Seawolf Class Propeller

[libord]

Hello,

I'm currently building a USS Jimmy Carter RC model as a conversion from a USS Seawolf plastic kit.

The set includes a kind-of propeller, which of course has to be replaced by steel thing. What bothers me is, that the included propeller has 12 blades, which is unlikely truth - no modern submarine has even number of blades, as they are much noisier than propellers with odd number of blades, particullarly with prime-numbers of blades (like 3, 5, 7, 13). I guess that USS Jimmy Carter has 7 or 13 blades, but couldn't find a single line of text (or photo) which would confirm this.
Do you know anything about it?

Regards,

Libor

[aeroengineer1]

Not too sure that you

Not too sure that you will find such a pic laying around, though if you so, I would love to see it. I can only find on pic that even shows the pj shrouded, and that pic is not the greatest resolution. Nonetheless, David Merriman has a nce conversion kit for the Trumpeter Seawolf. You can contact him through his website http://www.vabiz.com/d&e. I am not too sure that it is listed on his site, but the contact information is there. I believe, whithout looking it up his email is dmeriman@aol.com. Hope this helps.

Adam

[libord]

Hello Adam,

Not too sure that

Hello Adam,

Not too sure that you will find such a pic laying around...

Yes, you're right and I know this kind of information is classified. I'm not going to reproduce the Seawolf's screw, just want to know at least how many blades it has, as the 12 blades are a bug in my head, since I know it's wrong... . On the submarines with no ring around the screw, you can often get a photo of the propeller covered by a black plastic sheet, so you can stil count bumps and get the number of blades. That is not possible with Seawolf, but still, I doubt the number of blades is a big deal (i.e. top secret info) and sombody has to know it

Nonetheless, David Merriman has a nce conversion kit for the Trumpeter Seawolf. You can contact him through his website http://www.vabiz.com/d&e. I am not too sure that it is listed on his site, but the contact information is there. I believe, whithout looking it up his email is dmeriman@aol.com. Hope this helps.

I have already most of parts for the conversion, thanks anyway, will have a look to get some inspiration. Apart from that, he has conversion kit for the USS Seawolf and possibly USS Connecticut, but it wouldn't work for the USS Jimmy Carter, as this boat is different. It has 21cm (model) extra section - that means I have to cut the hull and insert piece of hull and relocated middle side sonar domes to match position on the Carter's hull... The conversion kit (without major changes) wouldn't fit due to buoancy issues and some minor problems (i.e. linkages).

Regards,

[bcliffe]

Libor,

You may want to review

Libor,

You may want to review "Building Masters for a 1/48 Seawolf Pump-Jet" at
http://vabiz.com/d&e/articles.html ...

Since Dave built that I think some new info may have surfaced ... you may want to search the subpirates site on this ...

Cheers
BC

[aeroengineer1]

All of David's conversion kit

All of David's conversion kit would work for your boat, you would just need to add the plug section and move the array. Also one thing to be aware of if you are looking to go for absolute scale is that the Trumpeter model is the wrong hull diameter by an 1/8".

Adam

[pirate]

Libor,
Latest info I have is

Libor,
Latest info I have is that Seawolf has 6 blade propulsor.

I also have a photo of the newer Virginia Class being built. It shows 3 blade exposed, but you can easily see by the spacing that only another three could fit around the hub, so it too looks like 6.

So much for your odd blade theory. A differnece here may be the quieting that the shroud provides, and that the six blades are more efficient than the seven, so they went with that.

Pete

[libord]

SSN-23 propeller

Thank you all for your replies!

Latest info I have is that Seawolf has 6 blade propulsor.

You're right, that with the shroud the theory gets much more complex and it is possible that 6 blades are not as big problem as if the screw is standalone. Although, I still have a bit of doubts. 7 blades seems to be still a more probable solution, as the interference of the noise from the propeller is much much less probable. A there could be a little difference between efficiency of the 6 blade and 7 blade screw, but there is a huge difference in noise radiation between them. 5 and 7 (11 and 13 and generally all prime numbered) blade screws suppose to be the most quiet (considering the it's size, type, finish,... are simillar) and that is one of the most important requirements.
Anyway, Pirate, where your info come from? I'd like to study it a bit in detail...

...David's conversion kit would work for your boat...

Thank a lot for your link and your point, I'll study it in detail. However, one of the point in building this model is, that I want to improve my model-making skills, because this is my first RC model. I did few static models and I was writing articles about RC submarines, but this is only my 2nd model (and first which will be finished), so I really want to do it by myself, so I can learn a lot. Besides, if I want a clean job, I could ask my friend to do the sub for me, he's excellent modeler (check out www.rcsubs.sub-club.org )!

Regards,

[libord]

Colors

Two OT questions:

Pete, BTW isn't the flag you have as your avatar a flag of polish Navy? Looks like Selezian Eagle with Polish flag at the background. Forgive me my humble knowledge...

"BC", your freind painted his Seawolf with 3 colours - black upper third of the hull and red bottom. Do you know why? I have photos of the Jimmy Carter (and I believe Seawolf as well) from US Navy's web site just before she was launched and she's all black...

Regards,

[aeroengineer1]

Hey no problem on David's

Hey no problem on David's conversion kit. It might be good material to study from. Also Deap sea designs have a pretty good set of plans for the SSN 21 which might be of some use.

As for the colors, I have not looked into this too much. Though I do know that one has to be careful of which dry dock pics to use. Many of the ones that I have seen are without the anecho tiles added. I have seen a few with them in place, and many not in place.

Adam

[libord]

Hello Adam!

Hey no problem on

Hello Adam!

Hey no problem on David's conversion kit. It might be good material to study from. Also Deap sea designs have a pretty good set of plans for the SSN 21 which might be of some use.

It certainly is a good material to study from! Good job

As for the colors, I have not looked into this too much. Though I do know that one has to be careful of which dry dock pics to use. Many of the ones that I have seen are without the anecho tiles added. I have seen a few with them in place, and many not in place.

That is an interesting point which one should take into consideration. IMHO it supports my theory that the hull is black.

• * I think the only reason to use red color is that it's very cheap and yet quality anti-corrosion paint. You would use it on the steel, not on the absorbing tiles.
  * I suppose that the tiles are being fitted before the sub is launched, so a pics of a sub ready to be launched should show proper finish
  * I think early GM EB pictures from workshop shows parts of their submarines red, while the late pictures shows subs all in black. I will have to go through my archive again, just to be sure.

[/i]

[pirate]

Libor,
You are right, it's the

Libor,
You are right, it's the Polish Eagle on the current Polish flag. I don't know if it's the Polish Navy flag or not, unless that's a joke, but I'm Polish so I wouldn't know. Do they have a Navy?

The Seawolf started out with antifoul brown on the bottom half. After that, the Navy decided to make all the boats following that all black. So the Connecticut and Jimmy Carter are all black. And all of the Virginia Class boats are all black too.

Here is Vigrinia propulsor—6 blades.

[libord]

I'm Polish so I wouldn't

I'm Polish so I wouldn't know. Do they have a Navy?

I'm a bit confused whether you are Polish or not, but I guess it's a joke and you know a lot about their navy

Here is Vigrinia propulsor—6 blades.

Well, I looked few times at the picture and I'm not confident about 6 blades! It certainly has 6 or 7 blades, but it's difficult to say and I tend to think it has 7 blades. The visible "opposite" blades seems to be not perfectly in opposite position.
It is possible to analysis pictures (even isometric and 3D) and retrieve information from them, i.e. approximate dimensions. You have to load them into CAD program and then you use lines to connect certain [known] points. It's not a strong part of my engineering skills but I have done that few times before. I'll try to do it at work tomorrow... I should be able to get an approx. angle between very well visible top blades. I should be also able to find two "opposite" points on the blades and connect them and see if they're intersecting the center. However, this could be difficult, as due to the gravity the cover takes different shape at different places, effectively hiding the shape of the blades.

Your information is very helpful, thanks a lot!

[anonymous]

Looks like 7 to me...
As

Looks like 7 to me...
As I mentioned before (in another site...) it's a deceptive angle...

Oh... And the two classes have different setups....

[libord]

No propeller on Seawolf and Virginia?? :-D

http://americanhistory.si.edu/subs/a.../taming2.html#]Of course, balancing all of these factors results in a compromise, and our newest generation of submarines, the Seawolf-class, does not even use propellers. Neither will the future generation, the Virginia-class, still on the computer design screen. Other options offer fewer disadvantages.[/quote]

Well, well, I wonder what this supposed to mean . I thought there is still a screw between the two sets of fixed radial planes...

[pirate]

They call them propulsors in

They call them propulsors in this shroud settup.

Figuring this is not that difficult, but believe what you want.




Pete