[PSUBS-MAILIST] model testing

[hank pronk via Personal_Submersibles]

I am not looking for drag comparisons, I am looking for failure due to pressure comparisons.  I though I read that the Nekton subs were built as a model first to establish crush depth.
Hank --------------------------------------------
On Mon, 12/29/14, Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Subject: Re: [PSUBS-MAILIST] model testing
 To: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
 Received: Monday, December 29, 2014, 3:06 PM
 
 Drag
 results between a model and full scale does not scale
 geometrically.  You have to scale model and full scale off
 the dimensionless  Reynolds number.   Reynolds number
 scaling enables you to scale results between model and full
 scale using either a water tunnel or air
 tunnel.
 Cliff
 
  
 
         From: Alan James via
 Personal_Submersibles
 <personal_submersibles at psubs.org>
 
 To: Personal
 Submersibles General Discussion
 <personal_submersibles at psubs.org> 
 
 Sent: Monday,
 December 29, 2014 1:55 PM
  Subject: Re:
 [PSUBS-MAILIST] model testing
  
  
 Hank,I just ran
 a test on my pressure program & you get the same crush
 depthon a
 sphere of A516-70 steel that is 1000mm diameter & 10mm
 thick as youdo on a
 sphere 100mm diameter & 1mm thick.What I am
 not sure of is if you can scale up the drag results on a
 model.If you
 have a scale model that is 1/50th & it takes X amount of
 force to push
  it at 3
 knots, can you multiply X by 50 to get the required
 thrust?Alan
   
 
   
    From: Brian Cox via
 Personal_Submersibles
 <personal_submersibles at psubs.org>
 
 To: Personal
 Submersibles General Discussion
 <personal_submersibles at psubs.org> 
 
 Sent: Tuesday,
 December 30, 2014 8:43 AM
  Subject: Re:
 [PSUBS-MAILIST] model testing
  
  
 Hank,
       I would say
 no.  It would have to be so exact that it would be
 virtually impossible to extrapolate from the small model,
 and
  aside from that I think there are other engineering
 principles involved that would come into play , Sean would
 be the person to ask !   I know that it is done in wave
 tanks and wind tunnels, but in those you are looking at
 laminar flow and such things, not structural strength so
 much.  You might be able to get a rough idea of how it
 would start to collapse maybe.  The larger the model the
 better I would think.
 
 Brian
 
 --- personal_submersibles at psubs.org
 wrote:
 
 From: hank pronk via
 Personal_Submersibles <personal_submersibles at psubs.org>
 To: personal_submersibles at psubs.org
 Subject: [PSUBS-MAILIST] model testing
 Date: Mon, 29 Dec 2014 10:52:46 -0800
 
 Hi all
 If you
 make a scale model of a submarine in complete detail. 
 Scale the size and metal thickness, is it a reasonable
 representation of depth capabilities when pressure
 tested?
 Hank
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