>that it is possible to create a viewport that handles the cycling fine. 
In
>fact, if I remember my reading right, there's a lot of good qualities
>attributed to plywood, ease of manufacture not the least among them. 
Just
>be prepared to have to re-create in wood the solutions people with 
steel
>subs had solved for them in the 50's, like viewports and penetrations.


if you use fible glass over every surfase of the wood then you can solve 
tese problem in all mose the same ways ie ports i am cuting a hole the 
exact size of the ports lense then buying pipe to fit in the hole using 
flat ruber presure gasket on both sides of the port lense and the pipe 
that iv'e welded a flang to sanwiching it in place (this is a por verble 
dicription but if tyou want e-mail me and i'll send you a drawing 
cmorlan@hotmail.com 

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