Merriman's Submarine Modelling

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The Anti-Proxmire
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You are very hands on—and I applaud that. I don’t even deserve to be called a kit-assembler less a model maker…but with some of the tech coming out…I wonder if you could make a sub…parts and all…absolutely clear.

Maybe metamaterial strips wrapping the metal bits?

It might disappear in the water…
 

merriman

David Douglass Merriman lll
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You are very hands on—and I applaud that. I don’t even deserve to be called a kit-assembler less a model maker…but with some of the tech coming out…I wonder if you could make a sub…parts and all…absolutely clear.

Maybe metamaterial strips wrapping the metal bits?

It might disappear in the water…

I think you'll find some clear, or semi-opaque resins suitable for 3D printing. Can't speak as the physical properties of that stuff as that's a game I refuse to play.

At least 20 years ago there was this effects guy out of California, Rick Galinson, a mechanical and electronics wiz, who produced a 3-foot long Acrylic r/c submarine. A true work of engineering and materials usage. A detailed demonstration of that model right here:

View: https://youtu.be/dJ4PtROgUvc


19:48 - 28:15

A transparent submarine? What's the deal, you just got a commission from Wonder Woman or somth'n? I demand a finders-fee.

David
 

merriman

David Douglass Merriman lll
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A single machine screw at the stern is the only thing holding the upper and lower hull halves together. This simple and quick means of attaching the hull halves is possible through utilization of the 'Z-cut'. Named because if you look at an assembled hull from the side you will note that the three breaks between the halves form a 'Z' pattern; the forward radial break, at the bow, runs from the keel up to the central longitudinal break that that runs aft nearly the entire length of the hull and transitions as a radial break traveling up from centerline to the top of the tail-cone. When assembling the two hull halves a recessed radial flange in the lower hulls forward end tucks up tight within the bow portion of the upper hull.

All it takes to assemble the hull is to engage the forward radial flange of the lower hull into the bow piece of the upper hull, then lower the after end of the upper hull down onto the stern cone radial flange and make up a single machine screw to hold that down tight. That's all there is to it.

A quick, fool-proof, and effective means of gaining access to the internals of the wet-hull type r/c model submarine. And who do we have to thank for this scheme that has been in vogue now for several decades? Dan Kachur and Greg Sharpe. To the best of my knowledge these are the guys who developed and popularized this method of internals access.



I modified the flange-forward bearing foundation piece by opening it up a bit. This done to facilitate a GRP reinforcement of the tail cone-to-hull union after tacking it in place on the lower hull with CA. Though this weakens the bearing foundation a bit axially, I determined that the backing loads presented to it in operation will be no where strong enough to distort or break the bearing foundation under extreme backing maneuvers. (best laid plans of mice and men...).

Cast polyurethane resin is easily milled away using a common drill bit spun at high speed. Only took minutes to perform this surgery.



It's vital that every kit part, be the substrate polystyrene, polyurethane resin, epoxy-glass, metal or wood be prepared for adhesive operations by removing all oils, greases, fuzz, pitch and water from the model parts surface. In the case of polyurethane and GRP structures I'm dealing with here, a good scrubbing with lacquer thinner is the best way to go. The soaking is short-term (too long in the bath and the resin parts will go wonky on you) and accompanied by vigorous scrubbing with a stiff brush, steel-wool, a green-pad or other such conformal tool that will get into every crevasse and crease.



With the radial flange-forward bearing foundation permanently adhered to the tail-cone I installed the forward Oilite bearing and centered it with a short length of handy 3/16-inch diameter brass tube. I then applied thin formula CA to secure the bearing in place.



The after end of the lower hull -- where the flange of the tail-cone would seat -- was ground to a wall thickness equal to the radial flange recess depth of the stern-cone. Repeated test fittings (a tight friction fit assured by the leading edges of the horizontal stabilizers nesting up tight against the outside of the lower hull) and grinding away at the internal wall thickness of the stern finally got things to the point where the surface of the tail-cone matted flush with the lower hull.

Initial bonding of the tail-cone to the lower was with CA adhesive. But only to fix the assembly in place. The real strength element holding the assembles together would be fiberglass tape saturated with epoxy laminating resin.



Before tacking the tail-cone in place I ran a 3/16-inch rod through the bearings, carefully adjusting the tail cone position till the rod ran down the hulls longitudinal centerline. This insured that the propeller shaft thrust-line would be perfectly aligned with the centerline of the hull.



The CA was applied inside and out, wherever the resin tail-cone met the GRP lower hull. Using thin formula CA insured that capillary action would drive the adhesive into gaps I could not get at otherwise.

It was in this condition that the CA was applied and left to sit for a night as the adhesive found its way and cured rock hard.



The trouble with most CA adhesives is that the cured bond fractures easily when subjected to a shear shock-load. And since most of us r/c submarine jockeys play hard and drive stupid-fast, collisions with pool sides, bottom, and each other are a fact of life. So, without a more resilient bonding medium, CA is not enough to hold the tail-cone in place.

Here I'm overlaying fiberglass cloth, saturated with West System epoxy laminating resin over the union between GRP lower hull and resin tail-cone assembly.



I laid three plys of fiberglass cloth to each side of the tail-cones lower rudder operating shaft hole. Each layer of glass long enough to extend about a half-inch forward and aft of the radial flange-forward bearing foundation piece.



NOW! This is one tail-cone assembly that won't be knocked off without a fight the other guy will long remember!

View: https://youtu.be/t7gDrTtxnWo




The single 4-40 flat-head machine screw that holds the upper hull down tight upon the lower hull. It's the recessed radial flange at the front end of the lower hull, engaging within the bottom bow piece of the upper hull, that holds the front-end in place.

The tapped hole in the resin flange of the tail-cone is not strong enough for field use. I'll install a metal insert drilled and tapped and glued within the radial flange eventually -- this will make the fastening strong enough not to strip out with usage.

 

merriman

David Douglass Merriman lll
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The tail-cone and lower hull now one, it came time to assemble the model and Bondo fill the inevitable longitudinal and radial gaps and miss-matches. But, before all that, I scrubbed the entire model with an abrasive green-pad soaked with Prep-Sol, a mild hydrocarbon solvent used by auto refinishing guys to prepare a surface for adhesion to fillers, putties, and primer. Same with model building -- clean that sucker right or your stuff won't stick with any permanence.



Here are the consumables and tools used to build up automotive filler to the low spots as well as those spots that out and out require a re-contouring --specifically the point where the stern of the upper hull half sits atop the tail-cone radial flange.

The Bondo is a two-part, heavily filled polyester paste that is trolled on with putty-knife, finger, or purpose shaped screeding blade. The wax is applied to areas I don't want to stick to the Bondo. The tools are used to knock down the cured Bondo till the low spots are brought to proper contour with the high spots. The file-card and stiff brittle brush are used to clean the teeth of the files as the Bondo quickly clogs the tools which markedly reduces their effectiveness.



The biggest non-conformance between the hull halves was at the stern where the end of the upper hull sits down on the tail-cone radial flange of the lower hull.

There is a sharp 'spine' atop the end of the upper hull which I've picked out here with a pencil lead. I not only had to apply filler atop the stern-cone, I had to continue the spine a bit. The hash-marked area is my estimate of how far the Bondo build-up will travel atop the tail-cone.



I've CA'ed a piece of plastic sheet to continue the spine atop the tail-cone. this will help me guide the putty-knife as I trowel on the Bondo.



After hash-marking where Bondo would be built up I dis-assembled the hull halves and applied wax to the areas I did not want the goo to stick.



The assembled hull was then given the Bondo treatment with the aid of a spatula type putty-knife used at the bow and stern, and a custom shaped screeding blade to address the longitudinal seam areas.

Once catalyzed the Bondo cures quickly, so once a batch was mixed up on the palette I had to get it transferred to the model and troweled out lickity-split.



Once cured hard the Bondo was carefully ground down with a big coarse file, followed by a second-cut file, then a sanding block faced with #200 grit sandpaper. It takes several applications of the Bondo till all the low spots are identified and filled. But, the work goes quickly. All the operations you see in this installment were done in a ten-hour period.



Almost there.



After block sanding the Bondo I brushed on a thick coat of air-dry touch-up putty (good old, Nitro-Stan) to fill file and sanding marks. Tomorrow I'll wet sand everything, then hit the model with a check-coat of gray primer.

I should note that after each application of Bondo and putty, the radial and longitudinal seams were chased open with an X-Acto blade. Gotta do this to keep from sticking the hull halves together once the Bondo or putty had hardened. Forget to do that and you are sooo screeewwweeeeddd!

 

merriman

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The hardened touch-up putty was wet sanded initially with #240 sandpaper, followed by #400. Along the length of the constant diameter portions of the hull, where the surface is a simple curve, I used a block to back-up the abrasive. However, when I got to the bow and stern tappers, where the surfaces of the hull transition to compound curves, I switched to a soft block. The soft block having the 'give' required to permit the abrasive to conform to those convex surfaces.



A look at just some of the abrasive tools I've gathered over the decades. Nice to have choices! For the tight, right-angle areas I use double-backed sanding squares and sanding sticks. Rolled up abrasive paper is used for chamfering and round and oval hole refinement.







When all the putty sanding was done, I wiped the work down with a well rung out damp paper towel and waited for everything to dry thoroughly. I then sprayed on automotive grade air-dry acrylic lacquer primer to check the work. Initially, with the two hull halves apart, I primed the edges, both radial and longitudinal.



Once those area had dried (this primer flashes hard enough to handle in no time), I assembled the hull and primed all areas that had been worked with filler and primer.



Time to turn my attention back to the WTC:

The motor-bulkhead was outfitted with a stern plane servo, a bow plane servo, and a rudder servo. The big deal was bending the servo pushrods so that they would experience the minimum amount of drag as they traveled through their respective watertight seals.

In hand is a vital piece of test-equipment, a servo-setter. This device produces the same pulse amplitude and width (variable from 1ms to 2ms) produced by the transmitter for a specific servo. Most helpful while working out the bends in the pushrods. Use of the servo-setter side-steps the need of hooking up the servos to the receiver and fiddling with the transmitter to wag the servos.



A little mill work to get the servos to fit their respective positions on the servo foundation.



Note the extensive milling done to the center of the cast resin servo foundation. This done to drop the receiver well below the servo control horns -- to avoid any contact between the moving parts of the servo and attached pushrod and the receiver.



It took some effort, but I was able to get the receiver to nest tightly between the three servos.



Each servo was set in place with two drops of thick-formula CA adhesive. As there is so little room within the tight confines of the cylinder, I had snipped off the mounting flanges that projected from the ends of the servo case. That move necessitated the need to make them fast with glue.

 

merriman

David Douglass Merriman lll
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Representative of the type water tight cylinder (WTC) I produce is this shot of a completed unit. Below are the basic parts of a WTC.



So, back to the WTC I've built for Casey's 1/96 BLUEBACK model. Before populating his WTC with the devices, I sat each one on the table and went through the set-up protocols outlined in the instructions that accompanied each device. Better to do this off WTC than in it... because things NEVER go right the first time you go through a set-up routine! No matter how well written the instructions are. And KLM instructions are the best I've seen written in the English language.



The first devices to be set-up and certified operational were those that required connection to the power bus.

Certified in good working order, these devices were attached to the motor-bulkhead mounted aluminum device tray and bulkhead with the aid of double-backed servo tape. Those items included the low pressure blower (LPB), battery eliminator circuit (BEC), battery & link monitor (BLM), and electronic speed controller (ESC). The input power wires of these devices were all ganged together in parallel and soldered to a male Deans plug. Later, power cables from the forward dry space battery would run aft, terminating in a female Deans plug.



The devices, all mounted to the motor-bulkhead, require only three plugs to interface with the rest of the WTC: The big power bus Deans connector just described, a small Deans connector between the LPB motor and ballast servo limit-switch, and the J-plug of the ballast servo itself. Use of these three connectors make installation/removal of the motor-bulkhead assembly from the cylinder a quick, and easy procedure.

Here I'm soldering the wires to a small Deans plug that makes up to the ballast servo limit-switch. The other half of the little Deans connector has already been made up to the LPB and power bus.




Casey wanted the KLM Depth Commander (DC) device installed. Here I'm verifying the sensitivity of this hydro-statically sensitive device with a column of water in that little hose I'm holding.

I found that the device will deflect the bow plane servo in the required direction with only an 1/8-inch variance in water height. Wow!

This device will automatically hold the submerged model submarine to a specific ordered depth. I've been using these depth-controllers for a couple of years now and found that they greatly reduce operator work-load when driving the model around submerged -- all you gotta do with this thing on line is steer and manage the throttle... if only it could cook!



In the very tight confines of the after dry space of the WTC one must make every effort to reduce the wire runs. Such is the case with the device three-wire leads (servos, DC, ESC, BLM, and angle-keeper). There was way too much slack in these wires, so I cut them short and crimped on new female pins designed to slip into standardized J type Futaba connectors.

Here you see discarded leads. Note the tight packaging of devices and short runs of their leads once everything had been tightened up. Good house-keeping is a virtue in this game.







The power bus is switched on-and-off by a magnetically actuated switch. Yet another KLM device. Here I'm making up the input and output wires to this little device. This switch is situated in series between the Lithium-polymer battery and power bus.



Just wave a magnet over the switch and power is delivered down the power bus to the motor-bulkhead devices. Wave the magnet again, and power is secured. Slick!



The gory details:









 

merriman

David Douglass Merriman lll
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With the WTC up and running (but not yet leak checked and suffering a yet to be determined servo chatter during a loss-of-signal event) I returned to the 1/96 BLUEBACK hull chores for a last round before integrating WTC and hull.

The hull parts again front and center I had found that the end of the tail-cone was a slightly smaller diameter than the propeller hub, which would necessitate a build-up of the stern diameter to match the propeller hub. Poor planning! I should have caught this before getting the tail-cone into primer gray. I got rushed. Stupid!

The end diameter was about .050-inch shy of that of the forward face of the propeller hub. Damn! Had to fix that.



And -- as the sail sat within a shallow well built into the deck of the upper hull -- during a test-fit I observed that there were significant gaps between the sides of the sail and the vertical walls of the well. That would have to be fixed as well. Another job for Mr. Bondo. I love that stuff.



Before slogging through all the muck, here's the end-game of this post:

A properly shaped tail-cone-to-propeller hub contour; and a tight, gap free, fit of the sails base within the shallow well of the upper hull. Looks nice, huh? Well... the getting there is the hard part, pal! On to the gory details.



There were many little pin-hole voids in the leading edge of the tail-cone horizontal stabilizers and leading edges of the vertical stabilizers. These were filled with CA adhesive and baking soda sprinkled on to form a quick setting, hard 'grout' that was then worked to contour with careful use of a small flat file. Those areas were then given a light brush-coat of Nitro-Stan touch-up putty. While brushing on the putty I also addressed some areas where tool-marks were still evident in spite of the heavy primer coat previously sprayed on.

At this point in the project I was still blissfully clueless of the too-small diameter at the end of the tail-cone. THAT should have been the first thing I identified before all the fill and putty work. What a dumb-ass... I'm supposed to be good at this shit.



When sanding simple curves on a uniform substrate, I make use of a stiff sanding tool formed from a brass strip outfitted with sandpaper on both faces. #400 grit on one face, #220 on the other. Here I'm wet sanding the putty.

Typically, I'll use a 'soft' sanding block when working a compound curve, like this union between the GRP lower hull and resin tail-cone. But here I'm using the stiff sanding tool. This because there are four different substrates being ground away, each of varying hardness to the other: GRP gel-coat of the lower hull; polyurethane resin of the tail-cone; soft touch-up putty; and hard CA at the hull and tail-cone union.

A soft sanding block would permit the backed-up sandpaper to flex into soft mediums, cutting too much, but ride over the hard mediums, with little cut. The result would be dips where the soft stuff is and bumps where the hard stuff resides. A stiff sanding block won't have any of that! It cuts to a straight plane regardless of substrate hardness.

Hence my use of the hard-backed sanding tools at the tail-cone-to hull interface point. But, later, once I'm just working primer, that's when I fine tune such areas with a soft block.



I use an adjustable radial screeding blade to build-up the diameter of a tail-cone. Not much to it: A pin that fits the bore of the stern tube, and a blade that can be set in diameter and angle to develop the required diameter and taper angle -- that new diameter the same as the forward face of the propeller hub.



Radial screeding is simple. Set up the screeding blade angle and diameter, slather on some Bondo to the ass end of the tail-cone, and rotate the tool by hand. It takes about three cycles to get all areas of the stern re-built like this, but total work time is less than ten-minutes. Bondo is our friend.



After some touch-up work with flat file and sanding block the Bondo areas are coated with a layer of CA adhesive. This fills and strengthens the otherwise porous Bondo. Another wet sanding and the re-contoured tail-cone is ready for primer (again!).



The sail initially sat with a pronounced lean to port when test fitted. That had to be fixed. Here you see the re-worded well corrected to both mount the sail perpendicular to the hull and tightened up to show only the barest of gaps between sail and well.



Within the well that accommodates the bas of the sail you can just make out the hash-marked area I'm going to cut out. Three reasons: first is that you want to take every opportunity to reduce the above waterline structures that would otherwise displace water -- the lower the displacement, the less ballast tank you need to assume submerged trim; second reason is that I need access into the hollow sail in which to pass the pushrod that operates the sail-planes; and third, this opening will quickly vent air and water in and out from within the hull and sail as the boat transitions between submerged and surfaced trim.



Using a standard 1/16-inch drill bit in a high-speed hand-tool I free-handed the bit within the outline -- a poor mans milling bit. The work went quicker and with more precision and speed than would have been the case had I done the work with a cut-off wheel and carbide burrs.

Note that only two machine screws, run up from within the upper hull, are used to secure the sail atop the upper hull. Whenever possible I make as many sub-assemblies removable in order to facilitate later repair, adjustment, or maintenance. The philosophy obviously shared by the kits designer, David Manley.



Initial dry-fitting of the sail atop the hull revealed that it sat canted several degrees from vertical; it was leaning to port. The solution was to lower the starboard side of the wells base to bring the sail into proper alignment. Where to shave? How to identify the 'high' spots? That was solved by coating the base of the sails starboard side with sticky, messy, gets-everywhere-you-don't-want-it oil based crayon.

The crayon black is smeared to the starboard bottom of the sail, the sail pushed down into the well, lifted out, and the high-spots picked out by the black smearing.



I went mid-evil with chisel and files.

The smear-chisel-check cycle repeated till the sail sat perpendicular to the hull.



As I only wanted Bondo to stick to the walls of the well I applied wax to the bottom end of the sail. Giving the wax an hour to harden, the sail was then set in place and secured tight with the two machine screws.



Only two 2-56 machine screws are required to hold the removable sail atop the upper hull.

I must say, David Manley, who is the guy who designed and produced this kit so long ago is still teaching me and guys like me new tricks. Just by working one of his kits the observant model kit-assembler can learn a lot about functional design and appropriate materials selection. I have stolen his ideas shamelessly and incorporate them into my own work whenever the opportunity presents itself.

Every aspect of the model-building Craft has its 'experts'. Off the top of my rather pointy-head let me rattle off a few of these dudes who have contributed so much to the Craft:

Those interested in static/display model aircraft (a more savage collection of anal-retentive, rivet-counters, and know-it-all's cannot be found) have guys like Ben Guenther (an alarmingly calm, gracious, and most helpful man); The static/display model car perfectionists have the unassailable icon of Gerald Wingrove; the model rocket egg-heads have the prolific Scott Lowther and Mat Irvin; the SF vehicle tin-hats have Martin Bower and David Sisson; the model ship guys have William Blackmore and August F. Crabtree; and we lowly r/c model submarine guys have our own David Manley, Matt Thor, Greg Sharp, Dan Kachur, and Robert Dimmack.




The sail secured to the upper hull I mixed up several small batches of catalyzed Bondo. Done in stages as the stuff cures quickly. The time it takes to do this job way exceeds the useful working time of this stuff if attempted in one cycle. The objective is to jam and force the Bondo into the voids between sail and sides of the well. The Bondo will... hopefully... stick to the sides of the well, but not stick to the sail.

Wooden putty-knifes were fashioned from tongue-depressors -- wood because a metal putty-knife would scrap away wax from the sail, leading to sticking of the Bondo to that structure. Something to be avoided.

Once the sail was popped off the well (no problems encountered), the wax was scrubbed off by a lacquer saturated abrasive sponge.

 

merriman

David Douglass Merriman lll
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There are many special interest groups (SIG) within the general hobby of radio controlled vehicles. Aircraft, be they fixed wing, helicopters, quad's, and blimps; cars and other wheeled ground vehicles; boats; robots; submarines; and a few other type vehicles -- they all require an operator in the control-loop, guiding the vehicle, sometimes at a great distance, through direct observation.

Hobby vehicle drivers have wanted the ability to shift their perspective from
their physical location to a view presented to them remotely from the vehicle itself; putting them, virtually, in the driver's seat, able to view the world from the vehicle itself rather than observation of the vehicle from a distance -- to see what the vehicle sees and control it from that perspective as though the driver himself was aboard the vehicle.

Today, hobby first person view (FPV) equipment is available, and we have the Juggernaut of the r/c model airplane community to thank for that. The fliers: those guys, tens of thousands of 'em, assured inventors, investors, and manufacturers that a market existed; a market large enough to warrant the effort.

Our very small group of r/c submarine drivers can now dine on the table-scraps of the airplane and drone guys; their win is our win. That gear is now available to us.



FPV equipment became a reality to the general public about the turn of this century with the availability of basic, low quality (by today's standards) camera-transmitters and virtual goggles. The intended market was those people interested in Home Security.

Over time advancements in picture quality, range, size and weight reduction, and standardization within the r/c hobby industry matured the equipment to the point where, today, a system can be bought at a very reasonable price and easily placed aboard the r/c model and put to work with little fuse or technical expertise.



Things started to ramp up for me in the FPV department when Walmart began selling these small, cheap camera-transmitter units, complete with ground-station receiver. This was my entry-level toy to the world of FPV as applied to r/c model submarines. That was about fifteen years ago.

By today's standard the image quality was bad -- these were the days before camcorders, cellphones, and dedicated video cameras went from 'standard' to high-definition (HD) quality imagery. But, for the time, the image was good enough if you really wanted that, I'm aboard the model experience.



The little Swann camera-transmitter unit, other than the power supply, was all inclusive. Only two modifications were required: first was to relocate the transmitting antenna via a shielded coaxial cable up to a position high atop the models sail, where it could project above the water as the model ran at periscope depth. This necessary as the high frequencies (typically in the 2-5gHz range) will not punch through water.

The second requirement was to install a voltage regulator between a 9-volt battery I recommended at the time and the camera-transmitter which typically dinned on 5-volts.

With these two relatively simply modifications the unit would fit within a 1.25-inch diameter acrylic cylinder outfitted with a clear lens forward and a streamlined after access cap at the stern. Atop this watertight enclosure was an antenna interface piece that mounted a streamlined aluminum fairing through which the coaxial cable passed, terminating topside in the 1.25-inch long 2.4gHz transmitter antenna.

Ellie and I produced the 'up periscope' watertight enclosure and made it available for sale during our tenure with the Caswell company. Market acceptance was, to be kind, awful!

Was it something I said?...



This was around 2007 and the associated virtual goggles, through which are projected the camera images into the eyes of the far distant driver, are nothing like what is common today: They was just two low resolution LCD's, one for each eye. Fuzzy. And the power supply had to be jacked into the goggles. Hence the need for this Batman utility belt my kid's wife sewed up for me -- just to hold all the gear needed to make me a walking, silly looking, 'ground-station'. (A tin-foil hat would have completed the look of a well-dressed techno-nerd).

The word, cumbersome, comes to mind about my early effort at FPV. But it worked. Not well by today's standard, but it was a thrill to finally drive a model submarine as though I was right there, in the water. One time, in a chop and trying to maintain periscope depth, I puked all over my pants -- it's that immersive! I've always had poor sea-legs.

All this as preamble to the gear offered today. Things have matured: the goggles now are consolidated with the other ground-station devices. The virtual goggles contain the OLED screen(s), receiver and antenna, audio output, power supply, and ability to scan the accepted bands and frequencies making matching of camera-transmitter and ground-station a simple operation. And somewhere along this road of evolution, picture quality went from 'standard' to 'high-definition'.

Below is 'old school' ground-station devices and utility belt. No more! To the Bat-Cave!



And what kind of r/c submarine is suitable for use of FPV? As the above photos illustrate, any model large enough for you to mount the watertight enclosure atop its hull or sail is a candidate for the system.

But for you purists like me, there are prototype submarines that have features that, without spoiling the look or hydrodynamics of the vehicle, lend themselves to internal camera-transmitters. I submit two fine examples: The 1/12 Williams Models, Japanese KAIRYU suicide submarine, and the 1/35 Bronco, German Type-23 coastal submarine. Both have a substantial 'opening' in the leading edge of their rather large sails from which a camera lens can peek out.



You can see my KAIRYU running submerged while towing a video camera here:
View: https://youtu.be/em5--spYYnM
and here,
View: https://youtu.be/H4q1NO_IQGk
(from 54:45 on)

I've built two of these models, this one, for me, was initially set up with a Swann type camera-transmitter set into a short watertight enclosure small enough to fit within the sail, its lens looking out the observers deadlight that was a feature of some of these little submarines developed to ward off amphibious invasions of the Home Islands. Two winks of God's eye negated any need for their use... thank you very much, Mr. Atom.



At this early stage of integration, I was planning on utilizing a long coaxial cable, attached to a float, permitting unrestricted maneuvering in depth. But, quickly abandoned this rather ugly approach to the simpler and more scale like, antenna-within-a-periscope approach.

A floating antenna is too juicy a target for racing hydro's and other fast boats. No thank you.



And here is the eventual arrangement: the antenna residing within the RF transparent hollow resin periscope head. It worked, but I quickly grew tired of squinting at the fuzzy picture presented me by the limitations of standard quality video which was only available during those early years of FPV.



I made a similar packaging of the Swann system for one of my 1/35 Bronco Type-23's, but never got it past the testing stage due to the poor performance of the same type camera-transmitter and ground-station used with the KAIRYU. Note how on this class of boat the camera lens looks out through the temporarily removed line-locker stowage canister door. Perfect!



The video worked, but never used operationally on this model. Arrangement was very much like that aboard the KAIRYU: coaxial cable leading up within the periscope tube, terminating in the antenna within a hollow resin periscope head.

It took over a decade later, but when the high-definition, even smaller camera-transmitter units became available did my interest in FPV operation of submerged r/c submarines flicker on again.



Now we're cooking!

I just received proper VR Goggles, with all the trimmings. And a companion camera-transmitter. They have been tested and worked right out of the box. I opted for the cheap goggles, so video quality is below HD, but much improved over the Swann type cameras I played with in the past.

When I get this set operational and tested in some clear pool water I'll decide if it's worth it to purchase a top-of-the-line VR goggles, like the $500.00 Fat Shark ground-station that is so the rage among the r/c fliers these days.

We'll see.



This basic, cheap, ground-station is fine for a guy just getting out of the stone-age, like me. Only cost about $70.00, but still is better than the old 'standard' quality video I got from the old Swann systems. And this ground-station is an all-in-one package. No more Batman utility belt required! The camera-transmitter could not be simpler: plug in a coaxial cable between the transmitter and antenna, run power to it from a 5-volt source, and you're good to go!



Nothing to getting both the camera-transmitter unit and power supply into a watertight enclosure and secured within the sail of the KAIRYOU and Type-23.



In the mid-90's I conducted my first practical experiments in receiving, from a submerged model submarine, intelligent RF energy converted to audio by a simple ground-station: an AM radio receiver. WA-La! Passive sonar.

I purchased a low-power AM audio transmitter kit, put it together, crammed it into the forward dry space of our just introduced WTC-3. Turning the thing on, driving the boat out a few feet at Lake Trashmore, then sitting the model submarine down in the muck. I tuned the AM radio head-set (my ground-station) to the transmitted signal and presto! I could hear what the submerged hydrophone was picking up. Boy... was it noisy down there, the Elite fleet had several boats in the water at the time and I could hear everyone except the sailboats (unless a sail-winch was in use).



Amazing! I could hear the over-head model boats running over or near my boats position. In time I could, just by sound, classify each type of model boat. Passive sonar, but without the ability to point at a source to get a bearing. Useless, but fun.

The entire 'sonar package', including its power supply, neatly fit into the cavity of the removable WTC forward bulkhead. The microphone was protected by a silicon oil filled condom and placed in the upper annual space between hull and the WTC's cylinder. Instant hydrophone.

Problem was, once my boat was off the bottom and underway and motoring about, the propulsion, servo, and other noises drowned out all outside sources. Yup! SKIPJACK's are loud boats. I have proof! My ears range for minutes.

I bring all this up because the new FPV equipment supports stereo sound as well as video. Now, with a little phase converter and a steerable hydrophone, I'll be able to get bearing info on a source.



Ah... the possibilities! Brave New World.
 

merriman

David Douglass Merriman lll
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To get a 'modern' FPV video camera-transmitter into a model submarine and in the water in time for the 2022 submarine regatta season necessitated some quick work. So, I set about completing a long-delayed assembly of my 1/35 Bronco, German Type-23 coastal submarine. Over ten years ago I assembled one and got it operational for our former employer, Mr. Caswell. So, I was well prepared to get this one in operational condition with few hiccups.

As I mentioned in the previous post, this particular model submarine is a good candidate for housing the camera system, as its large sail will fit the camera-transmitters watertight enclosure without spoiling the scale fidelity of the model.

First job was to split the upper portion of hull away from the lower, permitting installation of a watertight cylinder (WTC) and all the goodies required to wag control surfaces and make the spinning thing at the stern to go around-and-around.

Here are the tools used to mark and cut the hull sections away from one another: A hand razor-saw for the radial cuts. A waterline marking tool. And a Dremel circular saw to make the longitudinal cuts.



To enhance sales of the kit (Ellie and I were then working for the Caswell Company) we were encouraged to produce a product that would aid the average kit-assembler as he worked to convert the Bronco kit from a simple display piece into a practical well running r/c submarine. So, we produced a 'fittings kit'.

I think the hope was that the fittings kit itself would serve as a loss-leader; enticing customers to buy the real cash-cow of the conversion package, a WTC specifically configured for the 1/35 Type-23 kit.

Unfortunately, the labor-intensive fittings kit -- featuring machined cast resin and metal parts -- sold for more than people wanted to pay. Many observing that our product was more expensive than the plastic model kit itself (they were right). And with that failure all our hopes of brisk hull kit, fittings kit, and WTC sales went down the drain.

Availability of the fitting kits were received with as much enthusiasm as if we were trying to sell a shoe-box full of steaming dog shit with tufts of cat hair in it.

Lesson learned.


Anyway. I had a few fittings kits kicking around taking up space. One of these will speed assembly along as I work to turn this kit into a practical r/c submarine outfitted with a FPV camera-transmitter system.



Securing the hull down tight on a flat working board with taught waxed sail-twine.

That strong, slightly elastic, easy to tie twine was liberated from the TRUTTA during my navy days. Back then Torpedomen were the submarine forces answer to the Boatswain's Mate rate, and most of us became the boat practitioners of marlin-spike seamanship and line-handling. Decorative knot-tying a specialty.

Those skills shamelessly exploited by several commands as I caught 'extra duty' and found myself restricted to the ship till I overcame my evil ways. (Never caught brig-time, but boy did I come close sometimes). Those off-hour punishment hours spent producing bunting, bell clapper dog-dicks, macrame adorned door-grabs, monkey-fists, and rope splicing -- that's how I served most of my penance. Not to worry, I stopped being an all-out asshole once Ellie got hold of me. So, the story has a happy ending.

With the aid of a pen loaded waterline marking tool (analogous to the Machinist's surface gauge) I inked the longitudinal cut lines, port and starboard.



Sliding along the surface of a vertical reference plane, perpendicular to the boat's longitudinal axis, I again used the waterline marking tool, but this time to denote the radial separation lines at the bow and stern. The longitudinal cuts would be accomplished with the Dremel circular saw, the radial cuts done with a hand razor-saw.



Precision layout is EVERYTHING if you want things to be symmetrical and fit properly. Measure twice, cut once!



The circular saw, just like the waterline marking tool, is slide along the smooth surface of the mounting board -- the mounting boards surface is the model's longitudinal reference (datum) plane.

Note the use of a .015-inch-thick piece of strip to check for complete cut-through as I progress the circular saw along the length of the hull. The cutting goes slowly and with light pressure applied. At no time do I permit the plastic to melt. Slow and easy it the word-of-the-day during this operation. I was sure to make this a no-caffeine day!



Polystyrene plastic reacts poorly to high-speed tools as it will melt if the feed-rate is too high and/or depth of cut is too great.

So... duh!... the trick is to minimize tool speed, advance rate, and pressure applied. I found that five slow passes with slight pressure made for clean, wander-free travel of the circular saw along its assigned path. You try to get the cut in one pass and the model is sure to die a horrible death!

Patience!



Once I had made all the longitudinal cuts to the hulls starboard side, it was an easy matter of turning the work around and cutting the port side.



I was pleased to see that the Dremel circular saw produced a very narrow kerf, about .025-inch. I'll build that back up with some plastic strip stock tomorrow.



Carefully following the inked on radial lines, I cut the radial breaks at the bow and stern. Nominal wall thickness of the hull was around .050-inch so there was not much plastic to hack through. The work went quickly.



The remaining connective tabs (those portions of the longitudinal split that were hiding under the waxed sail-twine) were cut through with a razor-saw, completing the split between upper and lower hull halves.



This is as far as I got today. However, I'm ahead of the game as I already had in hand a decade old, assembled WTC for the model I just pulled down off the wall. So, in no time I'll be at a point where I can start integrating the camera-transmitter into the submarines sail.

 

merriman

David Douglass Merriman lll
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The interlocking registration tabs -- a set in the upper hull, and a set in the lower hull -- hold the longitudinal edges in alignment and pull the halves together when the tabs of the upper hull engaged the inside of the lower hull; the slight 'pull-down' compression of the upper hull tabs to the over-hanging lower hull interior provides this closure force.

Last thing to install was the forward and after radial flanges. Here I'm CA'ing the forward radial flange, using the same .020-inch thick polystyrene sheet I employed for the kerf-strips that run the length of the longitudinal edges of the lower hull.

One can never have too many clamps!



All model parts were given a ruthless scrubbing with an automotive grade surface prep, rubbed in with a green abrasive pad. Prep-sol is one brand. It's a hydrocarbon solvent that is strong enough to cut away grease, oil, dirt, and the like, but not quite strong enough to melt you or your model. Good stuff, and the last thing you do before body or paint work.

The scratching of the models surface produces some 'tooth' that adds a mechanical element to the adhesive 'stick' of glues, fillers, putties, primer and paint.



There were slight miss-alignments at the radial edges, forward and aft. These low spots would be filled with Bondo automotive filler.

The kit was assembled from four hull sections, The radial union between the forward and after hull sections presented a slight distortion around the girth of the hull -- an unfortunate artifact of kit design. (Oh, well, that's why God gave us Bondo). The dip there had to be Bondo'ed as well. All areas to receive Bondo automotive filler were marked with pencil, the hash-marks you see here.

#200 grit sandpaper provided the additional tooth needed to insure solid adhesion between the polyester Bondo and polystyrene plastic of the model.



(how many of you idiots will fixate on the thumb, but not the presentation?)

To keep Bondo away from places that don't need it, I applied masking.



After troweling on the Bondo I immediately ran a blade along the slight gap between hull halves. Failure to do so would result in the Bondo permanently 'gluing' the two hull halves together. Something to be avoided.

(Stop looking at that thumb!).



Bondo applied, the masking was removed and I got to work with rasp and sandpaper to feather the filled areas to the contour of the surrounding surfaces.



Once the Bondo had cured hard ('green stage' actually, it takes at least 30 days to cure properly) I ground away at the excess material with a rasp file, followed by hard and soft sanding block. The sanding started with #200 grit and worked down to #400. Both the filing and sanding were done wet to prevent clogging of the tools.



Cured Bondo, by itself is porous and weak. To those areas that would be subject to stress, such as the longitudinal and radial edges, I applied thin formula CA over the Bondo'ed areas. The adhesive soaked into the surface of the Bondo and greatly strengthened the substrate. After lightly sanding the CA'ed surfaces, things were ready for some Nitro-Stan air-dry touch-up putty to fill all tool marks and slight pits and dings not addressed by the Bondo.



I find air-dry putty is best applied with a brush. If need be the putty can be cut with a little lacquer thinner to make it more brush-friendly.

Bondo for contouring and major fill jobs. Putty is for shallow scratches and the like. Don't confuse the two.



Deep imperfections get the Bondo. Shallow imperfections get the Nitro-Stan. If applied thin (it should never be applied to depths greater than .030-inch) the putty will dry in about an hour. Regard air-dry putty as that last step before primer. Bondo for the deep ugly stuff; putty for shallow tool-marks and the like.

 

merriman

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Well, for some reason, the automotive de-greaser and abrasive pad was not enough to clean the surface of this model good enough to assure tight adhesion of some of the putty I applied. So, after an initial sanding of the putty work I resorted to that tried-and-true method of surface preparation: a slurry of abrasive scouring powder and water, scrubbed ruthlessly on all model surfaces that would receive adhesives, fillers, putties, primer, and paint.

THERE! Now, stick. Dammit!



... and rinsed off with plenty of fresh water, then toweled and left to dry.



The forward, starboard longitudinal edges of the upper and lower hull presented a significant gap. Too high for an air-dry putty. So, I elected to build up the lower hull edge with Bondo. First strip in that process it to place two pieces of masking tape, inside and out, with their upper edges even with the upper hull lower longitudinal edge.



Like so. Now, with the two pieces of masking tape forming a dam that would not only form the Bondo to the wall thickness of the hull but would also define the depth of the Bondo after it was troweled on and screeded off.



After troweling the Bondo into the masking tape dam I laid the blade down flat (with very slight pressure) atop the edges of the tape and screeded away the excess Bondo.



The work was left to cure to a state where I could remove the tape and proceed with fine-tuning of the built-up edge. As the bond between the Bondo and the previous edge of the lower hull is weak, I took exceptional care as I pulled down and aft on the masking tape as it was removed -- the objective was to avoid any force on the Bondo that would pull it away from the model.



Before anything else I strengthened the bond between the just applied Bondo and the previous edge of the lower hull by soaking in some thin formula CA. The process was the same as with the previous Bondo work: slather the CA over the work, then quickly wipe away the excess. Enough CA works into the porous Bondo to strengthen it as well as bonding the Bondo to the previous edge with assurance that it won't break off later.



The edge of the Bondo repair was trued up with file and a stiff length of #220 sandpaper. The hull was then assembled, and the worked areas given a few passes with #00 steel-wool. The model was blown down with low pressure air to dislodge any shards and sanding dust.



Time for primer... at last!



OK. The radial and longitudinal edges between the two hull halves are nice and tight. But all that cutting, grinding, filing and sanding removed some of the nice high-profile 'weld beading'. I want to restore that detail. So that's the next operation: re-building the beading and other high-relief items lost as I worked to separate and make tight the two hull halves.

 
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publiusr

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An idea that might make you some money on internet hits:

Put a simple, ugly sub with a go-pro atop its sail in the path of a waterspout and film it as it passes overhead. Maybe shoot an Estes rocket up into it…with its own camera.

That might be a million hits right there.
 

merriman

David Douglass Merriman lll
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An idea that might make you some money on internet hits:

Put a simple, ugly sub with a go-pro atop its sail in the path of a waterspout and film it as it passes overhead. Maybe shoot an Estes rocket up into it…with its own camera.

That might be a million hits right there.
Great Idea! I like your style. Hey, here's another idea:

I stick a broom handle up my ass, so that at the end of a work session I automatically sweep the shop on my way to the door. Whadything? Youtube would love that!

David
 

merriman

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In the areas where the hull was split some of the raised detail, the weld beads -- an element of the hull detailing on this fine kit -- were lost as I worked those areas with file and sandpaper. Time had come to re-build the weld beads, using old reliable Nitro-Stan touch-up putty.

Here you can see the nearly completed weld bead work (those red areas) on the hulls starboard side.



Note at the junctures along the longitudinal seam between hull halves, where the radial weld beads just fade away. The result of the evening-up work done to get the edges to match in gap and contour.

First step was to lay down masking tape dams. Incidentally, each strip of masking was actually four pieces of masking tape thick.



Putty was forced into the gap between the two pieces of masking.



And the excess putty screeded off with a putty-knife.



The first application of putty was given twelve-hours to harden, and in so doing shrank a bit as the volatile solvents were given up through evaporation during the drying process. A second coat of putty was applied and left to harden for twenty-four hours.





The masking tape dams were removed. Where I got sloppy with the putty a knife was used to scrap away the smears.



Where putty squirted under the masks a chisel-blade was used to cut and scrape away the putty, tightening up the work.



Feathering in the putty to the original weld beads height and width with bits of sandpaper.



A few strokes of steel-wool to soften the edges of the putty weld beads to better blend in with the original weld beads.



And, finally, a heavy coating of primer to even out the repair work.

 

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