Rectangular build space: X axis on the long or short side?

On a CoreXY with a build surface around 20x40cm, would it be best having the X-axis the on the long or the short side?
On the short side there will be the two Y beams to support shake and X would be rigid from being short.
Most of the motion will be done in the Y direction though, so there might be a point in not lugging along the whole X axis as much? (rather having the carriage sip along the larger distance on a long X axis?)

Not sure what to think, if anyone have some insight or opinion it would be appreciated Thanks for reading.

Edited 1 time(s). Last edit at 09/29/2016 10:31AM by orea.

My twopence worth. The x axis usually consists of just the hot end but the y axis has the hot end plus the x axis rails. Therefore the y axis will be heavier than the x axis so it'd make sense for that to be the shorter axis. On the other hand, having the x axis short would mean the rails are not so long and will therefore be stiffer. That will also make the y axis a bit lighter. Take your pick.

Thanks for chiming in, indeed, they options possibly outweight each other.. The carriage will be light (bowden for some speed) but even that factor don't help decide, as the benefits and inconveniences remain. hmm.

Edited 1 time(s). Last edit at 09/29/2016 12:38PM by orea.

Long supported Y axis would be my pick.

If you ever intend to put more than one extruder on it, make the X axis the longer one. Otherwise I'd make the Y axis longer.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

It will be a low cost PLA machine for my brothers art, so then long Y axis it is.
The bed will be something like 20x40 or even 15x50, so probably two beams are better for support of the long side.
Will probably use v-slot rollers on Y to keep price down, and reused smooth-rods for X. Speed and cost are higher priority than precision, the (finished) pieces he want to make will be 1-2m large
Thanks for the opinions, will post a pic when (if) it happens

Edited 1 time(s). Last edit at 10/04/2016 06:55AM by orea.