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Thread: Thor 1/96th SSN-21 Seawolf Rebuild

  1. #11
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    Nov 2010
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    Great work! Way to use that Dremel. Nice job on those photos while using the Dremel. Excellent clean up.

    On another note, I was so close to seeing the Seawolf that year 1998 at Groton. Missed it heading out to sea by 10 minutes. SUCK! I love the seawolf. Seriously my favorite american submarine of all time.

  2. #12
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    Now it is time to move along to the drive train. The existing drive train used a dog bone to connect the drive shaft to the output shaft on the WTC and it was not perfectly lined up, so we will have to remove the aft brass dog-bone receiver and remove the oilite thrust bearing.



    So lets start by popping the set screws loose on the receiver:



    After the receiver is pulled, slide the shaft aft and remove the thrust bearing.



    Now it is time to line the drive shaft up near perfectly with the output shaft. I have chosen a 4mm shaft for the drive shaft on this SSN21 model. It is a nice balance between the too large 3/16" shaft and the too small 1/8" shaft. To line everything up nicely slip a 2" section of 4mm I.D. brass tube over the WTC output shaft. Then slide the new oilite thrust bearing over the drive shaft aft of the thrust bearing bulkhead. Push the shaft forward to where it lines up with the brass tube and slides in smoothly with no interference. Tack glue the thrust bearing in place on the thrust bearing bulkhead. If you need to open up the bulkhead a bit to get it so slide into place easily, please do so. Place whatever shims you need on the sides of the WTC in the aft saddle to hold it in place while the epoxy cures on the thrust bearing.





    Walk away for an hour or so to allow the epoxy to cure.

    After the epoxy has fully cured it is time to set the final position of the WTC on the aft saddle. Repeat the process above that was used on the front saddle making sure to use plenty of epoxy and Cabosil to fully fill the entire gap around the WTC as it sits in the saddle. Don't forget to wipe a thin coat of Vaseline on the WTC before placing it into the epoxy filler on the aft saddle. If you don't, you'll be very sorry!!!!
    Regards,

    Matt

  3. #13
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    Now that the aft end of the WTC is now permanently set and the drive line is perfectly aligned to the WTC output shaft it is time to couple the two together! My universal joint of choice is the German made Graupner 4mm-4mm unit. They are VERY hard to find, so if you find a source buy a bunch. There is an alternative here in the states and they are sold by Traxxas. The traxxas Universal joints are made by Graupner, but they are not quite as rigid as the OEM Graupner boat Universal joints. The Traxxas version is, also, 1/4 of the price. You can find them at Tower Hobbies.



    After assembling the Graupner Universal Joint, slide the shaft back to allow room to slide the universal joint onto the WTC output shaft running the front of the shaft all the way through the universal joint, but not intruding into the space of the cross joint. After tightening the set screw on the WTC end, slide the shaft forward into the aft coupling half. If you did everything correctly, it will slide smoothly right into place without any interference!
    Regards,

    Matt

  4. #14
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    Before we can complete the drive train, the impeller assembly will need to be revised and repaired. First, we will repair the forward set of stator that were severely damaged during an incident with the boat. They were fractured and bent. To repair these permanently we will add a fiberglass 'splint' to each of the forward stators which will serve to return structural strength and stiffness to each stator. The challenge here is that each stator is curved to more efficiently deliver the flow to the impeller blades. The curvature is a 1.5" radius which makes it really easy to lay up a glass laminate that perfectly match the I.D. of the radius of curvature for each stator. What I chose to use is a 3" O.D. section of polycarbonate tube to act as our tooling mandrel for the layup. A single 6" long piece of 6 oz glass tape is prepared to be use as the "splint" material.



    After laying the section of tape up with laminating epoxy a time period of 24 hours is allowed to pass for the tape to fully cure.



    After the cure is complete the rigid section is easily removed from the polycarbonate tube mandrel.

    The next step is to cut exact matches for the stator profile. With an epoxy laminate this thin a sharp scissors can be used to trim it to shape quite nicely.



    The 'splints" are laminated to the sanded and prepared stators. Here I am only applying 4 at a time to keep it manageable.



    While the various portions of the repair have been curing, I have been working away on the lathe and 3D printer making an all new impeller to replace the very poor performing impeller originally supplied with the kit. (Yes, it was my design and was done to keep the US Navy happy after the incident at the Groton Submarine Base). This will, now, be rectified.

    I, eventually, plan on creating an all new SSN21 Seawolf kit in 1/96th. What a great way to get started by creating the new propulsor so to be able to utilize the impeller to return Mike's Seawolf to operation.



    Regards,

    Matt

  5. #15
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    The repair of the propulsor is now almost complete. I finished up with the lamination of the fiberglass "splints" with the rest of the eight stators. I didn't want to bore you with the repetitive details since this was shown with the repair of the first four.

    Here the newly finished white metal impeller is installed in the propulsor housing. I will be using 2 00-80 screws, one each on port and starboard side to affix the aft shroud to the forward ring housing.









    The 1,600 mah Lipo shipped earlier this week and should be here on Monday. With the propulsor complete, we will be able to push forward with the power cell internal installation and the final radio/electronics installation. After that is complete the final WTC installation will be completed.

    If time allows this spring, Mike has asked me to strip the boat down to get rid of the weathered look paint job. He has requested an "As Launched" finish on the boat. I think we can pull it off if we put it in the paint booth with the Permit and Sturgeon at the same time.
    Regards,

    Matt

  6. #16
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    The 1,600 mah lipo arrived today. It fits. However there is one thing I have noticed with the OTW cylinder. It was not designed for frequent access to the internals. It is not worth the trouble for installing the battery internally. It is just too much of a headache getting the battery back out.

    Mike will hate me forever if I drop this boat in his lap with the battery access designed as it is.

    With that in mind, I will build an external battery compartment for a larger 3S, 11.1 Volt Lipo cell. As much as I detest external battery supplies, I am left with little choice.
    Regards,

    Matt

  7. #17
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    The shear size of the OTW ballast unit really restricts the size of the external battery supply that I am able to install for Mike. It looks to me like about the largest size 11.1 V 3S Lipo is around 2,200 mah. I need to keep the overall battery container length under 6" and that is really pushing it.

    With that in mind, I designed a small end cap to fit a 2" ,1/16" thick wall polycarbonate tube. It took me all of 5 minutes to design and 25 minutes to print it out on highest resolution setting. That beats the heck out of spending all day to create something that can be done in 5 minutes.







    This unit will sit until the new battery arrives from Tower Hobbies. I will workup and 3D print a tube support bracket that will be attached to the existing forward bulkhead. I will have to remove a portion of the mating bulkhead that is attached to the upper hull half as the new battery container will protrude 2 1/2" into the bow section of the model.

    It is now time to begin the radio installation in the OTW WTC.
    Regards,

    Matt

  8. #18
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    The OTW system does not come with any method of mounting for servos or any of the radio equipment. That is left to the end user.

    With that in mind I though through the several possible methods of mounting the servos and came up with a surface mount method for two mini servos. I designed the unit up in 3D and sent it to one of the printers.









    I dropped the servos into the newly printed servo tray and adhered it to the OTW equipment tray with silicone adhesive. After it cures, we will install the pushrods and associated connecting components.



    Regards,

    Matt

  9. #19
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    Nov 2010
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    Spokane, WA
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    super nice!

  10. #20
    Join Date
    Nov 2010
    Location
    Spokane, WA
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    Are you doing new end caps for this?

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