Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Elon Musk: Boeing 787 battery fundamentally unsafe

flightglobal.com

Post reply on HN
Print view View original

81–90 of 253 posts

Re: Elon Musk: Boeing 787 battery fundamentally unsafe

#81

Post by commandar »

robomartin wrote: post #68

While I can't dispute anything that is being said I think it is unfortunate that this is playing out the way it is. I can't dispute it because there's virtually no reliable publicly-available information on the design of this battery pack. I think it is unbecoming of an engineer or scientist, particularly of prominence, to voice such opinions without access to design data from the source. Before I could even begin to…

>unless there was something so obviously wrong with the design that a conclusion was inescapable

Isn't that exactly what both Musk and Professor Sadoway are suggesting in the linked article?

Re: Elon Musk: Boeing 787 battery fundamentally unsafe

#82

Post by jessaustin »

"I design a cell to not fail and then assume it will and the ask the next 'what-if' questions," Sinnett, [Boeing's 787 chief project engineer] said. "And then I design the batteries that if there is a failure of one cell it won't propagate to another. And then I assume that I am wrong and that it will propagate to another and then I design the enclosure and the redundancy of the equipment to assume that all the cells are involved and the airplane needs to be able to play through that."

OK, maybe part of this is bravado, and it seems that the failure of one cell certainly has spread to another, but so far at least no plane has crashed as a result. I think Boeing's engineers should get some credit for that? One could imagine worse results than we've seen, especially in fields of engineering that don't have aviation's safety practices.

Re: Elon Musk: Boeing 787 battery fundamentally unsafe

#83

Post by willis77 »

robomartin wrote: post #68

While I can't dispute anything that is being said I think it is unfortunate that this is playing out the way it is. I can't dispute it because there's virtually no reliable publicly-available information on the design of this battery pack. I think it is unbecoming of an engineer or scientist, particularly of prominence, to voice such opinions without access to design data from the source. Before I could even begin to…

Furthermore, hindsight is 20/20. It's easy to rush in after the fact and make up reasons (even if those reasons are legit) to explain what is retrospectively obvious. Where was this warning before the incidents? As you stated, it's completely opportunistic and out of line to make this kind of claim without the due diligence.

Re: Elon Musk: Boeing 787 battery fundamentally unsafe

#84

Post by hnwh »

commandar wrote: post #81
robomartin wrote: post #68

While I can't dispute anything that is being said I think it is unfortunate that this is playing out the way it is. I can't dispute it because there's virtually no reliable publicly-available information on the design of this battery pack. I think it is unbecoming of an engineer or scientist, particularly of prominence, to voice such opinions without access to design data from the source. Before I could even begin to…

>unless there was something so obviously wrong with the design that a conclusion was inescapable Isn't that exactly what both Musk and Professor Sadoway are suggesting in the linked article?

Sadoway is one of the world's leading geniuses in this field.

Re: Elon Musk: Boeing 787 battery fundamentally unsafe

#85

Post by cpleppert »

jessaustin wrote: post #82

"I design a cell to not fail and then assume it will and the ask the next 'what-if' questions," Sinnett, [Boeing's 787 chief project engineer] said. "And then I design the batteries that if there is a failure of one cell it won't propagate to another. And then I assume that I am wrong and that it will propagate to another and then I design the enclosure and the redundancy of the equipment to assume that all the cells…

>>but so far at least no plane has crashed as a result. I think Boeing's engineers should get some credit for that?

There are a grand total of 49 planes total that have been produced and the plane has been in service for little over a year. The fact that no plane has crashed tells you nothing statistically about the safety record of the design.

The fact that aviation has a great safety record is MORE reason to worry about any issue, not less. Modern commercial planes are expected to fly for decades over tens of thousands of flights. Even a small issue that is incredibly unlikely is too dangerous when compared to the great safety record of existing airplanes.

Re: Elon Musk: Boeing 787 battery fundamentally unsafe

#86

Post by djt »

martinced wrote: post #31
djt wrote: post #8

Earlier quoted context omitted.

no doubt Boeing know that even if the batteries smoke and fail they wont be a threat to safety, but Musk has a better handle on marketing. If there is smoke on a plane or car people expect the worst, regardless of if it is actually a safety issue.

From my limited experience with smoke in cars, sadly they often turn to fire. Because, you know, like the first humans that did create fire, very often when a fire starts there's smoke... I've seen a Saab in which the ashtray started to smoke and then before we could pull out (on the highway) the dashboard had flames and started to melt. And I've seen a very nice and shiny Porsche 911 Carrera model 964 whose alternat…

yes in a Petrol car there is a problem with smoke = fire. My whole point is that smoke in a petrol engine usually means something as either caught fire etc. Smoke in a Battery compartment may or may not.

Is it a safety issue? Probably, but not definitely. Do the general public have a problem with smoke on a plane? Hell yes.

Our experience with traditional cars and planes is that where there is smoke there is fire. That may or may not be true with the batteries, I dont know but I do know that Boeing do a LOT of testing, so would be suprised to see a plane go down due to these problems.

I believe the cars you were talking about were completely submerged in sea water and then caught fire. Presumably any car or plane submerged in sea water will get written off which is probably why they dont worry too much about it.

Re: Elon Musk: Boeing 787 battery fundamentally unsafe

#87

Post by aptwebapps »

eduardordm wrote: post #9

Elon seems to really want to get involved in this. Make no mistake, Boeing and SpaceX are fierce competitors for government contracts with very dubious selection processes. I'm saying this because he is a businessman, not an engineer. He seems to be getting a lot of information about the 787s batteries inner workings when the number of airplanes and suppliers are very limited. Edit: I'm not trying to be cynical, but…

He did offer his help initially, although that may have been a political move as well.

Re: Elon Musk: Boeing 787 battery fundamentally unsafe

#88

Post by cpleppert »

chernevik wrote: post #67
starpilot wrote: post #63

Earlier quoted context omitted.

I'm an aeromechanical engineer, not an electrical one, but I suspect the fewer-cells design was chosen to save weight. Many unconventional design decisions in aerospace (everything with holes, novel materials which trickle down to cars and golf clubs) are driven by the need to reduce weight.

These systems replaced hydraulics for surface control, right? On a weight advantage? Making good on a decision like that is exactly what confirmation bias is all about.

The hydraulics are controlled exactly the same as any other fly by wire aircraft like the 777 or a modern airbus. The computer takes the pilot inputs and combines them with a flight computer that controls electric motors which move the flight surfaces with hydraulics.

The big increase in electrical supply (4x over the 777 i believe) is the result of the bleedless air architecture that boeing chose. There was a big push by boeing to make the system work as it was a selling point for the public and carriers. I think that decision didn't receive the scrutiny that it probably should have.

Re: Elon Musk: Boeing 787 battery fundamentally unsafe

#89

Post by Spooky23 »

jessaustin wrote: post #72
itp wrote: post #65

Earlier quoted context omitted.

Sounds like you only know people with Civil PEs, then. There are different examinations and qualifications for different disciplines. Source: my wife is a Naval Architecture PE.

Yeah that's the only kind of PE I've met. As a profession they do not impress. These guys are incapable of imagining anything they haven't done before a hundred times, let alone doing it and putting their seal on it.

Generally speaking, you don't want creative processes for the construction of overpasses, highways, and building construction. You want something that is structurally sound, safe for the application in question, and of a design suitable to being bid on by multiple contractors.

Re: Elon Musk: Boeing 787 battery fundamentally unsafe

#90

Post by btilly »

Retric wrote: post #80
bigiain wrote: post #54

Earlier quoted context omitted.

"Tesla's /cells/ are also "fundamentally unsafe", but they make the /batteries/ as safe as possible." While it's certainly true that the Li-ion chemistry used in the Tesla's batteries are flammable, keep in mind the current common alternative to those potentially burning cells is carrying round a metal or plastic tank with 10 or more gallons of gasoline in it. If there weren't a 100+ year history of people doing just…

Gasoline is not all that dangerous in the vast majority of failure modes. Li-ion is both corrosive and easier to set on fire which is a real issue for hybrids and aircraft.

Vast majority, yes. But I've seen failure modes where it was dangerous on more than one occasion.
Post reply on HN