OTW WTC leak and other front compartment issues

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  • Thorbrandr
    Lieutenant Commander
    • Mar 2022
    • 124

    OTW WTC leak and other front compartment issues

    Did some testing in my Sub Tub (2' deg water trough) to get the R-10 to dive on an even keel. That part was very successful.

    However, I had issues with the front planes shifting to "up" (almost vertical) as the ballast tack filled. I finally got it out of the water in that condition. It appears the pump is warping the plastic board, and the servo linkage is being pulled around. They ballast tank is very full when that is happening. Only about a 1/4" of air in the tank. The arm on the dive plane shaft has also slipped...easy fix there.

    The other unpleasant surprise was finding a teaspoon or so of water in the front WTC.

    I have opened the front compartment to dry it out, but in looking at it I have had more water from the ballast tank get in there. I suspect a loose fitting on the front of the ballast tank.

    How do I get one of the ends off the front WTC compartment? The water pump lines are stuck on really tight.

    Thanks
    Chris
  • wlambing
    Commander
    • Nov 2020
    • 291

    #2
    Chris,
    The water pump hoses can be massaged on and off their "barbed" fittings by careful levering with a small flat-tip screwdriver, then pulling with long-nose pliers. To reattach, you have to use the pliers to start and manipulate the hose back on. Long, curved forceps may work better. It also helps to hold your lips and tongue in a very determined position for the duration of the hose process!! It sounds like you got MBT water through the upper vent hole in the MBT/FWD Compt bulkhead. Very easy to do when the ballast tank is full and you lift the WTC with a down angle!!! Make sure your probe fittings are seated and tight after you clean the probes (use ONLY alcohol applied with a sturdy, lint-free cloth to remove any tarnish!!! Silver polish will make them look pretty, but will leave a carnauba wax residue on them, thereby decreasing their conductivity). Good luck! Bill

    Comment

    • Thorbrandr
      Lieutenant Commander
      • Mar 2022
      • 124

      #3
      !!!!!!!! well, well. Missed that small hole.

      First time with water in the WTC I had reached into the tank to roll the sub to check for trapped air bubbles. This morning I rolled the WTC on the bench to inspect it.

      Was thinking the probes might need cleaning.

      Many thanks!

      Chris

      Comment

      • coryhenry
        Lieutenant Commander
        • Jul 2020
        • 156

        #4
        Following up on a similar issue. The pump is surging in quick starts and only fills about a quarter of the tank. I'm assuming its a dirty probe and working on it, any other thoughts?

        Comment

        • Thorbrandr
          Lieutenant Commander
          • Mar 2022
          • 124

          #5
          Originally posted by coryhenry
          Following up on a similar issue. The pump is surging in quick starts and only fills about a quarter of the tank. I'm assuming its a dirty probe and working on it, any other thoughts?
          I had that happening as well. One of the lower probes was fouled. Cleaned it and no surging. YMMV. I’m still learning about this.

          Comment

          • coryhenry
            Lieutenant Commander
            • Jul 2020
            • 156

            #6
            Well I went and cleaned the probes very well again and still the surging problem. It did seem to work for a session then right back to surging again. Anybody have any other suggestions to check?

            Comment

            • Thorbrandr
              Lieutenant Commander
              • Mar 2022
              • 124

              #7
              Originally posted by coryhenry
              Well I went and cleaned the probes very well again and still the surging problem. It did seem to work for a session then right back to surging again. Anybody have any other suggestions to check?
              is it surging when one off the other servos is working?

              Comment

              • coryhenry
                Lieutenant Commander
                • Jul 2020
                • 156

                #8
                nope, only when I turn pump on to submerge, no other inputs and no other servos even twitching.

                Comment

                • Subculture
                  Admiral
                  • Feb 2009
                  • 2119

                  #9
                  This sounds like one of those issues that could be so many things it's difficult to nail down when trying to diagnose, especially by proxy online.

                  Could be a pump issue, pump controller issue, receiver issue on that channel, suppression (or lack thereof), or something really basic like a bad solder joint. I suggest isolating various components and trying them independently, like switching rx channels, running pump direct bypassing the controller and receiver. This should help narrow the culprit.

                  Comment

                  • Thorbrandr
                    Lieutenant Commander
                    • Mar 2022
                    • 124

                    #10
                    Originally posted by Subculture
                    This sounds like one of those issues that could be so many things it's difficult to nail down when trying to diagnose, especially by proxy online.

                    Could be a pump issue, pump controller issue, receiver issue on that channel, suppression (or lack thereof), or something really basic like a bad solder joint. I suggest isolating various components and trying them independently, like switching rx channels, running pump direct bypassing the controller and receiver. This should help narrow the culprit.
                    I'm still getting sporadic chirps on the pump with up control from the leveler, after moving the pump control a channel away. Not happening now on direct control of the planes after setting the end pt controls, but the original AST leveler is not taking programming for the limits. Waiting for my reprogrammed AD2's....

                    For cory, this illustrates subcultures comment....

                    Chris

                    Comment

                    • Subculture
                      Admiral
                      • Feb 2009
                      • 2119

                      #11
                      Don't know enough about your system to advise generics. Does the VEX RC have pulse conditioning built in. I'm not sure if the OTW board has some pulse conditioning built in. SO many things can cause this kind of behaviour from a dodgy BEC to a duff servo, wiring, iffy crystals etc. Sometimes these problems only reveal themselves at the lake, or are highly intermittent.

                      Comment

                      • Thorbrandr
                        Lieutenant Commander
                        • Mar 2022
                        • 124

                        #12
                        Originally posted by Subculture
                        Don't know enough about your system to advise generics. Does the VEX RC have pulse conditioning built in. I'm not sure if the OTW board has some pulse conditioning built in. SO many things can cause this kind of behaviour from a dodgy BEC to a duff servo, wiring, iffy crystals etc. Sometimes these problems only reveal themselves at the lake, or are highly intermittent.
                        Thanks!.

                        I changed the stern plane servo and all is good. I had a high torque servo on hand when the old servo failed and caused ESC/BEC issues, so I used that. I suspect it was causing a dip in voltage, but have not confirmed. Replaced the high torque unit with a basic Savox from the LHS, and all is good. Have not had any ballast chirps in a few hours of bench testing. Still am waiting on the repaired AD2's. the AST is still not taking programming, so trim was old school trial and error.

                        Now I am wonder how cold it can be before I cry uncle on another run....

                        Chris

                        Comment

                        • coryhenry
                          Lieutenant Commander
                          • Jul 2020
                          • 156

                          #13
                          Well in the effort to find the problem I changed batteries from a lead acid to LioN and it appears to be working well. Voltages are a little different so maybe it didn't like the juice :)

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