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RC help required.

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  • Daryl
    Needed a break from the infernal pop pops so I built an electric RC boat. Electrics and steering servo from an RC car and motor from a rechargeable vacuum
    Message 1 of 7 , Oct 11, 2010
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      Needed a break from the infernal pop pops so I built an electric RC boat. Electrics and steering servo from an RC car and motor from a rechargeable vacuum cleaner which I think is more powerful than the one in the car and easier to fit, all 9.6V. Battery pack is 1000 mAH Ni-MH.

      Problem:-Engine speed is all over the place from zero to full on when using RC. With no RC electrics connected and the battery connected directly to the motor it goes full speed and steady. The car worked fine and had litle use. Steering servo works OK.

      Does any one know what might be the problem? New motor drawing to much
      for the RC board or incompatible? Motor sending RC signal and causing
      interference?

      Don't think I will get more than a few minutes running time with this battery assuming it will work satisfactorily so also wonder if the RC board will handle a 3000mAH battery pack or will this compound my problems?

      When full power kicks in it goes really well.

      Please let me know if you have any thoughts on this. Thanks.
    • Donald Qualls
      ... It may be a problem with the vacuum motor drawing more current than the R/C speed control can handle -- which will eventually destroy the R/C control unit.
      Message 2 of 7 , Oct 11, 2010
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        Daryl wrote:
        > Needed a break from the infernal pop pops so I built an electric RC boat. Electrics and steering servo from an RC car and motor from a rechargeable vacuum cleaner which I think is more powerful than the one in the car and easier to fit, all 9.6V. Battery pack is 1000 mAH Ni-MH.
        >
        > Problem:-Engine speed is all over the place from zero to full on when using RC. With no RC electrics connected and the battery connected directly to the motor it goes full speed and steady. The car worked fine and had litle use. Steering servo works OK.
        >
        > Does any one know what might be the problem? New motor drawing to much
        > for the RC board or incompatible? Motor sending RC signal and causing
        > interference?
        >
        > Don't think I will get more than a few minutes running time with this battery assuming it will work satisfactorily so also wonder if the RC board will handle a 3000mAH battery pack or will this compound my problems?
        >
        > When full power kicks in it goes really well.
        >
        > Please let me know if you have any thoughts on this. Thanks.
        >

        It may be a problem with the vacuum motor drawing more current than the
        R/C speed control can handle -- which will eventually destroy the R/C
        control unit. As you surmise, it might also be radio interference,
        though I'd normally expect that to glitch the steering channel
        simultaneously. One possible source of motor-based interference,
        though, would be inductive noise from the motor's brushes and commutator
        feeding back up the power wires to the speed control -- assuming the
        motor's draw is within the controller's specs, you might try wrapping
        the motor wires through a ferrite ring to act as a choke (depending on
        how your speed control is built, that may or may not work -- or may
        require wiring a biggish capacitor across the motor wires between the
        speed control and choke to smooth out the control pulses).

        --
        If, through hard work and perseverance, you finally get what you want,
        it's probably a sign you weren't dreaming big enough.

        Donald Qualls, aka The Silent Observer http://silent1.home.netcom.com

        Opinions expressed are my own -- take them for what they're worth
        and don't expect them to be perfect.
      • zoomkat
        running 9.6v in equipment that usually uses ~7.2v might cause some electrical failures. For a simple motor drive you might want to use a standard servo with
        Message 3 of 7 , Oct 11, 2010
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          running 9.6v in equipment that usually uses ~7.2v might cause some electrical failures. For a simple motor drive you might want to use a standard servo with the reduction gears removed.Direct drive the prop from the servo motor. This would allow speed control and full foward/reverse capability. It would basically be a continous rotation servo without the reduction gearing.

          --- In pop-pop-steamboats@yahoogroups.com, "Daryl" <darylcanada73@...> wrote:
          >
          > Needed a break from the infernal pop pops so I built an electric RC boat. Electrics and steering servo from an RC car and motor from a rechargeable vacuum cleaner which I think is more powerful than the one in the car and easier to fit, all 9.6V. Battery pack is 1000 mAH Ni-MH.
          >
          > Problem:-Engine speed is all over the place from zero to full on when using RC. With no RC electrics connected and the battery connected directly to the motor it goes full speed and steady. The car worked fine and had litle use. Steering servo works OK.
          >
          > Does any one know what might be the problem? New motor drawing to much
          > for the RC board or incompatible? Motor sending RC signal and causing
          > interference?
          >
          > Don't think I will get more than a few minutes running time with this battery assuming it will work satisfactorily so also wonder if the RC board will handle a 3000mAH battery pack or will this compound my problems?
          >
          > When full power kicks in it goes really well.
          >
          > Please let me know if you have any thoughts on this. Thanks.
          >
        • Daryl
          Thanks Donald and zoomkat. Progress update and of course answers beget questions. I put the car motor in and the same problem which maybe eliminates the vacuum
          Message 4 of 7 , Oct 12, 2010
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            Thanks Donald and zoomkat.

            Progress update and of course answers beget questions.

            I put the car motor in and the same problem which maybe eliminates the vacuum motor as a source of the problem. Replaced the just new battery in the controller though it tested OK and a good improvement but not totally right. Did find out that the little car motor has
            enough power. The bow lifted out of the water, the stern squatted down and waves came to the top of my pond (when it would run at full power). Weight redistribution required.
            Enough power in fact that the prop sliced a hole in the bottom of the boat. I did not notice that the car motor was shorter so shaft and prop had moved forward and under full power would touch the hull.

            I wonder if the all metal boat is affecting the controller signal? Right now the controller is the prime suspect Is it OK to use contact cleaner on the controller? Is there any simple
            way to test controller signal? The original car motor has two capacitors. The vacuum motor none that I can see. If I put one on
            the vacuum motor what is "biggish"?

            All the components are 9.6V originally, no 7.2V stuff.
            I'm using direct drive with both motors and do have reverse that is as erratic as forward.

            Thanks again, Daryl.
          • frankmcneill
            Hi Daryl, Donald, Zoomkat and all-- Can you imagine the excitement that would be generated in boat model groups if pop-pop boats had not been invented yet and
            Message 5 of 7 , Oct 12, 2010
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              Hi Daryl, Donald, Zoomkat and all--

              Can you imagine the excitement that would be generated in boat model
              groups if pop-pop boats had not been invented yet and there was a news item about a mysterious new propulsion system that did not require IC engines, electric motors, batteries or moving parts?

              Frank

              --- In pop-pop-steamboats@yahoogroups.com, "Daryl" <darylcanada73@...> wrote:
              >
              > Thanks Donald and zoomkat.
              >
              > Progress update and of course answers beget questions.
              >
              > I put the car motor in and the same problem which maybe eliminates the vacuum motor as a source of the problem. Replaced the just new battery in the controller though it tested OK and a good improvement but not totally right. Did find out that the little car motor has
              > enough power. The bow lifted out of the water, the stern squatted down and waves came to the top of my pond (when it would run at full power). Weight redistribution required.
              > Enough power in fact that the prop sliced a hole in the bottom of the boat. I did not notice that the car motor was shorter so shaft and prop had moved forward and under full power would touch the hull.
              >
              > I wonder if the all metal boat is affecting the controller signal? Right now the controller is the prime suspect Is it OK to use contact cleaner on the controller? Is there any simple
              > way to test controller signal? The original car motor has two capacitors. The vacuum motor none that I can see. If I put one on
              > the vacuum motor what is "biggish"?
              >
              > All the components are 9.6V originally, no 7.2V stuff.
              > I'm using direct drive with both motors and do have reverse that is as erratic as forward.
              >
              > Thanks again, Daryl.
              >
            • Donald Qualls
              The metal hull can lead to receiver glitching, both in terms of blocked signal and reflection interference (we used to see similar things when I flew R/C
              Message 6 of 7 , Oct 12, 2010
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                The metal hull can lead to receiver glitching, both in terms of blocked
                signal and reflection interference (we used to see similar things when I
                flew R/C airplanes, if you flew too near a chain link fence or baseball
                backstop), where the transmitter's signal interferes with itself when
                the reflected signal goes in and out of phase with the direct signal.
                It's also possible the metal hull could be concentrating interference
                from the motor, which would be better when you have the original motor
                with the capacitors connected -- and possible you might not notice
                rudder glitches if the throttle's glitching, so we can't rule out
                interference from the motor.

                The squatting you describe, BTW, is what I'd expect if you're trying to
                push a displacement hull past "hull speed", the speed at which the bow
                wave's first peak hasn't come back down to water level when it reaches
                the stern (there's a calculation for the actual speed, but hull speed is
                the main reason aircraft carriers can always outrun destroyers despite
                the destroyer's much larger power to weight ratio -- because a destroyer
                is shorter).

                If the controller directly drives the motor, you could connect a dummy
                load (say, a 1 watt or better, 20-or-so ohm resistance -- an old style
                incandescent light bulb made for 120 V should work) and read the voltage
                across the load with an oscilloscope, looking for stuff that doesn't
                belong in what's essentially an on-or-off square wave. Lacking an
                o-scope, however, there really isn't any useful way to test other than
                to pull the whole rig out of the metal hull and see if you still get
                glitches when the signal isn't being blocked and/or interference
                concentrated.

                Daryl wrote:
                > Thanks Donald and zoomkat.
                >
                > Progress update and of course answers beget questions.
                >
                > I put the car motor in and the same problem which maybe eliminates
                > the vacuum motor as a source of the problem. Replaced the just new
                > battery in the controller though it tested OK and a good improvement
                > but not totally right. Did find out that the little car motor has
                > enough power. The bow lifted out of the water, the stern squatted
                > down and waves came to the top of my pond (when it would run at full
                > power). Weight redistribution required. Enough power in fact that the
                > prop sliced a hole in the bottom of the boat. I did not notice that
                > the car motor was shorter so shaft and prop had moved forward and
                > under full power would touch the hull.
                >
                > I wonder if the all metal boat is affecting the controller signal?
                > Right now the controller is the prime suspect Is it OK to use
                > contact cleaner on the controller? Is there any simple way to test
                > controller signal? The original car motor has two capacitors. The
                > vacuum motor none that I can see. If I put one on the vacuum motor
                > what is "biggish"?
                >
                > All the components are 9.6V originally, no 7.2V stuff. I'm using
                > direct drive with both motors and do have reverse that is as erratic
                > as forward.
                >


                --
                If, through hard work and perseverance, you finally get what you want,
                it's probably a sign you weren't dreaming big enough.

                Donald Qualls, aka The Silent Observer http://silent1.home.netcom.com

                Opinions expressed are my own -- take them for what they're worth
                and don't expect them to be perfect.
              • Daryl
                Thanks Donald, I ll work at it in the next couple of days and let you know what I discover. I had a tough time getting connected to the forum today so if you
                Message 7 of 7 , Oct 13, 2010
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                  Thanks Donald,

                  I'll work at it in the next couple of days and let you know what I discover. I had a tough time getting connected to the forum today so if you don't hear from me maybe I've been permenantly blocked.

                  Re hull design:-As speed in putt putts is my main interest and knowing that scale models don't always perform like the full size I spent a couple of weeks this summer testing various hulls with engines of the same or similar power. The results were interesting. May do a Youtube video on it. I'll send you the data if you are interested. It is a fairly narrow study as regards boat length and weight and engine power but there were very distinct differences in hull shape. Did not get the expected result.

                  Daryl.

                  --- In pop-pop-steamboats@yahoogroups.com, Donald Qualls <silent1@...> wrote:
                  >
                  > The metal hull can lead to receiver glitching, both in terms of blocked
                  > signal and reflection interference (we used to see similar things when I
                  > flew R/C airplanes, if you flew too near a chain link fence or baseball
                  > backstop), where the transmitter's signal interferes with itself when
                  > the reflected signal goes in and out of phase with the direct signal.
                  > It's also possible the metal hull could be concentrating interference
                  > from the motor, which would be better when you have the original motor
                  > with the capacitors connected -- and possible you might not notice
                  > rudder glitches if the throttle's glitching, so we can't rule out
                  > interference from the motor.
                  >
                  > The squatting you describe, BTW, is what I'd expect if you're trying to
                  > push a displacement hull past "hull speed", the speed at which the bow
                  > wave's first peak hasn't come back down to water level when it reaches
                  > the stern (there's a calculation for the actual speed, but hull speed is
                  > the main reason aircraft carriers can always outrun destroyers despite
                  > the destroyer's much larger power to weight ratio -- because a destroyer
                  > is shorter).
                  >
                  > If the controller directly drives the motor, you could connect a dummy
                  > load (say, a 1 watt or better, 20-or-so ohm resistance -- an old style
                  > incandescent light bulb made for 120 V should work) and read the voltage
                  > across the load with an oscilloscope, looking for stuff that doesn't
                  > belong in what's essentially an on-or-off square wave. Lacking an
                  > o-scope, however, there really isn't any useful way to test other than
                  > to pull the whole rig out of the metal hull and see if you still get
                  > glitches when the signal isn't being blocked and/or interference
                  > concentrated.
                  >
                  > Daryl wrote:
                  > > Thanks Donald and zoomkat.
                  > >
                  > > Progress update and of course answers beget questions.
                  > >
                  > > I put the car motor in and the same problem which maybe eliminates
                  > > the vacuum motor as a source of the problem. Replaced the just new
                  > > battery in the controller though it tested OK and a good improvement
                  > > but not totally right. Did find out that the little car motor has
                  > > enough power. The bow lifted out of the water, the stern squatted
                  > > down and waves came to the top of my pond (when it would run at full
                  > > power). Weight redistribution required. Enough power in fact that the
                  > > prop sliced a hole in the bottom of the boat. I did not notice that
                  > > the car motor was shorter so shaft and prop had moved forward and
                  > > under full power would touch the hull.
                  > >
                  > > I wonder if the all metal boat is affecting the controller signal?
                  > > Right now the controller is the prime suspect Is it OK to use
                  > > contact cleaner on the controller? Is there any simple way to test
                  > > controller signal? The original car motor has two capacitors. The
                  > > vacuum motor none that I can see. If I put one on the vacuum motor
                  > > what is "biggish"?
                  > >
                  > > All the components are 9.6V originally, no 7.2V stuff. I'm using
                  > > direct drive with both motors and do have reverse that is as erratic
                  > > as forward.
                  > >
                  >
                  >
                  > --
                  > If, through hard work and perseverance, you finally get what you want,
                  > it's probably a sign you weren't dreaming big enough.
                  >
                  > Donald Qualls, aka The Silent Observer http://silent1.home.netcom.com
                  >
                  > Opinions expressed are my own -- take them for what they're worth
                  > and don't expect them to be perfect.
                  >
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