1/144 Jorge Juan (ex USS McGowan)

[Willie]

Howdy, Tom, Kometa and all,

Glad to know you like the progress.

To advance this area I have devoted this week to the shafts and props, something always very interesting to build.

This is what has to be done :

Again one of the two pics that I have of Jorge Juan has helped me lots, as it shows several elements that confirm the previous pics :

Revell�s offer is not correct at all, both in thickness of the shafts, profile of the struts and some other minor details.

I considered improving all these elements, but after some attempts to thin the profile of the struts I dropped the job completely, as it would take longer and would not be better than making everything from scratch, that is what I eventually did.

On the other hand the props are quite nice in shape and specially in the profile of the blades, but sadly the middle section also had three deep cuts just between the blades due to the molding process. Anyhow, as I am not very willing to spends lots of money in aftermarket stuff I had a go with them, and after some (well, much) filing and sanding, I think I can consider them acceptable for service.

Over to the next post.[/size]

[Willie]

After this I made the two shafts, the six brackets and the six struts.

As all Evergreen tubing profiles are telescopic to each other, the shafts and brackets were no problem at all.

The struts were made with 1,00x6.3 mm. Evergreen stripe, so that they are identical in width and thickness. The longer ones were very easy to make and handle, but very difficult to refine, as they are placed at four different angles each, to undo the curves and profile of the hull, keeping the shafts at the correct angle and parallel to each other, which is the real problem, and, on top of it, everything had to be done with a dry fit for the most part. Really a pain.

The smaller struts have only two angles, and were easier to place, but much more difficult to make, because it is necessary to handle them with the very tips of the fingers to be able to apply the sandpaper properly at the right angles. I think that more or less I have them, and the thing is solid to allow further work in the hull, consistent with the pictures, and keeping the shafts absolutely parallel.

As a last touch, I also added the zinc anodes, an easy element that adds a very beautiful detail to a section of the hull that would be otherwise quite bare.

And the final product in its real position:

the macro pictures shows some minor details that have to be refined, but this section is coming out quite nicely.

I hope you like it, and very bets regards,

Willie.[/size]

[Fliger747]

Very nice Willie! I noticed one unusual feature in your dry dock photos, the aft nominally vertical strut has a curve at the bottom to intersect the shaft bearing at right angles. Just curious as I haven't examined the Fletcher appropriate drawings, are the shafts indeed parallel? Sometimes for whatever marine engineering reasons, shafts will be at a horizontal angle to the centerline. In Battleships this can be due to space limitations from the side protective system or other necessities such as machinery arrangement.

Have you found a decent realistic coating for plastic props (the brass ones nice, expensive and well, brass). I made one decently for the APA but it took four tries... And I only had to make one. I might try printing one for my next project. It's great that you were able to find enough photos to get this area correct! The business end of a very powerful ship which has more space devoted to engineering than any other!

Cheers: Tom

[Rick E Davis]

I posted these somewhere back in September 2020 about basically the same topic, from the BIW FLETCHER Class Engineering Drawings DVD.

The total length of the shafts from the steam turbines/gears to the props are different and exit at a slightly different place than the other, but are basically approximately parallel to each other.

An aside; The alignment of these shafts was tricky. In going through every FLETCHER BuShips file, it seemed like something like one out of ten or twelve units built had vibration problems due to mis-alignment and required a return to the yard to correct.

[BB62vet]

Willie,

Very nice work on the struts/shafts/screws, etc. You, of course, keep raising the bar on this so I'm probably going to follow suit. I don't really like the sloppiness of the kit parts and I think Evergreen styrene rods, etc. will work fine as replacements. I too, will use the kit props after doctoring the various surfaces you mentioned.

As for your zinc anode plates (coupons) - what are the sizes you came up with? I have left-over coupons from the NEW JERSEY build that I designed and had printed as PE and I think they may work for this model, as well. Difference in scales, but also difference in coupon sizes, also.

Rick - appreciate you posting these drawings again - Murphy's Law at work on FLETCHER construction, right?

Hank

[Fliger747]

Indeed vibration at speed was significant in my ancient recollections, at least on the fantail. The drawings, if not distorted as measured on the screen do show a slight divergence in the horizontal plane, though not enough to be noticed on a model. As RED mentions, the shaft lengths are considerably different due to the longitudinal placement of the engine rooms. In a long narrow hull with shafting at some degree of vertical angle to the shafting this begins to have impact on the available arrangement of internal engine room components.

The AOE Sacramento used 1/2 of the power plant form one of the uncompleted Iowa's, that must have been an interesting design project to build around an existing power plant from a very different ship.

Willie's ship uses the three blade props, some (Stoddard?) used a four blade prop, did this reduce vibration? The North Carolina's and SODAK's required prop replacement due to vibration issues. Any info on the history on that?

Thanks to Willie for bringing many questions and answers to light with his excellent project!

[BB62vet]

Yes, it's amazing the design/construction information that comes about from a simple, little ship model!!

I think NORTH CAROLINA and SDAK classes did have vibration problems and whether or not they were solved by the end of their active careers, I don't know - NC did experience several design changes from keel laying to launching due to engineering mistakes made during design; whether this was addressed thru their various shipyard overhuals might be an interesting subject to look into.

I also dispute the shafts being parallel to each other on FLETCHERs - the plan view RED posted above can clearly be seen to show the shafts slightly out of parallel. Interestingly enough, the IOWAs were also designed with out-of-parallel shafts as I recall.

Let me just reiterate that I'm no expert on nautical engineering, etc., and unlike politicians, can sometime s be wrong

Hope this helps!

Hank

[Willie]

Hi there Tom, David, Mr. Davis, Hank and all,

Thanks a lot for your comments.

I noticed one unusual feature in your dry dock photos, the aft nominally vertical strut has a curve at the bottom to intersect the shaft bearing at right angles.

I had noticed that, but apparently there are again variations in this element, and after studying the Jorge Juan dry dock pic I think my ship did not display this feature.

Just curious as I haven't examined the Fletcher appropriate drawings, are the shafts indeed parallel? Sometimes for whatever marine engineering reasons, shafts will be at a horizontal angle to the centerline.

I have no plans of the Fletcher class, and honestly I did not see that in the pics that I was dealing with, my mistake, but David�s and Mr. Davis�s observations seem to confirm that the deviation is virtually invisible, so I think my shafts can be given a passing grade, and therefore, thanks to David and Mr. Davis for their continuous interest and advice.

Have you found a decent realistic coating for plastic props (the brass ones nice, expensive and well, brass). I made one decently for the APA but it took four tries... And I only had to make one. I might try printing one for my next project.

I use a metallic gold/bronze coat, applied in liberal quantities with a brush, so that the superficial tension makes curves and covers the filing and sanding marks.

I have seen your prop at:

viewtopic.php?f=13&t=218743&start=120

Hats off to you, sir... Even if I had three lives in a row before me I would never be able to do such a thing !!!!!

The only thing I have been able to produce in this direction is the screw for my FFG, in plastic, of course:

It was not difficult to give some profile to the blades, and the final product was somehow hydrodynamic as well, as I could see when blowing gently:

With the final metallic coat, it came out like this, IMO at least aceptable:

[/size]

As for your zinc anode plates (coupons) - what are the sizes you came up with? I have left-over coupons from the NEW JERSEY build that I designed and had printed as PE and I think they may work for this model, as well. Difference in scales, but also difference in coupon sizes, also.

Hank, I have again no idea of the original measures, so I followed the idea of this pic of USS Kidd, that confirmed the coupons pattern in Jorge Juan:

I was using 0.4x0.75 mm. Evergreen stripe, in small sections of 2.5 mm., but as I say, this is only a guess. I would say that the effect is not bad, though, and can be considered realistic, that is the final goal of a model.[/size]

Rick - appreciate you posting these drawings again - Murphy's Law at work on FLETCHER construction, right?

Very right. Mr. Davis, ditto: with the years Murphy has become such a close, recurrent friend of mine that I already invite him to my birthday parties.

Very best regards from across the seas,

Willie.

[BB62vet]

Willie,

I'll use the same dimensions on my coupons, also. Still to compare to the PE I've already got on hand - maybe they'll work, we'll see!

Thanks again for posting the sizes, dimensions, etc.

Hank

[Fliger747]

Looks as if Kidd is all set to plow the field! I wonder how to get that dull bronze look as on Kidd. I somewhat weathered the brass props on Missouri using acid etc which is only a couple of baby steps in the right direction. But for coating a plastic prop, Willie's is a reasonable replacement of the shiny brass alternative. Hank is using some other concoction on the plastic props for Stoddard to achieve the bronze look, will see how that works out. Unfortunately bare metal always looks most like bare metal. As builders we are usually the most self critical as we know where all the compromises are. Any scale below 1:48, there are a lot of artistic licenses taken!

Interesting project! Tom

[Willie]

Hi all folks again.

Back to the job, and still thinking about the blast bags, so in the meanwhile I have started some other easier elements, this time the off board depth charge rack supports.

This is what has to be done, in the only specific picture that I have of this element on board Jorge Juan:

Anyway, the pic is not very clear, but as this element is quite a common place among the Fletchers, it was not difficult to find something else.
This is USS Ammen:

This, USS Picking:

And this, USS Isherwood:

With small variations, probably depending on which shipyard they were built, all these structures seem to have in common that they are not symmetrical, and that the inner plates are welded at a different height as well.

The construction was not difficult, but somehow tricky, as I had to adapt the bases of the triangles to the previous oil canning of the hull. It is now like this:

With the rack on, the fit is good, and the effect is quite convincing:

And that�s all for now. I hope you like it, and very best regards from this side,

Willie.[/size]

[BB62vet]

Willie,

Looks good, my friend!!! You've really got the hang of adding in all the small details - marvelous!! I have one question since you are back in modeling mode, etc. -

Did you glue the main deck to the hull BEFORE you began the oil canning treatment? I would think that you would as it would make the hull an easier unit to handle, etc.

Anyhow glad to see further construction on JJ!!!

Hank

[Willie]

Hi all once again,

I have being reviewing some pics in the last days, and in the process I have realized something that I had not realized before. After all the fun with the oil canning, and all the discussions about where and where not involved, after I had already taken pains making and placing the shafts, look at this...:

...tell me what you see, tell me what I did that was so wrong in three previous lives, what horrible mistakes I have committed and what sins are hidden in my past to deserve this punishment

Hank, if you are seeing this, take your time with the shafts.

Nice going and all the best from this side,

Willie.

[BB62vet]

Willie,

Well, I'm not exactly sure what I've supposed to be looking at (or looking for) - ???? You will have to explain yourself in a bit more detail. The callout arrows point to what? Again, I'm not sure what you are alluding to in your comments regarding the shafts.

Hank

[Willie]

Howdy Hank and all,

I'm not exactly sure what I've supposed to be looking at (or looking for) - ???? You will have to explain yourself in a bit more detail. The callout arrows point to what?

Oil canning, lots of oil canning on the stern bottom, where apparently, after all the previous discussions and pictures last summer, there should have been none.

I'm not sure what you are alluding to in your comments regarding the shafts.

I mean that you should find out whether you should apply some of this to USS Stoddard�s hull, or not, before you build the shafts, as it would make things way more complicated, as my case now is.

Best regards from the other side,

Willie.

[Fliger747]

I would guess (WAG) that one might expect some oil canning around the prop area due to the great pounding of the turbulence from the prop. Standing on the fantail of a Fletcher underway at speed, watching the boiling wake extend at least to eye level, the pounding is considerable. Perhaps this was a reason for the conversion to the four bladed props?

Regards: Tom

[BB62vet]

I'm not exactly sure what I've supposed to be looking at (or looking for) - ???? You will have to explain yourself in a bit more detail. The callout arrows point to what?

Oil canning, lots of oil canning on the stern bottom, where apparently, after all the previous discussions and pictures last summer, there should have been none.

I'm not sure what you are alluding to in your comments regarding the shafts.

I mean that you should find out whether you should apply some of this to USS Stoddard�s hull, or not, before you build the shafts, as it would make things way more complicated, as my case now is.

Willie,

Well, that's what I thought you would say - I just wanted to make sure we were both thinking about the same thing! My first impression from your photos was exactly that and also what Tom Falley said as well - the constant pounding of the hull against the water would result in similar hull distortion of the plates on the bottom of the ship. Makes sense. I think, however, these striations will be easier to achieve (at least in my case w/o having the struts in place) by clamping the hull in a wrapped vise and using a narrow curved chisel blade and a steel ruler to make straight, shallow troughs in the surface. Although, one photo I have of the STODDARD's underside stern doesn't really show this effect:

So, I'll do a bit more research on this before deciding how to address this. I thank you for pointing this out and just take two Aspirin, call Dr. Hank in the morning, and don't worry - it will be ok.

Hank

[Rick E Davis]

The four blade props on a few FLETCHER's (and BENSON-GLEAVES) during WWII was an effort to "cure" vibration issues on individual destroyers that weren't being solved by normal "tweaking" of the three blade props. Mention of them started to appear in Weekly Overhaul Reports in about 1944-1945. I have found photos of I think (my memory is too full and I'm too lazy tonight to go check my records :-} ) only two FLETCHER's with them.

[Fliger747]

With High speed turbine powered warships this seems to have been a persistent issue. The Sodak's and North Carolina's had prop issues. Perhaps Hank can chime in with regards to how well such issues were solved with the four and five blade prop combination were on the Iowa's.

Such vibration made optical gunnery difficult, even with director systems and could be deleterious to the somewhat fragile electronics (read tubes) of the era. On Capital ships of the time the blast and shock from firing the main battery could disable radar and other systems, an awkward circumstance.

Though I am not aware of any special vibration issues with the Alaska's, however the aft MK 38 director tower design featured some prominent external bracing.

Modern submarine propellers are designed and executed with very sophisticated and secret CNC machinery.

Interesting stuff for Naval Geeks!

[Rick E Davis]

Many times, the issue of vibrations were due to misalignment of the shaft sections. When I was going through the BuShips files on FLETCHER's about one in ten new built units had problems with "excess" vibration during trial runs and shakedown cruise. The problem could be traced to out of balance props or misalignment of the shafts/gearing. During construction and subsequent launching, misaligning could happen without being noticed. The problem ship would go back in the yard where alignment and balance were checked and if necessary went into drydock to rebalance or replace her props (replacement was normally done on the second visit ). USS CHEVALIER's (DD-451) operational release was held up due to this problem. It explained why she didn't follow her sisters to the Pacific earlier.

Also, there is such a thing as "natural resonate vibration" for all structures. At certain operating conditions, like speed, vibrations can hit one of these resonate frequencies and really shake things. When the USN moved the searchlight platform from the aft stack to the fore stack on early FLETCHER's, they encountered a bad vibration at certain speeds that were inherit with the basic design of the class that shook the platform. Trying various support structure designs were experimented with to solve the problem before a "standard" was adapted. USS SIGSBEE has probably the most unique bracing (along with the "standard" stanchions underneath the platform) ... two hefty U-beams and cross bracing were attached to the searchlight platform to the back of the bridge after shakedown at a private yard!!! They also installed a gangway on top of this structure from the bridge to the searchlight platform. No other destroyer went this route.