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Qantas is bringing back Airbus A380s from the California desert

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Re: Qantas is bringing back Airbus A380s from the California desert

#151

Post by Toutouxc »

Andys wrote: post #54
rootusrootus wrote: post #25

Earlier quoted context omitted.

The A380 is pretty smooth, but I found that the way it cruises is not great for me. It tends to surge and glide in a way that prevents me from actually falling asleep, more so than on other smaller planes like a 787. While the 787 might not be as silky smooth taking off and landing, I prefer it for the long term comfort that matters for most of the flight.

Oh, I thought it was just me! All the Airbus planes have horrible autopilots that gradually rise and fall, in a barely noticeable way. I found myself feeling irritated and wished the source code was opensource so I could have a look at it.

That’s intentional, it allows the plane to do minor speed adjustments without altering engine speed that much by wandering a bit above and below the set altitude. The autopilot mode is called ALT CRZ (as opposed to just ALT).

Re: Qantas is bringing back Airbus A380s from the California desert

#152

Post by klipt »

btilly wrote: post #148
wahern wrote: post #91

Earlier quoted context omitted.

Sure, it's obviously a matter of diminishing returns and opportunity cost. But the re-engine for the A380 was basically a rote, low-risk, B-team exercise for Rolls Royce. All they had to do was tweak their existing generation stuff. The program was already well underway, and they still dropped it; they all but explicitly said the reason was, "meh, we lost interest". Something seems to have changed. Putting my cynical…

Starship launches tomorrow. There is a non-trivial chance that point to point suborbital flights totally disrupt the airline industry. Hong Kong to Los Angeles in 30 minutes for the price of a first class ticket is pretty hard to argue with.

Surely the fuel costs massively more?

Re: Qantas is bringing back Airbus A380s from the California desert

#153

Post by ikrenji »

klipt wrote: post #152
btilly wrote: post #148

Earlier quoted context omitted.

Starship launches tomorrow. There is a non-trivial chance that point to point suborbital flights totally disrupt the airline industry. Hong Kong to Los Angeles in 30 minutes for the price of a first class ticket is pretty hard to argue with.

Surely the fuel costs massively more?

maybe not

https://www.nextbigfuture.com/2022/02/spacex-reusable-rocket....

Re: Qantas is bringing back Airbus A380s from the California desert

#154

Post by kylehotchkiss »

btilly wrote: post #148
wahern wrote: post #91

Earlier quoted context omitted.

Sure, it's obviously a matter of diminishing returns and opportunity cost. But the re-engine for the A380 was basically a rote, low-risk, B-team exercise for Rolls Royce. All they had to do was tweak their existing generation stuff. The program was already well underway, and they still dropped it; they all but explicitly said the reason was, "meh, we lost interest". Something seems to have changed. Putting my cynical…

Starship launches tomorrow. There is a non-trivial chance that point to point suborbital flights totally disrupt the airline industry. Hong Kong to Los Angeles in 30 minutes for the price of a first class ticket is pretty hard to argue with.

Given the similarity of the launch and flight stages to other scary things militaries look out for (icbms), I can't see how point to point rocket flights become a geopolitical reality. Airplanes can barely fly a straight line through Europe or Asia as it is. Point to point is only really a reality over North America, oceans, and Australia.

Re: Qantas is bringing back Airbus A380s from the California desert

#155

Post by 6nf »

ghiculescu wrote: post #111
testrun wrote: post #105

Earlier quoted context omitted.

I am glad you escaped. I am an Australian.

lol, this attitude is why so many Aussies don’t want to go back.

Yup. I'm in Sydney and it's one of the most disappointing things about Australians. The inability or unwillingness to understand things like this.

Re: Qantas is bringing back Airbus A380s from the California desert

#156

Post by cjrp »

bobthepanda wrote: post #53
diebeforei485 wrote: post #4

It's a magnificent plane. It's very unfortunate that they launched the "shortened" version. The design and engineering was done for longer fuselage, so it actually has extra structure (and extra weight!) and larger wings than necessary. And it launched just before engines got a lot more efficient. The upside for passengers is that it's still the smoothest flying experience, even in turbulence. Boeing's 747 was incred…

The 747 also had incredible product market fit, if only accidentally. They were all designed to be freight compatible, because the 747 was meant to be a stopgap before supersonics dominated the skies. Most 747s have happy second lives as freight workhorses. The A380 is too heavy to get off the ground with freight packed to the gills.

Not sure if it was in the original (cargo-carrying) spec., but it’s one of the few aeroplanes where the nose can be lifted to load awkwardly-shaped freight.

Re: Qantas is bringing back Airbus A380s from the California desert

#158

Post by zuhsetaqi »

diebeforei485 wrote: post #4

It's a magnificent plane. It's very unfortunate that they launched the "shortened" version. The design and engineering was done for longer fuselage, so it actually has extra structure (and extra weight!) and larger wings than necessary. And it launched just before engines got a lot more efficient. The upside for passengers is that it's still the smoothest flying experience, even in turbulence. Boeing's 747 was incred…

Maybe a dumb question but can’t you switch the engines to the more efficient ones? I mean it’s surely not cheap but maybe cheaper and faster than building whole new planes!?

Re: Qantas is bringing back Airbus A380s from the California desert

#159

Post by throwaway2037 »

MichaelZuo wrote: post #72
wahern wrote: post #66

Earlier quoted context omitted.

None of the engine manufacturers are interested. That's what killed the A380--Rolls Royce pulled out of a re-engine deal that would've brought A380 engines into the 21st century. "Green" concept showcases notwithstanding, all the engine manufactures seem to have decided to cut back on investment and coast for awhile. Something will need to change to spur competition in the engine space, and then we might see hungrier…

The latest and greatest engines are not that far from the theoretical thermodynamic efficiency limit. So future designs are running into the hard part of the asymptote. I doubt airlines are actually interested in committing tens of billions of capital, today, to get a dozen % improvement in fuel efficiency a decade from now. And why would a private investor take such a huge risk without guarantees of making it back s…

    not that far from the theoretical thermodynamic efficiency limit
This is an interesting comment. It is not my field of expertise, but I am interested to learn more. Can you share more info or maybe a paper/blog? Thanks.

Re: Qantas is bringing back Airbus A380s from the California desert

#160

Post by VBprogrammer »

adgjlsfhk1 wrote: post #103
SgtBastard wrote: post #62

Earlier quoted context omitted.

IANAP, but a lot of the root cause analysis around the 737 max crashes was that they were sufficiently different and so should have required re-certification of pilots before being allowed to fly them. Due to the costs involved, Boeing made the ultimately fatal mistake of minimising these changes to airlines so that pilots didnt know what they were flying (insofar as some of the subsystems).

IMO this is a bad take. MCAS was a fine system, the different aero charicteristics were fine. The only problem is that Boeing cheaped out and made MCAS depend on a single sensor for critical decision making. If they just had 3 sensors like any other saftey critical system none of these problems would have happened.

I've tried to explain this before but it's been pretty negatively received. The assumption that safety critical systems on jet aircraft have triple redundancy is a misconception. At least in so far as any kind of automated, transparent to the pilot, monitoring and switching.

For example, the front of the 737 does have 3 pitot tubes. However, these drive the air data computers for the pilot and the copilot positions. The 3rd one drives a small set of backup instruments. A fourth at the rear of the plane is an input to the hydraulic pitch and feel computer. The Airbus is closer to what some might imagine but the switch between the 3 data sources is still manual (AF447 might have reached Paris if this wasn't the case).

There is another argument that adding more AoA sensors would have had a negligible impact on safety given they are exposed to the same environmental conditions. The main outcome was limiting the authority of the system, it would have prevented both accidents.

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