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#31
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Is the 787 a failure ?
On Sat, 26 Jan 2013 06:46:22 -0700, Daryl
wrote: On 1/26/2013 6:00 AM, Jim Wilkins wrote: "Daryl" wrote in message ... It sounds like they are being overcharged. That is prevented by a simple card addition that prevents it on only of overcharging but undercharging. Easy fix. Daryl The Lithium medical and electric vehicle packs I worked on were controlled by ICs that monitored and recorded individual cell voltage and overall charge and discharge current. Those are point measurements that are easy to do. What's harder is detecting unexpected hot spots away from the temperature sensors. Minor differences (improvements) between the acceptance sample and production devices can change heat flow paths. http://www.mpoweruk.com/lithium_failures.htm I can see a problem that is being addressed in Electric Vehicles. Heat and cold. On an electric vehicle, getting the battery too cold will (not can) result in a degrading of the performance of the cells. The fix is adding an "Electric Blanket" to keep the battery warm (not hot). The residual power required by the blanket is negligible. You get back much more than you lose. Heat. I can see problems with the Lipo batteries. The battery they chose is one that is not on the list of Vehicle safe batteries. It is the best, the highest output but with it comes problems. Lithium cobalt oxide (LCO), for vehicles, is listed as unstable compared to the rest. It's very suspeptable to heat. And sitting on the ground running up on a hot day, the battery compartment will sky rocket in heat. The safest to use is the lead acid but it's very short lived in this application. To use any Lipo battery, it requires a cooling and a heating system to keep the battery at an optimal temperature. The LCO is just the worst of the lot for overrunning (catching fire, generating Oxygen when it burns) than any other Lipo battery. The Fix? Get rid of the LCO and temperature control the battery compartment. Even a Lead Acid doesn't like excessive cold or heat. But it won't turn into a major oxygen fire. Sometimes, newer isn't better. But the various other Lipo batteries are safer than the LCO which has a proven track record of burning. Lead acid is and has for quite some time been a "non-starter" for the application - for good reason.Nicads have been the standard for decades - and have their issues as well Lithium iron would be a better choice . BTW, the LCO isn't the cheapest by far. The LipoMG battery is the cheapest but it has a low service charge rate. The Lipo4 has a decent service rate and is what is primarily used in various vehicle applications. But, maybe, the old Lead Acids may be the way to go on this one. They are the most stable and the most safe if you keep them in a wide range of temperatures. Newer isn't always better. Daryl |
#32
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Is the 787 a failure ?
On Sat, 26 Jan 2013 20:56:43 -0500, clare wrote:
On Sat, 26 Jan 2013 01:42:01 -0600, "Mr.B1ack" wrote: On Fri, 25 Jan 2013 22:21:55 -0600, F. George McDuffee wrote: When you want it really really bad, that's generally how you get it... ----------------------- On Fri, 25 Jan 2013 20:54:55 -0600, "Mr.B1ack" wrote: snip Now from a business point of view however ... snip These URLs may be of interest. If an emergency is defined as an event that was unanticipated in occupance and limited in duration, clearly this is no emergency. That's TECHNICAL ... "legal" ... has NOTHING to do with how potential passengers should act or react. Passengers are convinced the 787 is a death-trap. That's ALL it takes to destroy it. You are convinced passengers are convinced. There have been no deaths, no injuries, and only limitted damage to this point. A minor tweek will likely solve the battery problem. It appears to be a problem with the APU not knowing how to handle Lithium batteries, as the problem occurs when on the ground with the APU running the system. I love it when people who have no ****ing idea what's going on, make **** up like "a minor tweek will fix it". |
#33
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Is the 787 a failure ?
Marvin the Martian wrote: I love it when people who have no ****ing idea what's going on, make **** up like "a minor tweek will fix it". Why? Just because that's what they said when they took you to the veterinarian to have you neutered? |
#34
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Is the 787 a failure ?
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#35
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Is the 787 a failure ?
On Sat, 26 Jan 2013 12:30:42 -0800, Transition Zone wrote:
On Jan 25, 9:54Â*pm, "Mr.B1ack" wrote: Strictly speaking, the 787 is not an engineering failure. Like anything complex and new it has a few issues. So far these issues haven't caused any fatalities. But, the then-new EU Airbus airliner (A320) did have mostly fatalities on an opening day mess-up, back on June 26, 1988, at Mulhouse-Habsheim Airport. Airbus's A380 had terrible delays, too. Irrevelant. It did not acquire the REPUTATION for being dangerous. That's all-important. That's all that counts. The 787 is *done*. |
#36
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Is the 787 a failure ?
On Sun, 27 Jan 2013 00:51:59 -0500, Michael A. Terrell wrote:
Marvin the Martian wrote: I love it when people who have no ****ing idea what's going on, make **** up like "a minor tweek will fix it". Why? Just because that's what they said when they took you to the veterinarian to have you neutered? Wow, you're clever. You must know everything given you have such a wit. No, the point being that NO ONE knows what the problem is. If it was a "minor tweek", they would have fixed it after the FIRST fire. |
#37
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Is the 787 a failure ?
On 1/27/2013 2:19 AM, Mr.B1ack wrote:
Irrevelant. It did not acquire the REPUTATION for being dangerous. That's all-important. And also wrong. The average airline traveler has no clue what model plane they are flying in. That's all that counts. The 787 is*done*. Nonsense. It's barely entered operation, and it's way too early to make that kind of judgement. This is a totally new plane working through the inevitable kinks. If history serves as any guide, we will be flying in 787's and it's follow on models for many decades to come. |
#38
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Is the 787 a failure ?
In rec.aviation.piloting Mr.B1ack wrote:
On Sat, 26 Jan 2013 12:30:42 -0800, Transition Zone wrote: On Jan 25, 9:54Â*pm, "Mr.B1ack" wrote: Strictly speaking, the 787 is not an engineering failure. Like anything complex and new it has a few issues. So far these issues haven't caused any fatalities. But, the then-new EU Airbus airliner (A320) did have mostly fatalities on an opening day mess-up, back on June 26, 1988, at Mulhouse-Habsheim Airport. Airbus's A380 had terrible delays, too. Irrevelant. It did not acquire the REPUTATION for being dangerous. That's all-important. That's all that counts. The 787 is *done*. Utter nonsense; The average person doesn't have a clue there is any problem as they don't read those little backpage articles about equipment problems. Now, if one had burned up in flight killing a couple of hundred people, then they would have noticed. The recent in flight engine lightening strike and fire with no casualties has gotten far more press than 787 battery issues. snip idioitic crossposts |
#39
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Is the 787 a failure ?
On Sat, 26 Jan 2013 23:29:30 -0600, Marvin the Martian
wrote: On Sat, 26 Jan 2013 20:56:43 -0500, clare wrote: On Sat, 26 Jan 2013 01:42:01 -0600, "Mr.B1ack" wrote: On Fri, 25 Jan 2013 22:21:55 -0600, F. George McDuffee wrote: When you want it really really bad, that's generally how you get it... ----------------------- On Fri, 25 Jan 2013 20:54:55 -0600, "Mr.B1ack" wrote: snip Now from a business point of view however ... snip These URLs may be of interest. If an emergency is defined as an event that was unanticipated in occupance and limited in duration, clearly this is no emergency. That's TECHNICAL ... "legal" ... has NOTHING to do with how potential passengers should act or react. Passengers are convinced the 787 is a death-trap. That's ALL it takes to destroy it. You are convinced passengers are convinced. There have been no deaths, no injuries, and only limitted damage to this point. A minor tweek will likely solve the battery problem. It appears to be a problem with the APU not knowing how to handle Lithium batteries, as the problem occurs when on the ground with the APU running the system. I love it when people who have no ****ing idea what's going on, make **** up like "a minor tweek will fix it". When you look at the complexity of the APU unit, it WILL be a relatively minor tweek. |
#40
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Is the 787 a failure ?
wrote:
... When you look at the complexity of the APU unit, it WILL be a relatively minor tweek. ... I don't think replacing the batteries with a safer, heavier technology and redesigning/recertifying the electrical systems of the plane can even be called a "tweak," let alone a "minor tweak." | | MIT Professor: Battery Fix Could Ground 787 Until 2014 | ... | In a nutshell, Sadoway thinks that Boeing needs to monitor | the temperature and cool each of the eight cells of the | 787's lithium-ion battery or switch to an older battery | technology that has a far better safety record -- nickel | metal-hydride (NiMH). | | If Boeing opts to substitute NiMH for lithium-ion, | certification could result in delays of up to a year -- | effectively grounding the 787 until 2014. | ... | When Sadoway got a look at the lithium-ion battery used in | the 787, he was surprised by "the seeming absence of a | cooling apparatus." | ... http://www.forbes.com/sites/petercohan/2013/01/27/mit-professor-battery-fix-could-ground-787-until-2014/ --bks |
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