> perhaps he should just ride a bike
one of these? //http://www.zeromotorcycles.com
Call it the curse of the exploding lithium ion battery. The Wall Street Journal reports that Michael Dell, the man, or MSD Capital, his personal investment arm, is on the list to get a Boeing Dreamliner 787. Perhaps Dell's MSD arm is just taking a piece of the investment action in the Dreamliner, the Journal speculates, or …
one of these? //http://www.zeromotorcycles.com
Unless those motorcyles also uses Li-ion batteries?
I know my bicycle has one...
(4Kg of aluminium-encapsulated Li-Ion batteries to help give me a boost uphill... )
Coat because I won't be caught dead in 'bike clothes'...
Dell was the first I thought of too with the story of burning 787 batteries :)
I must admit that I'm quite curious to the outcome of the investigation.
Hardly back-up. These damn things drive the all electric control surfaces, avionics, etc.
Two engined 777's are risky enough, I like my aircraft to have metal, not glorified plastic.
"These damn things drive the all electric control surfaces, avionics, etc"
Not really. The battery in question is used to start the APU, which itself can then power the electricity demand, if there's no ground power generator available.
Er, again not really. That's the way things are normally done and you've probably been in one where the APU failed to catch and the whole thing went dark or the cutover to engine power produced the same effect.
This does no harm but scares the willies out of the more nervous passengers, so Boeing decided that Something Had To Be Done to make the Dreamliner more passenger friendly. The battery associated with the APU is of a considerably higher capacity than usual and also acts as a UPS during power transitions.
The battery is indeed bigger (in kWh or whatever) than has been traditional. But afaict it's not big enough to drive *everything* that needs electricity that normally gets it from the 1100hp APU and therefore it's not really appropriate imo to describe it as a UPS supporting the APU in general.
I couldn't easily find a kVA figure for the APU but 500kVA would be a reasonable rough guess (based on 1100hp). That's a rather big UPS (far from impossible, just a lot of weight on an aircraft for something that mostly won't be needed).
Never mind passenger friendliness. Think saving weight (more passengers or less fuel).
Metal's a bit new-fangled for me. Let's go back to wood, after all it worked for millenia in boats.
And let's not forget that wooden aircraft are lighter than metal ones.
When I was young, we had planes made of stone, with no engines and propellers that the passengers had to pedal themselves etc etc
Wood is a quite sophisticated composite. One thing about it is that it has virtually unlimited fatigue life due to its combination of stiff fibres and a flexible lignin matrix. The bad news is that it mostly doesn't like fresh water and is food for a lot of beasties, fungi and bacteria.
On a pedantry note, "carbon fibre" is not a composite as in the article. The whole idea of a composite is that it is made of several things to get the best overall results. The little boat I am building will have a core of two layers of mahogany to give stiffness with light weight, over which goes epoxy laminated kevlar for strength, some carbon fibre to put additional stiffness where needed, and some glass fibre for scrape resistance. Overall will go external coating to resist UV and fungus attack.
Some people use balsa for the core but I got a really good deal on the mahogany. It's a pity it won't be visible in the finished product, but I'll know it's there and that's what matters.
That's a composite. Materials to do what is needed where it is needed, held together in a matrix that binds everything together firmly enough to keep things where you want, but with enough flexibility to handle bumps, thermal expansion and vibration.
Making planes out of composites is a Good Idea, because aluminium is nasty stuff - limited fatigue life, prone to corrosion.
Using what seems to be the wrong kind of battery - perhaps not such a good idea.
Hermann Goering, a bit of an expert on the subject, was both impressed and infuriated by the Mosquito, which was an extremely effective military aircraft that was almost invisible to German radar owing to its wooden construction.
Hitler, however, was sold on jet aircraft as superweapons of vengeance. They had to be made out of metal, given the technology of the day, to prevent them catching fire. He also had the problem that they were very wasteful in fuel, and Germany had a fuel shortage (which would have been even worse if more Mosquitos had been made and fewer Lancasters, and the Mosquitos had targeted fuel dumps and refineries.)
Carbon fibre/kevlar/epoxy is basically wood brought up to date.
Carbon Fibre Reinforced Plastic is a composite material- it is a material composed of other materials. Concrete is composite material, composed of differently sized hard lumps in cement. A structure of CFRP or GR around a core (wood, cardboard, foam, whatever) as you describe is a structure.
You're correct about wood being a sophisticated material though, and bamboo has been used in competitive road bicycles. Bamboo's strength/weight ratio (though very good) isn't the only consideration, and it is good at damping vibrations at undesirable frequencies. Wood and bamboo have a grain; on a microscopic level, a structure of long cellulose tubes- always a good structural shape.
The carbon impurities that differentiate steel from iron are usually randomly arranged. However, in a samurai sword, they are very long- approaching the scale of nano-tubes. This is achieved by repeatedly folding and hammering the steel, giving it exceptional mechanical properties.
Another recently reported problem with a Boeing 787 was a fuel leak. An on board fire at the same time could have made things much more interesting.
The 'revolutionary' 787 uses electricity to power control surfaces, actuators, etc which have traditionally been powered hydraulically or pneumatically. The 787 also uses electricity for wing anti-icing, and...
The battery in question is nothing directly to do with that, no sensibly sized battery could provide anything like sufficient power.
The battery in question is used to provide power to start a (relatively) small gas turbine engine (the auxiliary power unit, which on the 787 is rated at 1100 horsepower) which itself provides power for all these electric gadgets when the main engines aren't running and the aircraft can't plug in to a ground power generator.
It's still looking not good for the Dreamliner and the regulatory authorities though, see e.g.
Give me tried and tested pnuematics or hydraulics any day.
"Give me tried and tested pnuematics or hydraulics any day."
Quite. Nice predictable failure modes (not so much software) lead to nice predictable reliability.
A 1100 hp gas turbine powers *all* of the control surfaces?
'A', as in one? What's the MTBF for a gas turbine engine and does the 787 have a redundant system for backup? Surely it must have...
@Xamol , the APU is used on the ground to run lighting, heating/cooling, etc when ground power is unavailable. Most main airports have ground power available on articulated arms that swing out under the plane and a large plug is put into a socket on the plane just next to the front landing strut.
In flight the 2 main engines drive the generators for aircraft ops, and if the main engine generators are unavailable then the APU can step in to ensure the plane is still flyable.
However the BIG change from traditional electronics on the 787 is that the main engine generators are NOT fixed voltage. The APU starter battery was one of the components that had a fault, but I believe there have also been other batteries, likely used to try and help smooth out the voltage fluctuations from the main engine units, that have had problems on the 787
Boeing claimed that by not having a constant velocity drive for the main engine generators it would save weight, and thus fuel, but it has also added complexity to a system that MUST WORK. The A&B DC power buses on jets pretty much power every critical system on the plane (avionics, radio, nav systems, etc). Boeing took a big risk in messing with a decades old proven design. Interestingly, while Airbus is launching the A350 to compete (sort of) against the 787, they're not messing with the flight controls or power systems.
@AC 1 and 2
Hydraulics in older planes were driven from pumps driven from the engines. Some planes have A and B hydraulic systems, bigger wide body planes tended to have 3 separate hydraulic systems for redundancy.
Unfortunately, a number of accidents have proven the hydraulic systems have a massive single point of failure - in order to be useful, they have to back each other up. This tends to mean that for controlling the tail surfaces (horizontal and vertical stabilisers), all 3 systems congregate at that point. The JAL 747 crash and another crash in the USA, I think of a DC-10 if I remember right, where damage to the tail from an uncontained engine fan failure rendered all 3 hydraulic systems inoperative as the fluid leaked out
Preventative measures (including automatic cut off valves to stop the fluid leaking out when pressure is lost) have been introduced since, but the risk is still there.
The benefit of the electrically operated controls is that if you have damage in the tail, you MAY lose the tail controls but the ailerons, flaps, etc still work so you have a better chance to control the aircraft
Where do they get the juice to power the ailerons, rudder and elevators when they lose the main AND APUs--say because they run out of fuel, like a couple of Canadian planes did in the past. One coasted for 80 miles over the Atlantic and luckily has an island in their path.
"Where do they get the juice to power the ailerons, rudder and elevators when they lose the main AND APUs"
Some of the more critical systems will be powered by a "ram air turbine", which is basically a wind turbine, usually invisible, but deployed in emergencies. Wikipedia says they're typically up to 70kW.
The spelling is fibre not fiber
Don't give me any of that nonsence about US spelling, it's simply wrong
It's not simply wrong, it's locally wrong.
"nonsence" is also simply wrong.
"Nonsense" isn't, however...
Tell that to Phil Collins.
Given that the 777 is the very poster child for "don't outsource your core competency", I hope this causes Boeing a world of pain. It's the only way they'll learn.
Using Lithium Ion batteries on a plane was a ridiculous idea. This was obviously to save weight, but at the cost of stability.
I'll never ever fly on a 787, not that I fly often anyway.
Since someone accidentally mentioned the 777 instead of the 787, I thought I would take the time to say I hate flying on 777's, I have never been so scared in the air as I was flying back from Beijing on one, you could SEE the whole interior twisting in the turbulence - that CANNOT be good from a metal fatigue point of view.
The same route on a 747 or A380 is as smooth as silk, but every 777 ride has been like the worst parts of the Paris - Dakar rally.
Since most plastics get brittle from UV exposure, how many years before the 787s just crumble away??
So long as they are painted, a very long time. There are glass fibre boats still in use which date from the 1960s and 70s, and that is cheapo polyester, not epoxy.
Back when Dell the company was falsifying financial statements and Lance was being Lance.
Dell videos used in new-hire orientation used to feature both of them on bikes.
It's highly unlikely that Mickey Donut nor Boeing are responsible for the lithium ion battery fires, though Mickey should consider a few dozen less donuts for lunch so that his stomach doesn't hang over so far as to short circuit the battery terminals.
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