Walrus class 1/60 scale - Scaleshipyard

[salmon]

Thank you Matt, good information!

I made a 3D frame for the ballast saddles. I also made latches for the aft end of the upper hull. Here they are printed out.
The material is similar to plaster of paris, well kinda. It is a gypsum powder, but it needs to be fixed with either an extremely thin CA or there is an epoxy. The epoxy makes the part stronger, but for making a mold, CA is more than adequate.


Went to the local hobby shop and purchased a simple rubber kit. It is a very soft rubber, but will make a quick mold. Legos were my frame and clay sealed the edges.


Used Alumilite resin


Makes pretty good replicas. The master is not good for using because the water would soften the gypsum. Epoxy cured might work, but the epoxy used is questionable about how it would survive in the wet. Later I made a part that I used West Systems epoxy and a vacuum chamber to make a part that I believe will hold up (time will tell).

[salmon]

Now the prop shaft. The end I marked and drilled the center.
Using a 11/32" brass tube, I put 2 oilite bushings in. One at each end. My shaft is 3/16" high tolerance SS shaft from McMaster-Carr. I ordered 2 - 3' sections. One is what I will use for all future builds as a assistance in centering and the other will be cut for the actual shaft.


The hole at the stern was enlarged enough to allow the brass tube to fit into it. Then measuring and using a level, got the shaft in a straight and center alignment.


Sealed the hole around the brass tube with CA. When dried, I poured some epoxy in the end by standing the hull straight up and let everything solidify overnight.

[salmon]

Placing the sail on the hull just looked so cool to me. I enjoy building a submarine because it becomes intimate. I look at all the picture I can find and read what I can just to get to know the sub I am building. However, placing the sail on the hull brought it all together.


Making sure the alignment is correct.


In the sail I made a clay dam and filled the area with casting resin.
Now with the sail aligned, I drilled through the hull into the sail. Threaded the holes so a 4/40 ss flat head screw can go in.



Marked out areas I thought were not needed and to allow air out and cut out the sections.

[Ralph --- SSBN 598]

Cutting holes in your expensive hull is something I find new hobbyist have a problem doing.

Try looking at it this way.
Tom placed his sail on the hull after finding the location it needed to be.

If you look, you can see where he traced around the sail with a marker pen.
Next draw a line about 1/8" to 3/16" to the side that is under the sail.
You now have a cut line of material you really don't need.
Draw some support areas to keep the hole from spreading.
In the photo, that would be the area with the diagonal lines filling the area.
Make your frame supports larger than needed.
You can cut out more if needed.
You will find that if you plan it out, you can remove a lot of un needs material to make your boat lighter.
Don't worry about anything below the water line.
Concentrate on the areas above the waterline.

You will soon get to where cutting on your expensive model won't be an issue.

Then you will cut something you didn't mean to.
Now you get to learn how to make major repairs.
You are now a modeler, not just a model assembler.

Read Tom's signature line.

[salmon]

Thanks Ralph for adding additional information. I am never sure what is too much wording or not enough. Anyways I appreciate your insight.
Thank you.

[salmon]

The ballast saddles I cast up were placed in the hull. I thought there were needed, but only two were used.


I still had holes being drilled and filed.


Will showed me an issue he was having with his x-tail planes. He was going to redo the finish and wanted to see if there was a better way to secure the base of the plane. The current way it was continuing to crack on the edges.


I played around with an idea and drew up some thoughts.

The thinking was two long screws would go through the base and attach to a base inside the hull.

Loaded with an idea, I started to 3D draw out the base and guides that would go up through the hull and into the base. The screws will go into the pins and secure the base to the plate inside the hull.


With the concept working, I made a mold and cast up a set.


Well it did not go that smoothly, the clear resin needed to cure longer. When I used the pressure pot, to get rid of bubbles, I should have waited a couple of days before removing. The resin was still a little soft and some big pockets expanded causing dimples into the planes. It took 12 or more casts to start to get a decent copy.

To help make sure the holes were correct for the base plate, I made a drill template guide.


The marks I made by the locations from the template were opened up to receive the screws and the plane shaft.


Mounted the planes.




The rest of the story, by the time I got the set of planes done (it took me a long time), Will already finished his refit and fixed his planes and painted his sub.

[scott t]

There is a lot of good stuff going on here. So for me the question is how you made your
Drilling template?

[salmon]

Thanks Scott, I am glad you are asking questions, hopefully it is informative.
I measured the Walrus hull at various locations including the end diameter. Then using 3D software (I have used 4 different ones over the years) created a cone with the proper dimensions. I subtracted my base model from the cone (leaving the locations for the drill holes and repeated that 4 times to perfectly line up and be at a 90 degree angle. Then printed the model. I put a slit along the cone that centers on the drill holes and could also draw a line with it using a sharpie. It would allow me to make a circle or bigger dot where I needed to drill. Once I mounted the base of the planes to the hull, I drilled the hole for shaft for the upper potion of the plane or the moving section just to make sure there were no alignment issues or binding.
I forgot to mention, when I placed the shaft in the plane before casting, I flattened the end so there was something preventing the shaft from getting loose and rotating in the casting.

[JWLaRue]

Tom,

That's a very clever way to ensure a perfect 90/180 degree alignment. I need to keep that one in mind.

I forgot to mention, when I placed the shaft in the plane before casting, I flattened the end so there was something preventing the shaft from getting loose and rotating in the casting.

As an aside: I've been using square stock 'rod' for my rudder and dive planes for years. They rotate perfectly fine in/through a round bushing or hole on the hull. A side benefit is that I never have an alignment problem with the control arms. That set screw will always force the arm into the same place.

-Jeff

-Jeff

[salmon]

Jeff,
Thank you for that. I have read about using square stock in SCR, but have not myself tried it. I will put that on a todo list. Psychologically, it messes with our mind. You are not supposed to fit a square block in a round hole. I will have to get over that LOL! Seriously, it makes sense and keeps things straight as long as it is aligned correctly when you set it in the plane. Do you use a jig to keep it aligned?

[Ralph --- SSBN 598]

Square shaft in round bear.

You have 2 chances to get everything aligned.

1. Square shaft in control surface can be squared to the shaft. but not necessary.
2. Square shaft not squared to control surface, you adjust the control horn to make the horn 90 degrees to the control surface with the set screw snugged up to shaft.

Like you Tom, I flatten the end of the control rod.
Hit it with a hammer before installing.
Tighten it up in the vise.
Or grind a couple of flat spots on the shaft end.

I usually can not find square brass stock at the hobby store. (they seem to noit replace low stock very often)

[scott t]

Neato 3D printing. So what if you made a cone that fits on the inside of the hull to attach the planes to.
It could include printed holes that align planes. Have temporary shaft alignment support for positioning inside hull.
1) Drill oversize holes in sub.
2) Attach planes to cone.
3) Glue cone after planes attached and centered with silicone caulk.

[JWLaRue]

I don't use a jig. When I create the masters, I embed the square stock rod in it, which keeps the hole aligned when I eventually make the molds and cast the parts. If I am adding it to existing parts, then I use the control arm as a visual guide for (rotational) alignment when bonding to the part.

-Jeff

[salmon]

Thank you Jeff!
Scott, in effect I did that. The piece at the very bottom goes inside the hull and the base of the plane screws into it. You are such a creative thinker!

[salmon]

The bow (being a Z cut) has a lip that slides into the hull. We then need to fasten the aft end, but we also need to bring a bit of a holding mechanism for the aft end too. I created these (see earlier post)


I thought that looks great, simple small (no big weight added), and so smart of me.......well they all broke at one point or another. If I was too aggressive sliding the hull back it would jam into the parts and break the tip off. I did not take a photo of the lock I made, but it was bigger and screwed in fashioned off of what Will did on his Walrus.


So continuing on, it was time to address the sail planes.
I had a set of plans lent to me, that Will Oudmayer and Tom Anderson used when they made the original hulls. I used those, but I also knew that the Walrus went through a update and the sail had an exhaust heat diffuser added, did the planes change? Well one of the plans I found online showed an interesting shape. So I decided to verify. It turns out this plan drawing was very wrong! So verify if you can when you get plans.


The original plan was this one:


I had some courser foam that I bought and used to shape the plane.


A lot of sanding and comparing and it came out O.K.


Now I made a mold of this one and cast several sets (just in case I messed up some while drilling the shaft hole.


Mounting the planes turned out to be relatively easy!