Is my hull from a bad casting, and what can I do?

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  • maxmekker
    Senior Member
    • Jul 2010
    • 412

    #1

    Is my hull from a bad casting, and what can I do?

    Well as those of you that have read my tread about my Geico know that I'm struggling a bit to get my geico to run smooth.
    So I got the kintec rudder, and it did not help much. So today I got hold of an S/B 642 prop to test, and when I sat the boat on the tabel to set the strutt , I saw that the ride pad's were pritty off to each others. I thought about truing the hull , but how do mine compare to some off you're boats folks.

    Thanks.
    Attached Files
    Drammen rock City
  • Rumdog
    Fast Electric Addict!
    • Mar 2009
    • 6453

    #2
    The real problem, even with the Kintec rudder offset is that the way the strut is designed you can't get the correct adjustment. The bottom of the strut should be above the sponson bottoms. Around 1/8" and the porpoising will be gone. You cant do it with the stock strut, since the prop will hit the strut bracket.

    Comment

    • Rumdog
      Fast Electric Addict!
      • Mar 2009
      • 6453

      #3
      I'm also assuming that the dihedral in the left sponson is there on purpose, since they are intended to turn better to the right.

      Comment

      • maxmekker
        Senior Member
        • Jul 2010
        • 412

        #4
        Originally posted by Rumdog
        I'm also assuming that the dihedral in the left sponson is there on purpose, since they are intended to turn better to the right.

        Ok, I thougt it was maybe a bad cast , but maybe you're right.

        (I have another tread about tuning the boat, but I had more luck today with a 642 and the rudder, than last night with the prather 215 on. Video on it's way)
        Last edited by maxmekker; 06-09-2011, 05:54 PM.
        Drammen rock City

        Comment

        • Darin Jordan
          Fast Electric Addict!
          • Apr 2007
          • 8335

          #5
          Is the boat sitting down on the stuffing tube?? Most setup boards are cutout to give a relief for the strut/stuffing tube. Slide the boat back on the table and bit and make sure it's not rocking on the stuffing tube. If you have the back of the sponsons even with the table edge, then I'm certain that's happening.

          Otherwise, almost all of the MG hulls I've measured have a slight arch in the ride pads, and the left one usually has the middle step just a tad higher than the first and last one on that side. They are all also a bit concave on the ride-pads. Blueprinting will provide a cleaner running boat.

          HOWEVER, there are MANY, MANY examples on this site of out of the box samples, set-up properly, that run great.

          If you look at my "race-prep" thread, and any number of others here, almost any question you could have has already been answered, and I show in detail how to blueprint the sponsons.

          Hope this helps.
          Darin E. Jordan - Renton, WA
          "Self-proclaimed skill-less leader in the hobby."

          Comment

          • maxmekker
            Senior Member
            • Jul 2010
            • 412

            #6
            nope , not sitting down on the stuffing on this pic's , I had loosen the strutt bolt to get it 'factory' settings,and the back of the sponson was at tabel end , and I just thought, hmm, should there be so much difference at the back.

            here are the kintec + prather 215 and lipos back and forth for testing couple of day's ago:


            and here are from just a few hours ago with the 642.


            it's much better, especially after the water got some ripling after a few passes from the boat itself.

            But this tread was more ment to get an answer if they were supossed to be like mine were when they were sitting flat on the tabel. Not more stuff on the wa wa wa tralla lala stuff.

            Darin, I have read you're race prep tread several times, it's very nice.Will have another go at it when I do my hull.

            Thanks for having a look.
            Attached Files
            Last edited by maxmekker; 06-09-2011, 06:26 PM.
            Drammen rock City

            Comment

            • tiqueman
              Fast Electric Addict!
              • Jul 2009
              • 5669

              #7
              I think your on to something here. Ive got 2 Geico hulls here. One is even, meaning, if I sit it do that the left sponsons ride pad is flat on the table, the right sponson is up about 1/4" and vice versa. the other hull has about 1/8 inch difference. And yours looks to be even more than that!!!! Interesting discovery... good job! I never thought to check that.
              Geico epoxy laminate hatch sale thread Black Jack epoxy laminate hatch sale thread
              HPR06 6S Twin HOTR Genesis (SOLD) Vantex 32" cat Geico racing
              WEST FL MODEL BOAT CLUB www.scottskiracing.com

              Comment

              • wilsta67
                Senior Member
                • Feb 2011
                • 203

                #8
                Originally posted by Rumdog
                The real problem, even with the Kintec rudder offset is that the way the strut is designed you can't get the correct adjustment. The bottom of the strut should be above the sponson bottoms. Around 1/8" and the porpoising will be gone. You cant do it with the stock strut, since the prop will hit the strut bracket.
                if the strut is the problem would getting a round file or a dremel to it and increasing the slide adjustment fix that problem?

                Comment

                • maxmekker
                  Senior Member
                  • Jul 2010
                  • 412

                  #9
                  I think I've seen it be done. Cant do any harm to try.
                  Drammen rock City

                  Comment

                  • maxmekker
                    Senior Member
                    • Jul 2010
                    • 412

                    #10
                    some more shot's of the hull.
                    Attached Files
                    Drammen rock City

                    Comment

                    • Peacock8
                      Member
                      • Jun 2011
                      • 97

                      #11
                      My hull seems to have the same issues, especially on the left sponson looking from the back.

                      Ørjan.

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