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upgrading the SSY 1/96 ALFA kit

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  • Originally posted by DMTNT View Post
    Well I’ve only met Ellie once, but I know better than to argue there!

    Lecturer is a former career submariner who has a professional YouTube channel under the username Jive Turkey. Great resource for been there / done that commentary & analysis - that he can discuss in a public forum. Smart guy, but certainly not above a slip of the tongue.
    Yeah, I've seen some of his stuff. Informative, but he should stick with his rating. He can talk with confidence about TMA, and sonar systems. But torpedo homing methodology is sometimes sketchy. I don't trust gamers.

    Jive Turkey is a Norman Polmar of the Internet type. Generally informative, but definitely not the fact-checker technical history slueth of a Norman Friedman.

    David
    "... well, that takes care of Jorgenson's theory!"

    Comment


    • Originally posted by He Who Shall Not Be Named View Post

      Yeah, I've seen some of his stuff. Informative, but he should stick with his rating. He can talk with confidence about TMA, and sonar systems. But torpedo homing methodology is sometimes sketchy. I don't trust gamers.

      Jive Turkey is a Norman Polmar of the Internet type. Generally informative, but definitely not the fact-checker technical history slueth of a Norman Friedman.

      David
      And I, am just Norm.

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      Dead men tell no tales...

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      • With the majority of limber and flood-drain hole locations marked off onto the hull questions remained as to specific location and size of some.

        The plans are authoritative, as just about every photos of an actual prototype confirmed what was depicted on the drawing. However, there’s always items that need a better look at before building a part or engraving a line. It’s on those occasions that I drag the drawings and folders into the office, get into my computer folders dealing with the subject, and do a deep dive into the specifics in question.

        Ellie and I gave things a close look-see, bouncing our attention between computer screen, photos, and the plans to skull things out as best we could. Once we concurred the plans were annotated accordingly, and I tucked my documents under an arm and trudged back to the man-cave to work the magic.



        One area I wanted to get right was the exact position of the two secondary loop condenser intake scoops. In my folder I found this excellent drawing that had the look of a source document, permitting me to trust it enough to loft off the position of the scoops onto the bottom of the hull. Translating the small drawing to the size of the model was accomplished with the aid of proportional dividers.



        The two resin scoops were degreased, and conformably sanded to match the compound curve of the hull where they would be attached. First their outlines were scribed onto the hull so I could match an oblong hole in the hull with the ‘intake’ opening ground at the front of each scoop piece. Each scoop was then secured in place with plenty of CA and CA accelerator liquid.

        Not indicated on the drawing, but revealed in our study of prototype photos of boats in drydock, is a rather large radius fillet between the scoops and the hull. I scaled that radius to the model and selected a dapping tool of appropriate diameter, using it later to screed Bondo automotive filler at the union between scoops and hull, producing the fillet that so neatly blends these structures into one.



        Masking tape was used to minimize the mess of excess Bondo getting onto areas of the hull I don’t want it. You see here how the dapping tool – in this application, more of a wax melting radius tool – is used to produce a constant radius fillet between scoops and hull.



        After the Bondo fillets had hardened enough I used specialized round-files to refine the fillets and give their surface a roughness that would enhance the adhesion of the later applied touch-up putty. The files were used wet to avoid excessive grit between the teeth. The Bondo that got onto the scoops was abraded off with double-sided sanding tools used wet.

        There is a slight radius either side of the intake hole. These sharp, little fillets were formed by CA mixed with baking soda and filed to shape with purpose made riffler files.



        I’m hovering over one of the three ‘mobile’ work stations in my shop. These are modified old-style hospital tables, adjustable in height and supported over caster wheels. This type table permits me to adjust the height of the work to suite specific postures I need to assume, standing, sitting, or hunched over. When required these mobile tables can be ganged together for long work; and their particle board tops permit me to quickly build onto the table itself jigs or fixtures needed hold or align the work. They’ve been an important furnishing in this shop for decades.

        Here I’m in the process of boring out the flood-drain holes into the bottom of the ALFA’s hull.



        I found that the task of opening up holes in GRP substrates is best done with a variety of rotary bits followed by precision shaping with the aid of various small files.

        Location and shape of each hole is defined by an engraved line scribed into the hull. The initial penetration is done with a rough burr, and then the hole is roughed to shape with a suitable diameter drill bit, used as an end-mill. Once the hole approaches the scribed outlines of the eventual shape I switch to files. I make no effort to maintain a radius at the square hole edges, that refinement later achieved with putty.

        The four holes at the bottom illustrate the three stages I’ve just described. At the left I’ve started to dig into the glass with the burr; the hole to the right of that has been opened up as much as possible with the burr; the hole second from the right has been refined with a 1/16” drill bit used as a hand-held end-mill; and the hole to the extreme right has been worked to the engraved outline with jeweler’s files.



        Time has come to start integrating more of the cast resin parts on and within the hull.

        ‘Capture lips’ have already been installed within the upper hull – these work to hold the raised longitudinal flange of the lower hull up tight against the inside edge of the upper hull, insuring registration between the edges of the upper and lower hull.

        The two semi-circular SubDriver cylinder foundations and Velcro-indexing pin foundation will now be secured into the lower hull with the aid of 4-40 machine screws. And the forward propeller shaft bearing foundation will be sized and centered into the tail-cone, but not yet permanently installed – and it won’t be permanently installed till I’ve worked out a successful linkage for the rudders and stern planes.

        Next on my to-do list is manufacture and installation of the two operating shaft bearings for the bow planes.



        Giving me a bit more room on the marking jig was removal of the no longer needed plan bill-board. The jig is now used to hold the work and rotate it as I go about the laborious task of applying touch-up putty and later wet-sanding it off.



        After all that work grinding open the limber and flood-drain holes I coated the work with Nitro-Stan and pushed the putty into the inside edges of the square holes with a 1/16” diameter brass dowel. This does two things: swirling dowel around on the inside edges of the holes pushed the putty into the edges, filling tool-marks; and the round tool produced fillets at the four corners of each hole, more accurately capturing the shape of these openings at the bottom of the hull.





        "... well, that takes care of Jorgenson's theory!"

        Comment


        • You're getting skinny there sir!
          Looking good, Eggsy.
          If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

          Comment


          • Originally posted by trout View Post
            You're getting skinny there sir!
            Looking good, Eggsy.
            ….. feel'n good, Merlin
            "... well, that takes care of Jorgenson's theory!"

            Comment




            • An often unappreciated aspect of fine model-building is the design, manufacture, selection, and use of abrasive type tools. Files, sandpaper, grinding discs, saw blades, abrasive pads and steel-wool, all are examples of reduction tools that chip away at the work – abrasive tools. Below is a small selection of the abrasion tools used, or could have been used, on the 1/96 ALFA project.

              A competent model-builder knows what type of tool to use, where to use, how to use it, and (of course) have that tool at hand.

              The only tools made specifically for this job – and will find use on later jobs as they join the others in my collection – are the six specialized sanding tools to the left. All used to refine the shape of the many different sized limber, intake, discharge, and flood-drain holes of this subject.



              Specialized sanding tool, each dealing with a specific hole size and geometry, each equipped with a #400 grit sandpaper wrapped brass mandrel. K&S brass U-channel and square section tubes were used as the mandrels.
              The clear handles are length of Acrylic rod that were tapered and bored on the lathe, the bore slightly smaller than the brass mandrel it accommodates. Securing a mandrel to a handle was done by heating the brass mandrel, then jamming it into the handle. As the acrylic melted, the mandrel was pushed into the undersized hole. Once cool mandrel and handle were one -- no glue required.

              The original engravings on the hull, for the most part, did not jive with my documents, so that work was filled. You can make out some of the original engraving in red (filler).



              I twist sandpaper into a tapered, round sanding tool. Note how a length of brass tube, belled at one end, is used to girdle and keep tight the wound piece of sandpaper. One of these tools is being used here to clean up the inside of the scoop intakes.



              The job of applying touch-up putty continued, but the task made easy using the marking jig to hold the work steady – note the crutch under the hull that keeps it from rotating as I brush on the putty.

              In this case I’m evening up a slight disparity of height between the upper hull and lower hull longitudinal edges. As the wet putty gets into the seam between the two halves it had to be chased out before drying. A knife-point was used to break the putty bridge between the two halves.



              The fit between control surfaces and stabilizers was checked for non-binding movement. That accomplished I checked the fit and alignment of each stabilizer to its eventual location at the stern of the hull.



              I’m performing a bit of touch-up conformal sanding to the stabilizer roots. The objective here was to get each stabilizer to line up on the hull with its trailing edge perpendicular to the jigs bed and its cord in line with the profile plane of the hull.

              The conformal sanding was done with a light touch: sand a bit; check alignment; sand; and check again. Only after each stabilizer sat, unsupported atop the stern, its trailing edge and cord falling along the perpendicular and profile planes, would it be put aside and the next stabilizers root given this final contouring.



              Alignment of the stabilizers to the hull was assured by running a 1/16” brass rod through opposing stabilizers and hull. Checking that the holes through which the brass rods ran were properly distributed, a Machinist’s surface-gauge and right-angle triangles were used as well. Again, the marking jig was a useful tool as I went about this task of mocking-up the assembly of the stabilizers to the hull.



              The space within the tail cone where the control surface linkages terminate is very, very tight. So, I do not yet permanently glue the stabilizer to the hull. Just a mock-up test fit. I still have much grinding on the tail-cone interior and don’t want the delicate stabilizers glued back there yet – just too easy to break them off during such handling.



              Here I’m applying another coat of primer to find flaws not yet evident. First, at moderate pressure and the paint-flow dialed back a bit, I hit the areas that either are red touch-up putty or white gel-coat with spot applications. I then turn up the pressure to #11 and set the paint-flow to ‘kill’ and clobbered the entire model with a thick primer coat.



              After the work had dried overnight I inspect the gray surface for flaws and addressed them with a sanding tool or more touch-up putty.





              "... well, that takes care of Jorgenson's theory!"

              Comment



              • I’ve learned to keep as many items that make up a model removable for as long into the building process as possible. Fit and operability of the parts often does not go as planned and the ability to remove a part, or assembly, to perform a modification saves much time and aggravation. That guiding principle on display here: deferring permanent installation of stabilizers, SubDriver foundations, control surface linkages, and running gear. Such items permanently installed only after the entire system has demonstrated correct operation without anything getting in the way of the other.

                Even after the stabilizers are bonded to the hull I retain the ability to easily remove the operating shafts, control surfaces, and linkage elements for repair or adjustment; as is the case with the propeller, propeller shaft, and bearings – they all can be removed without damage.

                I design for scale-like appearance, performance; and easy access to all moving parts.



                The initial fit of the stern control surface operating shaft bell-cranks revealed a lot of interference between the inside of the stern and the bell-cranks. I found the most effective way of digging away some of the GRP was with this little pneumatic rotary grinder equipped with a Carbide ball-burr. The small diameter grinder permitted me to still eye-ball the work as I carefully ground away material from within the tapered stern. A most useful tool.



                At the start of this project I had hoped to use at least one interconnecting yoke between opposed control surface operating shafts in the stern. But, as it turned out, things are just too tight back there to permit that. So, I had to employ discrete bell-cranks for all four operating shafts, which of course meant a dedicated pushrod for each bell-crank. Note how the two pushrods operate as one by ganging them together with wheel-collars.

                The cast white-metal bell-cranks are of my own manufacture – just one of many sizes and styles I have in the spares boxes that litter the walls of my shop. The pushrods secure to the bell-crank with a classic Z-bend, and the bell-crank made fast to the operating shaft with a set-screw.



                A 2.5” diameter SubDriver, with suitably sized ballast tank, will provide the control, propulsion, and ballasting tasks for this model. Here I’m checking out the interface between the SD’s propulsion and control outputs.

                While investigating the best way to get the bell-cranks situated in the stern I eventually settled on this arrangement of pushrods – a pair for the stern planes, and a pair for the rudders. The SD pushrod atop the cylinder will eventually make up to the bow plane pushrod. There will be five channels of operation for this model: Rudder, stern planes, bow planes, ballast, and throttle. Additionally there will be autonomous control of the stern planes and bow planes by on-board angle and depth sensors.



                As is my practice the control surface pushrods make up to the SubDrivers pushrods through magnetic couplers – a concept I appropriated decades ago from the always inventive, Brian Starkes.

                Note the large diameter aluminum intermediate drive shaft under the pushrods, interface between SubDriver motor output and propeller shaft. Dumas dog-bones and couplers make up quick connect/disconnect unions between intermediate drive shaft, SubDriver, and propeller shaft.



                You see how tight things get at the tapered stern of the 1/96 ALFA. It took much fiddling to work out how the pushrods ran back there so as to prevent binding or interference between them. Note how the pushrods run over and even through the cast resin forward propeller shaft bearing foundation.



                Note that the horizontal and vertical stabilizers have temporarily been secured to the hull with Electrician’s tape. The stabilizers were kept off-model as long as possible to avoid damaging them as the model is handled as other operations are performed. They’re installed here to serve as alignment bearings for the control surfaces (not installed for this operation) operating shafts. At this point I’m test fitting the four bell-cranks to the internal terminus of each operating shaft, checking for clearance of the bell-cranks from the inside surfaces of the hull as well as assuring non-interference between the bell-cranks themselves, and centrally running propeller shaft.

                A 1/8” brass rod is a stand-in for the propeller shaft as I center the forward propeller shaft bearing foundation into where it will eventually be bonded within the hull.



                Initially I planned on interconnecting the slightly off-set bow plan operating shafts with a flexible length of surgical tubing between the two. Though practical, that arrangement would have been difficult to set-up and adjust in the tight confines of the bow.

                Instead, I went with this solution: magnetic couplers. This arrangement is much easier to set-up and install/remove. With this linkage there is near-zero back-lash; the magnets present enough force to move the control surfaces without slippage; but do not hold with a force strong enough to damage the linkage should the planes be subject to collision or rough handling – in those circumstances the magnetic union will pull apart, but will rejoin automatically once the unwanted force is removed. Pretty slick!



                Not applicable to this model, but I found that it might be possible to use the magnet attachment points as the center of rotation for bow planes that retracted by swinging in and out – this would be useful for practical retracting bow planes such as employed by NOVEMBER, HOTEL, ECHO, SIERRA, FOXTROT, KILO, and TYPHOON class submarine models. Just for fun, I demonstrate that capability on this set of ALFA bow planes.



                Each bow planes operating shaft rotates within a short length of brass tube, that bearing tube glued within the bow. A short length of the operating shaft extends into the hull and makes up to a magnet equipped bell-crank. A set-screw secures the bell-crank to the operating shaft. The press-fit magnet is influenced by a magnet attached to the forward end of the bow plane pushrod.

                Each of the stern control surfaces was made fast to its operating shaft through a small set-screw. The operating shaft makes up to its bell-crank and also is held in alignment by the stabilizer outboard and root bearing holes.





                "... well, that takes care of Jorgenson's theory!"

                Comment




                • This’ll be the last WIP on this topic for a few weeks: I’m dedicating the next ten days to getting my 1/96 r/c submarine fleet ready for the big North Carolina ‘fleet-run’ event this October 11-12. I’ll rejoin this project mid-October. The fleet-run at City Lake is the last big event of the year for me. After a few days of post-operation maintenance and some decompression time, it’s back to the salt-mine and production work for the Nautilus Drydocks. Bob has some tooling jobs and a new SD design he wants worked up before year’s end. It’s good to be employed!!

                  After checking the fit and function of all the internal hardware the time had come to establish where in the lower hull to place the fixed lead weight in order to position the model submarines center of mass (center of gravity for you old-school types) so that the model balanced at, or slightly aft of, the center of the SubDrivers ballast tank. That ballast tank, slightly forward of the submarines longitudinal center -- the desired location of the center of gravity annotated on the hull with a pencil marked, ‘C.G.’



                  This determination -- where to permanently mount the fixed ballast weight -- made after installing (or in the case of the stern stabilizers and control surfaces, ‘hanging’) all items in their correct locations within or upon the hull. Finding the c.g. was best done using a sling of Velcro as a suspension fulcrum as I experimented with the weight, moving it back and forth until I found a position in the forward hull where the weight placed the models c.g. where I wanted it.



                  The single Lead weight, like the resin foundations, was initially held in place with machine screws. Here, 2-56 X 3/8” flat-head screws. The holes drilled through the bottom of the hull pass the Lead weight retaining screws has been counter-sunk to accommodate the heads of the screws. A little CA and filler over the tops of the screw heads and one would never know they are there.

                  Note in the upper hull the use of my little ‘capture lips’. These work to hold the longitudinal flange of the lower hull up tight against the inside edge of the upper hull. The objective here is to produce narrow, hardly distinguishable seams between the two hull halves.



                  A better look at how the conformal Lead weight (a cast item) fits into the compound curve of the lower hull.



                  Colloidal Silica was used to thicken up the catalyzed West System laminating resin (high grade epoxy). This is the same thickening agent -- along with some doping with a color agent – I mixed with laminating resin to make ‘gel-coat’.

                  With the exception of the propeller shaft forward bearing foundation all hardware (resin and Lead) that had to be mounted within the two hull halves were already outfitted with machine screws to hold them in place as I mocked-up things to test for fit and function. It was only after everything was certified as an acceptable system were the resin sub-assemblies taken apart, glued, and re-assembled with the machine screws – this time things were in place for keeps! Glue fillets between parts and hull were formed with forefinger.



                  Straight from the cans, the resin is too thin and ‘runny’ for use as an effective adhesive. Colloidal Silica, depending on the amount, can adjust the mix viscosity from a creamy consistency to one that is clay thick – just depends on the application on how thick you make the adhesive with this stuff.

                  The thickened epoxy glue was smeared on each piece before assembly. Here I’m gooping up one of the two SD foundations before screwing it in place within the lower hull.



                  Note the long length of 1/8” diameter brass rod projecting from the two propeller bearings. Its purpose here as an alignment gauge – I used it to center the forward propeller shaft bearing foundation as the glue set – I had to be sure that the thrust line fell along the hulls longitudinal axis.

                  Note the vertical brass pin projecting from the top of the Indexing pin-Velcro strap foundation piece located between the two SD foundations: The pin fits a hole drilled into the bottom of the SubDrivers ballast tank to hold the SD rigidly in registration with the hull once the securing Velcro strap is made up.






                  "... well, that takes care of Jorgenson's theory!"

                  Comment

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