Model Expo 1/24 USN Picket Boat 1

[crazypoet]

Well, after a couple of holidays, waiting on parts and good weather for painting, I finally have an update.

 

The engine in this model is supposed to turn over - the crankshaft drives the piston, valve timing link and Stephenson linkage. This means that alignment and clearance between parts *really* matters (as if it ever doesn't?)

 

My first go ended up having issues. The crankshaft counterweights are laser-cut wood. As it happens, the laser beam begins to cut at a slight angle as one approaches the ends of the board stock. This is most pronounced in thicker wood. So. The counterweights each connect to a segment of the crankshaft and are joined through the piston rod. This assembly sits between the main bearings on the engine base plate, with not much in the way of clearance.

 

Because of the slight angle to the laser cuts, the angle between the counterweights and crankshaft was not exactly square, and I didn't catch this until I'd joined them through the piston rod and main bearings. When I turned the crank, the counterweights would bind slightly at two points and flex/warp around the join between the wood counterweight and the metal crankshaft.

 

Not a good thing, and my bad for not catching it sooner.

 

I made this situation far worse when I tried a shortcut fix to trim them square. Nope - I ended up damaging both counterweights and one of the main bearings badly enough that they needed to be replaced.

 

Model expo is good about this sort of thing, and shipped me out a sheet with replacements for the parts I'd trashed. i took a great deal more care in ensuring that everything was square and well-aligned this time! My Dremel was put into service as a mini lathe and I carefully trimmed the faces of the counterweights to make them exactly square to the holes for the crankshaft.

 

Then much sanding, filling, priming and painting to make the new bits match the old.

 

I'm happy with the results - the new engine core turns beautifully - I'll post a video after I put things together. In the meantime, here's the current state of the crank, counterweights, main bearings, piston rod and flywheel...

 

 

Most of the assembly is wood, with a bit of brass rod, aluminum tubing and brass hex bolts.

 

I'll assemble the rest of the engine core this week, and do a video of the whole thing turning over - it's kind of cool

 

Back on track!

[crazypoet]

Ooops - I deleted the pic that I linked in that last post. I'll fix the post later, when I can get to a PC.

 

In the meantime, I've got the back and top of the engine together. Baseplate, main bearings, crankshaft, frame, cylinder/valve box and flywheel.

 

This took far longer than it should have, mainly because of my own ham-handed attempt to fix the alignment problem I mentioned above.

 

So here are the components and steps...

 

the various bits and pieces:

 

 

Assembled baseplate, crank, piston rod, flywheel and main bearings:

 

 

Frame pieces and completed assembly:

 

 

 

I used brass hex bolts to connect the top plate and frame pieces, and to connect the frame to the baseplate. The kit provided hex styrene rod, which just didn't feel right.

 

The cylinder/valve box:

 

 

 

I added wood lagging around the cylinder, based on other examples of Clute engines from their 1873 catalog. I also decided to go with a black iron finish overall- again based on their catalog.

 

The completed assembly:

 

 

 

Next, I have to finish the front of the engine, along with the plumbing. This will include the Stephenson link for the valve, two feed pumps and a lever for setting the valve linkage. I'm heavily modifying all of these, as the kit approach left the Stephenson linkage completely unsupported and with no connecting levers for setting the valve timing. It also didn't have a good way to connect the feed pumps to the crankshaft - these would have been driven by cams on the crankshaft, and that was not well-represented in the kit pieces.

 

Pulling this all together will take some time, as I have to design and fabricate several of the assemblies from scratch. Fun stuff!

[crazypoet]

So... Starting the front of the engine.

 

The first challenge is the feed pumps, which sit on either side of the crankshaft and which were driven by cams and rods connecting the pumps to the shaft.

 

The pumps are white metal castings, which originally had too-bendable and out-of-scale posts on the end which one was supposed to simply rest against the crankshaft.

 

Two issues came up with this - first, it just looked wrong. The cams and drive rods would have needed some protection from the elements, and so would have had some sort of enclosure and guides.

 

Second, and more to a point of practicality from a building perspective, the lack of a cam housing would leave the Stepehson valve linkage unsupported insofar as spacing along the crank is concerned.

 

So. My approach, after much head-scratching, was to cut the posts off the castings, and drill them to accept a short length of 1/16" brass tubing. The tube will serve to guide and connect a length of 1/32" brass rod to the pumps.

 

At the crankshaft end of things, I scratch-built a cam housing to both anchor the connecting rods and provide support to the Stephenson eccentrics later. I used a bit of scrap wood, scale resin rivets and two more bits of 1/16" brass tube for this. To add a touch of interest, I also added a brad hex bolt to the bottom to represent a drain plug.

 

Here are the pieces as they exist today. The pain is Tamiya NATO black, with a bit of colloidal graphite and Vallejo rust wash to tone things down. The caps on the pumps are Alclad titanium gold with a thin wash of Vallejo light rust.

 

 

 

 

The next step is to connect things up, and use this as the starting point for the forward/reverse lever which was used to shift the Stephenson linkage. I need to design and fabricate that all from scratch, as there was no provision for it in the kit at all.

[crazypoet]

Thanks! This is going to be a long project. I'd hoped to have it done over the winter, but I suspect it will be well into Spring instead. At least it's not going to be boring... :-)

 

I got the pumps and cam housing done today, so I can start the serious design work on the Stephenson link fittings.

 

Cam

 

 

Pump one

 

 

Pump two

 

 

These needed to be installed to give me an idea about what I need to work around for the next straps. Much head-scratching to follow...!

 

;-)

[crazypoet]

Well. Ok. I did it. I finally had enough and pulled the trigger on a micro-mark home photo-etch kit.

 

I realized that what I am going to need in terms of fittings for this and other kits will require better control in shape and fit than I can get with a Dremel and needle file - not to mention those times when I'll need multiples of a given part.

 

I'll let y'all know when it arrives, along with how well it actually works...

 

Meantime, I'm still designing the parts I'll need to properly finish this engine

 

:-)

[crazypoet]

While I'm working on the remaining engine hardware, I'm starting the rest of the Steam Plant - hot well and condenser.

 

There were components that allowed for water/steam to be recycled through the system.

 

Both of these were made of iron in the original. I've done the initial shaping and sealing of the wood kit components, in prep for the first coat of Alclad primer/filler. They both will have a variety of pipes, fittings and braces installed before they're done.

 

[crazypoet]

No new pics on this, but I'm making some good progress on both the hull planking and the remaining parts of the steam plant.

 

I've reached the point where I have to stain and finish the inside face of each plank before attaching it to the hull, as the inside is both quite visible and quite impossible to finish after the fact.

 

What this means in practice is that each plank will take about two hours of active work spread over 2-3 days to measure, steam/bend/shape, finish and attach. And there are about 50 of them to go... I'm working them in matched pairs port/starboard, and working on the steam plant while the planks dry after steaming and shaping.

 

I'm also learning more about CAD, as I need to custom-etch some engine parts to get the exact shapes I need. Always something new to learn with this project!

[crazypoet]

Thank you!

 

Spiling planks is an interesting part of this build - it's the only way to develop and create the complex 3-D curve for each plank (bend and twist). It's a bit tedious, but the results are well worth it. It's also a bit of a meditation - you can't rush the process.

 

The same skill will serve me well in future projects, both in wood and plastic, so it's worth the investment in time.

 

On the home PE, I'll post the process as I step through it. The Micro-Mark kit provides all the essentials, with ferric chloride as the etchant. The things I have to provide are a good dark workspace (the photo-resist film is UV-sensitive), a few lighting fixtures and the artwork itself. Doing the artwork is my current challenge, as I have to transfer my thoughts from pencil drawings on graph paper into CAD images that I'll print onto transfer film. If I had a steadier hand, I could potentially draw directly on the film - but there is zero room for error with that approach!

 

The parts I'm creating have to have a specific geometry to enable the whole linkage to function without either wobbling or binding. It will likely take at least two or three tries to get it right.

 

I'll keep you all posted! :-)

[Grant]

Wow, there are some wonderful diverse skills on show here .. I thoroughly enjoyed reading through the entire process and eagerly await the next instalment

 

Grant.

[crazypoet]

Quick update, with pictures to follow later. I've not had near as much bench time as I'd like, but progress is actually happening.

 

I have more of the hull planked, and the hot well and condenser are both nearly done. I ended up doing a bunch of extra work on both, to make them a bit more period and purpose appropriate. Once through these, it's back to the home PE and finishing the engine.

 

Pics to follow!

[picket1]

any new updates??

 

thanks

[crazypoet]

Hey all - it's been a while! This has been a bad year, time-wise, and whiles there's been progress, there's nothing that is really photo-worthy.

 

I have a few more rows of planks, and I've made a ton of progress on the Stephanson Link for the engine valve, but neither is quite photo-ready.

 

I do actually have all the parts and pieces done for the main body of the Stephanson Link, but I'm only *just* to the point where they are beginning to look like anything other than random bits of brass.

 

So... I do expect that my next update will be the completed link and engine, at which time I'll update all the rest of the slow bits of progress that *have* happened...

[crazypoet]

Finally an update - with some pictures, no less.

 

For better or worse, 2016 was sort of a lost year, insofar as bench time is concerned. I've been lucky to get any bench time at all some weeks, and there's been more than a few months with none to speak of at all. That, plus the fact that hull planking is not the most exciting subject, made for not much postable progress...

 

However... there's stuff beginning to come together...

 

I did finally finish the engine - including fabricating parts for the Stephenson Linkage for which no plans existed - by referencing a Clute Brothers catalog from 1873 for style and engineering approaches. I also finished some bits of steam plumbing, rudder and tiller. Added into the mix as a bit of sanity-salve, I scratchbuilt a pair of ammo boxes and a toolbox. The ammo boxes aren't quite ready for their closeups but I'm rather pleased with the toolbox. Of course, now I'll have to research and make the tools...

 

The hull planking is complete, including a bit of fussy work for the fantail. I'm in the process now of final sanding/filling the hull and adding in the remainder of the decking that must be complete before I can paint.

 

Finally, I added a pair of compartments in the stern, as I imagine that no good boatbuilder would leave so much space unused. I framed-in and finished the compartment interiors and scratch built functioning hatches.

 

I'll post engine pictures as a separate update, since they are sitting on my iPhone and need still to be uploaded. Here, however, are shots of the main hull, compartments and various oddments...

 

Where I was, as of my last update...

 

 

Hull pretty much complete...

 

 

 

 

Stern Compartments

 

 

 

Bow compartments open and closed

 

 

 

And odd bits and pieces - rudder and toolbox

 

 

Lastly, a teaser for the engine update to follow:

 

 

so that's where we stand, just now... with a good bit of paint and detail work yet to complete, along with a number of finishing details. I am hopeful that 2017 will prove to be more fruitful in terms of time,

[crazypoet]

Happy New Year!

 

So... the Engine...

 

The engine for this boat was a single-cylinder high-torque, low speed plant produced by the Clute Brothers in New York. The type was fairly standard and similar engines are still produced today. The exact design and mechanical details are lost to history, but a close approximation can be made from other examples and period references. So the engine specs in the kit are close, so far as they go.

 

There is one glaring omission for the kit plans and contents though - links and levers that control the forward/reverse valve timing via the Stephenson Links. The principles and means of action for the links are well-known, and the core components are part of the kit. The omitted parts are those that would have been used by the engineer to control and manipulate the links.

 

Nada. Nothing. Not even a *mention* anywhere in the documentation. In principle, this would be a simple lever, connected to the engine frame and Stephenson linkage. The engineer would move it to different positions for both throttle and forward/reverse valve timing. The genius of the design is that the engine could be completely controlled through the use of this single lever - full forward though full reverse, with different combinations of speed and torque at each position.

 

Cool.

 

But how was that done for *this* engine, on *this* boat? That's what I had to research, design and build. The good news is that the engine geometry itself limits the possibilities. There are only so many places to put the thing, and only so many ways to tie it together. I had to choose between a direct push/pull rod and a lever with a connecting link. I chose the levered approach based on other examples and from the notion that it would give the engineer a bit of mechanical advantage in actual use.

 

Ok, fine. Now, where to put it, and how to tie everything together?

 

Here's where I left things in the last update on the topic:

 

 

This is the front of the engine, where the Stephenson Link sits. It drives a pushrod through the bottom of the square gearbox above the crankshaft whose motion and timing controls the valves. The link itself consists of two arms driven by eccentric cams and linked to the pushrod.

 

After tons of head-scratching, drawing and research I came up with the following bits and pieces to tie it all together

 

 

The two identical arms at the top and the pushrod itself came with the kit. Everything else was scratchbuit. I played around with AutoCAD and a home PE kit, but my CAD skills weren't up to the challenge. I ended up using graph paper for design and scale, carbon paper to transfer the final designs onto brass stock, and a ton of cutting, filing, soldering, cursing, re-soldering, fitting, throwing things and yelling a lot to finally get things working.

 

I suspect the original builders went through a not-dissimilar process, come to think of it...

 

Here's how the pieces connect...

 

 

 

And how they look after installation...

 

 

 

 

So this completes the engine itself. The remaining work is the plumbing and connections - boiler, condenser, hot well, engine, pipes, propeller and propeller shaft. The boiler, engine, propeller, compndenser and hot well are all built, but won't be installed and connected until the rest of the boat is complete.

[crazypoet]

I got a bit more work done on the hull itself over the last few days. The cover boards are installed - these cover and support the ends of the structural frames - and I've just about finished the coaming strip around the outside of the decks and cover boards.

 

As always, clamps, rubber bands and CA gel are a modeller's best friend!

 

 

 

 

There remains interior trim, mast and supports and a rub rail to install on the hull. Then, final sanding, sealing and paint,

 

Lastly, cleats and fittings, mounting the gun and spar torpedo and other oddments... and done! Maybe before the end of winter... hope springs eternal...

[crazypoet]

Milestone achieved - the hull is complete, ready for priming and painting... The coaming, trim, rub rails and cover boards are all complete, sanded and filled...

 

It took a couple iterations of sand/fill/sand/inspect/groan/repeat to get things ready for the first coat of primer, but I'm happy.

 

 

 

The paint will be black for the hull and gray for the topside. It will be a bit grungy - it had been on the water for several months by the time of the mission against the Albemarle. I'll add a touch of algae below the waterline and the usual bumps and dings that small craft tend to accumulate. In addition, smoke from the coal-fired boiler will have an impact, so on the whole this boat won't be a pristine example of the type...

[GusMac]

Looks lovely. It actually seems a shame to have to hide that lovely timberwork under paint.

[krow113]

Nicely done!

[crazypoet]

Looks lovely. It actually seems a shame to have to hide that lovely timberwork under paint.

Thanks!

 

One of these days I'd like to do this kit in civilian guise as a lake or inshore cruiser. It could be really pretty, absent the military trappings.

[crazypoet]

The first coat of heavily-thinned primer pointed out a couple small spots that need some more attention with the sanding sticks, but I'm very happy so far.

 

A bit of touch up, light overall sanding then the second primer coat. Meanwhile, I'm calculating the waterline, as it's not specified anywhere in the docs.

 

There won't be *much* of a difference above/below the waterline, but enough to make it obvious that it's been in the water for a while

[RalphSarc]

Really amazing progress!

[crazypoet]

Thanks, Ralph!

 

While I'm continuing with the first layers of paint, I gave a bit of attention to the prop and shaft.

 

The prop was cast in Britannia Metal, a soft pewter. I cleaned this up a bit last year and put a first light layer of copper electroplate on the casting. Today, I added the shaft and a scale bolt, then hit the whole assembly with a few more layers of copper to bring them together.

 

The shaft and bolt are brass, and needed a bit of drilling and tapping to get them fit properly to the prop

 

 

 

After snugging things up, I plated the finished assembly with two layers of copper, which gives a nice bronze finish over the brass shaft/bolt and pewter prop

 

 

I'm also adding a bit of extra detail where the prop shaft passes through the hull. There's a bit more head-scratching to do here, but I started by adding sleeves for the shaft.

 

 

 

These will both support the prop shaft and give me the foundation for adding some bearing detail after I paint the hull.

[krow113]

Exceptional work cpoet!

 Makes me cast an eye over my CSS David kit.

[crazypoet]

Working on the hull coloring, building up the color in thin layers, adding a bit more black each layer. It will ultimately be not-quite completely black with dull patches from wear and weather, and algae below the waterline.  The rub rails will be battered, chipped and water-darkened, as will parts of the stem and keel.

 

I'm mindful that the original was painted by hand, mostly with 3" and 6" brushes - so no airbrushing on my part for the base paint.

 

I'll spray or airbrush the algae and suchlike below the waterline and probably a dullcoat overall when it's done, but I'm doing the painted bits with a brush.  It gives me a bit of perspective - it's a *lot* of work to paint a boat by hand!   



Once the main hull is done, I'll get to work on the topside decking and details. Those will be a mix of wood and medium gray paint

Edited January 30, 2017 by crazypoet

[crazypoet]

It's taken a bit of back and forth but once again, progress is happening. In each step of this build I'm finding incomplete or conflicting documentation so I feel my way along, a bit at a time.

Two specific, current examples of this are in placement of the waterline and in the placement and number of masts.

The waterline is not specified in the kit as the designer assumed an all-over-black paint job and a museum-type display. Trouble is that I'm doing a point-in-time build showing the boat as it actually existed on a specific date (or as close as I can get). So off to the references I go... yes? Well, actually, no... the references available are all after-the-fact drawings of boats "similar to" Picket Boat One. Ok, I can work with that. The drawings don't say much about the color scheme, but do give guidance on the waterline location. And straightaway we run into a snag... to put the waterline where it *should* be would leave the kit propeller partially out of the water. The kit version puts the prop and shaft a bit over 1/8" - 3 scale inches - too high. Re-engineering this would involve major re-engineering of the kit. So bugger that, I'll change the waterline instead...

Two different near-contemporary drawings show the general layout:





So I split the difference and put the waterline even with the highest point of the prop arc. I'll be able to "fuzz" this a bit when I do the hull weathering, so it works. The upper hull follows the kit design in black, while the lower hull is dark gray. This aligns well with period descriptions.




I'll also need to fiddle a bit with the fittings between hull and prop shaft as well as the spacing between the hull, prop and rudder.  And, yes, I'm completely ignoring the difference in rudder design between the drawings and the kit.  Artistic license is at play here, since both rudder types were known to be in use at the time.  Problem solved! 

Next, as I'm ready to flip the thing over and work on the top-side fittings, I need to face a detail I've simply put off because I didn't want to deal with it. Masts.

The kit provides for a single mast near mid-ships, which handily covers some construction seams. It also matches a depiction of the boat from a later illustration:



Unfortunately, this layout doesn't match the earlier, near-contemporary views, which show masts at the fore and aft extremities - much more in keeping with period practice.

I've avoided this particular detail until now, but I can no longer put it off... so I'll go with the fore and aft masts as shown in the earlier drawings, and come up with a plausible way to cover the construction joint where the kit mast would otherwise be located:


 

I left that joint untouched early on in the build as I assumed that the mast in the kit was accurate.  I didn't discover the discrepancy until much later, well past the point where I could fix it easily.  Live and learn!  Now I have to get creative.

 

This is the fun stuff with models of this sort - interpreting and incorporating details that expand on what the kit has to offer.

Next head-scratcher... Hawse holes at the bow for running anchor ropes. One drawing shows with and the second shows without. At this point I think I'll add them in, since they just make sense. The engineering is pretty straightforward, as it requires just a bit of drilling and some brass fabrication. It's kind of a fun extension of the kit design.