Leopard 4074 1650 KV

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  • Newboater
    Senior Member
    • Jul 2016
    • 359

    #1

    Leopard 4074 1650 KV

    Running this motor on 4s and it seems to take a few seconds to get up to speed. Running 645 prop 30" deep V. Is it because of the low KV on 4s batteries are SMC 7200 90c. Boat seems very slow to come on plane, runs decent when on plane just slow to get there.
  • Thunder29
    Senior Member
    • Apr 2017
    • 155

    #2
    I'm not sure what motor you were running before. Could be the new motor is a little heavier than your last motor. have you tried adjusting the strut / prop angle to see if that helps at all? I had problems with my hydro coming on plane after i did a motor change. I adjusted the strut so the prop was a hair deeper in the water and problem solved.

    Comment

    • boatsrnew2me
      Senior Member
      • Oct 2016
      • 476

      #3
      thats a 6s motor .if you wanted to run 4s you should have got a higher kv motor .i am contemplating a motor change for my bj29 v3 .my research has told me lower kv for 6s and higher kv for 4s .

      i am still new to boats myself so someone with alot more knowledge should come along .
      volantex vector pro ,proboat veles 29 , traxxas spartan, hobbyking/tfl pursuit ,ft009 with rescue rigging

      Comment

      • Newboater
        Senior Member
        • Jul 2016
        • 359

        #4
        No motor prior. Have played with the strut not much difference boat just seems slow out of the hole.Almost seems like the motor is bogging down.

        Comment

        • Thunder29
          Senior Member
          • Apr 2017
          • 155

          #5
          Big thing to remember you typically want the motor running between 25-30000 rpm for messing around. 35-40000 or higher for saw runs. Kv rating x voltage gives you unloaded rpm. 1650kv x 14.8v = 24420 rpm.
          1650kv x 22.2 = 36630 rpm.

          Higher rpm generally = faster

          There are lots of things to take into account for boats though.

          Hope that helps.

          Comment

          • Newboater
            Senior Member
            • Jul 2016
            • 359

            #6
            Had the motor prior kind of knew it was A 6s motor based on kv. Was kind of surprised at how it seemed sluggish on 4s. I knew it wouldn't have good top speed but I thought it would have performed faster out of the hole.

            Comment

            • boatsrnew2me
              Senior Member
              • Oct 2016
              • 476

              #7
              is it new ?
              volantex vector pro ,proboat veles 29 , traxxas spartan, hobbyking/tfl pursuit ,ft009 with rescue rigging

              Comment

              • Newboater
                Senior Member
                • Jul 2016
                • 359

                #8
                Bought it off another forum member, stated it was only used once or twice. Motor at speed sounds fine. Probably just going to run the boat on 6s. Just looking for more of a fun cruiser at around 35-40mph. Thought I could do it on the 4s. Boat ran 33mph but it was windy and choppy conditions and didn't like the out of the hole performance. Probably will just run a smaller prop for 6s.

                Comment

                • fweasel
                  master of some
                  • Jul 2016
                  • 4281

                  #9
                  Originally posted by Newboater
                  Probably will just run a smaller prop for 6s.
                  a 447/3 outta do it...
                  Vac-U-Tug Jr (13mph)

                  Comment

                  • iop65
                    Senior Member
                    • Mar 2013
                    • 367

                    #10
                    not my cup of tea putting 447/3 props on a 30 inch mono
                    6s and a 42mm prop with that motor would be a better idea i guess

                    Comment

                    • rol243
                      Fast Electric Addict!
                      • Apr 2017
                      • 1038

                      #11
                      looks like with that kv motor you will need to go 6s plus don,t go too big on the prop size, start small and work up. my pick for the mono is a 440 x 3 for starters or maybe thats the one. oh. what size esc are you running ?

                      Comment

                      • fweasel
                        master of some
                        • Jul 2016
                        • 4281

                        #12
                        Originally posted by iop65
                        not my cup of tea putting 447/3 props on a 30 inch mono
                        Clearly a failed attempt at humor.
                        Vac-U-Tug Jr (13mph)

                        Comment

                        • Tamelesstgr
                          Fast Electric Addict!
                          • Jun 2014
                          • 1516

                          #13
                          You are running this in the "Princess" yacht correct? Based on your video I think it moves pretty good, not sure how much more speed that hull can deal with before getting out of control.

                          https://forums.offshoreelectrics.com...cht&highlight=
                          NEVER SATISFIED RACING
                          Fine Design 32 V-Hull 4082+6s

                          Comment

                          • Newboater
                            Senior Member
                            • Jul 2016
                            • 359

                            #14
                            Originally posted by Tamelesstgr
                            You are running this in the "Princess" yacht correct? Based on your video I think it moves pretty good, not sure how much more speed that hull can deal with before getting out of control.

                            https://forums.offshoreelectrics.com...cht&highlight=
                            That is correct here is the video


                            In the video it was 15 plus mph winds and the water jacket was leaking and filling the hull. I fixed the water leak as the water jacket was to far forward. In that video speed was 32mph on 645 prop. Went out the next day and boat ran completely dry but the wind almost blew it across the lake. I use the speed calculator on the forum and for me it is consistently off by about 8mph always faster then what I get, so I am starting to wonder if I am setting things up wrong.

                            The boat is running a Raider 150 amp esc. Just wondering if 40mph is attainable on 4s and 1650kv. I see some people run 5s how does that work if one pack is heavier then the other? and the packs are on the left and right sides of the hull and don't weigh the same.

                            Comment

                            • Newboater
                              Senior Member
                              • Jul 2016
                              • 359

                              #15
                              Okay just found a video of a pursuit with same set up 4074 1650 kv on 4s ran 35 and 6s ran 45 so I am not that far off being the pursuit is a lot lighter and not as deep a V.

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