40,000 rpm........what's the problem

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  • kfxguy
    Fast Electric Addict!
    • Oct 2013
    • 8746

    #151
    Originally posted by Rocstar
    I disagree. Excessive weight is added load on the motors and controllers. It's more about weight distribution and cg when running at high speeds and keeping the boat flying level. Rum is correct.... the extra battery weight is required to power the boat, not a necessity to keep it on the water.
    I'm not saying throw a ten pound weight in it and call it a day.
    32" carbon rivercat single 4s 102mph, 27” mini Rivercat 92mph, kbb34 91mph, jessej micro cat(too fast) was

    Comment

    • keithbradley
      Fast Electric Addict!
      • Jul 2010
      • 3663

      #152
      I've NEVER had a boat that was too light to go fast. If you think weight is going to keep you on the water you don't understand what's keeping your boat on the water in the first place.
      Excess weight is a necessary evil, that's it. If you could magically remove 50% of the weight from any of my boats I would thank you for it and then go faster.

      Suggesting that weight keeps a fast boat on the water is just as silly as saying heavier cars get better traction.
      www.keithbradleyboats.com

      Comment

      • Fella1340
        Fast Electric Addict!
        • May 2013
        • 1035

        #153
        Somebody should write a rule book on all this stuff. I don't know what you would call it though.

        Comment

        • kfxguy
          Fast Electric Addict!
          • Oct 2013
          • 8746

          #154
          Originally posted by keithbradley

          Suggesting that weight keeps a fast boat on the water is just as silly as saying heavier cars get better traction.
          That's a pretty contradicting statement there. I'm not going to argue with you. You can dice and chop up what I say however you like. I'll just retract my beforehand statement because what you say must be the gospel. I'm not sure what's been your issue here lately but I've been reading some of your posts and seems like you've got some serious opinions about stuff here lately and I'm not the only one who's noticed it. So maybe calm down a notch or two.

          Let me clarify what I said earlier as I was at a restaurant waiting on my family to get there to eat for my sons 5th birthday today. I had to cut it short as they drove up. I didn't think my statement would be scrutinized so closely.

          the guy mentioned getting rid of a 6s pack to lighten up the load. Then next guy says he really needed it more than the benefits of being lighter because it helped with amp out put. Yes. Now I chimed in a said excess weigh doesn't matter as much. This is true in my opinion, however I did not mean go purposely add weight to it. What I meant is the extra weigh of the battery is needed...because of current draw and capacity and the benefits out weighs the weight factor. I could go on and on explaining what I think and what I've found in this and that....but who really cares? On a sidenote I feel pretty certain that a 2 lb fantasm is going to be pretty hard to keep on the water at 100mph vs a 15lb fantasm. I think there's a certain amount of weigh you'll have to have to keep things under control. I've never seen a build done where someone is going through great lengths to lighten the boat up. I've always seen people adding weight, here and there, strengthening things up. Keith if your so he'll bent on building the lightest possible boats then why put all those weight adding dress up plates And do dad's in your boats? I see many pointless things you add just for looks. Pretty contradicting to your above statement I'd say.
          32" carbon rivercat single 4s 102mph, 27” mini Rivercat 92mph, kbb34 91mph, jessej micro cat(too fast) was

          Comment

          • Shooter
            Team Mojo
            • Jun 2009
            • 2558

            #155
            Originally posted by Ralf
            Another real critical issue: significantly reduced prop choices. The higher the rpm the more critical gets every mm pitch. Even different shaping of the props can be more dangerous.
            Sure, light running boat types reduce the risks. But there is a whole picture :)
            Ralf
            This guy had a real good point. At higher RPM's we've essentially reduced the resolution of our prop choices.

            Comment

            • Shooter
              Team Mojo
              • Jun 2009
              • 2558

              #156
              Regarding weight, I think Terry has it right. That extra weight is a huge deal when changing direction (i.e. turning).

              Weight is nice when you're running in race water/chop though.....for the same exact reason (more resistant to directional change).

              Comment

              • kfxguy
                Fast Electric Addict!
                • Oct 2013
                • 8746

                #157
                Originally posted by Shooter
                Regarding weight, I think Terry has it right. That extra weight is a huge deal when changing direction (i.e. turning).

                Weight is nice when you're running in race water/chop though.....for the same exact reason (more resistant to directional change).
                Agreed. I was referring to straight line all out speed.
                32" carbon rivercat single 4s 102mph, 27” mini Rivercat 92mph, kbb34 91mph, jessej micro cat(too fast) was

                Comment

                • Fella1340
                  Fast Electric Addict!
                  • May 2013
                  • 1035

                  #158
                  Big leaps and bounds being taken here. Something sure is silly, no doubt on that one

                  Comment

                  • keithbradley
                    Fast Electric Addict!
                    • Jul 2010
                    • 3663

                    #159
                    Originally posted by kfxguy
                    That's a pretty contradicting statement there. I'm not going to argue with you. You can dice and chop up what I say however you like. I'll just retract my beforehand statement because what you say must be the gospel. I'm not sure what's been your issue here lately but I've been reading some of your posts and seems like you've got some serious opinions about stuff here lately and I'm not the only one who's noticed it. So maybe calm down a notch or two.

                    Let me clarify what I said earlier as I was at a restaurant waiting on my family to get there to eat for my sons 5th birthday today. I had to cut it short as they drove up. I didn't think my statement would be scrutinized so closely.

                    the guy mentioned getting rid of a 6s pack to lighten up the load. Then next guy says he really needed it more than the benefits of being lighter because it helped with amp out put. Yes. Now I chimed in a said excess weigh doesn't matter as much. This is true in my opinion, however I did not mean go purposely add weight to it. What I meant is the extra weigh of the battery is needed...because of current draw and capacity and the benefits out weighs the weight factor. I could go on and on explaining what I think and what I've found in this and that....but who really cares? On a sidenote I feel pretty certain that a 2 lb fantasm is going to be pretty hard to keep on the water at 100mph vs a 15lb fantasm. I think there's a certain amount of weigh you'll have to have to keep things under control. I've never seen a build done where someone is going through great lengths to lighten the boat up. I've always seen people adding weight, here and there, strengthening things up. Keith if your so he'll bent on building the lightest possible boats then why put all those weight adding dress up plates And do dad's in your boats? I see many pointless things you add just for looks. Pretty contradicting to your above statement I'd say.
                    Nothing contradictory bud. I've stayed consistent on this matter for as long as I've voiced an opinion about it. Weight does not help you keep a boat in the water. It's very simple and i assure you that if you do continue in this hobby and ever go for big speed you will fully understand and agree. If i were to set one of my boats up to blow over, you could add weight to it and probably sink it before you could correct the issue with weight alone. I can explain this further and help you understand why, but it seems you would rather continue as you are. So be it.
                    As far as what you see me add to my boats... I'm all ears. I'm not sure which builds you have been going over but I'm not a trinket guy. Everything I do has a purpose. You may not know why some things are done, but that doesn't mean that they aren't done for a reason.

                    And in regards to calming down... I'm totally calm Travis. We are all friends here, no need to tell anyone else how you think they should behave. Perhaps you're not comfortable with the tone of my posts but I assure you it's an issue of comprehension. I'm a friendly guy with no dog in this fight, just offering advice where It can clearly be used. Some people can take info from others and apply it, and some people just spend their time trying to pretend they have nothing to learn. Don't be the latter. There's nothing wrong with reading something you didn't know and using that info to further improve your boats. I've built a lot of fast boats Travis, and I'm still learning. Surely you have a few things to learn too, yes?

                    My posts are typically straight to the point and honest, regardless whether or not honesty is popular among a given group. Some find that offensive or abrasive, I'll give you that. However if you read my posts you'll notice that they are informative and relative to the subject matter, even if not always worded to inflate everyone's ego. I surely don't know everything, but in regards to the things I HAVE learned, I choose to share them when applicable. If you're not perceptive to this let me know and I'll save my words for someone who is.

                    One other thing. No need to preempt what is clearly an argument with the sentence "I'm not going to argue with you". It's a bit disingenuous to suggest you are above something just before diving in. And in regards to people strengthening their boats, nobody's doing that with the intent of adding weight. To the contrary, the goal is always to strengthen a boat with the LEAST POSSIBLE weight penalty.
                    www.keithbradleyboats.com

                    Comment

                    • keithbradley
                      Fast Electric Addict!
                      • Jul 2010
                      • 3663

                      #160
                      Originally posted by Shooter
                      Regarding weight, I think Terry has it right. That extra weight is a huge deal when changing direction (i.e. turning).

                      Weight is nice when you're running in race water/chop though.....for the same exact reason (more resistant to directional change).
                      It is the resistance to directional change that will typically cause a crash though, wouldn't you agree? For instance, if you were to watch a typical crash in slow motion or frame-by-frame, you would almost never see a boat crash from a single action (except in the case of a clean blow-over on smooth water, which is a result of improper setup, not really a matter of weight). Crashes are typically a series of actions/reactions, which eventually cause a boat to dig in or leave the water. In an instance where a boat hits a wave and crashes, it's fairly assumable that the boat will go up from the wave, react by digging down into the water, then either hook the nose or recoil back up and blow over.

                      There are of course situations where big, heavy boats do well over their smaller counterparts, but the weight is still typically relative to the surface area of the hull. An overloaded small hull will not net the same benefits.

                      Do you agree, at least in part?
                      www.keithbradleyboats.com

                      Comment

                      • T.S.Davis
                        Fast Electric Addict!
                        • Oct 2009
                        • 6221

                        #161
                        Object in motion tends to stay in motion unless blah blah blah.

                        A heavier boat is simply less effected by waves, wind gusts, spray from other boats.

                        I've seen it work both ways. Light boat that's super fast can win. It will too in the right conditions. Too light and it will likely struggle if it's not leading. Like I said. It's a delicate balance and there absolutely is no exact formula you must adhere to with roundy round boats.

                        My first LSH boat weighed 9 pounds RTR. You could drive that pig right up someone's transom and not blow it off. Won a fair number of races that way. That boat couldn't run a 2030 because of its obesity. It was bit over the balance point.

                        Heat racing isn't SAW.
                        Noisy person

                        Comment

                        • kfxguy
                          Fast Electric Addict!
                          • Oct 2013
                          • 8746

                          #162
                          Originally posted by T.S.Davis
                          Object in motion tends to stay in motion unless blah blah blah.

                          A heavier boat is simply less effected by waves, wind gusts, spray from other boats.

                          I've seen it work both ways. Light boat that's super fast can win. It will too in the right conditions. Too light and it will likely struggle if it's not leading. Like I said. It's a delicate balance and there absolutely is no exact formula you must adhere to with roundy round boats.

                          My first LSH boat weighed 9 pounds RTR. You could drive that pig right up someone's transom and not blow it off. Won a fair number of races that way. That boat couldn't run a 2030 because of its obesity. It was bit over the balance point.

                          Heat racing isn't SAW.
                          Agreed.
                          32" carbon rivercat single 4s 102mph, 27” mini Rivercat 92mph, kbb34 91mph, jessej micro cat(too fast) was

                          Comment

                          • iridebikes247
                            Fast Electric Addict!
                            • Dec 2011
                            • 1449

                            #163
                            Heavy is ok but crashes are more violent, more hull in the water, greater chance of hooking the wrong edge (i think). Last thing you want is a boat hooking edges, loading up the hull in the wrong place because of a small ripple in the water, causing a chain reaction resulting in a...you get it.

                            I try to get a lot of hull out of the water when I can but I have never run over 95 mph so idk what comes into play with the really fast setups. This all is based on my observation from seeing and running 5 different boats all achieving 80-95 mph twice a week....perhaps i have too much time on my hands.
                            Youtube: https://www.youtube.com/channel/UCSr...6EH3l3zT6mWHsw

                            Comment

                            • keithbradley
                              Fast Electric Addict!
                              • Jul 2010
                              • 3663

                              #164
                              Originally posted by T.S.Davis




                              Heat racing isn't SAW.
                              Absolutely. That's an important point. Things that may work at 60mph don't always translate in a boat at higher speeds. I still don't think I would intentionally add weight to a heat race boat, but I also don't have anywhere near the experience Terry does in that realm so my opinion in regards to heat racing doesn't carry a lot of weight.

                              Also to be clear, I absolutely agree that 2p may be necessary for some setups, but if the intent is to go as fast as possible, the extra weight is coincidental, not beneficial. The energy a boat carries at a given speed is factored by weight, and any equal/opposite reaction will be suspect to the same factor.
                              The effects Terry is pointing out (via wind, waves, ect.) may be manipulated by weight at slower speeds, but as speed increases, forces outside of weight (hydrodynamic, aerodynamic, thrust vector, etc.) begin to play a much larger role. For instance, if you were to run a Mystic hull with the drives at neutral, you may be able to get to 60 - 70 mph before blowing over. Added weight might increase this speed by a couple mph, but at 100mph you will never keep the boat on the water, regardless of weight. However, the same hull with proper drive angle will be easier to manipulate and keep on the water at a lesser weight.
                              I didn't come to this conclusion by hypothesis alone, I have done a lot of testing at high speeds with various setups and experienced the results of different variables.

                              If you were to ask everyone that has ever ran a boat at 100+ (just picking a number) how they got their boat to go from blowing over to running stable, I don't think any would say weight.
                              www.keithbradleyboats.com

                              Comment

                              • Gary
                                Fast Electric Addict!
                                • Jan 2009
                                • 1105

                                #165
                                You are correct Kieth but I have found that weight is a {my} friend in trying to go fast multiple times over. At the speeds that I am at right now I NEVER have to worry about a blow over regardless of dead flat or slight chop waters and I believe its because of the weight of the boat given how big the hull is and how much air can really get trapped under the hull. This to me is extremely important to my wallet and mental state of crashing a hull.Would i love to have a lighter boat.....sure, would it go faster sure, but i feel a whole new can of worms will start to open up and boy I hate starting all over every time that happens.
                                PT-45, 109mph, finally gave up after last bad crash
                                H&M 1/8 Miss Bud 73 mph
                                Chris Craft 16 mph

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