Why don't dieseal subs use pumpjets propulsors

[LoBlo]

Whether its a simple shrouded propulsor or a pumpjet depends on the presence or absence of stator blades pre or post rotor iirc. Everything I've read says that the VA is using a pumpjet.

[Kapitan]

Well for an experianced researcher i will tell you this:

DO NOT BELIEVE EVERYTHING YOU READ ABOUT A NEW PLATFORM !

It took NATO a good 10 years to work out the tonnage of the typhoon alone, no navy in its right mind will give you the full specs of a new submarine or one in active duty, theres alot i do know about the russian submarines i cant post it here just like the people who work on the USN RN or any other navy cant.


This is a shrouded propellor (Typhoon class SSBN TK20 Severstal) this is what the virginia has but what she has is way more advanced, infact about 2 generations ahead.

Alrosa is one of a kind kilo SSK, but i can tell you the pictures of this lada class (st petersburg)

No matter how hard i try i can only come to say this submarine will not go to sea with this propellor period just look at it seriously why would the russians go 2 steps forward and then take 5 back?


This is the old style con (centeral command post (CCP)) normaly found in compartment 4 unless your a phoon its compartment 14, this is what a kilo looks like inside since this the russians are using waterfall displays in all new builds and when subs come in for refit and overhaul they will be changed if its financialy worth it.

Again why take 2 steps forwars 5 back

[LoBlo]

The difference between a shrouded propellar like shown on the Typhoon and a pumpjet is that on that typhoon their are no stator blades providing preswirl to the inlet flow or postswirl cancellation to the outlet flow that would increase propulsive efficiency. To tell if a pumpjet is present on the VA or SW one would need to look at the inlet or outlet in order to discern the presence/abscene of stator blades.

[Kapitan]

do not forget the oldest typhoon is now what 28 years old and this type of propulsion system wasnt around back then, the reason for the shroud on the typhoon is realy only to protect the propellor.

[XabbaRus]

Kapitan the Virginia dose have apumpjet like the Seawolf adn like the S-Boats T-boats. Who do you think designed the pump jet for the seawolf.

I can't say where I got the info but I have a detailed set of pictures showing the stern arrangement of the Seawolf and on good merit was told the Virginia has a very similar system, just the number of stator blades is less.

Pumpjets also don't have scythe shaped blades but rather constant chord profiled blades.

[Kapitan]

Who do i think designed them, no doubt us brits who then sold it on to the americans, and as for the SSN-21's having same similar propulsion system that would make sence.

[Linton]

Trial boat in the Rn was a C-boat back in the 1970s.[img]http://imagen.britishpathe.com/scrip...00000010&sif=1[/img]
Possible early installation??

[LoBlo]

I've always envisioned the SW outlet to look something like this...

http://en.wikipedia.org/wiki/Image:Propulsor_MK50.jpg

but scaled up to the SW diameters.

[Linton]

Can you back a submarine using a pump-jet or do you need some other propulsion device?

[LoBlo]

From what I understand you can go backwards, but the total amount of reverse thrust is much less than a normal prop. Something abou the stators that while increasing efficiency forward, decrease efficiency in reverse iirc

[Linton]

I didn't think that a pump-jet would be very efficient at going in reverse.I imagine it would probably cavitate more as well due to the flow being reversed through the stators.