edgeau wrote:Actually, after some similar advice elsewhere, I am in the process of making some curved pieces to go between the spars to get a torsion box effect.
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If you're making a conventional roof - interior plywood ceiling, roof spars with foam, then exterior plywood sheathing, then outer skin - it's hard to imagine getting any real-world advantages from adding curved blocking members. A torsion box is useful because it creates a flat, THIN surface that resists longitudinal warping. Your roof isn't flat. It's curved - hugely so. And unlike a true torsion box, your roof is "bounded" on four sides by the walls and floor. It can't really twist along its centerline by virtue of its geometry and boundaries, and once the skins are installed, it can't rack much, either.
Not trying to insult your intelligence. Just that I can't imagine all the hours it will take to manufacture curved blocking members that fit precisely between the roof rafters, and unless I'm way off in my analysis, I'd rather save you the hassle
Thoughts, anyone else?