R/C'ing the Revell 1/72 GATO Class Static Submarine Kit, Part-4

A Report to the Cabal:

While I was working to split the hull horizontally for good access, I continued work on the WTC. I hooked up the battery, speed controller, Voltage regulator, receiver and motors. It all worked just fine. Once things are checked out on the bench, only then is the mounting methodology worked out and implemented. It's only smart to verify that the electronics and prim-movers work before buttoning everything up tight within the cylinder.

I broke out my MK 1 Mod 0 reference board (a piece of particle board, 3/4" thick shelving board if you have to know!) and used it to guide the waterline marking tool as I marked off the horizontal hull demarcation lines onto the hull with a felt pen -- this was followed by some rather savage, ugly cutting work with a Dremel cutoff wheel to separate the hull halves at the lines.

And I took another look at how I was going to mount the stern planes and rudder.

Onward: You still, today, can't get away with equipping a WTC without having to soldering something together. Case in point are the solder connections between battery, speed controller, voltage regulator, and motors. Above I laid out, as neatly as possible, the components and the wires and interconnecting plugs needed to electrically make up these items. Note that it's my practice to make extensive use of interconnecting plugs between devices. Tamia type plugs to be exact. I do this as it gives me the opportunity to make field changes without the need of breaking or making solder connections -- just identify the offending component ('easter egging is the Navy term), disconnect its plug from the rest of the system, and plug in a new component.

And here you have all the plugs crimped and soldered to their respective wires, and all components of the system plugged together -- a bit less confusing than the initial photo, isn't it?

The battery supplies both propulsion and device power. It connects, in parallel, to the Voltage regulator and speed controller. I turn things on and off simply by making or breaking the connector at the battery. KISS!

As a practical matter, most r/c systems and the other control items aboard, can dine on the 7.2Volts coming straight off the battery (you guys operating a 12 Volt system must use a Voltage regulator!). However I use a 5 Volt regulator as a matter of habit, you see it hooked up in parallel with the battery input to the speed controller.

Danger ... Danger! Many speed controllers feature an onboard battery eliminator --don't trust 'em! A model submarine, with all those servos (some of those servos nearly stalled because of excessive pushrod drag) and other devices aboard drawing current and your nominal 'services' load (current not directed through the speed controller and motors) might be knocking of the door of 2 Ampere's. Most speed controller BEC's (battery eliminator circuit) fry the diode at a mere 1.5 Ampere's! Fry the BEC/Voltage regulator and you loose the boat. When you use a dedicated Voltage regulator and a speed controller with a BEC, you have to disassemble the speed controllers BEC (if you don't you might get Voltage spikes in the system that will fox your receiver) by disconnecting the RED pin from the speed controller plugs ... the one that connects to the receiver, boy's and girl's.

Though the Tamia pins are crimp attached to the wires, I always go the extra step and solder the wire to the pins -- 60/40 Lead solder is the best for this kind of work, but insure that you use a nonacid producing rosin/flux to clean the work as heat and solder is applied. I strip to bare a wire, insert the wire into the pin, crimp the pin (two sets of crimp tabs on these, one engages the wire, the other the insulator), brush over the pin with flux then apply the solder with the iron. While still hot I wipe the pin on a rag to remove excess flux while its still in the liquid state.

Tamia produces these connectors as male/femal units and they are polarized so you don't fry something by mistake during hookup. These connectors are cheap, work every time, and are still the industry standard for outfits that produce 'model car' battery sticks -- the kind most of us use aboard our r/c submarines.

Here I'm pulling the felt marker loaded Machinist's surface gauge along the reference board as I mark out the demarcation line between upper and lower hull halves. It's vital that the model be secured tightly to the board and that the model sit with its vertical axis perpendicular to the plane of the board. The superstructure has not been glued on yet, that comes later.

Damn ... I'm a good looking man!

This is my smaller 'reference board,' used to loft off measurements to an item sat upon it, most of those measurements transferred via a Machinist's surface gauge, like the black thing you see here (you 3D animators know all about these gadgets!). Note that strips of sandpaper adhered to the face of the reference board act to provide a non-slip surface for the hull mounted atop it. Also, note the use of hooks and rubber bands to hold the hull securely in place as I mark it off.

Though the felt marker demarcation line runs around the stern, I terminated the longitudinal cut just before the end of the superstructure turtleback. I transition the break to a vertical, radial line.

I took great care with the Moto-Tool saw blade to stay in the center of the mark ... get sloppy here and you will be compelled to come back later with lots of filler to fix your poor work. Goggles and ear protection a good idea during this phase of the work.

Here I'm pointing to one of the two internal transverse bulkheads that were supposed to be installed before gluing the left and right halves of the main hull together. I deferred there inclusion into the hull till after I had assembled the main hull and cut away the upper from the lower hull half, only then did I glue the bulkheads in (but only after cutting them horizontally -- in the same plane as the hull split -- in half).

Surprisingly, the upper and lower hulls did not spring outboard much at all, maybe an 1/8" maximum. I'm pointing to the 1/16" displacement of the hull as compared to the lower half of the forward transverse bulkhead -- not bad and required very little compression of the hull sides to get them to meet the matting face of the bulkheads.

So? Where did all that stress of the compressed hull go when I split it? Stand by for that horror story ...

The small amount of spring-out of the hull was pulled back in with two strips of low-tack masking tape -- pulled tight enough to hold the two transverse internal bulkhead pieces up tight within their flanges. Then it was a simple matter to flood the contact areas between bulkheads and hull with cohesive cement. The same was done to the top portion of the hull.

I'm blatantly ripping off Crazy Ivan's good idea here: George made the bottom skeg part of the kit removable -- securing it with two machine screws instead of gluing it in place as suggest in the instruction book. Doing so permits easy access to the stern plane operating shaft, even the ability to remove the stern planes completely, in moments, without any damage to the structure. You can follow George's work at, http://s181686668.onlinehome.us/phpBB2/messageboards.php5

Being a static kit there was no need for Revell to represent the propeller shafts as practical items, so they simply made the strut bearing foundation (with one leg of the supporting strut projecting from it), the shaft, and the shaft stern tube as one homogeneous polystyrene plastic part. Makes good sense to consolidate those three items into one piece for the kit. But, that makes the subassembly worthless on a practical r/c model submarine.

Three solutions present themselves here: 1. Cut out the shaft element, bore out the stern tube and strut bearing foundation to accept Oilite bearings sized to accept stainless steel 1/8" diameter propeller shafts. 2. Handcraft replacement masters of the stern tube and strut bearing foundation, or 3. Cut up the existing kit part and use the stern tube and strut bearing foundation as masters from which to produce either metal or carbon reinforced resin replacement parts.

I've sent Revell a letter requesting permission for the later, but if I secure a 'no,' or no answer I'll handcraft new masters.

Why go through the letter writing to the owners of this property?

As a practical matter Revell likely would not care in the slightest if I make copies of those model kit parts. But, from an ethical point of view, it's their product and they sell it for one time use, not to have it or components from the kit ripped off and exploited without permission and/or compensation.

I simply hate it when my products. And I wont steal anyone else's work; I won't copy their work without first securing their permission. That simple. I'll give them a few days. If no answer, I'll make my own masters of the stern tube, lower skeg piece, and strut and bearing foundation.

(And while I'm on the subject of copyright/patent protection: A very big, sloppy fuckyou to those defense contractors who demand compensation from kit manufacturers who produce kits that depict vehicles built with tax payer money).

I really appreciate the way the bottom of the skeg on this model was laid out. Making this piece removable does a lot to simplify installation and maintenance of the stern plane operating shaft.

Note the very small 1/8" i.d. bronze Oilite bearing near the after end off the strut bearing housing. One way or another -- be it modified kit parts or a new 'customized' parts -- the stern tubes and the strut bearing housings will contain Oilite bearings.