Building an N scale helix.

[Anonymous]

I am considering using a small helix on an N scale layout.

I have seen a couple on the web recently, but no real details of how they were built. I designed one about 15-20 years ago which was realised in 1/2" ply, but that seems like something of an overengineering exercise. There are commercial units avialble in Europe, but maybe I can build one and save some money.

Anyone got some suggestions about doign this? COntruction techniqe etc?

John

[Anonymous]

Give us a few days to make sure it works.... We are using 3/8" ply and 1x4s. The plan is to use eight trapezoids per loop to avoid circular cuts. We will be laying at least cork if not track on the first loop this weekend, and then we'll know how things are coming together. It looks a bit hacked, but it feels pretty solid. We are trying to keep the construction simple and cheap, so no threaded rod or anything like that. We will keep you posted.

[Anonymous]

Thanks Jeff!
I was beginning to think nobody used helices! I found another on the net today:

http://www.railfan.net/railpix/railfan/floor_layout/

Which looks like it might be using masonite or something similar and a simple pine and dowel ladder arrangement for support.

I have seen the commercial units made by Noch in Europe, one dealer in Hamburg (I think ti was) had a nice setup but I didn't have a camera with me. This page shows the Noch unit:

http://www.ontrackscart.co.uk/graphics/noch_layout_boards23.htm

The idea of using trapezoids sounds good! Much easier to cut at least. I look forward to seeing some photoes maybe.

John

[dgwinup]

QUOTE: Originally posted by jdtoronto

Thanks Jeff!
I was beginning to think nobody used helices! I found another on the net today:

http://www.railfan.net/railpix/railfan/floor_layout/

Which looks like it might be using masonite or something similar and a simple pine and dowel ladder arrangement for support.

I have seen the commercial units made by Noch in Europe, one dealer in Hamburg (I think ti was) had a nice setup but I didn't have a camera with me. This page shows the Noch unit:

http://www.ontrackscart.co.uk/graphics/noch_layout_boards23.htm

The idea of using trapezoids sounds good! Much easier to cut at least. I look forward to seeing some photoes maybe.

John

The floor level helix looks good, but I would be worried about the thickness of the plywood. 1/4" isn't very thick. It's enough to support N scale with no problem, but it will be prone to warpage with humidity changes. Since the crossing members that support the plywood look to be 1x2", I think I would laminate a length of 1x2" under the plywood for structural ridgidity. Seems like there is plenty of room between layers of the helix. This looks like a good example to copy from with the addition of the extra support under the plywood.

The Noch helix is nicely made, but I think it's around $300 or more. Kind of expensive!

If you are going to use trapezoids instead of curved cut-outs, why not build the helix from 1x3 or 1x4 lumber? You could use metal brackets as splice plates underneath and not have a clearance problem. Of course, to get a smaller diameter, you will have to cut a lot of smaller pieces and use a lot of metal brackets!

Is there any way you can avoid the helix? Going around the room against the walls can accompli***he same thing, give you a longer mainline run, allow for scenery instead of a massive 'tunnel' to hide the helix and allow for a shallower grade. Just a thought.

Darrell, thinking all the time, and quiet...for now

[Adelie]

I built two out of two 1/4" plywood layers. I drew a bunch of the arc sections on one half a sheet (4x4), then clamped the other 4x4 section to that and cut the arcs. I then glued just less than a complete circles worth, baking sure to stagger the joints so the upper and lower plys were joined together in different places. Each "near" circle had a 1/4" "tongue" that attached to the next "near" circle.

To suppor the levels, I used 3/4" square dowels that were screwed into the lower level before if was put into place. I think I was using around 1-7/8" height dowels.

So, the lowest level went into place with the support dowels for the next level attached. I test fit the second level, staggered the location of another set of dowels )to support the next level) and attached them. Then I bolted the tongues of the two levels together and screwed the second level to the dowels supporting it from the first. I repeated the process until I had the helix completed. It turned out to be a relatively simple process.

I don't know if that is the best method or not, but it worked twice for me.

[Anonymous]

John,

I built a helix earlier this year. Click on the link in my signture and scroll halfway down to see some photos of it. I went the traditional 1/2 ply route....Didn't take that long..The idea was worse than doing it. There was an article in RMC last Nov or Dec that describes the octagonal helix design that is mentioned earlier in the thread...

[Anonymous]

HI John

I to have been looking for plans for building a helix, it seems to be one of those "easier than it looks", type of project, thanks for the links and please keep me informed if you do find a plan......

Thanks guy for your link, you have quite an empire.........

Mike....

[pcarrell]

I think this is something like what Adelie was talking about. For N scale you could use lightweight materials like say 1/4 inch luan, if it was well supported, and I don't think you'd have any trouble. Just use vertical supports every 6 or 8 inches I would think. You could even cut down on the vertical separation of the laps by using thin strapping metal to support the layers.

Anyways, check this out;

http://anemrr.ejpj.ws/Seq02.htm

Hope this helps!

[Anonymous]

Thanks everybody for the comments and links so far!

I haven't been getting MR for that long, I will have to see if one of the folk at my LHS have a copy of the earlier article.

The link pcarrell gave is interesting, but like many others uses a relatively thick base. Somewhere I have seen a helix for N scale made using foamcore, but I can't find the link to it again.

I might just have to try building sopething and see what the outcome is!

John

[pcarrell]

I agree that it is a bit "over-engineered" for your puposes. That is why I suggested somewhat lighter materials using the same basic idea. I think 1/4 inch luan half circles, overlapped halfway and glued together, supported by verticals with strapping metal crossbraces to keep it thin so the grades don't get too bad, might be a good solution.

I think if you use foamcore you might find that the roadbed is so think (if it's going to be able to support itself well) that if you are going to have a manageable grade then your radius would have to be very large. Maybe you are abundantly blessed with space and this is not a problem, I don't know. That was just my first thought.

[Anonymous]

QUOTE: Originally posted by pcarrell

I agree that it is a bit "over-engineered" for your puposes. That is why I suggested somewhat lighter materials using the same basic idea. I think 1/4 inch luan half circles, overlapped halfway and glued together, supported by verticals with strapping metal crossbraces to keep it thin so the grades don't get too bad, might be a good solution.

I think if you use foamcore you might find that the roadbed is so think (if it's going to be able to support itself well) that if you are going to have a manageable grade then your radius would have to be very large. Maybe you are abundantly blessed with space and this is not a problem, I don't know. That was just my first thought.

I am trying to find some figures for the modulus of elasticity for plywood and for foamcore. I could set up and measure it of course, but I am at my desk for a few days not in the lab. Our experience with foamcore has been rather interesting. It's breaking load is, of course, not particularly high. But before it breaks it is more rigid than plywood.

I am trying to understand the fascination, or maybe fixation, with plywood.

Do we buy it because it is cheap?

Because as far as I can determine, form a pure performance viewpoint, not taking cost into account, products like foam-core, gator-board, core-flute (plastic corrugated cardboard look-alike) and foam products such as those from Woodland Scenics and Noch (Germany) offer far higher performance and much lower weight.

Of course, I should emphasise that I consider materials like MDF, masonite (hardboard), chipboard and the like to be unsuitable for model railroad use.

John

[Adelie]

The link pcarrell provided was very similar to what I was talking about....with the layered plywood being right on. The only difference was mine is supported with square dowels used as posts between the horizontal surfaces of the layers. I have a 24" radius single track and an 18.5" radius version. Using the 1/2" "sandwich" I put a pair of dowels in every 8-12 linear inches for support. Both are more than strong enough for the immense tonnage of N-scale and would work for HO, I'm sure.

I stick with plywood because it is strong, durable, I have the tools to cut it and the fact that weight is not a concern for me. Others have used foam for layouts with success (I have not heard of it used for a helix, but I know there is a company offering a helix made of plastic). All other things being equal, it depends on what one has used successfully before and is comfortable with.

[Anonymous]

Adelie;

Thanks for the additional comments. Your radii are somewhat larger than I am planning. Your Rmax is about double mine! I am only planning about 200mm for the inner and 250mm for the outer ( um, about 8 and 10 inches ) because I am using small rolling stock. The loco is maybe 2 inches. The freight wagons are barely any longer (most are 57mm long) - so I can get away with a TINY radius! I may go larger, just so I can keep the grade lower.

I suppose I keep throwing in the ideas about change because that is a big part of what people pay me for. Many times we have found new construction techniques or radical approaches to our design work, and ultimately not a few patents, by saying "why". It is said by some of my contractors that if they don't ask why often enought hey will be asking why they arent getting any more work from me.

As for the ease of working it, I totally understand!

Before I left Australia I had a table saw, band saw, scroll saw and all the power tools you could want and a workshop to put it all in. Not to mention the lathe, small mill, drill presses, gas, arc and MIG welding etc. But I also had a place to put everything, I had a 40ft x 20ft workshop. Here? Well, I suppose I have about 13ft x 8ft for ALL my workshoip activities which includes art and craft for my wife and daughter. Hence pretty much EVERYTHING is contracted out, which is fine when clients are paying but a pain when I want something for myself. So I get small 'favours' done for me by the jobbing shops I use.

My laser cutting guy said he can do ply, so when I have some tiem I will do a set of drawings and we will see what we can do with some 6.5mm ply. Might just take the same drawings and run a sheet of foamcore then compare the two.

Many thanks for the ideas,
John

[Adelie]

John, let us know the results of any comparisons. I'd like to think I have built my last helix, but who knows for sure. I've stopped work on my layout since there is about a 50/50 chance we will be moving next year, but my current brainstorm is to remove the two helix units fully built with the hope of reusing them as they are. The reason for my relatively large radii was simple (not extremely scientific) - the space was there.

I've never quite understood why people get unnerved at somebody asking "why." In some cases, I do understand it is because they don't have a reasonable answer to the question. I'm in the System Engineering business, and that one question can lead to either better techniques/ideas or at least ascertain that the current ones are still relatively effective.

Of course, there is the old legend about the Philosophy professor who gave an essay final exam consisting of one question. He simply went to the board and wrote "why?" Several students wrote for the entire exam period, providing an answer of tens of pages. They all got Bs for their effort. One student simply wrote a couple of words and left. That student got an A. The winning answer: why not?

[pcarrell]

Do post any test results please. I will probably be building another helix before long. I'm moving to a new house soon and I think I'm going to start from scratch. [8D]

This foam thing might be interesting........

[Anonymous]

Haven't had time to even go to the shop and get some foamcore, but I was prowling the internet last night and foudn this!

http://www3.telus.net/HarrisFamily/MidViews.htm

A small N scale helix, on a ONETRACK type module from a guy out in British Columbia - built with foamcore.

John

[Anonymous]

Anybody consider pocket screws to join helix sections? With a dab o' glue on the joint ... really strong connection ...would virually elininate a lot of the under bracing etc..

[pcarrell]

If you've got the couple of extra inches, this is a nice way to make the height between decks adjustable so you can fine tune it;

http://www.siliconvalleylines.org/benchwork/helix.html

Sorry, it uses plywood again......