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m463

> a big carbon-fiber pressure vessel at 5500psi

Other cars have these tanks, but full of flammable fuel, not just air.

Off the top of my head, the honda civic CNG (3600 psi)

https://en.wikipedia.org/wiki/Honda_Civic_GX#Specifications

the toyota marai (10,000 psi hydrogen)

https://en.wikipedia.org/wiki/Toyota_Mirai#High-pressure_hyd...

and probably the other cng or hydrogen cars.

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It looks like those tanks are 5-8kg? The Tesla's is apparently 250kg.

Hydrogen is 1/14th the density of air.

I thought carbon fiber wasn't good with pressure, hence OceanGate Titan implosion

Different forces: expansive (Roadster) vs compressive (OceanGate). This makes some logical sense since fibers/strands/ropes are good for tensile strength vs. compressive forces.

I guess this is the ultimate version of "you can't push a rope".

Professor Farnsworth: "Dear Lord! That's over 150 atmospheres of pressure!"

Fry: "How many atmospheres can the ship withstand?"

Professor Farnsworth: "Well, it's a space ship, so I'd say anywhere between zero and one."

SpaceX has been using carbon fiber pressure tanks for awhile. Rocket Labs has been using them too.

CF can make a fine pressure vessel it's just difficult to build and they require constant inspection that OceanGate didn't perform (and ignored evidence from their own monitoring system that the PV was responding differently to pressure after a hard bang it suffered when docking in one of the last few dives). SpaceX already has experience building the COPVs that Tesla is probably using and knows their limits pretty well though I don't want to be standing near one in a major crash either.

Some off piste skiers carry a carbon fiber canister with pressurized nitrogen gas, to inflate airbags from backpack in case of an avalanche. Carbon fiber is not that good with point pressure, but strong for evenly distributed loads.

At this point I look at wikipedia what happened to the submarine bamboozled mentioned. Ooops. Heh, the pressure of water is as evenly distributed as can be. Seems my background in watersports is not enough to moonlight in material engineering.

Submarine is trying to keep the pressure out, air tank keeps it in

oceangate isn't a good comparison.

carbon fiber is great in tension, i.e. a compressed air tank, or COPV

carbon fiber is much less great in compression, i.e. OceanGate

Also the OceanGate construction process was bad, even for carbon fiber, because the CEO didn't listen to actual engineers.

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