A U-Boat In Ireland

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  • trout
    Admiral
    • Jul 2011
    • 3545

    Stephen,
    Please start a WIP on what you are doing.....please (begging intended).
    If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

    Comment

    • The Boattrainman
      Commander
      • Mar 2016
      • 443

      Yes, looking forward to seeing another build.

      I'm reluctant to give an experienced modeller advice, but watch those Wikinger upgrades, they are super with a great mix of light weight and scale appearance, but they are wrong for many U-Boat models.

      For example, the deck for the tower has the circle for the mount of the UZO off centre, when it should be dead centre. Didn't spot this until it was fitted, a nightmare to sort. Also the various sections of deck are tricky to align correctly with the Robbe hull, and when fully fitted didn't place the tower in exactly the right place (out by a few millimetres). Not criticising the parts really, just that care is needed to get the best out of them.

      Rob
      ''We're after men, and I wish to God I was with them........!''

      Comment

      • Stephen Vick
        Lieutenant
        • Nov 2018
        • 67

        I will post a build thread ASAP, I stay pretty busy with work and home. I am working on a Masters in Education at the same time as I am working full time at Central Freshman Campus and finishing a special education certification. Add to this I'm building a Canterbury J sailboat for one of our club members, getting our sailing venue in the Texas radio sailing Race schedule, and restoring a Newport 12 meter. So, it will be slow going until winter break... However, the goal is to have this boat sailing this summer!. Also, my 1/32 scale type II is needing a refit....

        Comment

        • The Boattrainman
          Commander
          • Mar 2016
          • 443


          I had to surrender on making the KDB rotate on the foredeck, just couldn't get it to work, tried waterproofing servos, step dwon 12v motors, waterproof boxes etc. etc. Only project in 5 years that defeated me!

          So I've completed re-enforcing the weld lines and doublers, a boring job of 'spritzing' every one with thin superglue with a cocktail stick, and re-sanding. Top tip that I got from Dave M. on the Forum.

          Had to be done, the poly cement will not be enough with rough handling.

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          To prepare for trimming, I've created fore and aft subtrim cradles, plastic slots to take varied lengths of 12 x 5mm steel bars.

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          There is one each for the front and back sections with open access. My theory here is that with my Skipjack build even a slight change (for example, a different servo), affects the trim (especially submerged trim), so I've made various lengths of these subtrim bars to complement the 10 inch solid keel ballast that comes with the kit. A magnetic arm is used to drop the weights into the cradles once glued inside, I'll start with two full cradles for trim tests as it's easier to subtract weight incrementally than add it later.


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          The large keel weight is slotted down the lower hull, with string attached to front and back so that it can be joggled along to get the trim right. Given all the extra components in the WTC, this weight will almost certainly have to be cut down, but I'll have to wait for test tank results first.

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          Once the position inside the hull is determined, the only thing required to hold it in place will be two stainless steel 2.5mm countersunk screws hole through the bottom of the sub as it's a very tight interference fit and cannot move in any plane other than lengthwise along the keel.


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          Once I get the surface trim correct, I will never see this ballast again, so it'll get a final coat of enamel paint for final installation. Submerged trim will be by foam above the waterline and the small subtrim ballast weights fore and aft.

          And that's it!!!!!!!

          U-557 is finished the construction phase....... from April 2017 to date, I'm having an ice cold beer tonite to celebrate. Sure, there's painting and lots of on water tests to carry out, and wiring to be tidied up and I'm getting some expensive digital servos delivered (at 1,600 bucks I'm not scrimping on cheap servos), but there are no more bits to be stuck or screwed to U-557.

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          I did address most (not all) of Robbe's U-47s shortcomings, and with a half decent paint job, the remaining issues will only be known to the absolute purists. Given the challenges it presented (and a housefire) during the build, this is not a project for beginners.

          Off to the test tank this weekend..............

          The Boattrainman

          ''We're after men, and I wish to God I was with them........!''

          Comment

          • Stephen Vick
            Lieutenant
            • Nov 2018
            • 67

            Beautiful work! You have inspired my build, that is certain. Winter break is coming, I expect to get a lot of work done....

            Comment

            • Stephen Vick
              Lieutenant
              • Nov 2018
              • 67

              I'm looking at how you re-located the shafts to make them level inline. I am going to do the same thing, however, I plan to use a pair of Graupner Speed 500 brushless motors with a gear reduction. So the motors will mount in the stock positions, but the gear reduction will bring the shafts down lower where they should be.

              Comment

              • The Boattrainman
                Commander
                • Mar 2016
                • 443



                Great idea Stephen, it's one of the areas that has to improved or the sub will never look right (even at 'stand off' scale).

                In my view there are five major areas that have to be addressed or it'll never look right:-

                1. Tower
                2. Decks
                3. Shaft Alignment
                4. Central drainage slot
                5. Rounded rear end

                Everything else comes under detailing, and one can take that to the max or add just enough to satisfy. Once I decided that it would be U557, I went fot it as I had the reference book mentioned in the build. I doubt anyone will notice the exact number of drainage holes and slots are correct for that boat (especially here in Ireland where I appear to be the only R/C U-Boat modeller in the country).

                The one area I didn't tackle, and I'm still contemplating this before painting, are the knuckles on the hull where the rudder shafts are located. I've left these alone, as the amount of material that would need to be removed may compromise the structural integrity of that area. Still unsure if I'll tackle this problem, as it's below the waterline I can't make my mind up.

                There are a few smaller problems that I didn't tackle, for example the anchor well is too deep and slightly in the wrong place, I didn't bother with rivet detail either, as there are limits to my patience.

                What was very satisfying was I brought this in at around 1,600 bucks, the Engel and OTW Type VIICs are superior models and double that cost, but even they will require major work to get them to look like a particular U-Boat, so in a way the Robbe U-47 represents good value for money, even with numerous add ons.

                Finally, thanks to your mention of Maximus Modellbau, I noticed they have a WTC for the 1/35 Bronco Type XXIII for around 340 bucks, this may be my next project after my steam launch!

                Apologies for rambling on................

                Rob
                ''We're after men, and I wish to God I was with them........!''

                Comment

                • Stephen Vick
                  Lieutenant
                  • Nov 2018
                  • 67

                  I enjoy our discourse , I am in much the same position in Texas ( being a lone submariner) I’m with you on the level of details as well. I will address the issues cited, but, like you I don’t intend to get down to rivets. Funny, I’ve ordered the Type XXIII WTC from Maximus as well. I will be building the two boats simultaneously. When one gets boring , I’ll shift to the other. Whichever is closest to complete come spring, will get a final push.

                  Comment

                  • The Boattrainman
                    Commander
                    • Mar 2016
                    • 443

                    Here is my Test Facility for U557, buddies fish pond in his front garden.


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                    The elastic bands hold the lead keel under the boat till I trim it to size, then it is inserted inside.

                    And here is U557 on the waterline..........

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                    ...................took 3 hours of in/out of the water and cutting small bits off the keel weight till it was balanced.

                    The Boattrainman
                    Last edited by The Boattrainman; 12-09-2018, 06:14 PM.
                    ''We're after men, and I wish to God I was with them........!''

                    Comment

                    • Stephen Vick
                      Lieutenant
                      • Nov 2018
                      • 67

                      I’ve got a 13 by 10 foot pond in my back yard, I graciously allow my wife to put Koi Fish in. Your boat looks great on the water! How much weight did you end with?

                      Comment

                      • trout
                        Admiral
                        • Jul 2011
                        • 3545

                        that does look good!
                        If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

                        Comment

                        • The Boattrainman
                          Commander
                          • Mar 2016
                          • 443

                          I didn't weigh the main ballast bar, but I ended up removing around 1/3 of it before final installation to get the sub to the waterline.

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                          Plus I had 2 X 25 gram weights fore and aft, and a 70 gram weight within the WTC offest to the starboard side to get the boat level (it counteracts the weight of the motor on the piston tank which is slightly to port).

                          Rob
                          ''We're after men, and I wish to God I was with them........!''

                          Comment

                          • Subculture
                            Admiral
                            • Feb 2009
                            • 2119

                            Nice work. Just for your own reference, pretty much all servos these days use microcontrollers inside, whereas years ago they used analogue chips. So all the servos you purchase new are 'digital'. The so called analogue models are just coded differently, so they squirt out a lower frequency pulse to the motor- in effect they're programmed to emulate the old analogue chips. Digital servos give out better holding torque, but aren't necessary for model submarines and can labour a BEC more, so make sure that is good and beefy if you're running one.

                            Comment

                            • Stephen Vick
                              Lieutenant
                              • Nov 2018
                              • 67

                              I have used a “servo power board” in sailing models with multiple winch servos. It isolates the servo power from the receiver and provides a steady 6 volts to the servos. This then avoids the problem of overloading the BEC and overheating the receiver. Would this be of utility here?

                              Comment

                              • The Boattrainman
                                Commander
                                • Mar 2016
                                • 443

                                Thanks for the heads up.

                                The problem is the LR2 Pitch Controller from Engel that I'm using, getting servo twitch as per my Skipjack, which was cured by better servos.

                                Engel recommend using a high quality 'digital' servo, hence I'm upgrading my standard Futaba S3003s.

                                Rob
                                ''We're after men, and I wish to God I was with them........!''

                                Comment

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