cog for a micro hydro?

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • bustitup
    Fast Electric Addict!
    • Aug 2008
    • 3071

    #1

    cog for a micro hydro?

    I have one like the ones from minicatracing
    SPRINT CAT 40.........BOOGIMAN 25" MONO 8xl
    EX President of the Offshore FE Vultures Society
  • Simon.O.
    Fast Electric Addict!
    • Oct 2007
    • 1521

    #2
    The Cg, Cog for most hydros begins at 10% of the afterplane. That is the distance between the rear of the sponson ride surface and the prop.
    If this distance is 10" then your cg goes at 1" aft of the sponson rear and tune from there.
    See it....find the photos.....sketch it it....build it........with wood

    Comment

    • HOTWATER
      Fast Electric Addict!
      • Nov 2008
      • 2323

      #3
      Originally posted by bustitup
      I have one like the ones from minicatracing
      bustitup, I just bought one of these and the Instructions say 15.5 cm from the transom (rear of the boat) on up, or about 6.1 inches. Should end up right where the front of the motor (shaft) and flex coupler meet.

      -Kent
      "Will race for cookies!"
      IMPBA D12
      My Gallery: http://forums.offshoreelectrics.com/album.php?u=1738

      Comment

      • bustitup
        Fast Electric Addict!
        • Aug 2008
        • 3071

        #4
        thanks guys
        SPRINT CAT 40.........BOOGIMAN 25" MONO 8xl
        EX President of the Offshore FE Vultures Society

        Comment

        • HOTWATER
          Fast Electric Addict!
          • Nov 2008
          • 2323

          #5
          You got it man...
          "Will race for cookies!"
          IMPBA D12
          My Gallery: http://forums.offshoreelectrics.com/album.php?u=1738

          Comment

          • bustitup
            Fast Electric Addict!
            • Aug 2008
            • 3071

            #6
            well as it works theres not much room to move a battery around to adjust cog...so with simons method I took a measurment from the back of the sponson to where the drivedog meets the prop and it was 10" so using 10% of that which is 1"...when I push the 3s 2350mah lipo full forward my cog is 1" of the sponson...how lucky was that....this thing should rip with the rhino 3s 2350mah 25c...man its tight in this little hull....its got a 2445 3600kv feigao and a 32mm prop

            now I have to figure how to squeeze some flotation in there somewhere
            SPRINT CAT 40.........BOOGIMAN 25" MONO 8xl
            EX President of the Offshore FE Vultures Society

            Comment

            • bigwaveohs
              Senior Member
              • May 2009
              • 535

              #7
              Originally posted by bustitup
              well as it works theres not much room to move a battery around to adjust cog...so with simons method I took a measurment from the back of the sponson to where the drivedog meets the prop and it was 10" so using 10% of that which is 1"...when I push the 3s 2350mah lipo full forward my cog is 1" of the sponson...how lucky was that....this thing should rip with the rhino 3s 2350mah 25c...man its tight in this little hull....its got a 2445 3600kv feigao and a 32mm prop

              now I have to figure how to squeeze some flotation in there somewhere
              I have two of these and the recommended distance in the instructions works perfectly...
              I let the dogs out...

              Comment

              • Meniscus
                Refuse the box exists!
                • Jul 2008
                • 3225

                #8
                You may also be able to use a prop that has a little more lift, not too much though as it is easy to have too much lift at higher RPMs.

                Mine runs great with the recommended balance and the stock prop. How does she run on the water, or have you tried yet? I started mine really wet and started to move back. Note: be careful of the climbouts as you move back, she can easily flip on you and quick. However, it may be that my CF version is more susceptible to this, but I haven't run one of the fiberglass ones to confirm.

                As you're adding flotation, don't forget the hatch!

                What does your battery weigh in grams?
                IMPBA: 7-Time FE World Record Holder "Don't think outside the box. Rather, refuse to admit that the box exists in the first place!"

                MGM Controllers - Giant Power Lipos - ML Boatworks - Wholt's Wire Drives & Struts - Nano-Oil

                Comment

                • bigwaveohs
                  Senior Member
                  • May 2009
                  • 535

                  #9
                  Originally posted by bigwaveohs
                  I have two of these and the recommended distance in the instructions works perfectly...
                  There's plenty of room in the sponsons for flotation if you shape it to fit. I tried the 32mm prop but it didn't do much, probably because I'm only running 20C packs.
                  Attached Files
                  I let the dogs out...

                  Comment

                  • bigwaveohs
                    Senior Member
                    • May 2009
                    • 535

                    #10
                    Originally posted by Meniscus
                    You may also be able to use a prop that has a little more lift, not too much though as it is easy to have too much lift at higher RPMs.

                    Mine runs great with the recommended balance and the stock prop. How does she run on the water, or have you tried yet? I started mine really wet and started to move back. Note: be careful of the climbouts as you move back, she can easily flip on you and quick. However, it may be that my CF version is more susceptible to this, but I haven't run one of the fiberglass ones to confirm.

                    As you're adding flotation, don't forget the hatch!

                    What does your battery weigh in grams?
                    Do you have a source for a "lifting" prop?
                    I let the dogs out...

                    Comment

                    • bustitup
                      Fast Electric Addict!
                      • Aug 2008
                      • 3071

                      #11
                      Originally posted by Meniscus
                      You may also be able to use a prop that has a little more lift, not too much though as it is easy to have too much lift at higher RPMs.

                      Mine runs great with the recommended balance and the stock prop. How does she run on the water, or have you tried yet? I started mine really wet and started to move back. Note: be careful of the climbouts as you move back, she can easily flip on you and quick. However, it may be that my CF version is more susceptible to this, but I haven't run one of the fiberglass ones to confirm.

                      As you're adding flotation, don't forget the hatch!

                      What does your battery weigh in grams?
                      oh yes got to float the hatch...no I havnt run it yet

                      198grams

                      SPRINT CAT 40.........BOOGIMAN 25" MONO 8xl
                      EX President of the Offshore FE Vultures Society

                      Comment

                      • bustitup
                        Fast Electric Addict!
                        • Aug 2008
                        • 3071

                        #12
                        Originally posted by bigwaveohs
                        There's plenty of room in the sponsons for flotation if you shape it to fit. I tried the 32mm prop but it didn't do much, probably because I'm only running 20C packs.

                        I would like to see the inside of your boat

                        ben you too
                        SPRINT CAT 40.........BOOGIMAN 25" MONO 8xl
                        EX President of the Offshore FE Vultures Society

                        Comment

                        Working...