Re: [PSUBS-MAILIST] Twin screw vs single screw

[MerlinSub@t-online.de]

Make a single screw design but with two counter rotating props. 
Like a torpedo or a japanes A-class midget sub. 

Than apply each props to an undepedable engine or power source. 

Or better make two gears that way that engine one feed prop 1 or/and prop 2
and engine/drive 2 can do the same. 

That way you have the high efficency drive and two undepedable drive trains. 

Funny obviously nobody ever did this.. 

vbr Carsten


"Marc de Piolenc" <piolenc@archivale.com> schrieb:
> A single, central screw is definitely going to win the efficiency 
> contest; a single screw centered in an (almost) axially symmetrical wake 
> will have much higher propulsive efficiency than any other configuration 
> - see "wake-adapted propeller" or "wake-immersed propeller."
> I was wondering only about operational considerations, as touched on by 
> another poster. Things like redudancy, being able to maneuver in tight 
> places by going ahead on one shaft and astern on the other, etc.
> 
> Best,
> Marc
> 
> Archivale catalog: http://www.archivale.com/catalog
> Polymath weblog: http://www.archivale.com/weblog
> Translation services: http://www.proz.com/profile/639380
> Ducted fans: http://massflow.archivale.com/
> 
> On 9/26/2010 7:46 PM, JimToddPsub@aol.com wrote:
> > Marc,
> > During the development of the USS Albacore in the 50s (not to be
> > confused with the WWII sub of the same name), they did extensive
> > hydrodynamic and wind tunnel including twin-screw vs single screw
> > design. Single screw was the winner and became the standard ever after.
> > The Albacore was primarily a test bed and was most noted for being the
> > first with the tear drop shaped hull which also became the standard. The
> > Albacore is now a museum near Jon's stomping grounds in Portsmouth, New
> > Hampshire.
> > The only subsequent military sub I'm aware of with twin screws is the
> > Soviet Typhoon class, but that sucker has twin parallel main pressure
> > hulls as well and a beam of 75 feet!
> > Jim T
> > In a message dated 9/25/2010 10:52:34 P.M. Central Daylight Time,
> > piolenc@archivale.com writes:
> >
> >     Interesting. I wonder if subsequent operational experience confirmed
> >     Kittredge and company in their condemnation of single screws, or not.
> >
> >     Marc
> 
> 
> 
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