is this a bad idea?

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  • dreamland s4
    Senior Member
    • Dec 2010
    • 317

    #1

    is this a bad idea?

    is it a bad idea to add a wing on a cat? ive read a thread where this one guy that owns 3 expresscraft thundercats and stated that they tend to run wet. also, if you notice on the rear sides he has vents. i like them and was wondering if anybody knows where i can find them or how to make them. ideas are surely welcomed!
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    If the #2 pencil is the most popular, why is it still #2?
  • Himalaya
    Senior Member
    • Apr 2009
    • 251

    #2
    Nice thought. But I found my cat needs more down force at the nose when it reaches 80+mph, not at the transom. Different hulls might have diff characters though. But I've seen a a lot of cat stability problems at high speeds, all of them behave like their noses tends to go up when speed goes to a certain level, then soon within a blink of an eye they ended up with a brilliant fly dance in the air.

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    • Fluid
      Fast and Furious
      • Apr 2007
      • 8011

      #3
      Bad idea, that wing adds downforce exactly where it is NOT needed, plus a lot of unnecessary drag. The vents are for the gas engine and are available from several gas boat suppliers. Unfortunately he is not a very knowledgeable gas boater, he apparently does not have enough air inlet area to keep the motor supplied with cool air.




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      • dreamland s4
        Senior Member
        • Dec 2010
        • 317

        #4
        Originally posted by Fluid
        Bad idea, that wing adds downforce exactly where it is NOT needed, plus a lot of unnecessary drag. The vents are for the gas engine and are available from several gas boat suppliers. Unfortunately he is not a very knowledgeable gas boater, he apparently does not have enough air inlet area to keep the motor supplied with cool air.




        .
        your absolutely right! well, the wing looks nice but ill pass on that! think i can add the vents on mines just for appearance? maybe i can seal it up from inside?
        If the #2 pencil is the most popular, why is it still #2?

        Comment

        • dreamland s4
          Senior Member
          • Dec 2010
          • 317

          #5
          Originally posted by Himalaya
          Nice thought. But I found my cat needs more down force at the nose when it reaches 80+mph, not at the transom. Different hulls might have diff characters though. But I've seen a a lot of cat stability problems at high speeds, all of them behave like their noses tends to go up when speed goes to a certain level, then soon within a blink of an eye they ended up with a brilliant fly dance in the air.
          80 mph? i assume you have a different model? yea looks nice but ill pass on the wing. also if it were to flip over it will screw things up. (even though u could add breakaway nylon screws)
          If the #2 pencil is the most popular, why is it still #2?

          Comment

          • Himalaya
            Senior Member
            • Apr 2009
            • 251

            #6
            Originally posted by dreamland s4
            80 mph? i assume you have a different model? yea looks nice but ill pass on the wing. also if it were to flip over it will screw things up. (even though u could add breakaway nylon screws)
            140+km/h actually, yes, on another model. When I try to go faster I just can't stop my HPR115 from it's tendency of going flying.

            I came up with a similar idea, to add a small slope at the nose. It will have nearly zero effect at low speed but will some downforce when speeds up. This is just an idea, haven't got a chance to give it a try yet.

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            • dreamland s4
              Senior Member
              • Dec 2010
              • 317

              #7
              Originally posted by Himalaya
              140+km/h actually, yes, on another model. When I try to go faster I just can't stop my HPR115 from it's tendency of going flying.

              I came up with a similar idea, to add a small slope at the nose. It will have nearly zero effect at low speed but will some downforce when speeds up. This is just an idea, haven't got a chance to give it a try yet.
              Hpr now ur talkin lol. Well, im hoping to reach at least 55 with a twin lepard 4082. This is going to be hard I think.
              If the #2 pencil is the most popular, why is it still #2?

              Comment

              • Fluid
                Fast and Furious
                • Apr 2007
                • 8011

                #8
                I came up with a similar idea, to add a small slope at the nose
                An easier and more effective solution is to use a tunnel air dam about 3-4" back of the nose. About 1/2" high, it disrupts the air in the tunnel and reduces lift. I had to use one plus some trim tabs at the back of the tunnel (to lift the stern) to get into the mid-80s with my SprintCat. It has a lot more lift than an HPR, etc.



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                • Himalaya
                  Senior Member
                  • Apr 2009
                  • 251

                  #9
                  Originally posted by Fluid
                  An easier and more effective solution is to use a tunnel air dam about 3-4" back of the nose. About 1/2" high, it disrupts the air in the tunnel and reduces lift. I had to use one plus some trim tabs at the back of the tunnel (to lift the stern) to get into the mid-80s with my SprintCat. It has a lot more lift than an HPR, etc.



                  .
                  I thought the slope in my plan will make the hull look rather ugly, that's why I didn't apply it and was trying to find a better idea. Man you got my attention. Can I see how that looks like? Thanks.

                  Comment

                  • Rumdog
                    Fast Electric Addict!
                    • Mar 2009
                    • 6453

                    #10
                    Fluid's advice is spot on. He gave me the same for my Sprintcat. The airdam DOES work, and well.
                    I cut a piece of pool noodle square anf fitted it in the tunnel. However, it is unnecessary unless you're hauling some major butt. I'd run her first to see how she handles, and work with strut adjustments and props.

                    Comment

                    • dreamland s4
                      Senior Member
                      • Dec 2010
                      • 317

                      #11
                      Originally posted by Fluid
                      An easier and more effective solution is to use a tunnel air dam about 3-4" back of the nose. About 1/2" high, it disrupts the air in the tunnel and reduces lift. I had to use one plus some trim tabs at the back of the tunnel (to lift the stern) to get into the mid-80s with my SprintCat. It has a lot more lift than an HPR, etc.



                      .
                      will 2 outrunner 600 (heli) motors be a bad idea?
                      If the #2 pencil is the most popular, why is it still #2?

                      Comment

                      • Simon.O.
                        Fast Electric Addict!
                        • Oct 2007
                        • 1521

                        #12
                        Originally posted by dreamland s4
                        will 2 outrunner 600 (heli) motors be a bad idea?
                        I run outrunner (OR) motors in my big cat and like them, they get hot but I do hard short runs so it works for me.
                        They can be fun but have their own issues for cooling (if needed).

                        fwiw I am in love with OR's for now, I run 3 hulls with them and will have 2 more on the water with OR power soon. I may be biased
                        See it....find the photos.....sketch it it....build it........with wood

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