1/72 Revell Of Germany Type-9 .... It Starts!

[He Who Shall Not Be Named]

Hi
This type IX C SAS is on sale now sub-driver.com site?

Though I've developed the SD for that model, I have yet to write up the ad-copy and do the pictures Mike needs for the catalog. I'll get to it, got to dig out from a back-log of orders and tool-making to replace some burnt out rubber molds. So much to do, so little time.

M

[He Who Shall Not Be Named]

OK, times up! Time to start the proper WIP on this puppy!

The Revell of Germany 1/72 Type-9 U-Boat, represents the U-505 now on display in Chicago, is a fine kit. This is a work in progress (WIP) report on how -- using the Caswell-Merriman Type-9 fittings kit and Type-9 Sub-driver (SD) -- you can convert this polystyrene, injection formed plastic model kit into a well running, fully capable model r/c submarine.

A very well engineered kit, even the three-piece deck lends itself to being removable to afford access to the models interior. As packaged, there is a substantial cardboard barrier between the heave hull and deck pieces and the more delicate items (hand-rails in particular) of the kit. I've received and inspected two of these kits and not one piece has been broken or scuffed do to packaging or handling. Well done, Revell of Germany!

A comprehensive set of instructions with profile presentations of the boat will be very useful when it comes time to paint and mark the model. I was delighted to find that the separate stern halves (the entire hull assembly comprising two main hull halves, and two stern halves -- this done to keep the box dimensions down, as shipping is a big fraction of the final retail price) terminated right where the propeller shaft forward bearing foundations would fit. The assembled stern assembly is very easy to handle as you go about the tough business of installing the rudder mechanism, running gear, and stern planes -- operations made relatively easy because you're not swinging the entire hull assembly around as you work your magic at the stern. And the stern is the busiest place on this model, I can assure you!

As outlined below, you will initially -- during the work up of the basic model submarine structure with the components needed to make it r/c capable -- build the model up bare bones: no railing, no guns, no do-dads that will break off as you get it running and trimmed out. Polystyrene plastic model parts -- in thin section -- are delicate little things and break off even if you look at them wrong. Outfitting one of these type models with running gear, SD foundations, rudder mechanism, control surface linkages, SD induction float-valve mechanism, etc. involves a lot of handling and kicking about. So, most of the parts you snip off the part-trees will go into plastic bags, then back into the box for safe-keeping until your model is working, trimmed out in the water, and has successfully completed sea-trials. Only after the r/c model is working to your satisfaction will you plop it back down on the work-bench for the detail work, painting, markings, and weathering.

What you will do is segregate the model kit parts and the components of our fittings kit and SD into four discrete sub-assembly 'kits'. The sub-assembly parts are outlined below:

STERN SUB-ASSEMBLY This is the most involved item you will deal with and presents you with three main tasks: installation of the rudder mechanism; installation of the stern planes; and installation of the running gear (propellers, shafts, bearings, bearing foundations, and couplers). For those of you wishing to install weapons, torpedo tube nest foundations are also provided with our fittings kit.

SAIL SUB-ASSEMBLY A simple assembly job, the basic sail structure goes together quickly and the SD snorkel induction mechanism set within this structure. Magnet foundations and magnets will make fast the sail sub-assembly to the models deck.

HULL SUB-ASSEMBLY Another simple job is outfitting the basic hull. Installation of the SD hold-down foundation (which makes use of an indexing pin and Velcro strap to secure the SD within the hull); and run the bow plane operating shaft through the two holes already present in the kits hull. We've also provided torpedo tube nest foundations for those wishing to install weapon launchers in this model.

DECK SUB-ASSEMBLY Without alteration, the three kit provided deck pieces are secured to the hull with magnets. Though simple in operation, installation of the magnet foundations, and indexing the magnet pairs, is an involved and exacting process -- which I'll address later.

M

[He Who Shall Not Be Named]

Before anything is glued together your first task is to take the four hull parts -- two stern pieces, and two main hull pieces -- and drill out, file, and sand open the limber holes (near the top of the hull) and flood-drain holes (at the bottom of the hull). To facilitate this work, and to achieve a scale like wall thickness seen through these holes, you have to grind out the insides of the hull pieces. Additionally, you need to grind in a 'V' shaped well at the after end of the stern sections skeg to later accept the stern plane operating shaft bell-crank.

Also, within the two main hull halves , particularly in the keel trench, you'll see a series of cup like projections -- artifacts of the injection forming process. These have to be ground away too or they'll interfere with the fit of the SD and lead weights you'll later install as you trim the boat for water operation.

In the above shot I've identified most of the tools you'll need to open up the limber and flood-drain holes: Sharpe (brand new, virgin, never have seen metal or GRP) rotary cutting burs; rough and second-cut small files; various grades of sandpaper and 'soft' sanding block; X-Acto knife; and either '000' steel-whole, or a medium grade Scotch-Bright abrasive pad. And you'll need a 15-Watt incandescent bulb (sorry, Al Gore!) to back-light the work as you reduce the wall thickness of the hull parts, this to facilitate limber hole and flood-drain hole punching out.

You will do the gross grinding with a moto-tool using fresh grinding burrs of various round section. The finishing work from the inside constitutes sanding with descending grades of sandpaper, all done 'dry', starting with #60, then working down to #100. The objective is to reduce the wall thickness in order to minimize the amount of filing work after you open all the limber and flood-drain holes, hand-grab holes, and exhaust ports.

Yes, I've got three moto-tools here ... actually there are four more out of frame. So what!

Please don't ***** to me that it's not fair I have so many wonderful toys. I've worked for e'm!

You think this hobby is too expensive? You don't have enough money to play?! Then get out there, sell seaman and plasma or whore yourself out till you got the bucks to play!

Or ... failing that ... go out and get a frig'n job!

R/c model submarining is not a poor man's game. Welfare, stupid, and lazy types need not apply!

The upper red circles denote the objective: to grind away the wall thickness under the limber and flood-drain holes set into the outside surface of the hull parts. You must also grind away within the skeg, this to provide clearance for the stern plane operating shaft bell-crank, denoted by the lower red circle.

The best way to gauge how deep your going with the grinding tools is to hold the plastic model hull up against a 15-Watt bulb ... any hotter and you melt the plastic! As you grind away from within the hull part the recessed limber holes and flood-drain holes on the other side become ever more apparent to your eyes. Very quickly you will learn to grind away with great control and speed as the back-light indicates depth of cut.

In this shot you can make out, barely, the light coming through the relatively thick plastic just under the burr. The deeper cut, over a row of limber holes to the right are much brighter, indicating that I'm almost done with the grinding behind those limber holes.
If you have access to a light-table, then use it -- much easier than the lamp.

The small flood-drain holes near the bottom of the four hull parts are tedious because they are very shallow, and reside around a more severely curved section than the larger limber holes near deck level. In fact the upper limber holes are so easy to work that you don't need the back-light to guide you along -- just grind away the raised portion from within the hull and you are there. Once these holes start to open up, you put down the moto-tool and complete the work with a soft sanding block and descending grits of sandpaper.

The horror stories you hear about using high-speed grinding tools on polystyrene plastic is mostly bull-****. Use sharp (brand-new) bits, keep the RPM's down below 'chatter' speed, don't loiter in one spot for any length of time, and you're golden.

Once the wall thickness over the flood-drain holes is thin enough you use a small drill bit to open them up. Then, using a #11 X-Acto blade connect the holes to the correct shape as best you can. You then finish off the holes with a small, modified flat file.

Plan on giving up three evenings of work to opening up all the limber and flood-drain holes. Take your time. Walk away from it when things get tiring -- it's very easy to bugger things up when you are working hull areas of dangerously thin section. This aspect of the project is the most taxing -- that's why I want you to do it first.

A few pointers about the file used (as seen above) to render the final form to the flood-drain holes:

Go through your massive collection of old Jeweler's files (if you don't have such a collection, what the hell are you doing trying to assemble an r/c model submarine!?) and find one that is flat on both faces, is about .075" thick, and whose width tapers slightly from shank to tip. If you use it as is, it will produce tight right angles at the ends of the flood-drain holes -- you don't want that!

On a grinder (better have one!) slightly chamfer where the face and edges of the file meet -- the objective is to give your modified file an oval section, matching the holes you want to render on the hull pieces. As you shape the file, test off-model on a scrape piece of .080" thick styrene sheet plastic. Keep grinding those chamfers onto the file edges till you achieve holes that look like those on the model. OK? Now you can take that file and go to town on the model hull pieces.

While on the subject of abrasives -- and files are an abrading tool -- I might as well familiarize you (if you're not already ... and if not, WHY NOT!!?) with the specialized abrasive tools made from common sandpaper as well as those other commercially available abrassives such as Scotch-pads, steel whole, foam-core sanding sticks and riffler files. The sandpaper you want to use is wet-or-dry grade #240, #400, and #600 grit. Some of that sandpaper will be used with hard and soft sanding blocks, and some will be turned into double-sided sanding strips -- their manufacture outlined next.

Never free-hand sandpaper over a model part! If you do, don't let me find out!

Those commercially available sanding sticks (available at hobby-shops and Beauty supply stores) are excellent for large area sanding, but they can not negotiate tight spots like these double-sided sanding strips I've developed. With these things, you can cut them to any shape dictated by the application. Of course you make them from the grit required for the job (most of it will be #600 and #400, with the occasional need to go mid-evil and grind away with #240). As this abrasive tool is a laminate of two pieces of sandpaper with a stiff glue in between, the finished sanding strip is strong, but will bend just enough to be useful.

You make a double-sided sanding strip by folding over a piece of sandpaper to establish a crease. Open it up, smear some CA on one face, close it, put a towel over it and press for a few minutes. After the glue cures you have a stiff double-sided sanding strip ready to have its raged edges cut off with scissors to achieve the very sharp edges that make this abrasion tool so useful for cutting in on those hard-to-get-at spots on your model. Like the stern tubes.

'Running-gear' describes all the components that deliver the torque from the motor and convert that torque to an axle force, thrust. Thrust either in the ahead or astern direction, depending on direction of propeller rotation. The propeller translates rotary force to axial force and that axial force is presented to the submarines structure at the thrust bearing, which is secured to the structure solidly at the forward radial flanges of the stern section.

Our fittings kit contains the shaft, washers, wheel collar, thrust bearing, thrust bearing foundation, Dumas type universal coupler, and propeller to make up practical running gear for this specific model submarine kit. The kits polystyrene strut-bearing and stern tube are used, as is.

The long propeller shaft is stabilized from lateral vibration by the stern tube that fairleads the shaft out of the hull, and the propeller strut-bearing. It is important for you to appreciate that no thrust loads are presented to either the strut-bearings or stern tubes -- on this plastic model kit, they are not designed for it. All thrust loads, be they ahead or astern, are handled by the thrust bearing through the wheel collar and thrust washer, and Dumas coupler and thrust washer.

The German's who designed this kit MUST have had r/c conversion in mind when they engineered this kit: The internal bore of the stern tube and strut-bearing are perfect non-interference fits for 3/32" propeller shaft. And the beefy stern section radial flange is in the perfect spot to mount the thrust bearing!
Your job is to open up a hole in the stern pieces large enough to pass the propeller shaft into the hull and secure the thrust bearing to the inboard face of the radial flange.

M

[He Who Shall Not Be Named]

OK, you've spent a weeks worth of evenings opening up the limber holes and are chomping at the bit to glue something ... ANYTHING ... on this kit together. Here's your big show-business break, bunkie: You're going to glue the two, two-piece stern tubes together. Whoopiee!!

The stern tubes fair the propeller shaft into the hull. Their correct positioning onto the hull in relation to the strut bearing is critical if the propeller shaft is to fit correctly. Yes, there is an indexing pin and slot built into the mating surfaces of hull and stern tube, but there is a small amount of lateral slop between them, so it would be foolish just to glue the parts together and hope the bore of the strut-bearing and bore of the stern tube will be in alignment. Do that and sure as hell, Murphy will bite you on the butt.

As you will do to the edge of ALL plastic and resin parts to be glued together, you will run a flat-file over their edges to knock off ejection-pin marks, flash, injection and casting oils, and to rough up their surfaces to enhance the bond to those parts you will glue with either CA adhesive or a solvent type cohesive. I'm doing that to the mating edges of the two stern tube halves you see here.

About the glues you will be using on this kit: There are two types of glue joints.

1. Adhesive joints, where a third element (the two parts being joined constitute two of the elements) is introduced between the parts being joined. This produces a relatively weak bond. As it is not within our ability -- with the commercially available chemicals -- to make welds between different types of plastic and plastic to metal, we are compelled to use adhesives on all resin-to-metal, resin-to-resin, metal-to-polystyrene and resin-to-polystyrene unions.

Cyanoacrylate (CA) is the adhesive of choice here as it is available in a variety of thicknesses -- very thin for tight fitting unions, and thicker to gap-fill and build-up. With the aid of an accelerator (a liquid or solid with a high pH) this glue can be made to change state from liquid to solid in seconds!

2. Cohesive joints, where a fusion weld is effected between the two parts being joined.

Where ever the materials permit, you want to make the union a weld; you want to use a solvent type cohesive cement; a chemical that will partially melt the parts at their union and cause the material to cross-link into a fused whole. This is the strongest possible bond. With the chemistry available to us, we are able to weld polystyrene to polystyrene -- this is the type plastic used to form all the plastic parts in the Type-9 submarine model kit. That works out, as we want the strongest joints to be on the hull and sail parts.

As the stern tube halves to be joined will not be subject to much operational or handling loads, it;s good enough to employ CA to bond them together. Just press the halves together with fingers, and run a bit of thin-formula CA along the seams -- capillary action will drive the glue along the entire length of the seams. The glue will cure in seconds, and you can move on to the next operation.

Never squirt CA from the bottle onto the model parts -- a sure way to screw things up big-time! What you do is this: first squirt a bit of adhesive into a disposable container (say, a piece of tin-foil dimpled to form a 'bowel'). You transfer the adhesive from the disposable container with a small diameter dowel or rod to the work. This gives you absolute control over where the glue goes, and how much.

Before you can mark off on the hull the location and size of the hole needed to pass the shaft, you first have to mark off on the assembled stern tube where the shaft penetrates the hull. You do this by laying down cheat-marks onto the stern tube, then place the stern tube onto the stern section and mark out its outline and shaft hole forward and after termination points. Removing the stern tube you approximate the oval shaped hole with pen. You're now ready to blast away with moto-tool burrs to open up the hole.

In foreground you see the shaft, stern tube and thrust bearing already integrated into their stern section half.

To properly align the stern tube onto the hull with the installed propeller shaft you need to temporarily install the strut-bearings part to the skeg and strut well of the stern half you're working. You will remove this item after the stern tube is glued in place, so you won't permanently glue it in place. Either tack glue it in place, or as I've pictured above, use masking tape to hold the strut bearing piece in place.

The marked out hole -- to pass the propeller shaft --is started by punching a hole with a moto-tool burr. Keep the RPM's down or you'll melt the plastic! The ragged hole is smoothed out with a round-file. As you work the hole periodically test fit the propeller shaft with stern tube, running the after end of the shaft through the temporarily installed propeller strut bearing and check the work: work the hole till there is no interference between it and the installed propeller shaft.

Propeller shaft orientation to the hulls centerline is dictated by the positions of the strut-bearing and stern tube. it is vital that these two items be eventually secured to the hull in their correct positions. Fortunately, the indexing slots and tabs built into the three model parts insures this alignment. All you have to do is insure that the hole under the stern tube is large enough to pass the propeller shaft without interference. Continue to test-fit the stern tube to the hull, with the propeller shaft installed, until you have ground the hole enough to eliminate any interference with the shaft.

However there is a bit of lateral slop to the fit between stern tube and hull -- this is why all the work to true up the stern tube-to-hull interface point with the shaft running through the temporarily installed strut bearing piece.

Once you have the shaft in there, with the stern tube in place on the hull, spin the shaft to insure it is free. At that point, holding the stern tube down onto the hull with your thumb, apply a small amount of thin-formula CA to make the stern tube fast to the hull -- just a little bit. Remove your hand and spin the shaft. If it's still free, remove the propeller shaft and squirt more CA around the stern tube-hull seam and leave to cure.

Once the shaft is oriented by the temporarily installed strut-bearing and permanently bonded stern tube, the inboard face of the stern piece half is dug out with moto-tool burs till you have achieved non-interference fits between hull propeller shaft installed wheel-collar and thrust bearing. That wheel-collar set screw is going to be a problem: you'll have to grind out a well to pass the rotating set-screw that stands proud off the wheel-collar. Also, you'll need to cut away a portion of the stern pieces forward radial flange to achieve clearance for the thrust bearing -- but not too much of a gap between hull and thrust bearing -- you will later bridge the gap between thrust bearing and flange with thick-formula CA adhesive.

Test fit the running gear and rotate it -- your grinding work is done when the shaft can rotate without its the wheel-collar set-screw head making contact with the hull.

An alternative, which will negate the need to grind a well for the set-screw into the hull, is to machine a flat onto the shaft under that set-screw to a depth (about 1/16") that will put the had of the set-screw flush with the wheel-collar when installed onto the shaft. This quickly done with a moto-tool carbide cut-off wheel and file.

The interface point between the assembled stern and assembled main hull is a radial flange which projects forward from the stern piece. The major contact area, forming a lap-joint between the two sections, is this radial flange and a quarter-inch wide section at the inside, after end of the main hull.

Through damned good luck, or just them crafty German's thinking of us r/c types, the inboard face of the stern after flange is right where the thrust bearing should be positioned. And it's right there, on the inboard face of this flange that the fittings kit cast resin thrust bearing foundations sits, girdeling the thrust bearing between it and the cut-out in the flange that accommodates the thrust bearing. Once the thrust bearing foundation is in place, you then glue the thrust bearing to the flange and thrust bearing foundation -- this is how you affix the thrust bearing to the hull proper.

You may have to work the resin thrust bearing foundation a bit with files to get a tight, conformal fit between it and the flange, but that work takes only moments. Once you're satisfied, hold the foundation onto the flange and squirt some thin-formula CA onto the seam and let cure hard -- use of some CA accelerator is recommended or you'll be there all day.

Thick-formula CA (OK, the label says 'medium' ... it's thick to me, ******!) adhesive is used to secure the cast resin bearing foundations to the inboard faces of the radial flanges of the two stern section halves. Once in place, the propeller shafts are slid into place -- make sure they run all the way into the propeller strut bearings; the thrust bearings run in till they are centered in their respective bearing foundation; and thick formula CA is carefully applied between bearing, bearing foundation and radial flange.

Take exceptional care not to get any glue on the shaft and into the bore of the bearing or you're in for a long night of yanking and swearing! As you ladle in the CA hit the work with CA accelerator to cure what you got, then pile in more CA. Keep at it till you've built up a substantial fillet between thrust bearing and flange-thrust bearing foundation. The bearing is now one with the hull. Mission accomplished.

A good look at the glued-in-place thrust bearing. Have no fear, though oil impregnated, this Oilite type bearing will adhere permanently to the CA adhesive once you hit the goo with accelerator.

I should point out that I can only find Oilite bearings with a bore no smaller than 1/8" -- a difficulty, as the propeller shafts are 3/32" diameter. This compelled me to sleeve the bore of the bearings in order to make a tight non-interference fit between shaft and bearing. If you look hard enough you can make out the sleeve within this bearing. FYI.

Here's a good look at the forward end of the running gear. All astern and ahead loads are presented to the rather stout bearing foundations, flange, and onto the hull proper. The object of the game is to present no thrust loads at the propeller strut bearings or stern tubes -- their only function is to provide transverse stability to the after end of the propeller shafts.

When going ahead, the wheel collars press against the bearing through their thrust-washers and onto the after face of the thrust bearings. Going astern the Dumas couplers press against their thrust washers which presents the load to the forward face of the thrust bearings.

The cheat-marks, rendered in Sharpie pen, have to be removed as this magic ink will only leach through filler, putty, primer, paint, and clear-coat to spoil the finish if not either abraded off or scrubbed off with a mild solvent -- Prep-Sol being the ideal agent for not only removing inked marks like this, but also as a general degreaser used to lift off all injection lubricants and oily hand prints.

Once the cheat marks are off you start in filling the small gaps between stern tube fairings and hull, later working those areas with #400 sanding sticks and strips used wet.

M

[Kazzer]

[ATTACH=CONFIG]30564[/ATTACH] OK, you've spent a weeks worth of evenings opening up the limber holes and are chomping at the bit to glue something ... ANYTHING ... on this kit together. Here's your big show-business break, bunkie: You're going to glue the two, two-piece stern tubes together. Whoopiee!


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M

Good grief! How long did THAT take to write? No wonder our orders are behind!!!!!!

[He Who Shall Not Be Named]

Busted!......

[Peter W]

R/c model submarining is not a poor man's game. Welfare, stupid, and lazy types need not apply! [/COLOR]
;

Ha ha I applied

Peter

[He Who Shall Not Be Named]

Ha ha I applied

Peter

I bust my ass composing and taking shots; working out a presentation outline; write the text to wrap around the photos, do some of my best work on behalf of you ungrateful SOB's .... and all you can do is pull down one of my, let us say, less than temperate remarks!!!!

And the Boss chimes in with his cheerful comment (insert whip cracking sound here). Oh, yeah! This morning is shaping up nicely!

Hey! It was late, the cat just bit my ankle (again, little *******), and Ellie was screaming at me to get to bed. What can I say.

M

[Von Hilde]

I thought it was a rather nice tutorial. Didnt take very long to read it. But it was a long time comming. I didnt get to see all the slick carving tools for the hole cutting process before I did mine. so I went primitive with a flint knife and pectorial fin of a filefish. It came out the same, but a bit more time consuming. The other hull, I went with the PE. Still took a bunch of time but it cost more than a set of files, and dremmel bits. Cant win. My dad said "you gotta be tough, if your going to be stupid. but if your not tough, you better be rich"

[He Who Shall Not Be Named]

The assembled rudder mechanism, off model. The vertical machine screw keeps the master gear from riding up on its free-floating bore, but is removed during foundation installation and while you work out the correct mesh between master gear and the two rudder gears. Once all that's worked out, you re-install the screw so that the bottom of the screw-head stands off the face of the master gear about .010". It's the job of this retaining screw to keep the master gear from riding up on its shaft, yet still free to rotate.

The cast metal bell-crank -- secured by set-screw to the operating shaft -- rotates that shaft and the master gear, which is also secured to the operating shaft. The master gear drives the two rudder gears. In turn, the rudder gears, attached to the rudder operating shafts, swing the rudders in unison.

Note that all securing set-screws associated with the rudder mechanism face forward which makes everything accessible for adjustment or repair even after the rudder mechanism foundation has been permanently secured within the hull.

Preparing to install the rudder mechanism, you place the taped together stern hull section on the drill press bed and punch 1/8" holes through the face of the models rudder bearing tubes. This will give plenty of slop so there will be no interference between these holes and the installed rudder operating shafts.

(For clarities sake I'm showing off the rudder mechanism installed in only half of the hull stern section... don't try this at home!)

The rather massive resin foundation comes to you as a conformal fit within the hull -- there is only one spot it will fit. You should have no problem finding it. With the foundation in place position each rudder gear over its respective rudder operating shaft bore and note (with pen or pencil) where the hub of the gear rubs against the inside of the hull. Remove the rudder mechanism, separate the stern hull halves, to get easy access with the moto-tool, and grind out the marked areas within the hull -- this to provide clearance for the two rudder gear hubs. Re-assemble the stern hull halves.

Installing the rudders is a quick and easy operation: remove the master gear (with attached operating shaft and bell-crank) from the foundation; with a free hand, press the rudder foundation within the stern; pass a rudder operating shaft through the hulls rudder bearing tube, up and through the foundations bore; as the top of the rudder operating shaft clears the face of the foundation, position its rudder gear so the shaft, when pushed all the way, will pass through it; tightening the set-screw, which makes the rudder gear one with the rudder operating shaft. This action also locks the rudder mechanism foundation in place within the hull. Later, the foundation will be glued permanently in place -- but not now!

In this shot I'm making fast the bell-crank to the master gear operating shaft. As the master gear turns, the two rudder gears -- each affixed to a rudder -- turn in unison.

I credit my pal, Rick Teskey, with helping out with this design ... he turned my initial, rather silly looking Rube Goldberg arrangement into the simple mechanism you see here. Consultation with guys like Rick has pulled my nuts out of the fire on more than one occasion, I can assure you!

Once you have the mesh between the three gears worked out, the rudders will swing a full thirty-degrees either side of amidships. Once happy with the mesh, you put a pencil line on the rudder gears that runs up onto the master gear -- these marks index the orientation of the gears so the next time you assemble the unit, things will go much faster.


The two channels at the base of the rudder mechanism foundation pass the torpedo tubes if you wish to install them into your model. The fittings kit also provides aft torpedo tube nest foundations to facilitate such an installation.

The stern planes provided in the fittings kit feature a square sectioned operating shaft, not a round one. This because the very narrow skeg dictates a very, very narrow bell-crank be employed. A bell-crank without any room for a securing set-screw.

The body of the cast white-metal bell-crank is non-magnetic. However, the round-head machine screw set at its top is carbon-steel, which is magnetic and readily makes up to a magnetic coupler -- the after end of the pushrod that leads from the SD.

You'll eventually make up one of the magnetic couplers to a length of 1/16" brass wire, forming the pushrod that leads from the stern plane bell-crank to the SD's magnetic coupler. Use of magnetic couplers has two big advantages over other mechanical type connections: There is no slop in the linkage (next to zero back-lash); and the linkage is made up or broken easily by hand in only seconds.

If the fit within the bore of the un-glued stern plane is too sloppy, apply a small amount of CA within its bore and let it cure hard. The initial force required to push the plane onto the operating shaft -- insuring both planes are in alignment as you do so -- will cut four spline channels into the bore that will insure that future matting of the plane to the shaft will result in perfect registration with the opposing plane.

There are two operations you'll need to perform:

To insure a tight fit between bell-crank and stern plane operating shaft, first test fit the bell-crank to the shaft. If there is any rotational slop between the two you will remove the bell-crank, place it on an anvil and lightly tap the slightly raised flanges that surround the square hole of the bell-crank with a hammer.

LIGHTLY!!!!

Then test fit again. If done right you will have an interference fit between shaft and bell-crank -- the shaft will slide in and out of the bell-crank, but the bell-crank will not rotate about the shaft.

The second task is to increase the moment-arm of the bell crank by unscrewing the machine-screw 1/8". This will insure that the top of the screw head will clear the upper lip of the skeg well at each extreme of travel. Place a drop of thin formula CA over the screw where its thread engages the bell-crank.

Install the stern planes and bell-crank into the model and check for full-travel of the planes from 'rise' to 'dive'. An acceptable range of travel is ten-degrees 'rise', and ten-degrees 'dive'. You don't want a lot of travel on the stern planes as the force (owing to the high velocity of water from the propellers, and the hulls long moment arm) they produce about the pitch axis is considerable. Too much throw and these control surfaces can induce uncontrollable pitch oscillations.

The square hole at the base of the bell-crank permits installation of the operating shaft (glued to a stern plane), but prohibits rotation of the bell-crank on the operating shaft. As the operating shaft is driven in from the side of the skeg, it engages the bell-crank hole (the bell-crank inside, within the skeg well you previously ground out of the two stern pieces), and projects outside the skeg on the other side where the other plane is made up to the operating shaft through a friction fit -- this permits easy installation and removal of the stern plane assembly from the models skeg.

The magnet makes a tight connection to the iron machine-screw that fits atop the stern plane bell-crank. The magnetic force is adequate to keep the two connected during all in-water forces presented to the stern planes. Yet, when required, it is an easy matter to pull the magnet clear of the bell-crank by hand. Use of magnets in such linkages reduces to near zero any back-lash which is often encountered with most other forms of linkage connection points.

The inboard edge of the two stern tubes presented a .030" gap between their bases and hull -- these seams had to be filled. I could have gone with a two-part Bondo like automotive filler (air-dry putties are only for very small seams and scratches) or the more expedient route: using thick formula CA adhesive. Once the CA is laid down, you hit the work with some accelerant to harden it.

The application tool shape and size is critical -- you want to deliver a sizable drop of the adhesive right at the seam so capillary action will draw the glue off the tool and into the gap you're filling. Wrong tool and you get this nasty glue all over places you don't want it, making for more, not less work.

Always transfer a little adhesive from the container to a smaller container -- one you can dip your glue transfer tool into easily. In this case a piece of aluminum foil dimpled with a thumb.

No matter how careful you were with the lay-down, you still have to clean up the areas adjacent the filled seam with riffler file, knife, and sandpaper.

After the CA hardens riffler files and #240 sanding strips are used to remove the excess glue from around the stern tube-hull seams. Inevitably there will be slight gaps remaining between the parts as well as file and sanding marks. These are filled with a air-drying acrylic lacquer putty.

The best stuff in the world is the Nitro-Stan you see here. Check out your local automotive refinishing supply house for it. Don't use those putties sold at the hobby-shop -- they are formulated to be safe, not effective. You want a proper industrial grade peel-your-skin-off, curl-your-eyelids, give-you-Cancer super filler.

Nitro-Stan! I love the stuff.

Use it straight out of the tube or cut it a bit with lacquer thinner or MEK to suit the job. Don't use your fingers unless you need a 1/8" fillet. The best application tools are little spatulas (scratch filling), dapping tools (fillets), or paint brushes (tight spots).

How you apply filler or putty is important. Smear it on (I'm making eye-contact with you, Mark!) and you have hours of work cutting in with file and sanding tools to restore the proper shape of the items underneath all the goo. Apply it carefully, to just those areas needing fill, and when you come back with the abrading tools you'll have a much easier time of it. And that's how it went after the careful lay-downs of putty to the stern tube-hull seams and seams running down the center of the stern tubes. Filing and wet-sanding only took minutes after which the worked areas were ready for a spot application of automotive primer.

M

[He Who Shall Not Be Named]

Just some of the sanding tools I have collected and made over the decades. Hard and soft sanding blocks, abrasives wrapped around mandrels of simple and complex form, commercial sanding sticks, steel whole, Scotch abrasive pads, double-sided sanding strips, rolled sandpaper ... just some of the items bought or developed to address specific abrasion needs.

The Nitro-Stan, air-dry lacquer putty is very easy to cut with #400 sanding strips, provided you wet-sand. here you have two double-sided sanding strips scissored to useful shapes. Ninety-degree corners tend to soften and curl, but if you nip those corners it makes the sanding strip more maneuverable and the edges will remain stiff. The bottom stern tube seen here has already been wet sanded -- a job that took about five-minutes.

The sanding strip is occasionally dipped in water to keep the work wet. The water caries sanding dust away instead of the dust accumulating and reducing the effectiveness of the sandpaper. Work goes along much quicker wet sanding than dry sanding -- also, the sanding tool lasts a lot longer.

Note, in this case I've scissored this sanding strip to sharp corners, this so I can cut into the hard right-angles presented by that little square nub on the outboard side of the stern tube. The laminated double-sided sanding strips are much stiffer and last longer than a single ply of sandpaper. Stiff, yet flexible enough to be bent so you can work in tight areas like this without damaging adjacent surfaces.

Long before I became America's 'r/c submarine Guru, I was first, and will always be at heart, a display model builder.

Though now an oft misused term I am what most would call a producer of 'museum quality' displays; I'm adept at producing models with what appear to be perfect finishes, markings, and (where appropriate) weathering. I've built for collectors, industrial concerns, motion picture and TV producers, and book and magazine Editors. And today, I build product for the hobby trade.

It's not enough for me to simply glue some parts together, then gop on some paint from a rattle-can -- No! I go through every step required to render the models surface free from imperfections and to select and use the proper paints, markings, weathering and clear-coat.

A perfect paint job demands a perfect substrate. Hence all the bother and nonsense with tools, filler, putty, primer, paint, and clear-coat.

Once the putty was sanded, leaving only that material that filled the gaps, sanding and file marks a light coat of primer was applied to help identify any seams still requiring work. The gray of the high-fill primer throws shadows of sink-marks, scratches, and open seams better than the chaotic red, light gray, and clear of the putty, plastic parts, and CA adhesive. The putty-sanding-priming cycle repeated until an unblemished surface is attained.

Preparing all the model kit parts for assembly starts with filing flat all the little nubs left from when you snipped the model parts off their respective trees. Tedious work but important as you want the tightest possible fit between part edges before you lay down the solvent cement used to weld them together.

Following the excellent model kit instructions, you'll assemble the torpedo muzzle bulkhead and associated parts. This must be done before you can assemble the main hull halves together. To the left is the assembled three-piece sonar dome that fits at the forward end of the keel. The four torpedo tube shutter doors are lower left.

The torpedo muzzle assembly is installed into a half of the main hull and glued down. You do this only minutes before making up the two hull halves as you want that assembly to 'float' so it can slightly reposition itself as its platforms and bulkhead come into contact with and index to the other hull half.

Once all the nubs are filed down, you rough up the mating edges of the parts with #240 grit sanding sticks, blocks, or double-sided strips. This increases the contact area where the welds be made and also removes any oils that got onto the parts from the injection forming process and your grubby hands -- contaminates that would otherwise inhibit the work of the cohesive solvent type cement.

Before you can achieve an effective chemical weld you first have to soften the plastic -- much as some heat type welding jobs require bringing the work up to a specific temperature before striking an ark or presenting the flame. Here I'm using a broad, stiff brush to lay down a lot of solvent cement to the edges that will eventually be joined -- once the model hull halves are taped together.

Note the use of a foam board caddy to stabilize the bottle of liquid cement. How many of you have tipped a bottle of anything all over the bench as you swung tools and model parts around? The caddy is also a good way of keeping track of the application brushes used exclusively for cement application.

The two halves of the stern are assembled with the aid of strips of masking tape. A brush used to carefully push cement into the seams from the outside. Capillary action will flow the glue along the length of the seam between parts. Care has to be taken not to let any cement run under the tape -- should that happen the cement would flow about the edges of the tape where it would sit and eat into the fine detail on the model kits surface. So, you avoid the taped areas with the brush, and lay glue down where you can on the outside. Wait about five minutes, remove the tape and complete running glue along the seams.

The stern section of hull flipped over and a very liberal amount of cement brushed onto the seams. In twelve hours time the strength at the seams will have a sizable fraction of the strength of the rest of the plastic parts. This is cohesion... welding.


When properly assembled, the two hull halves have a natural tendency to orient the deck level edges -- that accept the three deck pieces on a slightly inlaid, narrow, longitudinally running flanges molded to the inboard faces of the main hull and stern hull halves -- squeezed in a bit. You want a little bowing in. But ... just a little to insure a tight fit between hull and removable (magnetically latched) deck pieces.

When they are installed later, the three deck pieces (forward, middle, aft ... duh!) will push the hull into shape, leaving the securing (latching) magnets to do one thing: pull down and keep secured the deck pieces onto the hull. But, that's all for the future. Back to the here-and-now:

It is VITAL that as soon as each of the the two stern haves and main hull halves are glued together, you install the deck pieces and secure them with tape. This will prevent the main hull and stern section from bowing too far inboard. After about a days drying time you can remove the deck pieces and carry on with the other work.


And this is why you don't wait after making up the torpedo tube muzzle assembly to a hull half -- on by kit there indeed was a misalignment between the muzzle assembly and the just added hull half. But, since the glue was still mushy, it was an easy matter for me to push and pull on the platforms and bulkhead till they met the second hull half, were captured by the indexing tabs and assumed the correct orientation. Once in alignment the hull halves are pulled together with masking tape and liquid cement is brushed onto the seams.

At this point the three deck pieces were taped at the top of the hull -- this to insure that the cement applied to the hulls keel area, bonding the two hull halve together, sets with the correct width of the opening at the top (deck level) established.

Every reasonable effort is made to reduce the displacement of all structures above the model submarines designed waterline (where it floats, in a scale-like manner, when the ballast tank is dry).

As the specific gravity of polystyrene is very close to that of water (a direct correlation as to density), it's a simply matter to compute the weight of water needed within the flooded ballast tank to get the model submarine to submerged trim: Weight of above waterline structures = weight of ballast water required to counter the buoyancy of the above waterline structures. Reduce the weight of the above waterline structures, you reduce the size of the ballast tank -- something worth doing at every opportunity!

The rotary finger eating shark was used to rough-cut the pieces of sail structure to be removed. The cut-out boarders were refined with sanding drum and rotary burrs.

Note that small channels in the inboard side of the main hull have been ground away to afford clearance for the slightly projecting thrust bearings that are set into the stern pieces forward radial flange. The ground out area also provides the clearance needed to accommodate the Dumas universal coupler that later fits onto the forward end of the propeller shaft.

Note the penciled in radial cheat-line at the after end of the main hull assembly. It marks the half-way point along the width of the after hull assemblies radial flange. You'll use machine screws to temporarily secure the forward and after hull assemblies together, and you want those holes to be at the half-way point along the flanges width.

Once the assembled forward main hull section halves and after hull section halves had been give at least two days to dry out you begin the test fit-grind-for-clearance drill. You will find that an easy matter as the after hull flange is a near perfect fit to the inside of the main hull section. Initially the two hull sections are held together with a single radial piece of masking tape wrapped over the seam between the two hull halves, after first temporarily installing the center deck piece atop the hulls -- this insuring proper alignment of forward to after hull sections.

Drill three equally spaced 1/16" holes through both hull pieces. The two hull sections are separated and the flange holes given thread with a 2-56 starting tap. The forward hull section holes were enlarged to 3/32".

2-56 X 3/8", round head machine screws will hold together and align the two hull assemblies as the applied solvent type cement works to weld the two assemblies together into one. If you can possibly avoid it NEVER us CA type adhesives alone for major structural unions like this -- CA is subject to fracture when subjected to shock loads, and is very weak in shear. When addressing a major assembly that will be subject to torsion and shear loads, and you have the opportunity to effect a cohesive or adhesive bond .... GO FOR THE WELD!
Duh!

When I was a kid, all plastic model kits were stuck together with a gelled cohesive cement, 'model airplane glue'. Hard to find these days. But, the plastic supply houses will sell you #16 Acrylic cement if you sound like you know what you're talking about.

Slather the #16 onto the after hull assemblies radial flange moments before ramming it into the ass-end of the main hull assembly. Wipe off the excess glue that squirts out at the seam. This gelled glue sets relatively slowly, which will give you the time needed to loosen and tighten the securing screws as you get the two hull assemblies in proper alignment with the aid of the center deck piece.

The outside screw holes (in the forward hull assembly) are a bit oversize so you can jockey the after hull assembly around a bit as you work to achieve symmetry between it and the forward hull assembly.

What you see in these two shots is the initial trial-fit of the two hull assemblies, held together exclusively with the machine screws. An added benefit to the screws is that they compressed the forward hull assembly up tight against the flange of the after hull assembly. The better you can get the alignment between the two assemblies, the less filler and putty work needed later.

M

[He Who Shall Not Be Named]

It's important that the periscope shears (those two tubes that later accommodate the #1 and #2 periscopes) be in perfect alignment as the glue sets at the bond between base of periscope shear piece and bridge deck. This alignment is assured in you first tape the assembled sail assembly atop the center deck piece , which in turn has been taped atop the hulls superstructure. The base of the shears are indexted by the two tight fitting holes in the deck. This assures correct orientation of the shears to the sail.

The base of the periscope shear assembly and bridge deck are pre-glued, and the periscope shear assembly pushed down till it seats onto the bridge deck, then more solvent glue is liberally brushed onto the seam. This is left to dry overnight.

As room must be made within the sail for the slightly above-deck-level SD components, the two periscope shears are cut back so that their bottom ends terminate about 1/8" above deck level. This is done with the rotary thumb-eating-shark.

Note the hash-marked areas on the long center deck piece over which the sail sits. You're cutting out all that with the exception of a bridge back aft and the area under the magnetic compass fairing, at the forward end of the sail. The open spaces will pass the Sub-drivers vent valve, SAS manifold, and safety float-valve that project slightly over the deck.

Once these two big cut-outs are roughed open, the holes are cleaned up with files and sanding sticks, you then proceed with installation of the sail-to-deck hold-down magnets.

Provided with the Type-9 fittings kit are more than enough resin magnet foundations and magnets to accomplish the job of latching the three deck pieces down upon the superstructure, and the sail down upon the middle deck piece. The odd looking foundation to the right makes a conformal fit within the sails magnetic compass fairing.

Each magnet foundation is cut from one of these blanks. Note that each blank has a different angular displacement from the vertical along one face. The sail foundations and few stations along the length of the superstructure are simple right-angles. However, other stations along the length of the superstructure have varying angles from the vertical -- of the blanks provided you'll find foundations that have the angle required for a specific station. Work it out!

To facilitate removal or re-setting of depth of a foundation magnet -- an operation made much easier if performed before you cut away the individual magnet foundations from the blank -- drill 1/16" holes thru each magnet bore. If the need arises later you'll be able to pop a magnet out of its foundation by pushing a 1/16" rod -- bent into the shape of a 'U' -- up through that hole.

After drilling out the magnet push-out holes the foundation blanks are sanded on all faces, with particular attention paid to the angled face that will later (after the individual foundations are cut off) make the bond between it and the inside of the sail or superstructure.
Criss-cross the top of each foundation with a saw-cut channel. These channels later insuring complete adhesive saturation of magnet and foundation.

A prepared magnet foundation receives a magnet, pushed in so that half its thickness is within the hole, and half projecting off the face of its foundation. The hole is tight enough so the magnet will stay there without glue as you go through the 'deck magnet location' operation. However, the magnet fit is just loose enough to permit you to push it in further during the 'seating' operation.

Later, after the foundation is glued to the inside of the superstructure or , with the deck magnet temporarily atop the magnet set in the foundation, and the deck piece is pushed down till it makes contact with the superstructure flanges; this pushes the foundation magnet deeper into its foundation; at which point the upper face of the deck magnet shares the superstructure-deck attachment plane.

Thin formula CA is used to glue the polyester resin magnet foundations to the polystyrene plastic kit parts. Prepare both surfaces with a good scrubbing of #240 sand paper or sanding sticks. This removes anything that might inhibit the glue, and also increases the surface area where glue will be applied.

The latching magnets for the sail are arranged a bit different than those used to latch down the deck pieces to the superstructure. Though, in common with the deck-superstructure latching magnets, the sail-to-deck arrangement employs magnet foundations -- two of them aft, a specialized one forward. However, the three deck magnets are set into holes drilled into the deck to receive them. As there is no detail to be ruined by the inlay work here.

Also note that the cast resin magnet foundation at the front end of the sail is a conformal fit within the cavity of the magnetic compass housing. The larger pair of disc-type magnets are employed at the front of the sail.

To better illustrate how the magnets are used to hold down the three deck pieces, I've made this training-aid. Note that the objective is to get the deck piece to sit solidly on the superstructure (hull) longitudinal flanges. To insure maximum atraction between superstructure and deck magnets it's vital that they either touch or nearly touch with the deck sitting on the superstructure flanges.

This illustration, with provided nomenclature, will help make clear what I'm talking about as I explain how the magnetic latching network goes together on this model. Magnets are used to hold the sail to the middle deck piece, and magnets hold the three deck pieces tight against the superstructure flanges.

('Superstructure' denots those non-pressure hull portions of the hull structure -- what the deck pieces sit atop).

Unlike the sail-to-deck latching magnets, the deck magnets are glued directly to the underside of the deck pieces -- with all that great detail molding into their top faces, to drill into these pieces would have been a crim! So, I was compelled to glue the deck magnets to the bottom face of the deck pieces.

M

[He Who Shall Not Be Named]

An SD securing foundation with attached Velcro strap. Next to it are the parts as they arrive with the 1/72 Type-9 fittings kit. You'll have to come up with the indexing pin round stock.

Grind away the right-angle portions of the keel well to fair the Velcro strap around the SD at the base. And while you're at it, grind away, at their bases, the radial indexing flanges molded within the hull that would have embraced the un-used hull bulkhead pieces -- these would otherwise keep the SD from getting as low into the hull as possible.

You will index the SD to the hull using the Dumas dog-bones as a guide: you drop the SD into the hull, slide it fore and aft as you engage the two dog-bones into the propeller shaft couplers and SD drive shaft couplers. Once the dog-bones are engaged and hard up against the propeller and SD shafts, move the SD forward 1/16" to give a little clearance. Hold it there and mark the hull where the 1/8" SD indexing hole is (at the bottom of the SD's ballast tank). Glue the SD foundation within the keel well so that it's indexing pin is in alignment with that mark. The indexing pin secures the SD from longitudinal and rolling movement. The Velcro strap keeps the SD from moving vertically.

Before gluing the magnet foundation to the superstructure you first round-file an indentation in the rail-like superstructure flange. This half-circle indentation affording clearance for the outboard portions of the deck magnet.

You want to provide three pairs of latching magnets to the forward deck piece; two pairs of latching magnets to the after deck piece; and four or five pairs of latching magnets to the center deck piece. At the two breaks between the three deck pieces place two sets of latching magnets no further than 3/4" from the break. Mark with pen or pencil on the outside of the superstructure where you intend to position the foundations -- consider what, if anything, will get in the way later and adjust accordingly.

.... I failed to do this with the after deck piece, finding later that the aft set of magnet foundations interfered with operation of the rudders. So, those had to be busted loose and repositioned. Check twice, glue once!

As the angle of the superstructure sides vary over the length of the hull you will select a foundation that suits that angle. If you find that none of the supplied foundation blanks account for a particular angle, then take the blank with the most extreme angle to its face, cut out the foundations you need, and grind its face to match the station on the superstructure it will be glued to.

You'll use thick formula CA to adhere the magnet foundations to the inside of the superstructure. This glue cures slowly -- giving you time to move the foundation up and down until the attached deck magnets upper face is about .010" above the superstructures deck mounting flange.

Leaving the deck magnet still atop the superstructure magnet you lay down the deck piece and push down on it till the bottom of the deck makes contact with the superstructures flange. While you did that the friction-fit magnet in its foundation bore slid down the required amount, placing the upper face of the deck magnet exactly in the same plane as that of the flanges upper face. In this condition the deck sits on the superstructure flanges and the latching magnets are as close together as you possibly could get them.

You then drop a 'finder' magnet atop the hull. This finder magnet permits you to identify the position where the deck magnet will be glued to the bottom of the deck piece later. As best you can, use pen or pencil to circle the finder magnet.

This is rather sloppily done by tracing with pencil or pen around the 'finder' magnet -- all that good high-relief detailing atop the deck makes marking-out a chore. Now you see why I don't advocate simply punching holes into the deck to inlay the deck magnets -- doing so would ruin all that fine looking detail on the deck pieces.

Once you've seated a superstructure magnet, you remove the deck, pull the deck magnet off the superstructure magnet and set it aside for later cleaning and abrasion -- steps that prepare it for gluing to the bottom of the deck piece.

A neater alternative to the pen or pencil marking is to punch out holes in pieces of masking tape and to place the tape around the 'finder' magnets. The holes in the tape, stuck to the top of the deck piece, indicate where to put the 'finder' magnets when it comes time to glue the deck magnets to the underside of the deck piece.

And here is a properly seated superstructure magnet -- the distance between its face and the top of the superstructure flange about equal to the thickness of the disc-type magnet. Exactly the distance below the bottom face of the deck piece the mating face of the matching deck magnet will be with the deck sitting on the superstructure flanges.

Temporarily pull the deck magnet away from the superstructure magnet. Soak in lacquer thinner, wipe clean then sand, with #400 sandpaper the edge and face of the magnet that will present to the underside of the deck. Reinstall the deck magnet to the superstructure magnet.

The cleaning and abrasion will facilitate a tight glue bond between deck magnet and deck.

A finder magnet, through magnetic attraction, holding a deck magnet in correct position preparatory to gluing the deck magnet permanently in place.

On the bottom face of the deck piece, where deck magnets will go, rough up the surface with #240 sandpaper. With a deck magnet properly positioned with the aid of a 'finder' magnet, lay down some thin formula CA adhesive and run the glue around the perimeter of the disc-shaped magnet. But, minimize glue build-up to the outboard edge area of the deck as it would interfere with a proper fit between deck and superstructure. Once you have a healthy puddle of glue down, hit the mess with a sprits of accelerator. Wait a few seconds and build up more glue to the inboard areas of the magnet to achieve a fillet between magnet and deck.

Don't forget to dab a small amount of thin formula CA around the superstructure magnet. This easily done by laying a drop of the glue to one of the channels previously cut into the upward face of the foundation, leaving it to capillary action to get the glue to every contact point between magnet and foundation.

The three-piece deck, through fortunate accident, works out for us: The forward section can be separetly opened up to gain access to the SD mission switch. This means you don't have to pop the entire deck to perform the simple function of turning the system on and off. It also gives complete access to the removable bow torpedo tube nest should you incorporate that feature. Through this opening you also get access to the bow plane linkage.

The removable stern section presents the rudder mechanism, stern plane linkage, and after torpedo tube nest should you install the weapon system.

The after set of magnet foundations you see here was a wrong move on my part, as they interfere with the later installation of the rudder mechanism. Fortunately, a quick twist on the foundation with a pair of pliers (what do you call two Filipino Aviators?... never mind) easily breaks the weak-in-shear-and shock cyanoacrylate adhesive used to bond the foundations to the superstructure. The foundations moved aft a bit, which worked to clear the rudder mechanism.

The end-game is a sail, three deck pieces and superstructure that attach to one another exclusively through magnetic force -- no other fasteners are required nor employed. This makes for an r/c submarine that is easily accessed, but whose access points are securely held together without need of unsightly screw heads.

[He Who Shall Not Be Named]

The Caswell-Merriman SAS Sub-driver (SD) -- the system that propels, controls, and manages ballast water --- makes use of a Semi-ASpirated ballast sub-system which requires a float operated induction valve (head valve) mounted within the model submarines sail. Here you see the snorkel mechanism (of the horizontal type) next to the 1/72 Type-9's sail. It's the job of the snorkel head-valve to open up to atmosphere only when the valve is above the water's surface. When underwater, the valve is closed, preventing a potential flooding path into the SD's interior.

The horizontal type snorkel mechanism has to fit within the sail, with care being taken to insure that the float and attached float-arm are not obstructed by any of the SD items projecting slightly into the sail. For that reason it's vital that you place the SD within the hull as I've outlined! Note that the inlet nipple on the SD's four-point manifold is well forward, clear of the snorkel mechanism. This is where the snorkel induction hose hooks up to the sub-systems induction line.

The horizontal type snorkel is used on low, wide and/or long sails -- as a general rule, submarine model depicting subjects built before the cold-war era. The vertical type snorkel is used on tall, narrow and/or short sails. Both the horizontal and vertical type snorkel mechanisms serve the same function: to isolate the induction line against water entry once the sail goes underwater. With the snorkel head-valve closed (underwater) the SAS ballast sub-system will draw blow air from the Sub-driver dry spaces until the model either surfaces (where the snorkel head valve opens, admitting air to the SD), or the pump stalls due to the high vacuum created.

This shot will help you understand how the snorkel mechanism fits within the sail . Also note that I've taken the added step here to provide optional snorkel mechanism mounts -- these permit me to quickly install and remove the mechanism should the need arise. Normally, you're fine tack-gluing the three legs of the mechanisms foundation to the underside of the gun-platform deck. Note that in this arrangement I've run the snorkel induction hose around the float and float arm with a fairing tube -- this insures the hose will not jam the mechanism by getting under foot, which would preclude the SD getting surface air when the sail broaches the surface, failing to break the vacuum within.

The sail connects, system wise, to the SD through the induction hose that runs between the snorkel head-valve and SD four-point manifold -- it's at this manifold that air is either taken to blow the ballast tank from atmosphere (through the snorkel) or from the dry spaces of the SD itself (through the safety float-valve, explained later).

Note that the stock foam float has been trimmed a bit with sandpaper to conform to the tight confines under the sails bridge deck. Also note that a short length of 3/32" o.d. brass tube is used as a connection point between sail and the rest of the model.

This is how things should look as you set the sail down onto the deck: the snorkel induction hose well forward and, as you lower the sail down upon the deck, the slack in that hose tucked within the annular space between the SD and deck.

Unless you are running coaxial cable up the periscope to feed a 2.4gHz r/c systems antenna, the induction hose is the only system related connection between sail and SD.

This SAS ballast sub-system mock-up will give you an idea of how the snorkel relates to the rest of the SAS type ballast sub-system (this particular snorkel mechanism is of the vertical type): air to blow the ballast water out of the ballast tank comes either from atmosphere -- through the open snorkel head-valve; or the air is scavenged out of the dry spaces within the SD through the safety float-valve).

That brass bottle is the safety float-valve -- its job is to prevent water within the flooded induction line (an abnormal condition, and real bad Ju-Ju) from getting into the SD's dry spaces.

The safety float-valve and snorkel head valve constitute the 'two-valve protection' I learned to embrace as a qualified submariner. Two-valve protection... don't leave home without it!

And here is a practical example of the relationship of the snorkel mechanism (in this case a vertical type, not the horizontal type used with the Type-9 model) to the other elements of a typical SAS equipped SD.
If you are interested in a detailed presentation of the SAS type ballast sub-system now employed by many of our Sub-driver's, I invite you to down-load and study the document found here:

http://support.caswellplating.com/index.php?/Knowledgebase/Article/View/363/23/the-sas-system---how-it-works

With the SD secured within the hull you need to make the external pushrods (that make up magnetically to the SD's internal pushrods) that actuate the rudders, stern planes, and bow planes. Study the above photo. As you can see, all you need are lengths of 1/16" diameter brass rod, and our magnetic couplers. All points of contact to the pushrods (with the exception of the rudder bell-crank) were secured with the magnetic couplers. The pushrod-to-rudder bell-crank connection was made through the more traditional Z-bend union. But, there is no good reason why that connection could not also have been achieved through the use of a magnetic coupler.

With the SD firmly indexed to the model there is no possibility of a shift of SD position, which would throw all linkages out of alignment. For the sake of simplicity, elimination of linkage back-lash, and ease of installation/removal, almost all unions between pushrods and SD and bell-cranks is done with magnetic couplers. We all have Brian Stark to thank for this innovation.

And here is an example of what the more traditional form of pushrod-to-bell-crank connection looks like. I employed the classic Z-bend to the after end of the rudder pushrod. The pushrod directly making contact with the bell-crank. I will later change this out by installing an iron machine screw into the hole of the bell-crank and outfit the after end of the rudder pushrod with a magnetic coupler -- which will make it look very much like what you see now in the lower stern plane coupling of magnet-to-iron bearing machine screw of the stern plane bell-crank.

Pushrod shape and length is driven by distance-to-SD coupler, and relative height of control surface bell-crank to SD magnetic coupler position, i.e. the pushrod for the rudder is a short, straight shot between SD magnetic coupler and rudder mechanism bell-crank; the stern plane pushrod, on the other hand, couples to the SD high, but must meet the very low mounted stern plane bell-crank. Hence the radical bends along the length of the stern plane pushrod.

The bow plane linkage, as you would expect is simple: the pushrod pushing and pulling on the bow plane operating shaft bell-crank. There is enough magnetic force to assure a non-break union between magnet and iron screw under normal conditions. However, it's a union that will part when pulled by hand or if the planes are subjected to a shock-force, such as would be encountered in a collision or rough handling. Such 'shock-absorbing' unions in the control surface linkages work to isolate the SD servos from gear-stripping loads.

M

[He Who Shall Not Be Named]

To be statically stable (tits down, not tits up) on and beneath the surface a vehicle must be dense down low, and less dense high. We pack dense material into the hollow keel area, lead is a reasonably dense material that is (relatively) cheap and workable. We pack high-volume, low weight (read: un-dense) material up high, but no higher than the designed waterline.
Center of gravity low; center of buoyancy high.

Ten-ounces of lead fixed ballast weight in the keel trough, and an approximate amount of foam up high hanging off the sides of the superstructure to displace at least ten-ounces of water. This is the initial load-out of fixed ballast weight and foam -- things will get fine-tuned later.
Always do the hard stuff first. In this arena the hard stuff is cramming foam between the installed SD and inside vertical surfaces of the superstructure. But, here's where the foam installation can help you: if you find that the port and starboard sides of the superstructure are bowed in too much, you can work the fit of the foam to push against the SD and push the superstructure out to where they should be. This can be a big deal as you will later install deck railing that could be damages by the deck pieces when they pop out of a badly sprung superstructure. Work the foam job right and those deck pieces will match the opening in the superstructure.

Here you see some of the tools and consumables used to work the foam blanks: round and flat sanding blocks, knife, Sharpie pen, and Permatex Gasket-Maker (the blue RTV adhesive).

You start with foam blanks. Pink or blue insulation foam. It's polystyrene, but the big deal is this: it's of a closed-cell structure .... it won't water-log on you! Don't use the white stuff -- it's open-cell and will take on water like a sponge over time, ruining your initial trim.

Start out with a half-inch thick sheet of the stuff, then strip it into a few two-inch strips, and cut those strips into three-inch long blanks.

All blanks are roughed out on the inboard side to a concave semi-circle with a one-and-a-quarter-inch radius (2.5" diameter cylinder ... duh!). Start at the center of the SD. Sand in a cursory convex curve where the foam meets the superstructure-hull. Each set of foam blocks is unique, owing to the tapper of the hull. As you work them to a tight fit make sure that each foam block is oriented so that the top face of each is even or no more than 1/16" lower than the bottom of the big limber holes running along the sides of the superstructure. This puts the buoyant foam just below the designed surfaced water line.

Periodically, as you complete the rough sanding of a foam block set, install it, and test fit the deck pieces to the superstructure. Keep shaving the outboard faces of the foam pieces till the deck sits properly on the superstructure flanges. Repeat for the rest of the foam blanks.

Work out how you're going to get the fixed ballast lead into that keel. You want ten-ounces of lead in there. Work it out! Insure none of the fixed ballast weight does not make contact with the bottom of the SD. It matters not a bit if the led is sheet, like what I'm showing; bar-stock; bird-shot; inlay strip; car tire balancing slugs; cast to suit; gravity model car weights; stained-glass lead wire; or transmuted waste from the Hanford B-reactor ... I don't care! Ten-ounces of lead.

You're going to give up a whole day to it, but when you're done, the foam pieces girdling the SD will push the superstructure out just enough to make installation of the deck pieces an easy operation.

Once you have them sanded to fit properly, mark the location of each foam piece onto the superstructure, and pull them out. Remove the SD. Finally, using Permatex RTV adhesive, bond the floatation foam within the superstructure.


Note that installation of the lead fixed ballast was deferred until all the foam work had been done -- as the foam fitting is a very labor-intensive process, necessitating extensive handling of the model hull, why burden yourself by making the model unnecessarily heavy with installed lead? So, with the foam pieces in place, your next step is to install the lead. More Permatex RTV adhesive.

M