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Is the 787 a failure ?



 
 
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  #191  
Old March 22nd 13, 05:15 PM posted to rec.aviation.piloting,rec.crafts.metalworking,rec.aviation.military,talk.politics.misc,alt.society.labor-unions
GunnerAsch
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Posts: 5
Default Is the 787 a failure ?

On Fri, 22 Mar 2013 12:40:50 -0000, "Keith W"
wrote:

GunnerAsch wrote:
On Fri, 22 Mar 2013 09:23:17 -0000, "Keith W"
wrote:


The conventional Batteries are sometimes called Sealed Lead Acid
Batteries but they are actually AGM batteries.

Modern passenger aircraft normally use Nickel Cadmium batteries


Why havent they converted over to NmH?


They have a relatively high self discharge rate and can lose
up to 20% of the energy stored in the first 24 hours. This is
acceptable for hybrid vehicles where the battery is primarily a
temporary buffer to capture the energy from regenerative
braking but not good for a system intended to initiate an
aircraft startup sequence after a week in the hangar.

Keith

Thats not true anymore. Since Sanyo developed the Enerloop NiMH
battery..they are being shipped charged from the factories. All the
makers are using the new tech and have been doing so for at least 3
yrs. Ive got NiMH batteries that I only need to put on the charger
ever 6 months, just to top them off.

Gunner

  #192  
Old March 22nd 13, 05:39 PM posted to rec.aviation.piloting,rec.crafts.metalworking,rec.aviation.military,talk.politics.misc,alt.society.labor-unions
Keith W[_4_]
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Posts: 39
Default Is the 787 a failure ?

Jim Wilkins wrote:
"Mr. B1ack" wrote in message
...

Not interested in burning to death over the Pacific ....

Better to fall into the South Atlantic because the Airbust didn't
inform the pilots that it had stalled.


Actually it did, they simply chose to disregard the stall warning
that sounded continuously for 54 seconds and the stick shaker.

Keith


  #193  
Old March 22nd 13, 05:49 PM posted to rec.aviation.piloting,rec.crafts.metalworking,rec.aviation.military,talk.politics.misc,alt.society.labor-unions
Keith W[_4_]
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Posts: 39
Default Is the 787 a failure ?

Daryl wrote:
On 3/22/2013 6:09 AM, Keith W wrote:

Battery energy density MJ per kilogram

Lithium-ion battery 0.720
Alkaline battery 0.671
Nickel-metal 0.28
Lead-acid battery 0.17


The reason the AGM isn't used in larger applications is that it cannot
be recharged as it is being discharged.


Hmm ISTR that my car alternator can charge the battery and
run the lights at the same time so I'd love to know what scenario
you had in my mind there

You left out a slew that use
Deep Cells.


Feel free to add them in.



IT does the job if you keep it over 50% just like clockwork and
can last at least 2 to 5 years without going below 50% charge if you
keep them above freezing and below 100 degrees (the same as the
Lithiums). I use AGMs on a daily basis and my battery provider says
I am the hardest on batteries he's ever seen. I am getting ready to
do another build that uses the heavier Deep Cell which is designed
to put up with my punishement. But the AGMs are more rugged than
the Lithiums that I also use.

Nacads also work but for about one run into town before they
overheat. Ever seen a Nacad blow up? IT's pretty anticlimatic. They
burst and make a mess out of everything around it. And it's
caustic. Same goes for a Lithium except they will go into flame
and feed the flame until all the liquid is used up. I have never
had a case break open on an AGM. I've crashed em, dump em, drop
em, used them for Rocky Mountain Offroad, and more.

I can see that the Deep Cell Sealed Lead Acid should be as tough and
have a longer run time but they are twice as heavy.


Which is something of a problem for aircraft


Just leave out that 1 six pack of Tomato Juice to make up the
difference. It's not a real problem where an extra 10 pounds is
really going to make a difference for something the size of the 787. An
added 10 pounds for safety sake is very important.



Its going to be a lot more than 10 pounds.



The lifespan of
the Deep Cell the way I use batteries should be as high as the
Lithium and cost less. But the weight means only my 3 wheelers will
use them. They just don't make 10 to 15 amp deep cells. But they
do make a very solid 35 amp at twice the weight and size of a 12
amp AGM. I am just not sold on Lithiums and I am certainly not sold on
Nicads. The Airline Aircraft Industry can use the AGMS and have
less problems, almost the same run time as the lower Lithium Mag
batteries and save a bunch of money.


Airbus use NiCads ,the Boeing 737, 747 (pre-800) and 777 use NiCads
, they disagree
with you.


Nicads are old technology. The AGM batter is much newer. When they
were designing the 737, 747 and 777 the AGMs weren't available. Single
Airplanes use the AGMs and that is more critical for weight
and safety than the big birds are.


AGM batteries have been around for at least 25 years and Boeing
have used them in military aircraft includng the AV8B so that
idea wont fly. They were certainly around when the 777 was
being designed.

I use all these batteries in transporation every day. I am a dealer
in the AGMs and the Lithiums as well as the motors and kits. I can
also get you a good deal in Deep Cells but the shipping would be a
killer.


I can buy them locally and have done so for use in towed caravan
installations.

Keith


  #194  
Old March 22nd 13, 05:57 PM posted to rec.aviation.piloting,rec.crafts.metalworking,rec.aviation.military,talk.politics.misc,alt.society.labor-unions
Keith W[_4_]
external usenet poster
 
Posts: 39
Default Is the 787 a failure ?

GunnerAsch wrote:
On Fri, 22 Mar 2013 12:40:50 -0000, "Keith W"
wrote:

GunnerAsch wrote:
On Fri, 22 Mar 2013 09:23:17 -0000, "Keith W"
wrote:


The conventional Batteries are sometimes called Sealed Lead Acid
Batteries but they are actually AGM batteries.

Modern passenger aircraft normally use Nickel Cadmium batteries

Why havent they converted over to NmH?


They have a relatively high self discharge rate and can lose
up to 20% of the energy stored in the first 24 hours. This is
acceptable for hybrid vehicles where the battery is primarily a
temporary buffer to capture the energy from regenerative
braking but not good for a system intended to initiate an
aircraft startup sequence after a week in the hangar.

Keith

Thats not true anymore. Since Sanyo developed the Enerloop NiMH
battery..they are being shipped charged from the factories. All the
makers are using the new tech and have been doing so for at least 3
yrs. Ive got NiMH batteries that I only need to put on the charger
ever 6 months, just to top them off.

Gunner


Trouble is they are not available in the size or capacity to be used
in an electric vehicle, last time I checked the largest was a D size.

Keith


  #195  
Old March 22nd 13, 06:23 PM posted to rec.aviation.piloting,rec.crafts.metalworking,rec.aviation.military,talk.politics.misc,alt.society.labor-unions
Ed Huntress
external usenet poster
 
Posts: 4
Default Is the 787 a failure ?

On Fri, 22 Mar 2013 16:57:55 -0000, "Keith W"
wrote:

GunnerAsch wrote:
On Fri, 22 Mar 2013 12:40:50 -0000, "Keith W"
wrote:

GunnerAsch wrote:
On Fri, 22 Mar 2013 09:23:17 -0000, "Keith W"
wrote:


The conventional Batteries are sometimes called Sealed Lead Acid
Batteries but they are actually AGM batteries.

Modern passenger aircraft normally use Nickel Cadmium batteries

Why havent they converted over to NmH?

They have a relatively high self discharge rate and can lose
up to 20% of the energy stored in the first 24 hours. This is
acceptable for hybrid vehicles where the battery is primarily a
temporary buffer to capture the energy from regenerative
braking but not good for a system intended to initiate an
aircraft startup sequence after a week in the hangar.

Keith

Thats not true anymore. Since Sanyo developed the Enerloop NiMH
battery..they are being shipped charged from the factories. All the
makers are using the new tech and have been doing so for at least 3
yrs. Ive got NiMH batteries that I only need to put on the charger
ever 6 months, just to top them off.

Gunner


Trouble is they are not available in the size or capacity to be used
in an electric vehicle, last time I checked the largest was a D size.

Keith


The Tesla Roadster has 6,831 lithium-ion cells, and each one is
between the size of a AA and a C in diameter, but a little longer than
either.

An AA is 14.5 mm x 50.5 mm. The 18650 Form Factor cells used in the
Tesla are 18.6 mm x 65.2 mm.

--
Ed Huntress
  #196  
Old March 22nd 13, 06:25 PM posted to rec.aviation.piloting,rec.crafts.metalworking,rec.aviation.military,talk.politics.misc,alt.society.labor-unions
Jim Wilkins[_2_]
external usenet poster
 
Posts: 52
Default Is the 787 a failure ?

"Keith W" wrote in message
...
Jim Wilkins wrote:
"Mr. B1ack" wrote in message
...

Not interested in burning to death over the Pacific ....

Better to fall into the South Atlantic because the Airbust didn't
inform the pilots that it had stalled.


Actually it did, they simply chose to disregard the stall warning
that sounded continuously for 54 seconds and the stick shaker.

Keith


It sounded for 54 seconds, then it stopped a little after 2h 11m 42s
when they were at 35,000 feet, 40 degrees pitch and falling at 10,000
feet/minute. See pages 22 & 23.
http://www.bea.aero/en/enquetes/flig...t.final.en.php

At 2h 12m ~15s the Pilot Flying made a pitch-down input that brought
their forward speed above the stall warning's lower limit of 60 Kts
and it sounded again, confusing them.

Page 44 of the final report:
" If the CAS measurements for
the three ADR are lower than 60 kt, the angle of attack values of the
three ADR are
invalid and the stall warning is then inoperative."

My real point is to remind Bill Black that he lives in a glass house
and shouldn't throw stones at Boeing.
jsw


  #197  
Old March 22nd 13, 07:16 PM posted to rec.aviation.piloting,rec.crafts.metalworking,rec.aviation.military,talk.politics.misc,alt.society.labor-unions
Jim Wilkins[_2_]
external usenet poster
 
Posts: 52
Default Is the 787 a failure ?

"Daryl" wrote in message
...

The method of charging is more complicated than the other versions.
NiMH batteries work well if you only have one cell (say, 12 volt
using 4 3 volt cells). But when you are trying to generate 36 volts
to 400 volts, each cell pack must be independently charged. Not
possible in that application.


If YOU don't know how then it must be impossible.
http://www.mpoweruk.com/balancing.htm
"To provide a dynamic solution to this problem which takes into
account the ageing and operating conditions of the cells, the BMS may
incorporate a Cell Balancing scheme to prevent individual cells from
becoming overstressed. These systems monitor the State of Charge (SOC)
of each cell, or for less critical, low cost applications, simply the
voltage across, each cell in the chain. Switching circuits then
control the charge applied to each individual cell in the chain during
the charging process to equalise the charge on all the cells in the
pack."

The balancing circuit is simply a resistor and a FET across each cell
to bypass some of the charging current when necessary. The FETs can be
optically isolated from the control circuit for high voltage packs.

And you haven't seen a burst case either. Bulging, deformed, etc.
case but the juice is contained in the case.


I sure have, it was displayed as a memorable example of how NOT to
design a battery charger. The plate edges were visible through the
crack.

The reason the AGM isn't used in larger applications is that it
cannot be recharged as it is being discharged. You left out a slew
that use Deep Cells.
Daryl


Again, YOU don't know how. A battery monitor circuit that measures
current and voltage can model the battery with a custom microcomputer
to predict its state of charge and tolerance for charging current, at
any point in the discharge cycle. They lose track as the cells age
which is why Lithiums need to be periodically fully discharged and
recharged, to recalibrate the model.
http://www.ti.com/sc/docs/msp/sine_on/batt_mgmt.pdf

Look at how much the bq2060 can do for $4.32. Connect it to a PIC and
you can record the full service and maintenance history of the
battery, like a little Black Box. That's how I know what really hurts
Lithiums.

jsw


  #198  
Old March 22nd 13, 07:32 PM posted to rec.aviation.piloting,rec.crafts.metalworking,rec.aviation.military,talk.politics.misc,alt.society.labor-unions
Keith W[_4_]
external usenet poster
 
Posts: 39
Default Is the 787 a failure ?

Ed Huntress wrote:
On Fri, 22 Mar 2013 16:57:55 -0000, "Keith W"
wrote:

GunnerAsch wrote:
On Fri, 22 Mar 2013 12:40:50 -0000, "Keith W"
wrote:

GunnerAsch wrote:
On Fri, 22 Mar 2013 09:23:17 -0000, "Keith W"
wrote:


The conventional Batteries are sometimes called Sealed Lead Acid
Batteries but they are actually AGM batteries.

Modern passenger aircraft normally use Nickel Cadmium batteries

Why havent they converted over to NmH?

They have a relatively high self discharge rate and can lose
up to 20% of the energy stored in the first 24 hours. This is
acceptable for hybrid vehicles where the battery is primarily a
temporary buffer to capture the energy from regenerative
braking but not good for a system intended to initiate an
aircraft startup sequence after a week in the hangar.

Keith

Thats not true anymore. Since Sanyo developed the Enerloop NiMH
battery..they are being shipped charged from the factories. All the
makers are using the new tech and have been doing so for at least 3
yrs. Ive got NiMH batteries that I only need to put on the charger
ever 6 months, just to top them off.

Gunner


Trouble is they are not available in the size or capacity to be used
in an electric vehicle, last time I checked the largest was a D size.

Keith


The Tesla Roadster has 6,831 lithium-ion cells, and each one is
between the size of a AA and a C in diameter, but a little longer than
either.

An AA is 14.5 mm x 50.5 mm. The 18650 Form Factor cells used in the
Tesla are 18.6 mm x 65.2 mm.


And a Tesla battery costs between $24,000 and $40,000.

The Toyota list price for the Prius battery is $2,299 but aftermarket
battery costs start around $1,800

Keith


Keith


  #199  
Old March 22nd 13, 07:51 PM posted to rec.aviation.piloting,rec.crafts.metalworking,rec.aviation.military,talk.politics.misc,alt.society.labor-unions
Jim Wilkins[_2_]
external usenet poster
 
Posts: 52
Default Is the 787 a failure ?

"Keith W" wrote in message
...
Ed Huntress wrote:
On Fri, 22 Mar 2013 16:57:55 -0000, "Keith W"
wrote:

The Tesla Roadster has 6,831 lithium-ion cells, and each one is
between the size of a AA and a C in diameter, but a little longer
than
either.

An AA is 14.5 mm x 50.5 mm. The 18650 Form Factor cells used in the
Tesla are 18.6 mm x 65.2 mm.


And a Tesla battery costs between $24,000 and $40,000.

The Toyota list price for the Prius battery is $2,299 but
aftermarket
battery costs start around $1,800

Keith


This is a typical price if you want a few to experiment:
http://www.amazon.com/Ultrafire-1865.../dp/B006QQ27BW
A voltage-and-current controlled lab power supply will recharge them
nicely. My 18650 battery holder is a small plastic box with brass
screws threaded into the ends as adjustable terminals
jsw


  #200  
Old March 22nd 13, 07:59 PM posted to rec.aviation.piloting,rec.crafts.metalworking,rec.aviation.military,talk.politics.misc,alt.society.labor-unions
Keith W[_4_]
external usenet poster
 
Posts: 39
Default Is the 787 a failure ?

Jim Wilkins wrote:
"Keith W" wrote in message
...
Jim Wilkins wrote:
"Mr. B1ack" wrote in message
...

Not interested in burning to death over the Pacific ....

Better to fall into the South Atlantic because the Airbust didn't
inform the pilots that it had stalled.


Actually it did, they simply chose to disregard the stall warning
that sounded continuously for 54 seconds and the stick shaker.

Keith


It sounded for 54 seconds, then it stopped a little after 2h 11m 42s
when they were at 35,000 feet, 40 degrees pitch and falling at 10,000
feet/minute. See pages 22 & 23.
http://www.bea.aero/en/enquetes/flig...t.final.en.php

At 2h 12m ~15s the Pilot Flying made a pitch-down input that brought
their forward speed above the stall warning's lower limit of 60 Kts
and it sounded again, confusing them.

Page 44 of the final report:
" If the CAS measurements for
the three ADR are lower than 60 kt, the angle of attack values of the
three ADR are
invalid and the stall warning is then inoperative."

My real point is to remind Bill Black that he lives in a glass house
and shouldn't throw stones at Boeing.
jsw


The real point is that the aircraft clearly

1) Indicated that it had reverted to direct law (manual input)
2) Sounded the stall warning
3) Showed that the aircraft was falling at a high angle of attack
and low speed

The pilot flying seems to have been fixated on keeping the
wings level and disregarded the angle of attack which at
2 minutes 12 seconds was 40 degrees ! During the entire
crisis it was never less than 35 degrees.

Keith


 




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