No announcement yet.

The Mysterious Isochronous Curve

  • Filter
  • Time
  • Show
Clear All
new posts

  • The Mysterious Isochronous Curve

    Hi Peeps,

    I'm in the early planning stages for a routed slot track. I've got about 4' by 18' to play with and am thinking of a 2 lane analog Bertrand 8 style track (pic below for rough shape).

    Through the wonders of youtube algorithms this video got prompted to me today and I found it really interesting:

    It got me thinking about making one of the big 180 degree corners at either end of the track an isochronus curve.

    Has anyone included an isochronus curve in their track? If so how does it run? And if not got any guesses? I tend to make my curves elliptical as I like a smooth transition from straight to curve. Do you think an isochronus curve would have an OK blend from straight to curve?


    You do not have permission to view this gallery.
    This gallery has 1 photos.

  • #2
    Great video.

    Knowledge, like slot cars, is a worthy thing to collect.


    • #3
      Eyeballing an isochronous curve, it appears that as you enter the curve the radius is sharpest. The radius opens out as you move through the curve, becoming largest at the middle of the curve, then becoming smaller again as you progress to the far side.

      If that is true, then a car following an isochronous curve will encounter the highest cornering forces at the entry and exit of the curve -- opposite of what happens when it travels through a 180 degree parabolic curve.

      If I were going to use an isochronous curve in a race track I would use only half of it, exiting at what would have been the mid-point, with the largest radius. That way the car could enter slow and leave fast. Probably onto a long straight.

      Or you could do the opposite -- enter fast and leave slow -- coming off of a long straight.

      I actually have a similar curve on my new routed 1/32nd scale track. It has a decreasing radius coming off of the main straight. I don't think it is isochronous -- the change of radius is smooth and continuous -- but the effect should be much the same.

      Driving through that corner on my track seems very natural. The car loses speed going through the corner, managing the increasing cornering forces very nicely, and typically launches onto the next straight without drama.

      The change in radius of that curve is not all that large. You have to look at it closely to see it.


      If you do built an isochronous curve into your track please let us know how it works out.

      Ed Bianchi
      Last edited by HO RacePro; 01-13-2022, 07:01 AM.


      • #4
        Not hard to test with sectional track, entering on an R1, then going into R2, R3, R4, before returning to R1 by the time you exit the 180 degree turn.
        I won't be testing, because my experience tells me it will be unpleasant to drive. I'd rather go straight into an R1, and have it stay R1. Or, have it open up on the way to a straight... NOT tighten up again.

        If you want to add a turn in your track that is (debatably overly) challenging to drive, and that most people will learn to hate, go for it. :P

        IMHO, YMMV.


        • #5
          Thanks for the suggestions. Much appreciated.

          Knowledge and slot cars have definitely got a lot in common

          Now that you've said it I see what you mean about the curve giving a sequence tightening, opening and then tightening again potentially being a pain in the a. Like you said Ed it might be better suited to a half curve. I've not got any plastic track to try it out on but I'll sketch it out in full scale (about 1200mm diameter) and see how it looks with a car our two sitting on it. With a bigger diameter it might present itself as more of a double apex that is fun to drive? At 1200 prob just gonna be a pain.

          Keep ya updated!


          • #6


            • #7
              I'm in the same boat with Greg. I can test on plastic and have and find the entering a gentler curve and then decrease the radius is easier to drive than a sharper curve opening up.


              • #8
                Thanks for the pic Flip. It's not the nicest looking turn in the world is it.

                Might just shelve the idea and stick to the tried an true parabolics.


                • #9
                  Last edited by thatguy01; 01-17-2022, 01:50 AM.


                  sex vidio
                  antalya escort
                  lara escort escort istanbul escort sirinevler escort antalya
                  beylikduzu eskort bayan taksim eskort lara eskort bayan bakirkoy bayan eskort
                  gaziantep escort gaziantep escort
                  izmir escort kayseri escort gaziantep rus escort
                  replica watches
                  kadikoy escort kartal escort
                  Blonde and brunette dirty 3some in semi obscure Профессор трахнул студенту толстым хером pelicula embarazada por accidente