USS Omaha Light Cruiser Class (Fast Gun/Treaty)

Discussion in 'Warship Builds' started by mike5334, Mar 31, 2010.

  1. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    Dang, I was thinking that with the guns so low, you'd have no balance issues!
     
  2. djranier

    djranier Well-Known Member

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    Don't know what the issue was, but my motors were getting super hot using direct drive. Was not happy with it at all. Tore out the motors, and installed 2 BC GB-300 gear boxes running 18 pinions. Boat actually is running faster now with the gear boxes. Motors are now cool, not hot at all.

    Leaning issue seems to be that I had the bottle way to far forward, moved it back about 6 inches, she rides much better now. In any type of turn she heels over close to 45 deg, will need a tight deck seal for sure, but comes right back to a even keel. Was very impressed with her stopping and starting, and with full reverse, her rear deck just goes under a little, was afraid that the stern would bury itself.

    Now I just need to finish wiring the gun componets, and she will be ready, if I can get myself to do it, I seem to be burned out right now, dont feel like working on any boats, so it looks like maybe only the Duke will make it to Nats.
     
  3. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    I wonder if the props were spinning so fast that they cavitated enough that the resistance of the water around the prop lowered, allowing the motors to spin faster, thus drawing more current and heating up? I knopw that some people disagree with me on cavitation, but it's well-documented in water pumps of all types. Spin too fast, pump less water, and draw more current. If putting in the gearboxes slowed the props down below their cavitation threshhold, the current would go down, (I^2R losses =>heat goes down, too), and more water gets moved by the props since less energy is being wasted making little air bubbles...
     
  4. djranier

    djranier Well-Known Member

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    Well the current would of gone down just due to the gearing in the gearbox, but following you thought, it was cavatating quite a bit, with the smallest amount of turn, or hitting a small wave, the props would just started spraying water all over. With the gear boxes that has stopped. I have the 380 Titan motors in it for the drive motors, may be a tad overkill. But the motors are not even getting warm now.
     
  5. Time Lapse

    Time Lapse Member

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    Cool Ship , I am looking to build my own ship real soon,This part here in the pictures ,How did you get the wood the curve and glue them in ,And what kind of wood did you use from the skin.Any video showing how you did this part.
    Image4.jpg Image2.jpg
     
  6. NickMyers

    NickMyers Admin RCWC Staff

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    Its balsa blocking, he just sanded it to the profile of the ribs fore and aft of the block. If memory serves, the Bearn build thread (On the Ways: Bearn CV | R/C Warship Combat shows it in a little more detail.
     
    Last edited: Feb 14, 2017