WWII Scharnhorst (IRCWCC)

Discussion in 'Warship Builds' started by Kevin P., Oct 14, 2020.

  1. Anvil_x

    Anvil_x Well-Known Member

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    Hey Kevin,

    where'd you get the five blade props on your outboards?
     
  2. ZARUBA1987

    ZARUBA1987 Well-Known Member

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    seriously great idea with the tape.
     
  3. Kevin P.

    Kevin P. Well-Known Member

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    Thanks, I’ve used electrical tape since my first build I think. I don’t recall where I got the props from, some scale model website. They aren’t very good for our ships, the blades have too much cup to them, so they are very directional. They are installed backwards so they will do well in reverse but produce no thrust when slowly rotating forward (hopefully act as drag).
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    working on rudder mount. Servo needs to go forward of the drop-off
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    Dimension to help with the CAD
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    rudders slightly taller than prop, two pivot points
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  4. Kevin P.

    Kevin P. Well-Known Member

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    More time spent on rudder mount

    The idea is to have 4x pivot points, so I can vary the balance of the rudders (proximity to the prop) and also the spacing between the rudders. One thing I've found by doing a lot of rudder testing is that it's difficult to predict the optimal combination, which is why I want to test a few set-ups.

    To make this work I'll have half of the mount get fiberglassed into the boat. It will have the 4x rudder post holes per rudder. The top half will be movable and can shift fore to aft. I'll make some studs to hold the halves together by installing screws with the lower half. The upper half will have two sets of receiving holes for the studs. I'll need to plug 1x hole that isn't in use, but the upper half should close up the two other unused hole.

    I played around and found that I could make 1x center gear work for both spacings by using a larger gear on the rudder post that is further from the centerline, without having to draw up another gear diameter. Here is the sketch I ended up with. Needed to use dummy gear between servo gear and rudders due to vertical spacing for servo. Large circles are the pitch diameter of my standard printed rudder gears (20P, 3/8" face). The outer lines show the confines of the hull. I'm planning to have 4x studs, shown by the blue circles.

    RudderMountScharnhorst v5 sketch2.png


    Here's round 1 that I'll print tomorrow

    RudderMountScharnhorst v5.png

    Other side
    RudderMountScharnhorst v5 stbd.png
    Fingers crossed. I tried to visualize how it will work, but need to get it to the boat to be certain, and can always dremel as needed as long as it's close
     
  5. Commodore

    Commodore Well-Known Member

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    Tres Fahncee!
     
  6. wfirebaugh

    wfirebaugh Well-Known Member

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    This mite sound like a odd question, but when a ship has 3 props and assuming they all have power to all screws, what is the usual rotation of all 3 props?
     
  7. Kevin P.

    Kevin P. Well-Known Member

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    The outboard ones are counter rotating, the middle one will go one way or the other.

    The prints came out OK today, hole spacing was right on, but will reprint tomorrow with a couple tweaks
     
  8. Kevin P.

    Kevin P. Well-Known Member

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    Got the rudder mount in tonight - definitely the most complex rudder mount I've done. 2nd print with a few tweaks came out great. Gear spacing was perfect, looks like the fore/aft shifting will work
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    printed a top piece to better support the brass tubes since they will be split between the halves
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    drilled first hole from bottom using the mount as a guide to get the hole centered, then drilled from the inside through the mount
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    servo fits great, perfect hole alignment
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    Clearance. important to consider subdeck height. Designed to be 5/8 from the deck edge, so 1/4" below subdeck
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    I always put a longer rod through to make side the post is vertical
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    Epoxy prep
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    low profile, filled in around the base to make it solid
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    fiberglass going up sides
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    Good grouping on the posts. They'll get cut down just slightly beyond the hull
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    Last edited: Nov 19, 2020
  9. Kevin P.

    Kevin P. Well-Known Member

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    Waterchannel in. Making video so not many pictures
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    Added drain pipes between the voids, 1/4” diameter
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    Last edited: Nov 22, 2020
  10. Anvil_x

    Anvil_x Well-Known Member

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    so are you using that break in the water channel foam to act as baffles?
     
  11. Kevin P.

    Kevin P. Well-Known Member

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    The break is for the aft turret, if needed for hose routing. The ultralite around the motor mount will also serve as a baffle for water moving aft, but it's primary purpose is a mounting surface for the solenoids and accumulator tanks. We'll see how it works out, might be too much channeling aft but my goal is to get boats to sink bow first
     
  12. wfirebaugh

    wfirebaugh Well-Known Member

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    Why bow first out of curiosity?
     
  13. Kevin P.

    Kevin P. Well-Known Member

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    Most boats sink stern first, and there is less freeboard in the stern. If the water inside the boat is evenly distributed with the boat stationary, then when running in forward the water will pool in the stern and the boat will sink sooner.

    If more water pools in the bow, the boat will sink level when running forward, and there is more freeboard in the bow so it will stay afloat longer. Most importantly, bow sinks look cooler.

    Like everything, there is a happy medium, as either approach taken to the extreme won’t work out (prop comes out of the water too early)
     
  14. Kevin P.

    Kevin P. Well-Known Member

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    Working on deck now, subdeck cut to size
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  15. Kevin P.

    Kevin P. Well-Known Member

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    Lots of work today, deck rim and getting rudder post done. Making videos so fewer pictures
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    Rudder posts had to change to solid tube all way through since I had alignment issues with the split tubes.
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    Now just servo piece moves as needed
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    various gear tests, through the 4 rudder post locations
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    Showing the removable piece
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    deck pieces
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    subdeck in
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    Last edited: Nov 29, 2020
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  16. NickMyers

    NickMyers Admin RCWC Staff

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    Bow first sinks also have the happy side effect of not using your rudder and props to find the bottom before the rest of the ship...
     
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  17. Kevin P.

    Kevin P. Well-Known Member

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    Deck rim came out good, deck pieces fit pretty good
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  18. Kevin P.

    Kevin P. Well-Known Member

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    Not much work with reserves this weekend, got the barb holes cut tonight, probably will print them up this week, also probably bilge keels. It’s nice how quickly a build goes when only working on one boat
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  19. Anvil_x

    Anvil_x Well-Known Member

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    Hey Kevin, I used your electrical tape trick to glass in my new shafts on Texas and ran into a lot of epoxy leaking through the tape. what's the secret here?
     
  20. Kevin P.

    Kevin P. Well-Known Member

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    No secret really. I’ve only had issues with one brand of tape that was very cheap - but it was clear that the tape did not adhere well so a few leaks were expected, and those roles went to the grab bag pile. I found a pretty cheap 3m version that holds great, came in a pack of 5-10 role. I overlap the edges, make sure one piece sticks to the next, and double up a few longer strips over the top. Need to get creative at the end of the shafts with some folded pieces. Nothing crazy though