Re: [PSUBS-MAILIST] gelcoat

[MerlinSub@t-online.de (Carsten Standfuß)]

Hmm, have heard something of a new russian test torpedo called "the big
one" 
with a kerosin / peroxide drive. Was on board "Kursk". Very effective, 
can reduce a 30.000 ts warship in a view seconds to under 15.000 ts... 

Was delivered from the factory with a handbook, page 1 : 
Do not store/use onboard of any russian naval vessel until its wartime 
and all other torpedos are allready fired and war-luck went badly down.. 
  
Maybe simillar thing like walter-peroxide rocketengine torpedo (1944)
called "Mondfish" (G7ur = Rückstoßtorpedo/Rockettorpedo later T XIV). 
But this was a small unit developt for midgets, runs just 50 knots 
for 1200 m with the rocket engine at the stern. 
Test report conclusion was : Some test shoots with "different luck"...

If you build some rocketengines on the forward end of the torpedo - 
like the rescue rockets system on Apollo spacecraft - 
the peroxide/kerosin engine produce a hell amount of CO2 and steam ..
its maybe very fast underwater - but control is maybe another point. 

Carsten

John Pier schrieb:
> 
> The new Russian torpedo, still under development goes 200 miles an hour
> under  the water, yes 200 miles / h
> however it is kind of a rocket more than a torpedo and  to reduce the huge
> drag at this speed , the torpedo releases a "skin" of gas between the water
> and its hull. No sand paper here !!!
> Herve Jaubert
> 
> ----- Original Message -----
> From: Tim Curtis <navark@yahoo.com>
> To: <personal_submersibles@psubs.org>
> Sent: Tuesday, February 27, 2001 11:58 AM
> Subject: [PSUBS-MAILIST] gelcoat
> 
> > The idea behind all of this is to reduce the amount of
> > flow that is touching the surface in question.  Like
> > you said, laminar flow is better for as much of the
> > hull (wing) as possible in terms of drag.  There will
> > almost always be turbulent flow over the majority of
> > the hull though.  These turbulent vortices suck energy
> > from the hull to maintain their motions.  If you were
> > to place micro-grooves along your hull that were
> > matched to 80-90% of the diameter of these turbulent
> > vortices, then you would have a reduction in drag.
> > The reason being, is that the turbulent flow actually
> > touches less of the hull this way - if you picture two
> > triangles, like two mountains next to each other, with
> > a huge sphere/cylinder supported by the two points.
> > The sphere is too large to fall into the valley
> > between the mountains, so it only touches at two
> > points.  If you can get your turbulent flow to only
> > touch at two points instead of dragging completely
> > across the body, you will decrease your drag.  This is
> > probably poorly worded, and I apologize.  It is much
> > easier to describe with diagrams.
> >
> >    -Tim
> >
> >
> >
> >
> >  I seldom post anything but often take a look in to
> > see what is going
> > on.  Now I am truly puzzled.  First, I am not a fluids
> > engineer, but I do
> > know some facts about aerodynamics from years of
> > studying airplanes.  I
> > think you fellows are talking about turbulent boundary
> > layer.  As air flows
> > over an airplane wing the velocity of the air
> > approaches zero as it comes
> > in contact with the wing itself.  In an airplane an
> > undisturbed boundary
> > layer is very important.  This creates laminar flow
> > down to the wings
> > surface and greatly reduces drag.  One reason that the
> > P-51 in WWII was so
> > fast was that they could maintain this laminar flow
> > well past a third of
> > the wings cord.  The British gained advantage with
> > this effect also until
> > they started painting their Spitfires with a rough
> > dull finish camouflage
> > paint which disturbed the laminar flow and caused
> > greatly increased
> > drag.  Everything I have studied suggests that you
> > want to minimize
> > turbulent boundary layer flow to reduce drag.  I have
> > no doubt that putting
> > something like course sandpaper on the hull of a sub
> > would be a massive
> > mistake.
> >      Perhaps there is some finish that promotes a type
> > of turbulent flow
> > that is benificial but before anyone goes for the
> > rough look I think you
> > need to research this extensively.
> >
> > G, Boucher
> >
> >
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