agracer said:

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this is a good video about the "engineering" of the sub.

The most salient points are about Stockton Rush's comments about "pilot error" and "certification organizations". Stockton was an idiot.

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Fightin_Aggie said:

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agracer said:

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this is a good video about the "engineering" of the sub.

The most salient points are about Stockton Rush's comments about "pilot error" and "certification organizations". Stockton was an idiot.

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Good analysis but the knock on SpaceX for moving fast and breaking things like the David Rush ignores that Elon only breaks things when people are not involved. Elon has said that was one of the major flaws with the space shuttle because you were testing with people on board

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bthotugigem05 said:

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The very first launch of the Shuttle had crew members on it with no crew evac possibility once the SRBs fired up. I think that was Elon's point.

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NASAg03 said:

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The Fife said:

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I watched through it a couple of times and had to dig a little deeper

https://www.engineering.com/story/the-titan-tragedy-a-deep-dive-into-carbon-fiber-used-for-the-first-time-in-a-submersible

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A 2017 article in Composite Weekly describes the carbon fiber construction of the Cyclops 2 (later renamed as the Titan) as "alternating placement of prepreg carbon fiber/epoxy unidirectional fabrics in the axial direction" with "wet winding of carbon fiber/epoxy in the hoop direction, for a total of 480 plies."

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Building it this way, with no autoclave cure and I'm assuming no meaningful inspection for voids or porosity, FOD, wrinkles, ... is criminally dumb. Go for extra thickness but don't bother with ensuring there's a good bond because who needs that? Probably no attempt to scan the IML or OML for damage between dives either.

I'm surprised it didn't fatigue out before it finally did, but I guess in a way they did their fatigue testing with actual passengers inside and got a data point for what the life limit is.

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100% agree. Even more critical when fibers are in compression.

Tanks on space flight vehicles typically have a metal liner that is plastically deformed during testing (autofrettage), preloading the interface and reducing strain extremes, increasing cycle life. The liner also allows for autoclave use to remove air bubbles and voids. Even so, failures STILL occur due to voids between layers.

In the of the Titan, with no autoclave and hand-laid layers, a single void in the exterior and can result in high-pressure water getting pumped further into voids, finding low-pressure pockets to travel into, and gradually cutting into the polymer matrix. 5600 psi water finds a way. Waterjet cutters run at 10X that pressure, but 5600psi still does damage.

This process does weaken the structure, especially with cycling. Combine that with local fiber buckling, stress concentrations, and shearing from water pressure, and it's easy to see how this could fail.

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Elon fan here, but Challenger was STS-51 and Columbia was STS-107...so about 50 flights and 100 flights in to the program. Doesn't sound like the test phase to me.

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Ag83 said:

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First 4 flights had ejection seats for crew.

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BonfireNerd04 said:

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Ag83 said:

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First 4 flights had ejection seats for crew.

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For these first 4 "test" flights, there were only 2 crew members.

The ejection seats were removed for "operational" flights because it wasn't possible to provide them for an entire 7-member crew, and the commanders and pilots generally held the opinion that they wouldn't want the ability to eject if it meant having to leave others behind.

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JABQ04 said:

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I seriously doubt that. No pilot is going to abandon their aircraft while the rest of their crew can't bail out.

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JABQ04 said:

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I think the most logical comparison is bomber pilots who stayed in control of their ship long enough enough to give their crews times to bail out in WWII and other wars. At least one of our Aggie MOH recipients did this. While not the same as a space shuttle, these men knew what they were doing and what the likely outcome of them staying in the plane longer than their crew was. To be fair, none of them wanted to die, but they could have just as easily said something like we're going down and bail out, but willingly chose to stay in control of a burning and crashing plane to give others a chance to get out. They also knew that their own chance to escape safely was diminishing every second and the aircraft would no longer be stable for their own escape. I have a hard time believing a military pilot/NASA astronaut would yank the ejection handle and leave their crew and passengers to their fate. Those guys and girls aren't wired like that.

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Ag83 said:

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First 4 flights had ejection seats for crew.

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AgsMyDude said:

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Correct, Apollo never had ejection seats

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AgsMyDude said:

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Correct, Apollo never had ejection seats

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agracer said:

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this is a good video about the "engineering" of the sub.

The most salient points are about Stockton Rush's comments about "pilot error" and "certification organizations". Stockton was an idiot.

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eric76 said:

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There are reports that if you put a light to one side of the carbon fiber, you could see light on the other side from gaps and imperfections and the gradual damage to the carbon fiber.

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To assess the carbon-fibre hull, Lochridge examined a small cross-section of material. He found that it had "very visible signs of delamination and porosity"it seemed possible that, after repeated dives, it would come apart. He shone a light at the sample from behind, and photographed beams streaming through splits in the midsection in a disturbing, irregular pattern. The only safe way to dive, Lochridge concluded, was to first carry out a full scan of the hull.

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yawny06 said:

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eric76 said:

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There are reports that if you put a light to one side of the carbon fiber, you could see light on the other side from gaps and imperfections and the gradual damage to the carbon fiber.

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I posted the article earlier in the thread, but the person who said this was the engineer who got fired for raising concerns.

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To assess the carbon-fibre hull, Lochridge examined a small cross-section of material. He found that it had "very visible signs of delamination and porosity"it seemed possible that, after repeated dives, it would come apart. He shone a light at the sample from behind, and photographed beams streaming through splits in the midsection in a disturbing, irregular pattern. The only safe way to dive, Lochridge concluded, was to first carry out a full scan of the hull.

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https://www.newyorker.com/news/a-reporter-at-large/the-titan-submersible-was-an-accident-waiting-to-happen?mc_cid=3ccf735a10&mc_eid=9fa07cff91

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Burdizzo said:

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AgsMyDude said:

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Correct, Apollo never had ejection seats

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Apollo had rockets on the command module that were supposed to fire in emergency cases during liftoff if the CM were to jettison and pull the CM away from the rest of the rocket. It always seemed to me that if the Saturn launch vehicle failed it would happen so fast that escape system was kind of useless. Fortunately, they never actually needed it. The only astronauts to die because of Apollo were the three that died in the Apollo test on the ground.

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JABQ04 said:

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I think the most logical comparison is bomber pilots who stayed in control of their ship long enough enough to give their crews times to bail out in WWII and other wars. At least one of our Aggie MOH recipients did this. While not the same as a space shuttle, these men knew what they were doing and what the likely outcome of them staying in the plane longer than their crew was. To be fair, none of them wanted to die, but they could have just as easily said something like we're going down and bail out, but willingly chose to stay in control of a burning and crashing plane to give others a chance to get out. They also knew that their own chance to escape safely was diminishing every second and the aircraft would no longer be stable for their own escape. I have a hard time believing a military pilot/NASA astronaut would yank the ejection handle and leave their crew and passengers to their fate. Those guys and girls aren't wired like that.

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agracer said:

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AgsMyDude said:

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Ag83 said:

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First 4 flights had ejection seats for crew.

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Don't think Apollo 1 did.....

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he's talking about the shuttle.

And Apollo did have a crew escape system that would rocket the capsule away from the rest of the rockets stages, parachute land and allow the crew to, hopefully, live.

Apollo 1 is not even comparable though. They were testing, not launching.

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