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Brakes, why do some work better?

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  • Brakes, why do some work better?

    Why do some cars seem to brake much better than others. Similar motors but some cars seem to slam on the brakes while others seem to coast. Example, my Fly sidewinders hit the brakes hard when releasing the throttle, my newest Scalextric Cuda slows up a bit easier and my Monogram Greenwood Corvette just coast thru without stopping at all sometimes, the other times it does brake.

  • #2
    I find gear ratio and mesh quality make a huge difference, along with front tire ride height. If you have a controller with brake sensitivity, they do require cleaning more often to fully engage the brake switch.

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    • #3
      Some motors have tons of brakes whilst some have negligible brakes. Just because you have motors of similar types doesn't mean similar brakes. I presume motor magnets and armature winds have the biggest affect all else being equal.
      Kevan - Isle of Man
      Print It, Build It, Race It, Improve It, Repeat...

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      • #4
        Very briefly...
        "Brakes" work by shorting the power back against the motor. It's basic physics....the current running through the wire on the armature creates a field that interacts with the magnets in the motor so when you short the power supply against that it "pushes" against the arm and slows the motor. Crude and inaccurate in the details, but that's the basic idea.

        There are LOTS of variables. Magnet strength, armature wind, magnet spacing (air gap to the arm), spring tension, brush friction all play a part in the motor. And yes, friction in the drivetrain also matters. As does car weight.... heavier car takes longer to stop. And gear ratio also plays a part.

        As does good contact with the track.....poor braid contact will impact braking as well as acceleration and top end.

        So....hard to say, depending on the car and setup.
        Come Race at The Trace!
        Timberline Trace International Raceway - SW of Mpls, MN
        https://www.thingiverse.com/chappyman66/designs

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        • #5
          Your comments suggest motor configuration matters. I have many Fly sidewinder cars and they do seem to coast/brake the same. My Monogram cars (Greenwood Vettes and Can Am cars) are inline and do coast well. Also, just because motors look alike doesn't mean they have the same internal characteristics.

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          • #6
            Originally posted by Michael Squier View Post
            Why do some cars seem to brake much better than others. Similar motors but some cars seem to slam on the brakes while others seem to coast. Example, my Fly sidewinders hit the brakes hard when releasing the throttle, my newest Scalextric Cuda slows up a bit easier and my Monogram Greenwood Corvette just coast thru without stopping at all sometimes, the other times it does brake.
            Michael, Lots of things affect the braking on a slotcar..........strength of the motor magnets, armature wind, gear ratio,/mesh, driveline friction, braid contact, rear tire diameter, motor orientation, and overall car weight.

            While adjusting the brake pot on your controller (assuming you have this feature on your controller) will certainly have an effect, there are many other factors involved (above ) in a cars braking capabilitiy.

            Cheers
            Chris Walker
            Last edited by chrisguyw; November 2, 2021, 02:08 PM.

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            • #7
              Typically a motor that draws more amps will have better braking. So if you are looking at the braking equation for a car the motor portion of it will be dependant on this fact.
              Cheers

              Dan
              G.P Alberta

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              • #8
                Thanks for all the answers. Good info to store in my memory banks.

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                • #9
                  Does motor placement affect braking? I have a Fly 911, that has the motor behind the back axel .And that thing literally skids and hops under braking.
                  That is the only slot car i have come across that has the motor in that location. Does anyone else own one of theses? and if so do u have the same brake performance?

                  john

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                  • #10
                    Originally posted by tracyridge View Post
                    Does motor placement affect braking? I have a Fly 911, that has the motor behind the back axel .And that thing literally skids and hops under braking.
                    That is the only slot car i have come across that has the motor in that location. Does anyone else own one of theses? and if so do u have the same brake performance?

                    john
                    Hi John,.........short answer, No !!

                    I have built several "Rear motored" fly cars for club members/customers, and while the motor position does raise some handling issues, braking is not one of them.

                    This chassis was heavily modified to improve its longitudinal stiffness.......which caused axle tramping (the major issue with this chassis)

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