# Need ideas for Helix



## edsimmons

I'd like to build a 2 track HO helix and was wondering if you guys had any plans you'd like to share. Playing around at work I cam up with this, keep in mind this is just a digi prototype.

A few questions.
How wide of a deck for 2 tracks?
How much space between the deck and the ceiling?
What is the best radius (I'm guessing the bigger the better)
What the best pitch (1" per revolution)
What's the best material and thickness (0.25" Plywood or OSB?)

I found a ton of nice helix's on You Tube and a lot of those use all thread to connect the levels, is that necessary to adjust the pitch? Those appear to be hanging for the ceiling or similar structure is that the best way to do it?

Here is my basic idea.



















Thanks for any input!
Ed


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## shaygetz

Are you ever hitting the ground running...

There's plenty out there on helixes, I prefer all-thread for its ease of adjustment. You'd want at least a 3" rise for every revolution to clear your trains. OSB works in a low humidity area but I would stick with plywood. Curves = wider is always better...the wider the radius, the easier the grade. With track on 2 1/2" centers, your roadbed will run about 5-6" wide.


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## edsimmons

shaygetz thanks for the info.

Here is what I'm thinking and your comments confirm that I'm on the right track.

3" Pitch

47.5" OD so I can get two "Rings" from one 4' x 8' sheet if I use a 0.25" router bit. I think Plywood (0.25") will give a better edge finish once sanded, so that's cool

6" Deck

Here the newest rev. 4' x 6'








(I should really try to get some work done)

Thanks!
Ed


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## shaygetz

Looks great...looking forward to finished pics.


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## tankist

i would do minimum radius of 22" with outside line being 24". with 4" (don't forget the thinness of the plywood and the track itself stealing vertical clearance) the rise each turn it comes up to ~2.7% for the outside and almost 3 for the inside unless i'm horribly miscalculating something. as you see less of a radius will introduce even more significant grades + tighter curvature making the grades even harder to negotiate 

which software do you use to model this?


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## Reckers

Man, if I tried to do a helix with my S scale, it would eat up half a room!:laugh::laugh::laugh:


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