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1/96 scale ThorDesign USS Permit

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1/96 scale ThorDesign USS Permit

Postby PaulC » Fri Nov 03, 2006 12:36 pm

In order to help this forum get kicked off I'm going to post the build-up I did of the ThorDesign USS Permit kit in 1/96 scale. This was originally posted to the ThorDesign site which no longer exists. It was also published in issue #57 of the SCR in an abridged format.

While the kit is no longer being offered by ThorDesign, used kits can be found. Building the kit incorporates most of the skills needed to build an entry level GRP SSN kit and will include updated tips where appropriate.

Of course, if you have a kit languishing on your bench and just haven't found the time to start it yet, just follow along and we'll build together!

THE KIT

1. Below are the contents of the Permit kit. Included is a sheet of 1/96 scale Permit class hull plans (hang them over your work area for quick reference), two epoxy hull halves, cast polyurethane appendage set and sail, a white metal fittings set with propeller, stainless steel drive shaft, stainless steel photoetched MBT vent detail set, and running gear linkage set. Upon receipt of any kit be sure to inventory the contents with the enclosed parts sheet prior to assembly. Notify the manufacturer immediately of any damaged or missing parts.

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2. Shown is the resin sail with brass diesel exhaust diffuser molded into the upper trailing edge. Mounting bolts with nuts extend from the bottom of the part. To the right of the sail, and below, are the resin masts and sail mounted diving planes. To the left of the sail is the white metal fittings set with bollards, cleats, zincs, periscopes and other mast parts. Below them is the white metal propeller (a stainless steel set screw is provided).

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3. Here are, beginning at left, the drive train resin parts (thrust bearing bulkhead and two WTC saddles). Next at top are the control linkage jumpers, thrust bearings, universal coupler and allen wrench. Below them are the stainless steel photoetched MBT vents and cast resin mushroom anchor. Continuing to the right are, first, the rudders, then the stern planes. If everything is present and accounted for, proceed with assembly.

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PREPARATION - Parts Washing

1. Prior to assembly, care must be taken to prepare each part to ensure that glue and/or paint will properly adhere to it's surface. Using warm soapy water and a scotchbrite pad, scrub and wash each part thoroughly to remove any remaining mold release agent. Dry the parts and set them in a container to ensure they will not be misplaced.

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2. Certain essentail tools and raw materials will be required to complete the kit. They include:

3/8" electric drill
Drill bit set
Dremel moto tool & bits
Needle file set
2 hour cure epoxy
Micro-balloons
CA adhesive
1/2" fiberglass tape
1/8" o.d. brass tubing
Tubing cutter
X-acto knife
Razor saw (small)
Ruler & drafting compass
Sand paper (assorted)
Masking tape
Dixie cups
Disposable brushes
Baking soda
1/4" closed cell foam
10-15 ozs. lead weight
1 tube Nitro-Stan putty
Last edited by PaulC on Mon Nov 03, 2008 5:29 pm, edited 3 times in total.
Warm regards,

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Postby PaulC » Fri Nov 03, 2006 6:48 pm

PREPARATION - Parts Trimming

1. Before actual assembly begins, care should be taken to trim up any access flash, or rough edges, on the resin parts. This can be accomplished with an Xacto knife. Gently whittle away any excess resin, making sure that you don't damage the part itself. Take your time and work with each part carefully.

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2. Once the parts are trimmed, use 600 grit sandpaper and sand the hull and the parts. This will provide the "tooth" necessary for proper paint and glue adhesion. Take care not to sand away any of the scribing or other detail on the hull and/or parts. Sand enough to make the surface uniformly dull. Resin parts can be sanded further to provide a smooth finished appearance.

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3. Now is the time to trim the indexing lip. First, a cutting line must be marked. I improvised a simple marking tool. Place the lower hull on a flat surface and find a flat object on which you can place a sharpie. This object must be tall enough so that the point of the sharpie touches the hull approximately a 1/2" above the boat's centerline. In this case a small cup and ruler were used. Holding the hull steady, slide the object with the sharpie around the hull, marking a line on the indexing lip.

Trimming of the indexing lip on other Thor kits is not required. Matt recommended it on his Permits as the lip was a little longer than normal. Cutting it down improves the hull fit.

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4. Using a Dremel Moto-tool with a cutoff wheel, cut along the marked line and removed the excess material. Use a file to knock down any rough edges along the cut. REMEMBER: always use eye protection and a dust mask when using the Dremel. And use the Dremel outdoors or in the garage - the dust is very messy!

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With parts preparation completed it is now time to proceed to Hull Assembly.
Warm regards,

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Postby PaulC » Mon Nov 06, 2006 4:01 pm

HULL ASSEMBLY - Cut the Stern

1. Place the upper hull on an appropriate work area and locate the scribed cutting line. It is an arc approximately 3.5 inches from the stern of the hull. Utilize a razor saw for the cutting process. The thinner the blade, the less material will be lost during the cutting process. This will allow for a tight fit between the two parts once the hull is assembled.

Webster's dictionary defines kerf as: "the channel made by a saw, or the width of such channel". When sawing on models remember: the thinner the saw blade, the narrower the kerf!

NOTE: I don't use a Dremel and cut off wheel for this procedure. While some do, my hands aren't steady enough. :D

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2. Place the razor saw on the scribed line. Gently draw the saw across the line to ensure that the blade is following the scribing perfectly. Continue to saw until the stern is separated.

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3. If done carefully, you should have two parts with a perfectly matched seam. This will enhance the appearance of the hull when the stern piece is joined to the bottom of the hull -- which is done next.

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Postby PaulC » Mon Nov 06, 2006 4:13 pm

HULL ASSEMBLY - Gluing the Stern

1. Test fit the two upper hull pieces onto the lower hull. File the stern of the lower hull if necessary to ensure the upper stern piece fits snugly. All parts should seat completely with minimal gaps between parts.

The following raw materials (left to right) are recommended to glue the stern pieces together: disposable epoxy brush, micro-balloons, dixie cups (for mixing), and two hour cure epoxy (for maximum bond strength). WARNING: Never use 5 minute epoxy on joints which will be exposed to water. It is NOT waterproof.

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Please note there are a wide variety of adhesives for the modeler to chose from. Optimum results can be obtained by observing several rules:

Epoxy resin can be used to bond epoxy and polyester hulls and parts.

Polyester resin should only be used on polyester hulls.

Quick cure epoxies (5 minute) are NOT waterproof.

The less resin used when bonding a joint, the better. Excess resin actually decreases joint strength.

Adding micro-balloons to an epoxy will significantly increase it's cure time.

2. In 2 dixie cups, fill the bottom of each with approximately 1/8" of epoxy parts A & B respectively. Be sure to observe the proper mixing ratio as stated on the epoxy label (such as 1:1, part A to part B). Add to each cup an equal amount of micro-balloons and stir until the liquid and micro-balloons are mixed thoroughly.

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3. Add the two mixtures together in one cup and blend them together thoroughly with an epoxy brush. When completed, the mixture should have the consistency of toothpaste. If it is too thin, add more micro-balloons. If it is too thick, add more epoxy (be sure to add both parts in the proper ratio).

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4. Brush the epoxy/micro-balloon mixture onto the lower hull where the upper stern half will be joined. NOTE: Be careful not to apply any epoxy to the indexing lip in areas where the forward half of the upper hull will seat.

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5. Place the upper stern piece in position on the lower hull. Allow the epoxy/micro-balloons to work into the seam. Wipe away any excess resin with a paper towel. Use strips of masking tape to hold the upper stern piece in place.

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The inside of this crucial seam should be reinforced at this time. Continue to the next post for the procedure.
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Postby PaulC » Fri Nov 10, 2006 12:35 pm

HULL ASSEMBLY - Gluing the Stern (continued)

1. In order to reinforce the inside seam of the stern piece, 1" heavy weave fiberglass tape will be epoxied over the inside joint. With scissors, cut two strips of fiberglass tape three inches long.

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2. While working on a sheet of wax paper, brush the remaining epoxy/micro-balloon mix onto the strips of fiberglass tape. Wet both sides of the tape, then remove excess resin with the brush.

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3. Inside the hull, place a piece of wetted tape over the stern seam on each side. Wick out any excess resin with the brush.

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4. Making sure there is no epoxy on the exposed indexing lip, place the upper forward hull onto the lower and make any adjustments in the position of the upper stern piece that is necessary. What's a sure fire way to keep an adjacent part from being bonded while you use it to align another part that is being glued? When working with epoxy, spread a thin film of petroleum jelly on the surface you want to remain free from glue.

Once everything is lined up, secure the pieces with tape. Dispose of epoxy mixing cup and brush. Set the hull aside and allow the epoxy to cure overnight.


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Postby PaulC » Sat Nov 11, 2006 1:21 pm

HULL ASSEMBLY - Hull Openings

1. With the stern piece completely cured, it is now time to open the many holes necessary to correctly model a Permit class SSN. Using the supplied plans as a reference, locate the dimple in the hull where the mushroom anchor is mounted just forward of the lower rudder. Using an electric drill and a 7/32 bit, drill out the dimple to receive the cast resin mushroom anchor. Use a round file to widen the hole to fit if necessary.

NOTE: Following the curing of the stern pieces, I painted the Permit hull with primer. This allowed the scribed hull opening lines to be more clearly seen during the drilling process. Details on how to prime and paint the boat will be outlined later.

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2. Switch to a 1/8 bit and drill one or two holes in each Main Ballast Tank flood hole. The MBT floods are rectangular in shape and there are 5 grouped just forward of the anchor. These holes will allow the use of a Dremel grinding bit to further cleanout the opening. To prevent mistakes, take the time to mark each flood to be opened with a pencil or marker prior to drilling.

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3. Moving forward, locate the next set of floods amidships and drill similar holes in them as well. There are 20 MBT floods in this section.

NOTE: Do not drill in the T-shaped area scribed in between the flood groups. This is the cover for the Secondary Propulsion Motor (SPM) and should be left intact.

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4. Locate the forward group of floods near the sonar dome demarcation line. There are 14 scribed rectangles. Drill pilot holes in each of the floods.

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5. With the floods completed, switch to a 7/32 bit and drill pilot holes in the two Main Sea Water openings on either side of the hull. The lower hull opening pilot holes are now complete.

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6. On the upper hull you will notice dimples representing the Main Ballast Tank vent openings. A set of stainless steel photoetched parts will accurately depict the MBT vents and will be installed in a later section. However, holes must be drilled in the hull to allow trapped air to escape through each vent during r/c operations. Using a 3/32 bit, drill a single hole in the center of each of the 6 MBT vent dimples in the forward section.

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7. Moving amidships, drill holes in each of these 6 MBT vent dimples.

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8. Finally, locate and drill the single MBT vent in the upper stern section of the lower hull. It is located slightly forward and to starboard of the upper rudder.

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Don't be alarmed. Though your model may look more like Swiss cheese than a submarine at this point, it will soon take on a scale appearance. And if you're curious as to what all those holes do on the real boat, check the following short hull opening glossary:

Main Ballast Tank (MBT) vent: Round, stainless steel vent valve in the top of main ballast tanks that open to allow air to escape for diving and close to trap air for surfacing.

Main Ballast Tank flood/drain: Rectangular opening in the bottom of main ballast tanks that allow the free flow of water into, and out of, the tank during diving and surfacing.

Secondary Propulsion Motor (SPM): A small retractable electric motor mounted in the lower hull amidships. Used for maneuvering the boat in close quarters such as pierside.

Main Sea Water (MSW) intake/discharge: Large round hull openings through which reactor coolant water is taken into, and expelled from, the boat.
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Postby PaulC » Sat Nov 11, 2006 1:29 pm

HULL ASSEMBLY - Hull Openings (Pt. II)

1. With all the pilot holes drilled out it is now time to change tools. For the next phase you will need a Dremel moto tool and several needle files. Small needle files can be bought in sets with varying shapes.

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2. The Dremel tool should be used first to grind out the flood holes. A steel grinding bit is preferred. Shown are the two bits. The larger cylindrical grinding bit in the tool was used for the majority of the holes. The smaller round bit to right was used on the smaller floods (the object to the right of the second bit is the mandrel needed for the smaller bit).

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3. Moving outside, insert the Dremel in each pilot hole and grind out the hull material. You want to get close to the scribed lines but not actually to it. Use two hands as the epoxy hull is tough and the tool can wander if your grip isn't firm. Switch to the smaller bit and do the same thing in the smaller flood holes. Be sure to clean the dust off your clothes before going back inside. NOTE: Always wear safety glasses or goggles and a dust mask when grinding with a moto tool.

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4. With the grinding completed, pick up your needle file set and file out each opening to the scribed outline. Flat and square files work best and new, clean files make the job go quicker. A thicker square file is good for bringing the hole out to the scribed line. Use wider flat files to make the sides smooth and straight. Then, go back with the square file and true up the corners.

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5. One down, forty-two more to go! The upper right hand flood hole is what you should work for. The edges are straight, the corners true and the scribed line is no longer visible. With sharp files and some practice the average time per hole should be about five to ten minutes. But don't rush. The effort and care you put into the process will yield a better looking model.

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Once your floods are filed out and looking good, there is one more step to the hull assembly section.
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Postby PaulC » Fri Nov 17, 2006 5:07 pm

HULL ASSEMBLY - Mushroom Anchor

1. Permit class boats carried a single, mushroom shaped anchor mounted under the stern on the starboard side. This anchor is represented in your kit by a cast resin part. Notice the contour of the part at left. The curve follows the contour of the outer hull. Placed in its mounting hole and properly positioned, the anchor sits flush against the outer hull. Locate the anchor mounting hole and check the part for fit. Familiarize yourself with the anchor's proper orientation in the hole.

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2. Rough the surface to be glued around the hole with some sandpaper.

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3. Apply Cyanoacrylate glue to the anchor's underside...

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4. Place the mushroom anchor into position in the hole. Hold or tape the part in place until the glue is completely cured.

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Intial assembly of your Permit hull is now complete. Soon we will be adding rudders, stern planes and propeller. But first let's turn our attention to the Sail...
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Postby PaulC » Mon Nov 27, 2006 1:03 pm

SAIL - Assembly & Mounting

During the design stage, it was proposed to completely remove the sail on the Permit class boats to reduce underwater drag. However, the impracticality of having to tow the submarine out to sea at the beginning of each patrol due to the near zero freeboard quickly negated the proposal. Instead, the sail was designed with a minimum height. The sail planes were mounted as high as possible in an attempt to increase depth control close to the surface. The final design was so narrow, one could almost reach through the sail via the maintenance access plates.

1. For radio controlled operations, it is necessary to open up a hole in the top of the sail to allow trapped air to escape during diving. Study the plans, then choose an area to open such as a mast or the bridge clamshells. For this project, the VLF loop antenna opening was selected.

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2. Using a very small grinding bit, grind out the VLF loop opening with the Dremel. NOTE: periscope and mast assembly/ installation will be outlined later.

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3. Using round and half-round needle files, file out the VLF opening to the scribed lines.

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4. Here you can see the opening through the sail top. It is important that the hole accesses the interior void of the sail otherwise air will remain trapped inside. By working files at an angle, the interior side of the hole can be beveled wider.

With the VLF opening complete, we can turn our attention to the sail planes. Because of their small size in 1/96 scale, the kit's sail planes afford minimal control influence during r/c operations. Therefore I mounted them in a fixed position. However, if active sail planes are desired, skip steps 5 - 7 and use the plane connecting rod as your control shaft. By mounting a bellcrank on the shaft and running the linkage through the sail and into the hull, you can effectively animate them.

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5. Locate the planes and test fit them in the pre-drilled mounting holes. They should fit snugly against the sail and protrude from either side of the sail at a 90° angle. Both port and starboard planes should be aligned with one another through the sail. Slight filing of the mounting holes can correct any variations in alignment.

Apply cyanoacrylate to a plane with the supplied connecting rod inserted. Apply glue only to the surface which will rest against the sail side.

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6. Slide the connecting rod into the pre-drilled hole and glue the plane to the sail. Slip the other plane on the opposite side in order to check the alignment of the two planes as the one dries.

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7. Apply glue to the opposite plane and slide it onto the connecting rod and against the sail. Hold it in place until the CA dries, then set it aside.

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8. Moving to the upper hull, locate the two sail mounting bolt dimples in the upper hull. They are at the forward and after end of the scribed sail outline in the hull. Use a 7/64 bit and drill out the mounting hole hull dimples.

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9. Switch to a 3/16 bit and drill two drain holes on center between the mounting holes. Be sure to keep the holes within the scribed outline of the sail. The holes will allow air to escape more quickly from the lower hull during dives and will quickly drain the sail during surfacing. NOTE: there is no scribing or dimples to indicate placement of the holes. Just select a spot within the sail outline on the centerline of the boat.

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10. Slip the mounting bolts of the assembled sail into the holes in the upper hull. Don't apply glue to the sail or upper hull. Install the nuts on the mounting bolts and tighten until snug. Be careful not to overtighten. NOTE: using the mounting bolts without applying glue enables the sail to be removed for transportation and greatly reduces the risk of accidental damage during trips to the pond.

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11. Turn the upper hull over. The sail should be firmly mounted and rising vertically from the hull. If the sail leans to port or starboard, unfasten it and gently sand the underside of the sail to remove the high spot and bring it into proper alignment. As always, be careful not to remove too much material at one time.

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It's now time to work on the essential hull appendages used in radio controlled operations. First, the rudders...
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Postby PaulC » Wed Dec 06, 2006 10:53 pm

RUDDERS - Bearing Fabrication and Alignment

1. With a 3/32" bit in the chuck, drill the mounting hole for the upper rudder bearing. It's exact location is the dimple in the upper stern.

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2. Turn the hull over and drill the hole for the lower rudder bearing. Again, a dimple in the hull indicates the exact drill point.

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3. Insert a length of 1/8" o.d. (3/32" i.d.) brass tubing into the upper rudder bearing hole. Extend the end of the tubing through the bottom rudder bearing hole until it is flush with the exterior of the hull. Then mark the tubing with a sharpie at the upper rudder hole so the mark is flush with the exterior of the hull.

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4. Using a K&S, or other similar, tubing cutter, cut the tubing on the sharpie mark.

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5. Deburr the freshly cut end of the tubing with a small round needle file or deburring tool. The control shaft of the rudder pieces should be able to slip into each end of the tube and rotate without binding.

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6. Slip the tube back into the holes in the hull and insert the rudders in the top and bottom.

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7. Make marks on the tube with a sharpie approximately 1/8 inch from the hull on both ends.

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8. Cut the tube on each mark with the tubing cutter. The two small peices will be used as the upper and lower rudder bearings. Do not discard the center section of the tube. It will be used in the gluing process. Deburr all three pieces of tubing with a round needle file to ensure that the rudder control shafts do not bind.

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9. Place the bottom rudder in the hull with the small bearing on the shaft. Slip the longer, middle tubing piece over the shaft. With the small upper bearing on the control shaft, insert the upper rudder into the hull and the middle connecting tubing.

The middle brass tubing piece, though it won't be used in the final operational rudder setup, serves to keep the bearings properly located in the hull holes for gluing and also keeps the upper and lower rudder control shafts properly aligned. NOTE: the image below depicts how the rudders and bearing/tubing pieces will be arranged in the hull during the gluing process.

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10. Visually check the rudder alignment at this time. When viewed from astern, the rudders' trailing edge should form a vertical line through the center of the hull. If any correction needs to be made, use a round needle file on the hull holes. NOTE: a little filing goes a long way on the alignment of these holes. Work carefully.

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Once everything checks out, it is time to glue the bearings in place...
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Postby PaulC » Thu Dec 07, 2006 11:32 am

RUDDERS - Bearing Installation

1. At left are the necessary raw materials for installing the rudder bearings: 2 hour epoxy (not shown), tape, mixing cup, Vaseline, 5 minute epoxy. NOTE: While 5 minute epoxy is not to be used for joining materials to be exposed to water, because of its rapid drying properties it can be used to tack pieces in place prior to gluing with more suitable adhesives.

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2. First, apply a thin film of Vaseline to each rudder shaft to prevent gluing it to the bearings. Place the bearings on the rudder shafts. Prepare a small batch of 5 minute epoxy in a cup. Using a toothpick, place a small drop of 5 minute epoxy on each bearing and insert it into the hull (be sure to use the middle tubing piece to connect the rudder shafts as depicted in step 9 of the previous section).

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3. Secure the rudders in place with masking tape. It is best to support the lower rudder. Use the sail's trailing edge as a sight guide to help ensure proper alignment. Allow the 5 minute epoxy to cure completely.

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4. Carefully remove the tape and rudders. Mix a batch of 2 hour cure epoxy and micro-balloons (see section 2 "Hull Assembly" for mixing instructions). Using a Q-tip, apply a bead of epoxy/micro-balloons around each bearing. Be sure to fill any gaps between the hull and bearing. Avoid getting epoxy in the bearing itself.

It is best to reinstall the rudders (don't forget a thin film of Vaseline) and shaft connecting tubing and re-tape the rudders to ensure accurate final alignment. Set the hull aside and allow to cure overnight.

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5. With the epoxy completely cured and the bearings bonded firmly to the hull, a small flat file can be used to shape any part of the bearing which is exposed above the hull contour.

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6. Slip the rudders in their respective bearings and check for fit and movement. They should rest snugly and evenly against the hull. Each rudder should freely turn at least 35° past the centerline both to port and starboard. If either rudder piece is found to bind against the hull during movement (binding usually occurs when passing center), use a small flat file and shape it until the necessary freedom of travel is achieved. NOTE: setting up the rudder control linkages will be covered later.

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By now the model is beginning to take shape. The next section will combine the techniques already mastered and will cover the installation of the stern diving planes.

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Postby PaulC » Sun Dec 10, 2006 4:24 pm

STERN PLANES - Plane & Appendage Location

1. The first step in installing the stern planes is to locate and mark their position on your model's hull. Using a ruler and your Permit plans, measure the distance from the end of the hull to the trailing edge of the stern planes (7/8").

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2. On your model, measure the same distance from the end of the hull along the hull's side seam. Place a mark in pencil on the seam to indicate the point of the stern plane's trailing edge. NOTE: the trailing edges of both rudders and stern planes should be the same distance from the end of the hull.

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3. Remove the hinge pin from the assembled stern planes.

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4. Using the plane itself, align it's trailing edge with the mark placed on the hull. Mark the point where the control shaft touches the hull seam with a sharpie. Repeat steps 2 - 4 on the opposite side of the hull for the starboard stern planes.

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5. Drill a hole for the control shafts on the sharpie mark using a 3/32 bit. Make sure the hole is centered on the hull's side seam.

NOTE: bearings will be installed in the holes for the stern plane control shafts as was done for the rudders. However, at this point we only want a hole sized for the control shaft itself.

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6. Slip both stern plane control shafts into the holes and check for fit. Their trailing edges should form a straight line across the hull and should be in line with the rudder trailing edge.

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7. Reassemble the stern plane appendages with the hinge pins and reinsert the stern plane control shafts in the holes. Line the appendage mounting tab up with the hull side seam and mark where it touches the hull. Do this for both sides.

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8. With the Dremel tool and cut off wheel, cut a slot along the hull side seam where the stern plane mounting tab was marked. NOTE: do this procedure outdoors or in the shop observing proper safety and health precautions.

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9. With a flat file, open up the slot to fit the stern plane mounting tab.

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10. Reinstall the stern planes into the holes and mounting tab slots. Visually check for alignment and fit. Make any necessary adjustments by further filing out the mounting tab slot. Carefully file the forward stern plane appendage where it meets the hull to ensure a close, accurate fit. Once everything looks good, it is time to install the stern plane bearings.

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Postby PaulC » Fri Dec 22, 2006 9:15 pm

STERN PLANES - Bearing Fabrication and Alignment

1. Using the existing control shaft holes as pilots, drill out the mounting holes for the stern plane bearings with a 3/32" bit.

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2. Insert a length of 1/8" o.d. (3/32" i.d.) brass tubing into the starboard stern plane bearing hole. Extend the end of the tubing through the port stern plane bearing hole until it is flush with the exterior of the hull. Then mark the tubing with a sharpie at the starboard stern plane hole so the mark is flush with the exterior of the hull.

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3. Cut the tubing on the sharpie mark and deburr the freshly cut end with a round needle file. The control shaft of the stern planes should slip into each end of the tube and rotate without binding.

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4. Slip the tube back into the holes in the hull. Make marks on the tube with a sharpie approximately 1/8 inch from the hull on both ends.

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5. Cut the tube on each mark. The two small peices will be used as the port and starboard stern plane bearings. Do not discard the center section of the tube. It will be used in the gluing process. Deburr all three pieces of tubing to ensure that the control shafts do not bind.

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6. Place the port stern plane assembly in the hull with the bearing on the control shaft. Slip the longer, middle tubing piece over the shaft. With the bearing on the control shaft, insert the starboard stern plane assembly into the hull and the middle connecting tubing.

NOTE: The middle brass tubing piece, though it won't be used in the final operational rudder setup, serves to keep the bearings properly located in the hull holes for gluing and keeps the control shafts properly aligned.

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7. Recheck the stern plane alignment at this time. When viewed from astern, the trailing edges should form a horizontal line through the center of the hull. If any correction needs to be made, use a round needle file on the hull holes. REMEMBER: a little filing goes a long way on the alignment of these holes. Work carefully.

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Once everything checks out, it is time to glue the bearings in place...
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Postby PaulC » Sun Dec 24, 2006 6:18 pm

STERN PLANES - Bearing Installation

A Suggestion: a good time to pay a little attention to the hull seam around the bearings and stern planes is prior to their permanent installation. Use a file, sandpaper and putty to smooth out this seam. Once the stern planes are bonded to the hull it gets much harder to work on the area with the planes in the way.

1. First, apply a thin film of Vaseline to each stern plane shaft to prevent gluing it to the bearings. Place the bearings on the control shafts. Prepare a small batch of 5 minute epoxy in a cup. Using a toothpick, place a small drop of 5 minute epoxy on each bearing.

REMEMBER: While 5 minute epoxy is not to be used for joining materials to be exposed to water, because of its rapid drying properties it can be used to tack pieces in place prior to gluing with more suitable adhesives.

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2. Insert the stern planes into the hull. Be sure to use the middle tubing piece to connect the stern plane control shafts as shown at left.

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3. Secure the stern planes in place with masking tape. Use the horizontal hull seam, rudder trailing edge and sail planes as sight guides to help ensure proper alignment. Allow the 5 minute epoxy to cure completely.

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4. Carefully remove the tape and planes. Mix a batch of 2 hour cure epoxy and micro-balloons. Using a Q-tip, apply a bead of epoxy/micro-balloons around each bearing. Be sure to fill any gaps between the hull and bearing. Avoid getting epoxy in the bearing itself.

NOTE: It's best to reinstall the stern planes (don't forget a thin film of Vaseline) and shaft connecting tubing and re-tape to ensure accurate final alignment. Set the hull aside and allow to cure overnight.

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5. With the epoxy completely cured and the bearings bonded firmly to the hull, a small flat file can be used to shape any part of the bearing which is exposed above the hull contour.

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6. Slip the stern planes and appendages in their respective bearings/slots and check for fit and movement. The forward appendage should rest snugly against the hull. Each stern plane should freely move at least 30° past the centerline both up and down. If either plane is found to bind during movement (binding usually occurs when passing center), use a small flat file and shape it until the necessary freedom of travel is achieved.

NOTE: setting up the stern plane control linkages will be covered in a later section.

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Next, the stern plane appendages will be installed. Until then, Merry Christmas!
Warm regards,

Paul Crozier
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PaulC
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Postby PaulC » Tue Dec 26, 2006 3:00 pm

STERN PLANES - Appendage Installation

Permit class boats were the first SSNs to have hulls made completely of HY80 steel. Their stern planes steered them to operational depths of over 1200 feet -- unheard of in prior classes of US submarines.

1. Prior to installing the stern planes and appendages, care must be taken to ensure proper clearance of the propeller shaft between the stern plane control shafts. Here one can see that the control shafts are almost touching. This would prevent passage of the prop shaft down the center of the boat. Thus, the control shafts must be shortened.

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2. Working with one stern plane set at a time, mount a control collar on the fully inserted control shaft. Leave about 1/32 between the collar and the installed bearing. With a sharpie, mark the exposed end of the control shaft.

NOTE: If necessary, file down the control arm on the collar for proper hull clearance.

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3. Using a Dremel and cutoff wheel, remove the excess control shaft at the sharpie mark. File the new control shaft ends smooth.

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4. With the shortened control shafts installed, insert the propeller shaft to test fit. Plenty of clearance is available now. It is time to permanently install the stern planes and affix the appendages to the hull.

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5. Mix a 50/50 batch of epoxy and micro-balloons. Apply the epoxy with a brush to the appendage mounting tab.

WARNING: Do not allow epoxy to encounter the stern plane or control shaft, only the hull end of the appendage and the mounting tab.

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6. Insert the stern plane control shaft into the bearing and slide the mounting tab into the hull. Do the same for the opposite side.

IMPORTANT: Do not use the brass control shaft connecting tube used during bearing installation. Once the appendages are cured, the tube cannot be removed and will prevent installation of the propeller shaft and stern plane control collars.

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7. Secure the stern plane appendages in their proper location with masking tape. Double check for proper alignment. Set aside and allow to cure overnight.

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With the control surfaces installed, the next section will provide a scale metal propeller and mounting saddles for a water tight cylinder (WTC) to enable your boat to get underway.

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Warm regards,

Paul Crozier
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PaulC
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