Steamship Barbicane

[Ted Cochran]

When I was in Minnesota, I was tremendously impressed by Jeff Taylor's steampunk rockets (as illustrated elsewhere in this forum). This led me to try my hand at it, albeit in a school of steampunk that shades more toward retro. First came little Nemo, which made one successful flight on a C6-3 before ending up in the Museum of Flight's fusillade of model rockets:



Then came a more refined and larger Nautilus, and finally a retro Mars Lander, both designed for 24mm D and E motors, and each of which has made several glorious flights:



For those interested in details on the building of these models, they were described in a Sport Rocketry article in February 2016, along with some of Jeff Taylor's and Todd Carpenter's similarly-themed rockets.

It's been a few years, and while I've kept busy during the quarantine building traditional rockets, the time has come for another scratch build. And, inspired by a recent thread on the NAR Facebook page and the next kit in my queue, an Estes Silver Comet, it's going to be a scratch-built Steam Ship.

Introducing the S.S. Barbicane:

The drawing is full scale; that's a stock Silver Comet fin used for inspiration.

More on the development of the initial design, and the considerations involved in steampunking a rocket, in the next post.

 

[FatBoy]

THIS. Will be good!

 

[Ted Cochran]

Non-cylindrical body shapes aren't that common in rocketry, although it seems most early sci-fi illustrators were captivated by them. These models are constrained by the size of the motor tube needed at the aft end, and the need for space for a sufficient recovery system forward.

There also needs to be provision for nose weight--sometimes significant nose weight-- and the curvy body requires the diameter of the nose cone shoulder to be different from the diameter of the body tube at that point. As a result, they need to be build up from a core of body tubes of different sizes, with outside fairing(s) approximated by a series of conical transitions or, alternatively, made up of bulkheads, stringers, and body panels.

Rocket design software isn't well-suited for steampunk designs. Smoothly curving body shapes can be modeled by a series of secant-ogive transitions, as shown below:



But there is a lot of fiddling that is necessary to get the shapes to look "fair"--a shipbuilder's term for smoothly curving and pleasing to the eye. To move the maximum diameter fore and aft requires adjusting the fore and aft diameters of every transition in the drawing! And fin shaping, pods, protrusions, conduits, etc. can be difficult and time-consuming to add. Also, I personally wouldn't bet my life on the accuracy of the stability calculations or simulations.

In the past, in both nautical and aeronautical design, faired lines were developed by lofting, which is a method of converting a set of coordinates taken from a small-scale drawing to a smoothly flowing full-size shape. Battens--flexible strips of wood--are pinned at coordinates laid out on a lofting floor, and bent to form a smooth curve.

Barbicane is a far simpler shape than the hull of a ship, but the curve of the hull and the shape of the fins benefited from laying out a full-scale drawing that started with the tube sizes and configurations and nose cone length and the maximum diameter of four inches--the largest outside centering ring that could be cut from a single sheet of balsa. A 1/32" basswood batten, pinned fore and aft, allowed easy experimentation with the placement of the large centering ring, and in turn yielded the diameters of the other centering rings needed:



Once centering rings were fabricated from balsa, the core of the model could be dry fit:



I'll talk about the nose cone and centering ring fabrication next time.

 

[Mugs914]

You had me with the name...

Are you planning to strip plank the fuselage? I've planked many model ships and airplanes and have to say that I found it pretty relaxing, actually.

 

[Ted Cochran]

I'm thinking I'll panel it, like Nautilus above, and the ship below.



BTW, If you like ship building, check out the Sampson Boat Company on YouTube. Awesome craftsmanship!
https://www.youtube.com/channel/UCg-_lYeV8hBnDSay7nmphUA

 

[Ted Cochran]

Since no retailer sells 3-7/8" diameter centering rings for a BT-80 motor tube, they need to all be fabricated. The process isn't too difficult--I take accurate measurements from the drawing using a dial caliper (finally got a decent one to replace the cheap plastic slide caliper I've been using). I transfer the measurement to a good quality compass and draw the concentric circles. Note that centering rings larger than 4" will likely require laminating edge-glued balsa sheet stock, but that's standard practice, too. You'll likely need several larger rings of similar, but different, sizes, and a few smaller rings as well.



I use a new X-acto blade to cut the centering rings out, leaving margin on both the inside and the outside. I trim the outside edge to the line using a disk sander, and since I don't have a spindle sander, I trim the inside edge to the line using a drum sander chucked into my mini drill press. If you're not familiar with these drum sanders, check them out here.

The smallest size of the drum sander attachments fit through the drill press table's center hole, ensuring that the edge is square.



You'll almost always need to plan to have a fairing of some sort on the aft side of the nose cone to blend in the body, and you can expect to have to turn a custom nose cone for your design. I turn smaller nose cones on my drill press as well, using a body tube that fits over the chuck and appropriate centering rings to hold a body tune that fits the nose cone shoulder. You only need sandpaper to do this. Here's the Nautilus nose cone getting turned:



Barbicane could have been built similarly--a smaller nose cone, for example BT-60-sized, with a big fairing. But I happened to have a 5" balsa nose cone from a broken Super Sprite:



This needed a lot of sanding to turn it into a secant ogive, but a belt sander, followed by careful hand-sanding, took care of that. We'll get back to fairing the nose cone a bit later.

Next up: Fins and fin pods.

 

[Ted Cochran]

I borrowed an unbuilt Silver Comet kit’s fins for inspiration for Barbicane. My first Silver Comet was a workhorse—it had over 65 flights on C, D, E, and F motors. Initially the fins were problematic, with frequent cracks on landing, because they extend way past the bottom of the body tube. I ended up laminating them with adhesive metal foil tape, cut into rectangles to resemble panels, and the fins were much more robust after that. In retrospect, that was my first flirtation with steampunk.

So for sure Barbicane’s fins will be laminated, although whether with foil tape or paper or even fiberglass has yet to be determined. First I needed to get the shape right, and figure out the tip pods.

Tip pods are made from nose cones, turned on the drill press. I make up a jig using a tube that fits over the drill press chuck, some centering rings to hold an appropriately-sized smaller tube, and some internal centering rings in that tube to hold the tip of the nose cone in place so that it spins properly. Shaping is done with a sanding block. Once the jig is done, it only takes a few minutes to do a pod.



Then it was time to cut slots for the pods. These are tricky, since they need to be exactly on the long axis of the pod and exactly the right length. I made a fixture for my miter saw to hold the nose cone exactly in line with the blade. The length of the cut is determined by the depth of the blade, and the starting point is determined by the placement of the pod in the fixture. This worked very well. Since the saw kerf is 1/8”, the fins will be made of 1/8” balsa.



Fin shapes were transferred from the plans—the root edges look weird because they will be mounted to the 24mm motor tube, and they're still to get a notch at the top for the BT80 inner tube and a slot for the fourth centering ring, and the fairing isn’t on yet. Gotta trust the plans…



It likely has occurred to many of you that this would be a lot easier, and more precise, with CAD software and a laser cutter. You are probably right, but I think doing manual drawings, transfers, and parts fabrication is a lot more fun!


Next up: Experimenting with finishing techniques while waiting for glue to dry.

 

[Ted Cochran]

I’ve glued the first five centering rings in place--two internal and three external. The aft-most ring and the fins are dry fit for now. That's a shoelace sticking out the top--an inexpensive, mid-power version of tubular nylon that I've inserted through a centering ring and tied around the motor mount.



Meanwhile, I’ve been thinking a lot about finishing, which is probably the most important factor in making these rockets what they are.

First, we need to decide on whether the model is supposed to represent a real-world, albeit fictional, ship. If it’s supposed to be real-world, we have to figure out the scale for the model—is it more like 1:100 or 1:20? That determines the number of crew that would be in it, and the size of canopies, portholes, hatches, and the like. And also rivet and plate sizes.

One key feature of steampunk/retro rockets is riveting. The Sport Rocketry article describes a lot of different ways to make rivets, and I’ve been experimenting with some of them, as well as different colors of paint on different types of surfaces, to help decide on how Barbicane will be finished.

Nautilus used raw poster board cut into plates and strips for its body; rivets were made from dabs of yellow glue thickened with epoxy filler. The finish was a shiny lacquer (Testor’s Diamond Dust) which was then antiqued. Before committing to that approach for Barbicane, I tried a few other lacquer colors (Inca Gold, Bronze) on a glossy surface this time, and a whole lot of ways to make rivets using Todd Carpenter’s make-a-dent-in-metal-tape approach.



The results of the first batch of tests are below, with different types of metal tape. Most of the rivet heads of different sizes were extruded using a set of ball bits for Dremel tools (like these) used as forming tools. I tried several different backing plates to adjust the depth of the punch marks, and rubber from an inner tube worked best. Many of these look pretty good at first, but the “rivet heads” squash into donuts when they’re handled.

This is 2" wide metal foil tape, with various punches used (not very successfully) at the top right, and various sizes of dremel bits used on the left, and some other shapes used as well. You can see the effect of rubbing the tape in the middle, where the "rivet heads" are squashed.



Some more systematic experiments are shown below, with different kinds of metallic tape with and without paint.


I'm going to keep experimenting on that when I have to wait for more glue to dry.

Next up: Papering and installing fins.

 

[Ted Cochran]

Feel free to jump in any time with suggestions, comments, or questions!

I elected to paper the fins, both to reinforce them and to provide a nice semi-smooth but not glossy surface for eventual antiquing. The roughness isn't a problem for steampunk/retro models, especially if they are intended to look old and used. The grungy look adds to the character, as I think this photo of Nautilus illustrates.



Some degree of bashing is authentic! Check out these ship hulls, for example.



To laminate the fins, I used regular 20 lb printer paper. I diluted yellow glue with just enough water to make it brush well, then brushed it liberally on one side of a fin. I pressed the paper on with my hands, then rolled the paper down with a wall paper seam roller. I did the other side immediately to avoid warpage, then pressed the fins between layers of wax paper and two flat plates with a bunch of weight on top. I did all four fins this way, and left them pressed overnight between layers of wax paper.



When they were thoroughly dry, I cut off the excess paper (use a new knife blade for this!), and bevelled the edges—first with a drum sander, then by hand.



Finally, I used heavy duty (69 lb) glossy photo paper, dull side out, to “plate” the leading and trailing edges, making relief cuts as necessary. This makes for nice sharp leading and trailing edges. These strips will get “riveted” eventually. I’ve completed one fin so far.



Meanwhile, I’m building up the last (top) centering ring at the body/nose cone seam from strips of balsa curved with the grain around the top of the inside body tube and the bottom of the nose cone. A standard centering ring here would be about 3" in diameter and1/4” wide, and so very fragile; I’m hoping this will be a bit more durable. I prebend the strips a bit, and then glue them and either clamp or pin them in place, whatever works best.



Next up, stringers!

 

[neil_w]

The leading and trailing edge plating on the fins is quite interesting.

Am I literally the *only* person in the world who sands off excess paper rather than cutting?

 

[John_461]

I use Avery sticky label paper to laminate my balsa fins (no worrying about warpage). Then I sand off the excess paper while airfoiling and CA the exposed balsa/paper edges for strength.

 

[BABAR]

I use white glue. I think Apogee Rockets suggests having a damp towel nearby to keep wiping off your finger so you don’t get glue on the outside of the fin and spoil the surface.

I also liberally apply the glue to the paper so the full internal surface is covered, then use a key card or old credit card to squeegee off all the excess. I do this on top of an old magazine or journal, so I can lift the paper off cleanly, put it on the fin, when done I tear off the page of the magazine and have a clean page for the next. You have to work quickly as if the water from the glue soaks through the paper it disintegrates.

Adhesive Label paper works great cosmetically and is much easier to work with, but doesn’t provide nearly as much strength to the fin.

I usually don’t have curved surfaces, so I frequently will use a single cutout and paper both sides of the fin with a single piece, wrapping around three sides (I often use square sided fins, I.e., no curve or airfoiling), always leaving the root edge uncovered with about 1/8” gap for the fillet.

 

[Ted Cochran]

The leading and trailing edge plating on the fins is quite interesting.

Thanks. The edges came out fairly well, I think.

Am I literally the *only* person in the world who sands off excess paper rather than cutting?

Sometimes I do it that way, especially if it's a dope and tissue covering.

I use Avery sticky label paper to laminate my balsa fins (no worrying about warpage).

Have you ever had problems with paint dissolving the adhesive (Lacquer-based spray paints, in particular?)

Adhesive Label paper works great cosmetically and is much easier to work with, but doesn’t provide nearly as much strength to the fin.

I agree on both counts.

 

[GuyNoir]

Thanks. The edges came out fairly well, I think.
View attachment 416024

You sure you got enough clamps on that thing?

 

[Ted Cochran]

Ha! I score it on the wrong side to keep the leading edge clean, and that plus the curve on the leading edge makes the edges want to pop up before the glue dries.

 

[Ted Cochran]

I've glued the fins on the body structure, aligning everything by eye.



While waiting for the glue to dry, I carved a notch in the nose cone where the fairing blends in--this will need to be faired to the final curve later, but for now it gives me a reference mark at the fore end of the stringers. To make the circular cut, I used the base as the height reference, put it on a flat bench and rotated the nose cone against a reference height, then scored and carved the notch.



Once the fins are all on, Barbicane can stand on her legs for the first time. This completes the core structure; everything else is fairing and decoration!



Time for the stringers. These are made from 1/32" basswood strips. I'm cutting them from 1/2" wide stock. They need to be wide enough to support gluing two panels side by side, but not so wide as to interfere with the fairness of the fuselage. Pinned or clamped at the top and bottom, they fall right against the bulkheads, as expected. The rubber bands help hold them in place while the glue dries. Oh, yeah, I put a 1/4" launch lug on the main body tube awhile ago. Have to think ahead for initial guidance for these curvy models!



I didn't glue the top two points, since they're on the nose cone and that needs to separate. I'll figure out a way to make that edge clean and fair as I go. I expect there to be two stringers along each fin and three in between each fin for a total of 20, but that might get adjusted as I think ahead to finishing the ship with a steampunk motif.

 

[neil_w]

I'm extremely interested in the stringer process, how to see lots of pictures of that if you can manage it. What order you do them in, how you shape each piece to fit, how you work around the lug. Looks really interesting, and I have a spare sheet of 1/32" basswood so....

 

[John_461]

Have you ever had problems with paint dissolving the adhesive (Lacquer-based spray paints, in particular?)

I haven't. Possibly because I use thin CA to seal the edges really well.

I agree with BABAR that it isn't as strong as the glue/paper method. However, it's still plenty strong. I've launched an Apogee Aspire on a G80 to supersonic speeds while using this fin laminating technique.

 

[neil_w]

I haven't. Possibly because I use thin CA to seal the edges really well.

Me neither. I seal my edges with TBII.

 

[Ted Cochran]

I'm extremely interested in the stringer process, how to see lots of pictures of that if you can manage it. What order you do them in, how you shape each piece to fit, how you work around the lug. Looks really interesting, and I have a spare sheet of 1/32" basswood so....

I do the finside stringers first, to get the alignment correct, so I can use them as a guide for the others. Stringers aren't hard at all--cut 1/4" or 3/16" strips, pin or clamp them to the top, bend them into place, and pin or clamp them at the bottom. Glue at each centering ring. There will be sanding later to smooth any rough spots. [*Spoiler Alert* I'm going to be gluing trapezoidal panels of card stock/poster board to these and it will be quite solid when I'm done,]

Here's a few pics from Barbicane and Nautilus (click to expand); let me know if you have questions!

 

[neil_w]

Ah, I see, you aren't planking the whole thing. That's what I was curious about, when you have to fill all the area with planks of different shapes.

In any case: looks wonderful so far.

 

[Ted Cochran]

Ah, I see, you aren't planking the whole thing. That's what I was curious about, when you have to fill all the area with planks of different shapes.

In any case: looks wonderful so far.

Thanks. Planking this wouldn't be too hard based on the plans, I think. I'd have to draw some lines like the ship builders do. In theory every full length plank would be shaped the same, and there would either be 20 big ones that you'd have to shape into a curve with ammonia, or a bunch of narrower ones--some full length and others that would start and end at the second and fifth centering rings, and some others start and end at the third and fourth centering rings. There's a link to a wooden ship rebuilding youtube series up thread that really gets into it.

 

[Ted Cochran]

Construction continues. The pace seems to slow a bit since there are lots (20) of stringers and pretty much each one has to dry before the next. The launch lug is centered between two fins, so the stringer that would be there has to be in pieces: one long one from where the launch lug tube exists the body fore and aft, another from the stern to the underside of the launch lug where it exits the body, and (maybe) another from the nose fairing to a spacer under the launch lug at the nose. [That nose-body joint looks ugly because I added some wood filler to bridge what would otherwise be a gap between the nose centering ring and the body. I'm not done with it yet; it'll be fine.]

I ended up gluing all the stringers the full length of the rocket to fix their curves in place. This of course locks the nose cone to the body, so when everything is dry I take a razor saw and cut each stringer at the nose-body junction on a line measured down from the top of the nose cone.




A couple of rubber bands near the wide part of the hull hold the stringers while the glue dries. They are pinned at the top and clamped at the bottom, and once in awhile I'll use a little microclip to nudge a stringer against a centering ring while the glue dries. So far, so good.



I've also continued to experiment with riveting techniques. The experiment below uses straight Titebond, Titebond with West 406 and 407 filler, and Titebond with balsa dust (recovered from sanding nose cones and pods). The mixtures with fillers usually require a water to thin it enough to apply, and the amount of water turns out to be pretty critical to making the rivet head assume the proper shape--not peaked, and not flat. I use a straight pin with a tiny head stuck into a dowel as the applicator. It's sitting on top of the mixing cup on the far left below. I'll let you know how it all turns out.



Current weight is about 6.5 ounces. Nautilus is about 12 ounces empty, but that includes 6 ounces of nose weight!

 

[neil_w]

Have you tried Titebond Quick and Thick for rivets?

 

[Ted Cochran]

No but if you recommend them I'll add to my glue collection!

 

[neil_w]

It holds its shape and shrinks less than regular wood glue. Might work for that purpose.

https://www.titebond.com/product/glues/d1b48beb-7d60-4ce7-b57b-6bf19351778b

 

[kuririn]

A suggestion for rivets: try puffy paint, available at arts and crafts stores.
I used a brand called Scribbles on my Apogee Flying Machine, SkipperChuck used a brand called Tulip.
https://www.rocketryforum.com/threads/build-thread-apogee-flying-machine.147034/One small bottle cost less than $2 and did over 1200 rivets with half a bottle left over.

 

[Ted Cochran]

Thanks for the tips. Looks like Titebond Quick and Thick is the same formula as their molding and trim glue, which I have and is on my list to test. I ordered some puffy paint. Always willing to experiment! And I think I can always fall back on the method I used with Nautilus, which worked just fine albeit a bit tedious, especially for the littler rivets which will be the majority on this new ship.

 

[neil_w]

I ordered some puffy paint.

If I recall correctly, puffy paint proved to be a top choice when the Apogee Flying Machine came out and everyone was trying to figure out the best way to make all the rivets. I'm still curious to find out if the Titebond M&T works; as I think about it I'm unsure how to apply a nice round blob. Might just have to go experiment with it myself, even though I have no riveted rockets on the horizon.

 

[Ted Cochran]

I'll do a bunch of tests with M&T for ya!