Today's work on the little Revell SKIPJACK fittings kit

[junglelord]

Oh, I am working on all those little skills that I can apply, and getting better each day. I have assembled several models that needed repair and this has helped a lot. thanks.

[He Who Shall Not Be Named]

Oh, I am working on all those little skills that I can apply, and getting better each day. I have assembled several models that needed repair and this has helped a lot. thanks.

Keep at it then!

David,

[He Who Shall Not Be Named]

Here's an opportunity to show you some specialized tools I use. Some commercially available, some made on the spot for specific jobs.

Also, I'll show you how to simple lay-out; to use plans to identify location and to loft a location off the plan and onto the work.

A good example is the sail planes: These cast resin items replace the little SKIPJACK's planes, which were too fat and not of the right outline. I was presented with the problem of cleaning them up (removing the remnants of sprue and vent channel stubs and de-greasing), outfitting the two opposed control surfaces with a common operating shaft, and punching a hole in the side of the sail to accommodate the operating shaft.

A sanding stick was used to remove any flash from the parts straight edges, but the concave curve at the root of the sail planes required a special tool. What I did was to identify the area of the sail under which the root of the planes would sit, mount a piece of #240 sandpaper onto the side of the sail with some double-stick tape, and to use the sail itself as a form upon which I would slide the root of a sail plane piece. In so doing I got the root of the sail planes to confirm exactly to the shape of the sail under which they would later be permanently mounted.

But before that I had to de-grease the sail plane parts (as I did all resin parts of the little SKIPJACK fittings kit). This is done by soaking each part in a container of lacquer thinner, then pulling a still wet piece out, and running it over a lacquer saturated piece of abrasive greenie-pad. The abrasive action of the pad insuring that the lacquer would make contact with all surfaces of the part, washing off the grease.

But, resin part preparation is not complete by just the lacquer thinner scrub, no, you have to take the extra measure of sanding the part to insure its completely clean. Also, the sanding imparts a rough surface that presents the tooth needed to mechanically hold the primer firmly down once applied.

And this is where one of the shop 'special tools' comes in. Actually, nothing more exotic than a hand-vice, also called a Jeweler's vice. This particular one employs a wedge on one end to for the jaws. The jaws themselves are sheathed in leather to afford 'grip' and to prevent marring of the work. The degree of holding pressure is dictated by how hard you force in the opposed wedge. You make use of this tool when the work is so small you can't conveniently hold it in your fat, greasy, sausage like fingers.

A set of sail planes was made up (I'm working five sets at a time here) to its .020" brass wire operating shafts. Then each set was secured in the jeweler's vice as I sanded the control surfaces lightly with #400. This prepared the parts for their first coat of automotive acrylic primer.

Using the copy of the Greg Sharpe SKIPJACK plans I had reduced to the scale of this kit, I identified the location of the sail planes on the sail, and lofted that location onto the models sail and drilled a hole either side of the sail to pass the sail plane operating shaft. To insure near perfect symmetry between the port and starboard holes I used the pencil loaded surface-gauge (waterline marking tool) to establish the height of the hole. A set of dividers was used to fix the longitudinal point for the holes, using the sails leading edge as a datum line. The holes were drilled and the planes test fit to insure they sat level. Perfect!

The majority of todays work was identifying flaws in the surface of the model hulls and sails and addressing them with repeated cycles of putty and sanding.

[He Who Shall Not Be Named]

In addition to the jeweler's vice, surface-gauge, and sanding stick I employed the special screeding tool previously described. Used to apply, with a great deal of precision, Evercoat filler, to re-contoured the bow of the SKIPJACK kit.

Also note that I made three little 'pin holders' -- basically a handle with a pointed wire, sized to be a tight fit in the bore of the resin control surface parts. This tool used to hold the work as I filed and sanded each to remove sprue and vent remnants and to give the part tooth in preparation of priming.

For priming and painting, the little parts, like the control surfaces, were held, in mass, onto a scrap piece of board with either double-stick tape or a piece of tape rolled back on itself to present the sticky-side up.

[He Who Shall Not Be Named]

Not available in the little SKIPJACK fittings kit, but something I wanted on hand to further detail my subs, is a complete set of scribing stencils. If you're a detail freak like me, you can follow along here and build a set for yourself. If not, you'll find the little SKIPACK to be OK without them. Personal preference here.

Scribing it the technique of mechanically cutting/scraping the surface of the model to achieve engraved lines. These lines representing access hatches, reversible cleats, hull penetrations, sonar windows, torpedo tube shutter doors, waterline (used later as a datum line when you get into the 'weathering' stage), and any other engraved line needed to represent demarcation points between hull and flush fitting components.

The act of scribing/engraving itself is done with a scratch-awl/scribing tool. The scribing tool can be one of those useless things you buy for a bunch of money from a catalog, or it can be a proper tool made by grinding the tip of a jeweler's needle file to a thin shanked point. But the scribing tool in hand is only half of the tool-kit you need for professional looking engraving -- you also need a guide, or stencil, to direct, with exacting precision, the travel of the tool as you cut the lines into your model. The guide can be a simple straight-edge, a curved piece of plastic, or purpose built scribing stencil. And that's the meat of this discussion here, how I make a scribing stencil

A scribing stencil is a guide, or form, with specific cut-outs in it, those cut-outs corresponding to the outside form of the eventual engraved lines we wish to cut into the surface of the model. Three requirements need to be fulfilled in order to achieve a useful scribing stencils: First, the stencil has to conform as close as possible to the shape of the models surface over which it will be applied. Second, the scribing stencil has to be thin of section, permitting an exact tracing of the scribing tools shank within the cut-outs without worry that any slight pitch change of the scribing tool (variance of the scribing tool from any angle but a right-angle to the work) would result in a significant distortion of the engraved line. And the scribing template has to be strong enough to tolerate manufacture, machining of the cut-outs, and pressure of the scribing tool shank as you bear it against the cut-out outline during the scribing/engraving operation. I build my scribing stencils strong enough for repeated production work.

To meet the above requirements I fabricate my scribing stencils from four to six layers of four-ounce fiberglass cloth saturated with West System laminating epoxy resin. The meet the first requirement of such a stencil -- to get it to conform exactly to the models shape (no mater how radical a compound curve) -- I take the model itself, apply a mold release system (to keep the epoxy resin from permanently sticking to it), and lay up the glass over the area of the models surface where I will later be engraving lines.

Even six layers of this very light-weight fiberglass cloth produces a very, very thin sectioned stencil. If I keep the resin component low (the ideal resin to glass ration is 50/50) I achieve stencil thickness of about .025". And being a glass reinforced plastic (GRP) structure, the stencil is plenty strong for the job.

For the little SKIPJACK I determined that I would need six dedicated GRP stencil blanks. I would be draping 4-6 laminates of fiberglass cloth to six specific areas of the SKIPJACK model. To protect the model, forming the mold release system, were multiple, alternating coats of poly vinyl alcohol (PVC) and Buno type polishing wax -- this would keep the epoxy from bonding with the model, ruining the job.

I made paper templates, these capturing the geometry of the lay-down for the specific areas of the hulls surface I would build-up the stencils -- a trial-and-error process. Using a pizza-cutter type tool I cut out the fiberglass and laid it up to form a stencil blank. Later, after the resin had cured hard, I pull the stencil blanks off the model, soaked the model in water to remove the majority of the mold-release system (PVA is water soluble even after drying), and then sat down to performing the work of lay out -- transferring the plans details location and shapes from paper to appropriate scribing stencil blank. More on that work later.

[toppack]

David,
Interesting Info!
I've been trying to figure out a good way to do scribe lines in th FG-gelcoat of the T-class. It's very hard material, so in the testing I've done, I can't control the depth of cuts at all, with a scribe.
A dremel cutoff wheel has worked the best, but very difficult to control and cuts are too wide.
I've thought about refilling those wide cuts with epoxy-putty and then scibing the putty but that will be a heck of a lot of work. :( and may weaken the hull if I get them too deep into resin. :(
Attaching something to surface doesn't look good either.
I've about desided that I'll have to leave 'er Belly Smmoooth. :D
Does anyone have any suggestions for doing fiber-glass hull scribe-lines, to simulate hull-plating joints, etc. ???

[He Who Shall Not Be Named]

Spent the weekend and today cramming ten-pounds of r/c gear into a two-pound container -- got everything into the little 1.25 SubDriver and working. Whoopee ... end is in sight!

Tomorrow I'll work out the linkages, which won't be much of a problem as the rudder and stern plane push rods are magnetically coupled to the servos, so those two push rods will simply rest atop the cylinder, the magnets at the ends of them making up to the magnets (with a watertight Lexan lid in between) embedded within the servo bell-cranks. The propeller shaft will make up with a simple flexible tube type universal coupler to the SD's shaft.

There are three main structures to the SD: after battery, LiPo safety circuit and ESC space, servo box, and the forward receiver and ADF space. No on/off switch, I simply pop the after space open to access the little connector between battery and ESC. Simple.

It's down-hill from here.

David,

[Slats]

Good you can stop playing with little toys and get back on to bigger ones: like the Torpedo system.

J (serial torpedo system pest)

[He Who Shall Not Be Named]

In spite of Slats 'suggestion', I'm pressing on with the little SKIPJACK project. In time, John ... in time.

Here are some comparative shots of the raw little SKIPJACK model kit along with the fittings kit parts needed to get it up to my standard of perfection. Other shots are direct comparative studies of the raw kit and the kit modified to make it more scale-like as well as practical as a proper r/c submarine.

Note that changes to the models physical appearance include a new stern section, new propeller, sharpened sail leading edge, and a more pointed bow.

And you'll see that of the many kit parts provided with the basic Revell kit, only the hull, sail, and display stand parts are used -- the rest of the kit (the decals are also retained) is discarded.

And a close-up shot of the final SD arrangement shows how the battery is accessed (never charge the battery while it resides within the cylinder!), and the unit is turned on and off. And this shots indicates of the new SD design: you can access the internals through four access points, all made with O-ring seals. This design feature permits me to custom fabricate (by varying cylinder length and servo box style) the little 1.25 SD to fit and operate specific small scale plastic model submarine kits.

Today I'm playing with the possibility of inserting a small toggle-switch within the forward bulkhead to serve as the means of turning the SD on and off without need of breaking the cylinder as pictures. Stay tuned, sports fans.

[Nuke Power]

Very clean work and good improvement to the plastic kit but.. Where is the water? Shouldnt this have been in the water a week ago ?

[redboat219]

You model is a great improvement over the original. Looks just like an Alfa. Hmmm:rolleyes:Wonder if you can swap the SJ sail and planes with those on a Russian boat to make one?

[He Who Shall Not Be Named]

You model is a great improvement over the original. Looks just like an Alfa. Hmmm:rolleyes:Wonder if you can swap the SJ sail and planes with those on a Russian boat to make one?

Be my guest.

David,

[Subculture]

Dave, is this going to be made available as a complete kit, or will you sell the hull parts as a Skipjack 'hop-up' package. Also, it might be useful if just the endcaps and cylinder were available for those wishing to grow their own internals.

We have a little radio board available over here called the 'breezeblock'. This is so small it could easily fit in the stern of the cylinder freeing up space and permitting the use of a ballast system.

[He Who Shall Not Be Named]

Dave, is this going to be made available as a complete kit, or will you sell the hull parts as a Skipjack 'hop-up' package. Also, it might be useful if just the endcaps and cylinder were available for those wishing to grow their own internals.

We have a little radio board available over here called the 'breezeblock'. This is so small it could easily fit in the stern of the cylinder freeing up space and permitting the use of a ballast system.

Damn timely post, Andy. I was just finishing up the cost projections of the little SKIPJACK fittings kit and SubDriver for Mr. Caswell.

To address your first paragraph: No, we will split the fittings kit and the SD as two separate items for sale. Of course, those wishing to r/c the little SKIPJACK will be compelled to buy both the fittings kit and the SD.

The fittings kit will be sold separately for those wishing to enhance and make more scale like the Revell kit for static display.

And your second point is addressed here: The 'basic' little SKIPJACK SD is devoid of all devices save the installed motor (with watertight seal and spark-suppression made up) -- it's up to the customer to work out the internals. Caswell will work up a 'package' of the internals needed or the customer can come up with his own. Choices, Andy.

If you would please share with Mr. Caswell and me the technical specifications and source of the little receiver you mentioned -- if it is frequency compatible with our FCC it would be the perfect companion for this (and other small plastic model submarine kits) product. Yes, we might be able to but a LPB system in this thing if we can minimize to a significant degree the size of the receiver. Tests have shown a practical 90 minute-run time with the 800mAh pack, a shorter LiPo battery of, say, 400mAh would still give a good run time and would free up additional real-estate for the ballast system -- yes, a possibility, Andy.

David,

[toppack]

We have a little radio board available over here called the 'breezeblock'. This is so small it could easily fit in the stern of the cylinder freeing up space and permitting the use of a ballast system.

I've seen pictures of a micro-receiver called a 'freezeblock', somewhere on internet.
It was a circuit-board with no enclosure box and connector pins at end of board, (similar to other modern micro-receivers). I think it had only 4 channels for servos, tho?
I think it was FM.
I'll try to locate it again.