R/C'ing the Trumpeter 1/144 SEAWOLF (SSN21) Submarine, Part-1

A report to the Cabal:

I've not been ideal, just busy with shop work, some of which is chronicled below. This project, development of an 'enhancement fittings package' is aimed at improving the Trumpeter 1/144 scale SEAWOLF submarine kit to the point where it can be operated as a practical r/c submarine.

Introduced a few years ago, this injection formed, polystyrene (styrene) kit is a fine example of what can be done by a big injection kit manufacturer if they do the research, check their sources, and take advantage of modern tool making machines and the software needed to direct those machines -- all this; this integration of market analysis, subject documentation, development of useful CAD software and the use of machines able to turn this digitized information into molds of exacting form, is the big reason Trumpeter has been able to put out high quality (with a few stinkers along the way), faithful reproductions, in model form, of the prototypes we kit-assemblers want to stick together.

Sure, there are a few things wrong with this kit -- and I'll list them below. However, I think it unfair and petty to harp too much on this kits shortcomings; rather, I think it proper to sing the praises of what Trumpeter got right, and to express our thanks to Trumpeter for doing such a fine job on such an 'secretive' subject.

I love the way they have divided the hull into four main sections: the major length of the hull is split into an upper and lower half -- ideal for later buildup as a split hull that gives access to the r/c internals. And the bow and stern are entire two-piece assemblies, which lend them to completing the hull assembly into the classic Kachur/ Sharpe 'Z' break -- it's as though someone over at the Trumpeter design staff was thinking r/c when he laid out how this kit would go together.

Oh ... and it looks like the Trumpeter people availed themselves of the Deep Sea Designs plan set on this boat; reducing my copy (I'm the guy who sent Greg the source material) of that drawings to 1/144 scale, and laying the kit parts over it, revealed almost dead on registration between kit parts and plan. Well done, Trumpeter!

Now, the bad news: There's an issue with the shape of the bow, but not enough for me to get my panties in a wad; the fixed deck cleats are way too thick in section; the sail sonar window is bulged out (obviously the Trumpeter guys were working off pictures of the boat before it received the anechoic 'skin'); the two anhedrals at the stern are just a tad out of form, but not by much; and, finally, the pump-jet, though the duct is of reasonable outside form, is internally impractical.

About the kit supplied pump-jet (PJ): The two sets of stators -- structural elements that support the duct off the hull and (should) work to twist the water flow into and out of the rotor disc -- will permit the flow of water into and out of the rotor. But, and underline this, the kits rotor is supposed to be mounted at the extreme stern of the shroud. For some unaccountable reason, some dope over there at Trumpeter decided that the rotor goes there!? ... what the hell were those people thinking? And the kits rotor is not at all a practical item, it's an almost two dimensional representation of a multi-bladed, skewed back type propeller, not an impeller. Bottom line is that the Trumpeter SEAWOLF propulsor won't work!

Very nice hull, reasonable appendages, crapy propulsor. What to do? I got it ... offer an after-market enhancement package and sell it at a confiscatory price! Yeah ... that's the ticket!

So, in a few weeks I'll be going to market with a Trumpeter 1/144 SEAWOLF enhancement package that will cure most of the kits scale fidelity problems and, at the same time, will permit conversion of this handsome display piece into a practical, easy to maintain, r/c model submarine.

You buy the Trumpeter SEAWOLF; then buy my SEAWOLF upgrade kit; buy my WTC-2.5/SEAWOLF;, buy an r/c system, APC-4, fail-safe, battery, servos; and kick in some other goodies -- pour the mess into a big bowel, pour in glue, paint, mix well, pour out onto a cookie sheet and you will have a very capable r/c submarine of museum quality. Nothing to it!

The magic ingredient? MONEY!

Tentative price for the D&E miniatures Trumpeter SEAWOLF upgrade kit: $175.00, plus shipping. The WTC-2.5/SEAWOLF: $403.50 plus shipping Don't like the prices? Then, don't buy it ... you cheap Bastard! OK, enough of the gentle sell, lets see how this enhancement kit takes form.

Let the saga begin!

The Trumpeter 1/144 SEAWOLF kit is one very fine product! I've heard some grousing out there, but trust me, overall this is one fine kit. The pump-jet is right in length and diameter, and the two sets of stators are a reasonable guess as to what things look like in there (hell, I'm the resident 'expert' on pump-jets and I'm not positive on what the real thing looks like!). The only major screw up with the propulsor is Trumpeter's placement of the rotor/propeller at the stern of the duct, just plain old wrong. So configured (because of the bogus shape of the so-called propeller) this thing will not move water.

It's my intent to make 'enhancement' items, in kit form, to improve the looks of this model. And this will be done as I also increase the scale fidelity of this display --there's no need to sacrifice looks to achieve performance (well, sometimes there is, but not on this project, I can assure you!).

The integrated horizontal stabilizer-stern planes on the TRUMPETER kit of the SEAWOLF are wrong. The general shape is fine, but the hinge line separating stabilizer from plane is way too far forward, and the tip portion of the stern plane system is not indicated at all! On the real boats the split control surfaces worked either together or the outboard tip sections operated differentially from one another to produce torque forces to counter unwanted ship rolling motion. The plans you see here are the Deep Sea Designs drawings. I was pleasantly surprised to find that the model parts were very close in shape and size to the drawings. Well done, Trumpeter!

Upper left are some extra cast white metal blades left over from the rotor master fabrication. For a detailed look at how I fabricate a propeller/rotor master, check out,

http://vabiz.com/d&e/CABAL/Building%20Masters%20For%20A%201_48% 20SEAWOLF%20Pump-Jet,%20Part-3.htm

I worked the kit supplied PJ duct on the lathe: First, I slathered on some Metal Glaze filler (love that stuff!), inboard and outboard, near the leading edge. Once that cured hard I chucked it up onto the lathe and machined the filler smooth -- this to improve the shape of the duct and to build it up to a wall thickness near its center to later permit incorporation of a flanged break when I split the duct into a forward and after section.

At this point in master fabrication I've added an outboard bearing to the horizontal stabilizer, the inboard bearing is simply the hole in the hull through which the stern plane operating shaft passes. As you can see, on the SEAWOLF (I assume!) the stern plan operating shaft extends past the tip of the stern plans and into a hole within the tip planes. I guess that on the real boats there are two coaxial stern plane operating shafts, the inner shaft operating the tip, the outer shaft operating the stern plane positioned aft of the horizontal stabilizer trailing edge.

The two stator assemblies were fabricated from Renshape 40 hubs and sheet styrene blades. The two masters went together pretty much as I build propellers, on an assembly jig.

The stator assembly jig with the forward stator assembly master in hand. Sitting on the jig are the kit supplied forward and after stators. The stator blades were pre-shaped by scraping and sanding to a flat-bottomed, Clarke-Y foil section before being bonded to their respective hub positions.

Periodic test fitting of the five PJ masters insures that things fit tightly and with small tolerances when the work is finally done. Later I will sleeve the bore of the rotor down to 1/8". The 3/16" bore of the forward stator hub will be preserved. The eventual resin or metal parts (not sure what kind of substrate the final model parts will be yet) will feature the 3/16" bore -- just the right size to receive a press fit Oilite bearing of 1/8" bore.

The hubs of the rotor and two stators are lathe turned Renshape 40; the stator blades are styrene sheet cut and sanded to a Clarke-Y foil section; and the blades of the rotor are cast from white metal Showing off how the tip plane is ganged to the same shaft that operates the main stern plane. Relatively simple, but 'busy' enough looking to make for a very interesting display -- and, more importantly, it's a practical control surface. Much better looking than the kit supplied horizontal stabilizer-stern plane unit.

The Trumpeter supplied anhedral stabilizers are pretty close to documented shape and dimensions, but I got a little anal and went ahead and made a better anhedral master by taking the root portion of one of the kit horizontal stabilizers/stern plane pieces, chopping off the tip, and grafting on a new one -- which started life as a block of Renshape 40 -- marked out here for shaping with band saw and sanding blocks.

After fattening up the kit supplied PJ duct with filler, inside and out, I mounted it on the Taig lathe. With the use of an inside compression mandrel I machined the surface of the filler with cutting bits and sandpaper. The re-contouring of the duct done I set about cutting in a radial groove midway along the length of the duct. The depth of the cut equal to the thickness of a band of styrene plastic that will form the radial flange. After cutting the groove, the after and forward half of the duct are separated with a very narrow parting tool.

I wrapped and glued the ribbon of plastic into the aft duct part groove. The width of the ribbon sized to equal the width of the groove cut into the two halves (plus the width of the kerf lost to the parting tool). The projecting forward end of the flange tightly engages the groove of the forward duct piece. When assembled, the completed two-piece duct appears to be 'seamless'.

Damn, I'm good!

Looking at the stern of the 1/144 enhanced PJ I've built to upgrade the Trumpeter SEAWOLF kit. To complete these masters I'll glue the two stator assemblies within their respective duct half's, then make rubber tools from which to cast resin and/or metal parts.

If you look real hard you can just make out the radial break between the forward and after duct halves. Splitting the duct this way permits easy access to the rotor should the occasion every arise where it needs replacement. I hate building an r/c model who's mechanisms I can't get at without breaking something!

Looking into the intake side of the 1/44 SEAWOLF's propulsor. Things at this point are so refined of shape that they are held only by friction. Rotor/duct clearance is less than .003"! This thing should move plenty of water.

The major kit modification on this project was rebuilding the duct by first fattening the inside and out with layers of Evercoat Metal Glaze filler -- this done to give me a wall thickness substantial enough so I could make the 'Z' cut that separates the forward and after sections of duct. This feature is a direct copy of how Matt Thor engineered access to his groundbreaking 1/96 SEAWOLF kits rotor. I copied that feature earlier when I scratch build masters, tools and parts in support of a 1/48 SEAWOLF/ CARTER pump-jet for a client -- that work can be seen here: http://vabiz.com/d&e/

CABAL/1_48%20SEAWOLF%20Pump-Jet,%20Part-6.htm

The two duct halves, on the actual model parts, will be held together with spots of RTV sealant -- strong enough to hold, but weak enough to fail if the after portion has to be removed to access the rotor and/or shaft.