DreamLiner and Li-ion

When I worked for a client that did a lot of research in this area they had a visit from a Japanese Professor who was giving lectures on LiIon design. He stated that the current design of LiIon cells was all wrong, leading to an increased risk of overheating and fire, but the manufacturers had invested a lot in the design and couldn't back out of bad design decisions quickly.

I wish I could remember what the suggested fix was.

Oh hang on, ancient brain cells ticking over, it may have been that he was proposing a design for solid polymer electrolytes.

Oh I agree,

the point is such an event is not going to make the plane fall out of the sky because the controls no longer work

tim

No, but in this case, they are (when in the air)

tim

In message , tim..... writes

They used to have an emergency generator with a propellor strung underneath but don't know if that is still the case.

In message , Jo Stein writes

Generally yes, but if a particular plane has a specific safety problem then the generalisation no longer applies to that plane - e.g. Comet. That is why when such an issue is identified the fleet is grounded.

En el artículo , Jo Stein escribió:

Because they're idiots?

The FAA seemed fairly sure there was a risk that needed to be managed when they placed special conditions on the li Ion batteries in a 787 as part of it licensing.

Most have an auxiliary engine / generator in the tail. I guess the idea of a battery was to dispense with this, making the aircraft cheaper and possibly more aerodynamic.

Not sure what use a propeller is for generating power whilst on the ground.

No, but it might easily make the gear not come down. Batteries are useful ways to absorb PEAK loads.

Aircraft on the ground have umbilcals IIRC.

About as much as the wind turbines blighting our countryside, ie "not a lot".

--=20 Davey.

I've never been on a flight where anybody did that.

If they do it through fear, it is more probably a fear of flying.

Not everybody is

The fact that entire groups of peoples do not fear heights suggests it is nurture, rather than nature.

Have you ever asked a goat whether it is unafraid or simply confronting its fear?

Colin Bignell

Because they are made that way by evolution.

Science is difficult and require a lot of explanation. You are afraid of heights because you are made by parents that are afraid of heights. People not afraid of heights fell down from cliffs and did not leave children around; their genes are gone.

Why are goats not afraid of heights? Because goats afraid of heights failed in the struggle for life. They died from starvation. You see?

If people were less afraid of height they would have forgotten to clap their hands after landing. I never clap my hands when landing because I am busy studying those passenger that clap their hands.

The damage to the aircraft is usually quite minimal

I heard that comment too, but I find it very hard to believe. Why would you add that sort of weight to a plane, which it doesn't use when flying, when planes on the ground are powered by umbilicals anyway when the engines are off?

Sounds like a bit of technology whose only real purpose in life is to fail...

There is also the possibility when relying upon gravity that the gear might drop but fail to lock in position, which could result in it collapsing after landing.

Colin Bignell

The propellor driven generator or hydraulic pump (the RAT) is for emergencies in flight.

Batteries are not a replacement for the APU, batteries are required on all aircraft even if there is an APU. You need something to start engines and to provide power when all engines, including the APU, are stopped. Same as you need a battery on a car.

I'm guessing someone missed out the "normally". These batteries form an "uninterruptible" supply in the air, and a guaranteed clean supply on the ground, charged by the aircraft system in flight, and the ground supply at the airport.

Hmmm... "The 787 battery is from Japanese manufacturer GS Yuasa and relies on cobalt oxide (CoO2), which has the highest energy density, but is also susceptible to ?thermal events? (read: fires). And the cells release oxygen in a fire, meaning it is easy for them to continue burning." Oops.

Extracted from:-

The only flight I've been on (unless I was P1) where anyone clapped was after a go-around at Gatwick mid last year - a bit (ok a lot) of wind shear on late final and TOGA power applied in an expeditious manner followed by a sedate circuit to make a greaser!

Avpx

Wow! I'd say that took a LOT of skill and nerve.