I spy!

[NavyICman]

USS Pittsburgh was the test bed for the PJ design. I worked with a gentleman at my last command who was there when it was installed. He is currently a retired CPO working as a Govt Contractor. He said that the design while very sound was not a good fit on the ship and they had many problems. other boats who did testing for things (most out of DEVRON 12): USS Augusta - First WAA Array, ARCI Sonar/Fire control, Thinline arrays, USS Memphis - DiHedral stabilizers and external countermeasures, and a host of other things that shall not be named, USS Cheyenne - Seawolf Propulsion Plant, USS Phoenix and several others - NHP Photonics masts, USS Boise - Increased torque shaft line and thrust bearings. Some of these I was stationed on, some I know people from.

Tim

[He Who Shall Not Be Named]

That's right, is was one of the DevGroups out of New London. One or two boats had not only the propulsor, but some of the engineering plant elements designed for the SEAWOLF class.

David,

[greenman407]

Great pictures Dave!! I think that it was one of the 688I that did some testing on that.

[spankey]

In the same vein, Does anyone know what (US) submarine they tried this ducting on before they actually employed it on the Seawolf boats? Like most things, it seems like this stuff was probably tested on boats before it was employed on a new build boat.....Unless the Brit's were kind enough to give us a bunch of data on their stuff..?

[spankey]

Right, because the duct, along with the stator is taking all the tip vortecies (wasted energy that normally would be spinning/swirling radially off of the blades) and shoving it backward...

[He Who Shall Not Be Named]

More than that: the stator translates swirl flow to axial flow resulting in more thrust than if there were no stator involved. It's the stator(s) that differentiates a pump-jet from a ducted (Kort) nozzle propulsor.

David

[spankey]

Ok, so its the stators that are imparting the counter-torque to compensate for the rotor torque roll. Good to know. I always wondered if there was a single or double rotor.

[He Who Shall Not Be Named]

Under that shroud is a single rotor, and behind that, a single stator.



David,

[spankey]

I suspect that underneath that duct/shroud is a pair of contra props.... Or another means to keep that device from torque rolling all the way to target.

...Late post...

[He Who Shall Not Be Named]

Spencer Tracy

[greenman407]

I SPY A CELEBRITY. Who is the famous man coming up out of this submarine? Heres a hint. His initials are ST

[He Who Shall Not Be Named]

Counter rotating propellers and a properly designed pump-jet do the same thing:

They both recover swirl energy and impart zero net torque onto the vehicle.

David,

[greenman407]

Thats interesting. Most other Torps that I have seen are contra props

[He Who Shall Not Be Named]

The MK 48 pump-jet has changed little since the early 60's.

David

[greenman407]

I SPY SOMETHING COOL! I think that this is a Mk. 48 Adcap but it looks to have a ducted fan type propullsor. Can anyone comment on this?