
Boeing 777X: World’s largest twin-engine jet completes first flight - DemiGuru
https://www.bbc.co.uk/news/world-us-canada-51253066
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cstross
The 777X is a program, covering two (or more) models: the 777-8 and 777-9. The
one that flew yesterday was the first 777-9 -- a replacement for the
777-300ER, with significantly increased range, a stretched fuselage (it's
slightly longer than the 747-8), and up to 426 seats. Increased use of
lightweight materials and those whizzy folding winglets mean it's no heavier
than its predecessor.

Maximum cargo capacity is roughly three-quarters that of a 747-8 by weight.

There's also a possible 777-10X model that will seat up to 450 passengers and
is being pitched as a rival to the A-380 superjumbo.

The real miracle here is that the big four-engine jumbos are being replaced by
a twin-jet. (This says something profound about advances in engine technology
since 1970. Or even 1990.)

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vasilakisfil
Doesn't that make a plane less engine-fault tolerant? Completely noob here,
but I would feel better if I flew in a 4-engine plane than 2-engine. In a
4-engine plane, even if 2 engines faults (like, bird strike), the other 2 will
still make the plain airbone.

~~~
dehrmann
You don't necessarily lose engines instantly to bird strikes, they're most
likely to happen at takeoff and landing, and it hasn't been an issue for the
massive fleet of twin-engine short-haul jets.

The real concern is trans-oceanic long-haul. Supposedly modern engine failure
rates have improved to the point that you're less likely to have problematic
engine failures than a four-engine 70s-era 747.

~~~
dx034
Which is shown by statistics. There are thousands of daily flights over
Atlantic & Pacific. Engine failures over the ocean are incredibly rare (I
couldn't find any recent ones). Most reasons why airliners choose to divert at
this stage are medical issues nowadays. And for the plane to crash not one but
both engines would have to fail.

~~~
dehrmann
> for the plane to crash not one but both engines would have to fail

I recently rode in a 2-person jet. The pilot said the only reason we might
bail out is an engine fire. If the engine fails, the plane's an excellent
glider, and we'll glide to an airport/airstrip. Now, this was somewhere with
airports all over, not an ocean.

[https://en.wikipedia.org/wiki/ETOPS](https://en.wikipedia.org/wiki/ETOPS) is
a good read.

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velox_io
I am fascinated by the wings, you can see that they have been heavily
optimised and wonder how much compute time went into perfecting them. I'd love
to see a documentary on the design & construction. I have a carbon-fibre road
bike and it is incredible how much they can tune the materal. Where it is
rigid and where/ even how it flexes to dampen vibrations.

Interestingly, most of that article is about the 737 Max issues (the MCAS
software is a disaster, it's a push to even call it engineering).

~~~
bfieidhbrjr
Recently I've been doing a teeny tiny bit of CFD again. You might be amazed at
how _little_ CFD goes in to wings. It's still a huge amount, but tunnel
testing still wins. I was kind of surprised.

As best I can tell, CFD is still kind of like impedance-based home body fat
scales. They're kind of directionally accurate but have a pretty high error.

I thought CFD would be a solved thing by now, but then I remembered how good
(e.g. bad) weather prediction still is.

~~~
LeifCarrotson
You might be interested in this bet on the LongNow site:

[http://longbets.org/753/](http://longbets.org/753/)

Some people think that wind tunnels will be obsoleted by computational fluid
dynamics within the decade. Others think that the problems with CFD are not a
lack of compute power but a lack of comprehensive understanding and modeling
of the physics at play, and expect that wind tunnels will be with us for quite
a while. (Personally, I believe in the progress of technology and expect an
eventual if not near-term breakthrough in CFD software will eventually
obsolete the wind tunnel, but I also think that institutional inertia will
keep a lot of wind tunnels and businesses that purchase time in them in
operation for a decade or more after CFD's big breakthrough...)

~~~
Gravityloss
There are sources of error in wind tunnel testing too.

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clement_b
> The 252-foot-long passenger plane had been due to launch this year but has
> been delayed by some technical difficulties.

Is that related to the recent MAX issues, or to the fact shipping such a large
aircraft on two engines only was much harder than expected?

~~~
l31g
Neither. The main delay is due to a problem with the GE9X engines. Some of the
internal components were wearing out faster than expected so they had to
redesign them.

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sschueller
Does this plan have a market? I thought the airbus A380 was having a very bad
time and airlines don't want it anymore because it's too big.

~~~
p_l
A crucial difference is that, ultimately, 777X is a much smaller plane with
easier operations compared to huge A380.

It needs no new special handling compared to the existing 777, which already
had a higher amount of airports available as destinations, if only because it
didn't need two-level tunnels for speedy embarkation/disembarkation.

Also, 777 has always served the long distance market, and this plane is
essentially an extension for it without many of the downsides of both A380 and
747

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ComputerGuru
Presumably the fuel efficiency (and emissions) are improved by a good chunk?
40 percent?

~~~
ac29
That would be amazing, given that current jets are already pretty efficient.
Looks like its a little over 10% more efficient compared to older 777's:
[https://en.wikipedia.org/wiki/Boeing_777X#Efficiency](https://en.wikipedia.org/wiki/Boeing_777X#Efficiency)

~~~
ComputerGuru
You’re right. I didn’t realize how much larger the new engines were.

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vondur
Apparently they’ve only sold 300 of them. Same thing with the new updated 747.

~~~
zweep
Only 300? That’s like $150 billion of orders.

~~~
vondur
I was told they need like 1500 sold to turn a profit.

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trekrich
how many airlines are going to be thinking, hmmm lets let someone else fly
them and see what happens.

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vermontdevil
This site has some more info about the 777 etc. Some articles may be paywalled
though.

[https://leehamnews.com/2020/01/25/third-time-is-the-
charm-77...](https://leehamnews.com/2020/01/25/third-time-is-the-
charm-777x-takes-to-the-sky-today/)

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mavhc
Who wrote the software?

~~~
noja
It wasn't a software problem.

~~~
mavhc
It? I just mean in general, have their paid enough attention and money to the
software as to the hardware?

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aritmo
If something comes out on the 777X that is similar to the 737MAX, it will
break Boeing irreparably.

~~~
gizmodo59
They can ride quite a while due to the fact that there is only one alternative
in commercial flight (Airbus). I hope there is not a time when both companies
have such an issue at the same time. That would disrupt travel.

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IMTDb
So this plane has : a different fuselage, different wings, and different
engines than the "regular" 777 but somehow is still called a 777.

Has Boeing learned _anything_ from the past 12 month ?

~~~
threatripper
It just needs to behave like a regular 777 and you can partly do that using
software emulation.

~~~
aritmo
Just like the 737MAX?

~~~
p_l
Actually the opposite. Had 737MAX gone the way of 777, there would have been
no MCAS - but it would involve significant rework of control system, new
avionics, and a lot of training.

The core difference is that even the original 777 is a Fly-By-Wire system with
programmed behaviour, in fact it was a well known case study in building
civilian safe FBW systems.

Because of that, there's no need to "patch over" differences like it was done
with MCAS, as the minute adjustments can be done across the whole flight
envelope protection system that is already there since first 777. In fact, 787
controls are derived from that and use software adjustment extensively in
order to make control surface generate less drag yet still be usable.

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wchar_t
Considering recent events I'm wouldn't be to interested in flying in it

~~~
clSTophEjUdRanu
No thanks. I don't mind beta testing software but I draw the line at beta
testing the next Boeing aircraft.

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mikece
Did the military division of Boeing have a hand in engineering the folding
wingtips? It would make sense since McDonnell Douglas/Boeing have decades of
experience doing this with the F-18. Then again it wouldn’t surprise me if the
777X team reinvented the wheel on this point.

