Dome build: Shutters: Drawer slides or skate wheels?

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The shutter doors of a dome could be thought of as arc-shaped levers nearly 7' long and 5' high. They are effectively pivoted at their lower support point. Because the shutters are "leaning" away from the base a sideways force is applied at the top support point. If drawer slides were used at the top then they ought to be rotated to match this lateral force component. Drawer slides are usually only subject to vertical loads.

Or not? The separation of the slides can be thought of as having both vertical and horizontal spacing.  If leverage was present it would surely have to work both ways. From top to bottom and bottom to top. So the slides must equally share the vertical loads. There being no real lateral loads involved at the top as occurs with a ladder leaning against a wall.

In the case of a ladder the wall is considered frictionless. Some taller ladders are even supplied with vertical wheels at the top to ease erection. Which proves that only lateral loads need to be resisted. All the weight on such a ladder can be considered as being at the bottom and resisted by the ground. Though the actual geometry of forces changes when a person climbs higher.

The most obvious alternative to drawer slides, for supporting the shutters/doors, might be inline skate wheels running in channels. Aluminium is cheap and won't corrode. Nor will plastic cable conduit but may be more flexible than aluminium.

The downside of this arrangement is the exposure of the open channels when the shutter doors are closed. Snow and ice are very likely problems in northern climes. Given our winter climate that would mean being unable to open the shutters because the channels would be full of ice.

Drawer slides are telescoping from the minimum length. So always remain within the structure of the shutters. Giving a sleek, 'stealth' appearance to the shutter opening system. Enclosure of wheel channels in larger protective covers will always be visible as extensions of the doors whether open or closed.

After endless [internal] discussion I have opted to buy 2 pairs of drawer slides in 40cm length and 50kg load capacity, online. I'm hoping the load bearing figure is cumulative. It will need to be!

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