Comments by "" (@GWNorth-db8vn) on "Solar Eclipse Timer" channel.

"You can't push a rope" - my first year Statics teacher. He always did have a way of explaining things so we could understand them.
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Repeating trigger words doesn't count as thinking.
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More unknown material properties from using unknown techniques on an untested design. They might as well have tried that.
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"You don't get torsional moments underwater". On paper, where everything is geometrically perfect and never changes and the environment doesn't exist. Just like designing a bridge without giving any thought to wind, rust, or metal fatigue.
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They got a clear warning on a previous dive when some of the sensors started giving different readings than previously at the same depth and the difference became a consistent artifact. Something gave and changed the shape of the hull. That was enough to scrap it right there, but they just learned to accept numbers in the new range.
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@spybaz - The wing bends. One side, usually the bottom, is in tension and that's where the strength comes from. The top is in compression.
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The more I look at that dome, the more I wish I'd kept up my calculus. That's probably the most complex piece of engineering on the whole vessel. I'm almost surprised Rush didn't just sketch something on a napkin and insist it would work. The people who made it must have known the flat back was a bad idea.
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That actually seems like the most robustly designed and made part of the whole system. They're made to survive children rage-quitting and throwing them across the room.
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Bumps weaken the structure, too. It's a surface at an angle to radial and wants to push sideways and cave in. That's one of those torsional moments Rush said you don't get underwater. Bumps and ridges like it had make the whole cylinder want to twist and give it a head start toward collapsing like a squashed beer can.
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Any curve is better than a straight line.
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I'm a fan of air-spaced myself. No issues with leakage or oil going cloudy with age. A corrector plate wouldn't have to be thicker than your usual window glass, and it could be easily removable for cleaning.
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I have a big official NASA sticker with the meatball on one half and "Critical Space Item - Handle With Extreme Care" on the other. It's been on my telescope for years, and now I have to worry about lawyers seeing it. I know the hats with the simple NASA logo are alright. They sell them at the gift shop at KSC.
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I don't think the cylinder needed to actually fail. Bending inward in the center would put a lot of strain on the end joints, pulling the carbon fiber off the titanium. If it failed there, the inward shock wave of water would shiver the carbon fiber into shards. The design failed because of the wrong materials, and that caused the final failure of the materials.
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They make expensive motorcycle mufflers with carbon fiber cans.
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@allwrathnograpes - I think it comes down to Rush's arrogance again. He seems to have come up with bright ideas and refused to be persuaded by anyone or anything that it wouldn't work. Hard data didn't do it, and experts who disagreed with him were all nervous fuddy-duddies or making personal attacks. He knew a flat window wouldn't distort the image, so he wanted a flat window.
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@Agouti - I agree, after much doodling and massive headaches. I think it would take two lenses that can be adjusted in distance from each other and the inner face of the dome. The innermost one would have to be bigger than the viewport, and you could make things look closer if you wanted. You don't need correction unless you're at the bottom. Nothing to see on the way down anyway. To make it adjustable you'd need a mechanism like a Schmidt-Cassegrain telescope with one knob driving three jackshafts to move each lens evenly. Yup, a stretchy membrane across the back and filled with oil would probably be simplest.
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@ - Sub hulls go down to a small fraction of the depth a submersible does, and they have internal frames. No sub can reach the depth of Titanic.
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@ - A cylinder provides more internal volume than a sphere. Submarines have a completely purpose and needs than a submersible. Subs are expensive because of all the things that go inside them. The hull is just steel. That's the cheap part.
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@alexpyattaev - Spheres provide that volume in a shape that provides less useful room for humans and machinery. Cylinders can be made longer without having to make them also higher. Subs are more like 20 mm thick, and they're generally made of Y80 steel or an equivalent. The steel's fairly cheap. It's used for a lot of other applications. It's the machines that roll and form it that cost a fortune to own and operate. Massive equipment used for tiny volume production.
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@alexpyattaev - Numbers are rare, but 3/4 inch of Y80 is rumored to be standard for american hulls. They only go down to a thousand feet or so, about 400 psi external pressure.
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