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What is Recommended Track Incline/Decline Slope for Elevation Changes?

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  • What is Recommended Track Incline/Decline Slope for Elevation Changes?

    Last edited by Wet Coast Racer; 08-12-2019, 10:39 AM.

  • #2
    Hi Bonez.

    Not sure of slope but make as gradual as possible. Say at least 1 metre either side of bridge but more is better. Remember some cars only have about 1mm of ground clearance so you do not want cars bottoming out. This is even more important with set track but I think you are routing a wooden track.

    Regards Chas Le Breton (charlesx)

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    • #3
      Of course it depends what type of vehicles you're driving but any incline would be part of the challenge anyway just like a corner.

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      • #4
        Why did you post this twice?

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        • #5
          I have mostly endurance/IMSA/Trans Am/Can Am/F1 cars from Scalextric, Slot It and Fly. This will be a road course with undulating hill type scenery.

          So so am thinking 5-7% grades. That will make a rise of 5-7 inches over a 100 inch distance. To me that does not appear to be too drastic but would like help from those with experience.

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          • #6
            I donít know how this happened. Do you know how I can delete the duplicate?

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            • #7
              Hi Bonez. The amount of elevation you have indicated, is very easy, and will be barely noticed by cars or driver.You COULD do quite a bit more acute if you wanted.
              Be aware that if elevation takes place going through corners, the track will want to pop in - or more usually "outwards" creating reverse camber.
              If the elevation is acute, you may need to "bend it" over a few days, gradually applying lift pressure until the track creaks a little, but not too much - you don't want to break it.
              There is a technique called "kerfing" where you cut shallow grooves across the width from underneath, to allow the surface at top to bend more easily, but I doubt you will need it, and it does weaken the construction.
              Below a pic of my track My hill has a 1 in 10 lift or more - ie It is 10 feet wide looking from the other end, and I have a foot of elevation
              I did need to do this over a week using braces and a car jack, as my 12mm (half inch) MDF was creaking and protesting loudly, especially as all sections were already screwed and glued together, and the elevation involved 4 corners all trying to flex the track to different cambers. - I didn't use kerfing at all.

              primed.jpg

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              • #8
                In response to a similar question a while back I conducted a simple experiment to test how much rise could be achieved in four feet.

                The MDF I used was 3/8" thick. Your 1/2" MDF will be about 77% stiffer. I was easily able to get 3-1/2" of rise in 48". A strict rise/run calculation gives a 7.3% slope.

                The center of the rise is actually steeper than that, since the track starts and ends level. I didn't measure the steepest part of the slope, but I don't think it would be far off 14 or 15 percent. In the real world that is a danged steep slope. Still, for a slot track, it looks pretty modest.

                The amount of force needed to put that much bend in 3/8" MDF was not that much. I think your 1/2" MDF will handle it without overstressing.

                MDF Slope Test 1.jpg

                MDF Slope Test 2.jpg

                FYI, when MDF gets overstressed it tends to separate into layers, almost like a stack of paper sheets. As Bonez states above, MDF will "take a set" over time, so you can reduce the chance of it failing by bending it in steps and giving it time to adjust between steps.

                Ed Bianchi

                PS - Love the new photo insertion tool! Much, much less work than the old one.

                PPS - The motorcycle in the background is my 1984 BMW R80RT. I call her "Carmina". Sweet old gal, but I do have to work at keeping her down to anything like a legal speed. She wants to run!

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                • #9
                  Probably pm an admin.

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                  • #10
                    Nice work on the stress/lift calculations Ed.
                    I am interested in how you describe MDF separating into layers.
                    What is sold as MDF in the USA must be a quite different product to what is sold as MDF in my country, which is not layers at all, but a slurry of glue and something finer than the "chips" of what we called old fashioned "Chip-board"- more a slurry of dust and quite fine grit particles and Urea Formaldehyde resin, which is injected onto a bed, then progressively rolled flatter and denser over stages - like a progressive hot metal roll press, until it reaches final density and thickness for the specification - typically 0.72 to 0.73 of the weight of water for a given volume.
                    - It also comes in lower density versions where weight is critical, for use in caravans, motor homes and marine joinery.

                    Our MDF obviously can't separate in the way you describe, it just reaches critical bending force points then snaps like a cannon going off - quickly followed by loud expletives from the builder
                    And from what you describe, yours is probably more flexible. Interesting


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                    • #11
                      I have artwork on the rear wall that limits my border to about seven inches so I can view while sitting on the stools. So I think I will go with a 4% slope (1-inch rise every 25-inches). That will give me about 6-inch elevation change from front to back.

                      Plan 003 by bonez 300

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                      • #12
                        I put my sections together then raised where I wanted. The corner sections are flat.

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                        • #13
                          SlotsNZ,

                          I don't know the details of how MDF is made here in the USA, but I think you are right that it is a different product. It is close to the same density as water -- heavy! I am not aware of any low-density versions.

                          I have described MDF as being similar in composition to kraft paper. That layered construction becomes obvious if the material gets soaked with water. The stuff expands like a cellulose sponge.

                          Our MDF has no perceptible granularity. When you rout it it produces a very, very fine sawdust that gets everywhere. Some people are allergic to it. I hook up a shop-vac to my router to suck it up before it can become airborne. I wrap an old T-shirt around my shop-vac's filter to keep it from blinding. Otherwise that dust packs solid into the filter pleats and blinds it quickly.

                          Our commercial tracks use 1/2" MDF, which can be bent into extreme banked corners. I am not sure just how much cussing is involved, but the professional track builders seem to have it down.

                          I use 3/8" MDF for my HO tracks. As shown in the photos above, it flexes rather nicely. I rout the slots 3/16" deep (actually 0.188" to 0.210"). That is also deep enough for 1/32nd scale cars with guides designed for the shallow slots of plastic track. I'm not recommending using 3/8" MDF for 1/32nd scale tracks, but it could be an option.

                          Ed Bianchi
                          Last edited by HO RacePro; 08-12-2019, 03:36 AM.

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                          • #14
                            I think that the bigger issue here is how much of a slope the cars can tolerate. If you have some spare MDF you can dummy up a sloped track section to see if your cars will drag. 1/32nd scale wood tracks ore often made of 3/8" MDF and they have slots a smidge more than 1/4" deep in most cases. 3/8" MDF is not carried by home improvement stores and most lumber yards, so people that don't want to do a special order will tend to go with 1/2" MDF.

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                            • #15
                              Ed - yes definitely a different manufacturing system altogether. I used to ship about 1,200 tonnes a year of industrial ammonia, which is used in the production of the resins, so I periodically found myself wandering through an MDF plant with the purchase people to meet the production line ones.
                              Ours will eventually expand and take on water, but the surface polish and glue content give it a measure of resistance.

                              Yes, as per Rich - drag could be an issue, though I think the elevation would need to be pretty extreme or the car very low; and I have also wondered at what point a twist in a track to accommodate slight banking which occurs as you elevations through corners, might affect having all 4 wheels on the track art once - but haven't encountered a problem with either on any tracks I have driven.
                              Rich, we mostly rout 8mm slots in NZ, so need to use half inch (12mm), so we can accommodate the Slot.it and Scaleauto wood guides.
                              I routed 9mm (3/8th) to 7mm once, but it was pushing the envelope, and we still had wood guides bottoming out.

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