Project 945 - Sierra I (1/60 scale)

[cstranc]

Well you may remember earlier

Well you may remember earlier in the post I lost my concentration while drilling the hole for the stuffing box (that the prop shaft will live in). Time to fix that little error.

This time I started earlier in the evening and ensures I had a fresh cup of coffee... Must get alignment right... What to do.



That's right. Anytime you want to pay extra-ordinary care aligning things you build a jig. This was just a piece of scrap plywood. I cut two grooves (for the hull sides) 6" apart. Then I drilled a 3/16" hole at the mid point. This gave me alignment side to side, and since the centerline of the hole was aligned to the top of the grooves top to bottom.

I was determined not to goof on this again.



Looking carefully at the tail you can see the washer between the prop and the stuffing box. It needs to be there, but I don't want the prop that far away from the hull. So I recessed the stuffing box into the hull 1/2 the thickness of the washer. I had to file the resin around the stuffing box also to allow the washer to sit into the hull.

At this point the plywood jig was holding one end of the shaft true, and I used the prop to ensure the tail end of the stuffing box was in the right location. Then I carefully removed the prop and applied a drop of CA to hold the shaft in place.

Then I checked the alignment and it was all good. On to the next phase.



I applied packing tape to the end of the sub, making sure the stuffing box was sealed. The the hull was stood up on it's tail so I could pour resin into the enlarged hole that I created earlier. I put tape over everything that I might spill resin on by mistake.

The front / top end of the shaft is still in the plywood jig.

Then it was left overnight to harden up.



The shaft was fixed in place. The resin did not seep all the way down to bottom of the stuffing box hole so I used CA to fill the void. Then I took some files and removed the resin / CA from around the tail of the shaft to give me the space for that washer recess.

While the shaft was setting up the night before I took the time to glue in collets to the flaps for the rudder & dive plans.



As you may recall there is a brass tube running the length of the flaps. This tube will align with the tube in the fins. On each flap I had drilled out a hole deep enough to recess a collet into the fin. So now was the time to glue.

I had a nice slow setting waterproof epoxy. Before applying it I made sure I had 4 spare peices of 1/8" rod. I would use these to ensure the collet aligns with the tube inside the flap. I also sanded the end of the collet and filed grooves into the edge of the collets. This would give the expoxy something solid to hold on to.

The glueing was relatively un-eventfull. I started out with the brass rods in place for alignment. I was worried that if I left them they would be glued in permanently. So I popped them out, cleaned off any glue, and then every couple of minutes I would just check that the collets were still aligned with the tubes. All looked good.

If I found the collets were floating around and needed to have the rod in place to ensure alignment I had a plan B. I was ready to apply a layer of vaseline to the rod. I hoped this would prevent any bond forming with the alignment rods. But thankfully plan A worked.

So the next day it's assembly time.



While I have easy access the push rods are attached to the shafts that go through the flaps. Note the "extended" allen key wrapped in green tape. I could not reach that far without it.



That's the shaft support. The stuffing box lives in the center. You can see the vertical shaft that is the secondary control rod for the rudders, and the horizontal one for the dive planes.



And here it is installed. Now we have flaps that work as they should...



And we are looking more and more like those plans on the wall...



But oops. Man's best friend thinks I should pay more attention to other things, like his favorite pink tennis ball...

[cstranc]

You may have noticed the

You may have noticed the occasional cameo appearance of the sail and towed array pod in some of the pictures. As I have been moving forward with the hull I have been using them as side projects. So now let's see the construction of the towed array pod.



It all started on my Dad's wood lathe. Thank you, again, Dad. He created the master. It was too nice a shape so I just left it in the study until I realized I really had to get the towed array pod done before I could finish the fins. So it was time to create a mold.



I think I remember seeing someone use playdoh for a mold material. So I created a box out of MDF, layed the playdoh into place, applied a light coating of vaseline to the master and then pressed it into the playdoh. Then I pulled it out and looked at the results.

Well it turns out when I was needing the playdoh down into the box I created a couple of small fauts (grooves) in the surface. The were still visible after pressing the master into place. I figured it will never be easier to correct this so I re-prepared the playdoh surface and pushed the master (freshly coated with vaseline) into it. The second time I was happy with the result. You can see from the picture that I pushed the master 1/4" deeper into the mold then the center line.



Next I applied a coat of resin to the mold. I found that enough of the vaseline had left the wooden master to ensure the resin would not stick to the playdoh. As the resin was setting up ( I used more catalyst then usual and it set inside 25minutes) I kept the mould rotating to try and evenly spread the resin. When I noticed the gelling that marked the start of serious hardening I thought it was safer to just put it down and leave it alone. This gave a thicker layer of resin on the bottom of the mold. In the end I was happy to have this thickness because I needed to sand a flat spot there while mounting.

If I was doing this again I would consider applying a second coat of straight resin.



Next was two layers of cloth. I had the cloth pre-cut (of course) and could easily get both layers of cloth in place before the resin set. I did have to be carefull to ensure there were not air pockets between the cloth. This tended to happen close to the top of the mold.



After letting the resign dry I pulled the part out of the mold. It came out quite easily. I used scisors to cut away the extra cloth. Then I repeated the process to make the other half of the pod.
Then it was time to get the two pod halves to join. That mean marking and cutting an accurate centerline.



To mark the centerline I went back to the master and found the maximum diameter. I halved the diameter and then setup a pencil so that it was at exactly the right (1/2 diameter) height.

I created a small U shaped block of wood to support the tail of the towed array, then adjusted the location of the block to get the thin end of the towed array to the right height according to the pencil. Then I drew the midline all around the peice. Repeat again for the second half...



Then it was off to the band saw for a rough cut. As I did the cut I made sure I was at least 1/16" away from the line on both top and bottom. Then I had sanded them down to the line and frequently checked they fit together.



I drilled the hole for the tube that would hold the control rod for the top rudder. Then I dropped the pod into place. It did not sit correctly, so I marked the high spots and then sanded....



Soon the fit looked a lot better:



I mentioned the shaft that will control the upper rudder. Well I wanted to be able to remove this after the construction was complete. So I shifted the navigation light over a little so that it was right above the shaft. Then I created a little square plate that would hold the LED and be a friction fit into the pod.




When I was happy with the fit of the LED holder I used CA to glue the two halves of the pod together, and it was time for more bondo.

.

When you look below the pod you can see it is actually supported by two brass tubes. The rear one hold the shaft that controls the rudder. The front one will hold the LED electrical cables.

And here it is sanded with 220 to roughly the right shape, and with the LED installed.



If you look on the vertical centerline you can see a couple of holes. I figure the pod needs a way to allow the air to escape, so I gave it these holes. The front one is 3/16" and has a brass rod across it's centerlne.

[cstranc]

That leaves the sail. Hmm.

That leaves the sail. Hmm. I don't have pictures of it's early stages. It's the normal cut the foam to shape, glue it, shape it, ... that we saw with the hull.

We join the sail at the stage when it is due to be assembled to the hull. It has been cut to 1/16" of the desired height on a band saw, and now we need to get it to fit to the curve of the hull.



The centerline on the tail of the sail is obvious because it comes to a point. On the front I wanted an accurate centerline marked. So I took a square and a long straight edge. I adjusted the straight edge until there was the same disance to the square in front of the sail and behind. This gave me a good reference. Then I rotated the sail until the tail end was perfectly centered. Then I marked my center point on the front.

Then I looked at it to do a quick sanity check, because that never hurts...



I taped two sheets of 80 grit paper together and placed them on the hull. Then being carefull to align the centerline of the sail to the hull I started sanding...

The sanding actually went faster than I anticipated. I would remove the sanding paper frequently, clean any dust that got onto the hull, and checked the sail was also sitting correctly on the centerline.

At the beginning, middle and end I also took a level and put it on the hull (fins actually) to get the hull level side to side and then verified the top of the sail was also level.



When the sail fit nicely I aligned it carefully and then marked it's outline on the hull. Then I needed to mark the line for the cut to access inside the hull.



It is not very clear, but I am using a little wood spacer (part of one of those really great stirr sticks from Starbucks). On the left of the wood is the faint outline of the sail. The stronger line to the right is my cut line.

Using a little peice of wood allowed me to follow the curved line nicely. In the areas of tight curves at the front of the sail I would only draw lines 1/2 the length of the wood so I could keep a smooth curve.



That was the finished planned cut line. I gave myself a starting point for the cut by drilling a 1/4" hole at the tail end. Then it was time for the jig saw.



You can see the Bosch jig saw on the left. I highly recommend it. I have had it for years and it is a pleasure to use. I taped the bottom of the saw to ensure it did not mark the surface of the hull.

You can see I have completed the right half of the cut.



I did not want the center piece to fall loose as I was completing the second cut so I used tape to stabalise the cut side.



All cut through.



Next it was time to file the edges smooth and then it was time to break.

[cstranc]

It sure has been a

It sure has been a long time since I have been here in this thread. The overall construction of the model was put on hold while I worked on testing out automatic pitch control
http://s181686668.onlinehome.us/phpBB2/ ... 26&start=0
and started working on the torpedoes
http://s181686668.onlinehome.us/phpBB2/ ... 73&start=0

Many thanks to all the people on those threads that helped me out / gave me guidance.

But it's time to make some more progress here. I have been working on the periscopes while I had a few moments here and there. As a result the pictures may not all be in the correct order. Hopefully they still tell the story...

I am looking to have two functional (they go up and down, not take pictures) periscopes / antenna / radar.

A normal attack periscope (second from the front) and the "Snoop Radar" (weird thing 5th from the front).

As usual the work begins with looking at the plans and trying to get more pictures etc. If you do measure the plan carefully you can see that the snoop radar mast head is bigger that the rectangle on the top of the sail Ooops. I guess people have to jump out and push it back into the hull. I decided to scale the radar down so that it actually fits into the hatch in the deck.

I found some pictures of the snoop radar. None on a Sierra, but some on it's brother: the Akula. About the best I could see was:

But the one thing I did note. It seems like there are many different versions of this radar in different pictures. Maybe this gives me a little creative license.

I am using a Taig Micro Lathe (which I got recently and really love) to turn the mast head. Here you can see it taking shape.

This is actually the 3rd version. I create the mast head on the lathe, then insert a 1/4" aluminum rod for the mast. I have to turn down the aluminum rod to 3/16" and have a 3/16" hole in the mast head to fit.

The real radar has some interesting round things beneath the main mast head. I am simulating these by attaching ball bearings. If you look at the thin section of the mast head you can see a groove cut into it. This allows the bearings to rest in close to the center, minimizing the overall diameter of the mast head (which is just under 5/8").
This groove also increases the surface area for the glue to hold the bearings in place.


This is me gluing the bearing in place with some gap filling CA. I would put a drop of the CA into the groove and let it run down to the flat section, then place one bearing. Rotate and repeat.

Before gluing the bearings I cleaned them with acetone and a mild abbrasive to give the glue as much bite as possible. The bearings were free of any contamination before gluing. You can see in the picture that recessing the bearings into the central shaft minimizes the gaps around the bearings and allows the CA to fill them completely.

I have had no indication of a bearing losening from the grip of the CA.

I left a little space in the ring of bearings. This is for the "vertical pipe" feature on the mast. I drill a 1/16" hole (which is difficult after giving the base a nice curved surface) and then insert 1/16" stainless rod. This is visible in later pictures.

With a 5/8" mast head this was not going to slide in and out of a little hole in the top of the sail. I needed a split hatch that will open and close. The design and some of the parts look like....


It's probably easiest describing it top to bottom in the brass parts.

First we have the actual brass hatch doors. Each one has 3/16" L stock CAd to it. The L stock has a 1/16" hole drilled through it. A rod goes through these holes to be the hinge to open / close the hatch.

Next we have some brass plates that have 1/16" holes drilled into them to accept the rods that will be the hinges.

Next we have some brass plates that do not have the 1/16" holes. These keep the hinge rods in place.

Between this there is a 3/4" aluminum square stock. This is used to give me the base shape.

Eventually I will probably route out some of the metal in this assembly that I don't need. But that's a late in the game detail. Who know what parts I shall have to re-fabricate before then.

The dimensions on this assembly are quite tight. Everything has to be aligned properly, etc. I got the milling attachement for the micro lathe. It was a life saver. I could never have got the accuracy from a drill press (I tried...) Even with the ability to make accurate holes I still think I will be re-fabricating things. It's just such a tight space that I know I shall have to play with this part or that to get it to work.

This is the assembly put together.

Sorry it's out of focus. In the foreground you can see some brass tubing that is mounted (friction fit right now) into two plates. The mast will slide through this tube.

Test installed it looks like:

Way better when it's in focus. You can see the mast rod in place and a "dummy" mast head sticking out the top. If you look closely between the two bolts you can see a little brass shim stick out. This serves two purposes. There was just too much friction for the doors to fall closed, so I needed to move the side plates a little. Also the shim extends up the side and becomes the resting point for the closed hatch.

This is what the hatch should look like in operation. Closed:

Starting to open:

Open more:

I really should have one final image. The hatch should open to just past vertical. If you look inside the mast storage area you can see the top of that little shim and understand how the hatches come down to rest on it.

Here you can kinda see the closed hatch with the mast head installed:


This is a better view looking down into the mast storage area.

The big round thing is the mast head. The hatches are top and bottom on the picture. Looking inside the mast storage area you can see the screw heads that attach to the nuts. I had to grind these down so they could fit in the space...

Even then the mast head just touched them. Actually the little ball bearings extended out a little and caused interference as the mast extended / retracted. Since the retract will be driven only by the weight of the mast itself I could not affort the interference... so I had to make a new, slightly smaller version with better recessing of the bearings.

It's good practice.

Here you can see the 3 generations of mast heads:


I did the first one before I got the micro lathe. The second one looked good, but it was just 1/32" too large. Then there is the work in progress for #3.

In theory it will look something like this when all is done...


Obviously the hatches will align to the top of the sail.

[redboat219]

Any updates on this thread?

Any updates on this thread?

[cstranc]

Well, first spring happened and

Well, first spring happened and all my free time suddenly got used up with other things. Then I realized how little time there was until the regatta in Carmel.

I am grabbing each precious moment so that I can get her in the water for the regatta. I would like to get the mechanical aspects done, and then I can take my time on the hull finishing this winter.

Thanks for asking,

Chris

[mylo]

*DROOL*

.....Ooooops *wipes mouth*, sorry, I

*DROOL*

.....Ooooops *wipes mouth*, sorry, I was just looking at your "snoop RADAR" mast.

Beautiful machine work.


Mylo

[Rogue Sub]

whered you go man!

whered you go man!

[cstranc]

Hi Nuke, thanks for asking

Hi Nuke, thanks for asking

At the start of the summer I decided to spend more time with family and outdoors. and work has been really really busy.

These days I do still grab a few moments to work on the Sierra, just to prove there is something in my life beyond work.

I am just putting the finishing touches on a 4 torpedo launcher (using pneumatic cylinders not those clunky linkages). Have taken lots of pictures and will probably post it next weekend.

[Rogue Sub]

great to hear. Im glad

great to hear. Im glad you finally figured out how you were going to do your torpedoes

[talwar]

Hi there, are you still

Hi there, are you still alive?
And where are the pictures? I'd like to see any progress on this magnificent beast!

[cstranc]

I have not made a

I have not made a lot of progress recently. But I promise to put together some pictures and post on the weekend.

Thanks for the question.

[cstranc]

Oh my the SubRegatta is

Oh my the SubRegatta is approaching fast. Panic sets in.

So I have no illusions that I will be finished the Sierra this summer, but I sure want it sea worthy by regatta time. So I am putting some things on hold to get the basics implemented...

This is what she looks like now:

You can see there is a plexiglass base that runs most of the length of the hull. There will be a lead weight on a lead crew beneath the plexiglass. This is part of the "automatic pitch control".

From the front you can see the platform where the torpedo tube assembly will mount.


This is it with the torpedo assembly in place.

There are a couple of torpedoes sitting on top for size. The aluminum one with the white nose is true to 1/60 scale.

Sitting above the torpedoes will be the retractable front diving planes. They will have to be another post...

Looking from the back of the boat...

You can see the motor running outside in the wet. I'm not even sure what type of motor I have installed right now! But it's dead easy to change.

Next is the rear side thruster pump. There will be front and rear side thrusters. I am planning on being able to toggle the rear thruster. If it pushes the same direction as the front then it will allow the sub to shift sideways. If it goes in the opposite direction then they will turn the sub. What I lack in sub-driving skills I hope to make up for in "maneuverability for dummies"...

The model will run on two 7.2v battery packs. I have them in a small lexan case. Nice and watertight. Small and mounted as low in the hull as I could make it.

You can see the 1/8" brass control rods heading to the front of the boat.

Looking forward of the batteries the next thing is the on board air supply.

That's the base for it. There are four aluminum angles that clip the unit onto the plexiglass that runs the length of the hull. So it's no-tools to clip it in / out.

Right now you can see the two brass regulators. One will control the pressure going to the ballast tank. The other will control pressure to the cylinder that operates the periscopes. The torpedoes are attached to full pressure.

Then there are the clippard valves are used to operate the ballast, and periscopes. There will be four more of them in the front of the hull to operate the torpedo tubes.

Being a cautious type the clippard valve that blows the ballast tank is a "normally open" type. So if something fundamental goes wrong and I loose all power it will open and blow the tank.

The air tanks fit above this hardware.

As you can see they are fuel bottles from a camping store. I have tested them to 120PSI without issue.

Originally they were going to be my only ballast system. They would refill the oversized ballast tank 3 times. Now I have heard about using surface air in a "snort" ballast setup these tanks remain, and will provide air to get back to the surface, and fire torpedoes etc.

Moving further forward:

That's the ballast tank. According to my early testing it's oversized, but that's easy to fix...

You can see the little cylinder on the to used to vent the tank.

The entire tank is mounted on two rails. I am hoping this will make it easy to adjust the static trim.

And in front of the ballast tank...

The WTC. As you can see it's an 8" wide lexan box. Fits neatly in the hull. If happen to drill a hole in the wrong place I can replace it for $15.

I am planning on pulling out the control rods from the front of the box, and all the electrical connections from the back.

In terms of driving the model I am working to the following layout for my transmitter:

(I wonder why I called it reciever? and spelt it worng.)

I am using a Robbe F-14. Channels go like...
1 = Dive planes.
2 = Rudder.
3 = Throttle.
4 = Side thrusters.
5 = Adjust the level of the APC.
6 = Ballast control

On channel 7 there is a 16 function decoder. I use this to control the lights, torpedoes, periscopes, etc.

It all sounded pretty simple when I was thinking about it. When it came time to plan out the electronics it got pretty complex.

Hmm shall have to finish that soon...

Some of the stuff that has to go in the WTC...

I have the WTC split into 3 basic levels. The lowest has the servos for control surfaces. Then as we go up we get more and more electronics.

Sorry about the focus...

You can see the servos that will be on the bottom. They will control the rudder and rear dive planes.

There are two vacuum pumps for the ballast. They come from Caswell. They are great. I'm running 7.2v so I stayed with the smaller pumps. When I tested them I found 1 pump was a little slow. So I put in two.

As the ballast control servo moves it actuates one pump, then the second, then the air from the fuel tanks. This gives me a level of control on the rate I fill the ballast tank. Did I mention I love those little pumps and the concept of using surface air...

If you look into the fuzzy middle of the WTC you can see a servo on it's side. That one is modified for continuous rotation. I shall be chaining it to the lead screw that will control the ballast weight.

Looking from the side...

You can barely make out the APC level control. It is mounted so that a servo can adjust it's angle. This way while on the surface I can angle the hull so the stern points down like it does on the drawings. When it is submerged it can be adjusted to level. At least I hope so.

The APC will control the rear dive planes and the ballast weight (if it is enabled).

Now we can count the weeks to the regatta I am a little worried about the number of things to get done. Ahh the excitement.

[Rogue Sub]

Wow this thing get more

Wow this thing get more and more exspensive. It is gonna be insane to drive

[petn7]

cstranc,

Maybe it doesn't matter, but

cstranc,

Maybe it doesn't matter, but know that those smaller sized Caswell airpumps cannot hold an airtight seal under pressure. I'm guessing the "snort" system doesn't need to hold any air under pressure, but just in case...