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Helix windings

Started by Ruud M, September 16, 2021, 02:00:38 PM

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Ruud M

Hello All  :)
I am in need of an explanation, concerning the windings of a Helix.
When I use the Helix command (on a single 9125) I can fill in the height startpoint & Height Endpoint, and the amount of Windings. Then the following will be filled in by the program: slope percentage and Windings, slope percentage is clear, but the Windings are unclear.
Does the Windings show the Height between the tracks (For N Gauge you need at least 4.5cm/45mm.)
Or is this figure telling me something different.
I have to make a Helix with a height difference of 35cm/350mm, if I fill in my figures, it tells me the following:
Height Startpoint: -35
Height Endpoint: 0
Amount of Windings: I choose for 9

Then the slope percentage will become 2.7% (which is okay, in my opinion)
The Height per Winding then becomes 3.9 (i think Centimeters 39mm)
If so then I can't get my trains through.

If I try to get this height higher then the slope is increasing rapily towards the wrong heights.

Am I wrong, or am I overlooking something els


The problem is that the radius of the curve is too small.

This means that at an incline of 3 percent, you will not gain enough height in one loop (or winding).

If you select curve 9130 (we're talking about Fleischmann Piccolo), you only need 5 loops and get 7cm (70mm) clearance.
Note that this is rail top to rail top. You need to deduct the track height and the plywood thickness you use to construct the helix. If this is still not enough, you can use R4 curves (9135).
David Hoogvorst. Founder and Owner of DRail Software. Creator of AnyRail.

Ruud M

Thanks David for the swift reply.

Then i have a challenge with my plan for creating a new lay-out.
I already have a helix from Noch with 9120/9125 radii bows. Slope percentage of 3,2 %. Which i intended to use, and fabricate one myself. Slope is already at te limit. But it worked in my previous lay-out.

Then i will have to create oval ones, for compensating the height difference of 350mm, from the maim layer to the shadow station.
Nice job to do in Autocad.

Wkr. Ruud M


The slope of the inner radius (9120) is always more than the slope of the outer radius (9125).
Best to use the inner radius for downward direction and the outer radius for upward direction.