Time to rebuild - BJ26 dual

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  • kookie_guy
    Senior Member
    • Jun 2008
    • 897

    #1

    Time to rebuild - BJ26 dual

    Ok, boat is starting to look a little rough. Cracked the transom along the join line when I smoked a tree root just below the surface. Gonna rip it apart, lay down some CF to stiffen it up.

    So my plan, please tell me if my thinking is off on something....

    Motors - use 2x BJ26 motors. What are other comparable options, for a low price?
    ESC - 2x Turnigy 180Amp marine ESCs

    I will be using stinger struts, and will more than likely stick with my dual rudder setup to start.

    One area I really need help with is props. What should i be getting? From watching mudl's progress, looks like octura x442 l&r is the way to go. Is that a safe baseline? Or should I go smaller first? Again, I have no idea where to start with the setup I'm planning above.

    cheers.
  • blackcat26
    High Speed Junkie
    • Sep 2009
    • 1598

    #2
    Stiffen as much of the hull as you can because at the speeds you are about to enter this hull wont handle a tumble. You are on the right path......Two blackjack motors will be very fast on acceleration but the one time I ran them didn't get em topped out before smoking something. (so I can't give you a top speed estimate) Gonna try again soon. Yes use the x442's counter rotating. Reg rotation on the starboard and reverse on the portside. Don't forget to use the left hand and right hand lay cable and dont get em mixt up! 6s is the way to go with these motors by the way. You didn't mention voltage but this will fly!
    FE BOATING: Less like a hobby and more like an addiction!

    Comment

    • kookie_guy
      Senior Member
      • Jun 2008
      • 897

      #3
      Originally posted by blackcat26
      Stiffen as much of the hull as you can because at the speeds you are about to enter this hull wont handle a tumble. You are on the right path......Two blackjack motors will be very fast on acceleration but the one time I ran them didn't get em topped out before smoking something. (so I can't give you a top speed estimate) Gonna try again soon. Yes use the x442's counter rotating. Reg rotation on the starboard and reverse on the portside. Don't forget to use the left hand and right hand lay cable and dont get em mixt up! 6s is the way to go with these motors by the way. You didn't mention voltage but this will fly!
      I will be starting with 4s. We'll see how things go from there. Good point about the cable. Wouldn't have thought of that.

      Comment

      • blackcat26
        High Speed Junkie
        • Sep 2009
        • 1598

        #4
        You gonna run one battery pack of 4s or (2) 2s in serie?
        FE BOATING: Less like a hobby and more like an addiction!

        Comment

        • kookie_guy
          Senior Member
          • Jun 2008
          • 897

          #5
          Originally posted by blackcat26
          You gonna run one battery pack of 4s or (2) 2s in serie?
          I have a bunch of 2s packs, so for starters it'll be a total of 4 2s packs. Each ESC will be getting 4s2p.

          Here's the concept so far. What are the pros and cons of putting the props in front of the rudders (closer to transom) and behind the rudders? In the drawings they are even, so that will have to change.



          Comment

          • kookie_guy
            Senior Member
            • Jun 2008
            • 897

            #6
            I think I have my shopping list......doesn't include the stinger struts.

            X442, X442R



            X447, X447R



            .150 cable with 3/16 shaft (L & R)



            ESC
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            questions:
            1) Should I bother getting the 447 props? Or are they too much prop?
            2) The Turnigy 180A is a big (size) ESC, can I use just one to run both motors?
            3) How are the swordfish 120A ESC's? Are they waterproof?

            cheers, and thanks for the help.

            Comment

            • blackcat26
              High Speed Junkie
              • Sep 2009
              • 1598

              #7
              Ditch the 447's too much prop. Mudl on this forum got up to 78-79mph with the 442's. One esc cannot power two motor you will need 2 esc's. Swordfish are not water proof they are watercooled only. Two of the turnigy 180's would be a good choice for your boat they are simple to use/program.
              FE BOATING: Less like a hobby and more like an addiction!

              Comment

              • kookie_guy
                Senior Member
                • Jun 2008
                • 897

                #8
                Originally posted by blackcat26
                Ditch the 447's too much prop. Mudl on this forum got up to 78-79mph with the 442's. One esc cannot power two motor you will need 2 esc's. Swordfish are not water proof they are watercooled only. Two of the turnigy 180's would be a good choice for your boat they are simple to use/program.
                Turnigy 180s it is then. I can always use them in my future boats. Thanks for the prop advice. Save some money right there.

                Comment

                • blackcat26
                  High Speed Junkie
                  • Sep 2009
                  • 1598

                  #9
                  NO problemo. I used the sv27 stingers on my twin. The only problem with those are the back of the mounting plate needs to be machined straight. They are made on a slight angle for v hulls.
                  FE BOATING: Less like a hobby and more like an addiction!

                  Comment

                  • kookie_guy
                    Senior Member
                    • Jun 2008
                    • 897

                    #10
                    Originally posted by blackcat26
                    NO problemo. I used the sv27 stingers on my twin. The only problem with those are the back of the mounting plate needs to be machined straight. They are made on a slight angle for v hulls.
                    I'm going to be making my own stinger struts. Just finished drawing them up. They are essentially like the speedmaster ones. They look badass.

                    Comment

                    • BakedMopar
                      No Mo Slipah
                      • Sep 2009
                      • 1679

                      #11
                      If your going to run 4s the 447's may be the way to go. On 6s 42 gets the nod. Whichever you choose ALWAY check your temps. Good luck. Gotta love twins!
                      If all of your wishes are granted, many of your dreams will be destroyed!

                      Comment

                      • kookie_guy
                        Senior Member
                        • Jun 2008
                        • 897

                        #12
                        Can anyone tell me the length of the 3/16 shaft on this??


                        I am going to start cutting my struts tomorrow, and I wanna make sure I make em the right length.

                        cheers.

                        Comment

                        • RCKong
                          Fast Electric Addict!
                          • Sep 2009
                          • 1545

                          #13
                          The lenght of a supervee stinger is 70mm from the transom. The tubes have 3/16 brass bushings in them. Hope this helps

                          Comment

                          • blackcat26
                            High Speed Junkie
                            • Sep 2009
                            • 1598

                            #14
                            Originally posted by kookie_guy
                            Can anyone tell me the length of the 3/16 shaft on this??


                            I am going to start cutting my struts tomorrow, and I wanna make sure I make em the right length.

                            cheers.
                            Length of the stub shaft is 2 1/4"
                            FE BOATING: Less like a hobby and more like an addiction!

                            Comment

                            • kookie_guy
                              Senior Member
                              • Jun 2008
                              • 897

                              #15
                              sweet. thanks for the answers guys. So the 2 1/4 is the full length? with the threads?

                              cheers.

                              Comment

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