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dare100em
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RE: 777X Updated Information And Developments Part 11

Tue Jun 30, 2015 7:37 am

Quoting tortugamon (Reply 84):
He could be talking about about the length of the fuse is changing or even how the fuse is assembled with increased automation as being changes. Outside of that I don't think we know of any other changes. We know it is going to be the same material (Al and not AlLi), sidewalls is the other thing but I see that as an interior and not the furse, per se.

The other items would be increased window size and increased strength for higher cabin humidity and lower altitude.

That sums it up. I’m not sure the internal widening will leave the fuse total unchanged but it’s true that it can’t really chance structural aspects.

What I mean is that the combination of a stretch, internal widening and bigger windows plus higher pressurization aspects is actually probably the biggest chances we ever have seen on a fuse while still keeping the geometry and principal structure. Not much else could be done except maybe the lowering or lifting of the main deck.
 
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KarelXWB
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RE: 777X Updated Information And Developments Part 11

Tue Jun 30, 2015 7:42 am

Quoting tortugamon (Reply 88):
Some have speculated that the OEW could be less than the 77W

Currently the OEW is speculated at 190 tonne, i.e. heavier than the 77W.
What we leave behind is not as important as how we've lived.
 
tortugamon
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RE: 777X Updated Information And Developments Part 11

Tue Jun 30, 2015 7:47 am

Quoting nomadd22 (Reply 90):
To put it more rudely, denying Airbus income isn't a minor factor.

I did not say it was. But to gain market share (calculated by airplanes sold/delivered or top line revenue) at the expense of your own profit (bottom line net income) is foolish in all but a few industries. This is not one of those exceptions.

Also, I am of the belief that the quality of the customer is as important as the order itself as some customers are more prone to back out or have based their purchases on anticipated growth that could or could not come from passengers destined to other airlines. There is a lot of duplication in the narrow body backlog meaning that two airlines can't fly that same passenger and I think that will prevent itself. Not to mention big backlogs prevent capitalization on short-term availability price hike opportunities.

No, I don't think market share is the most important thing.

Quoting ThReaTeN (Reply 89):
Can I interpret what you are saying, tortugamon, as meaning that the pulled MZFW figure (562,000 pounds) from the old ACAP could be in the ballpark while the OEW figure on Wikipedia (415,000 lbs) was (perhaps intentionally) released as too high, so that the real delta between them (=MSP of the 779) would still be higher than the MSP of the 77W?

Yes, well stated. I don't believe the quoted OEW has a credible source behind it and the only way these other items can be right is if the OEW is lower than it is on the 77W.

Its not so unbelievable. The length is only increasing 4% and the wing being CFRP should make that lighter. Add in the reduction in the number of Type I exits and the simple improvements they are rolling out in 2016 for a retrofitable 3,000lbs reduction are indications of further possible weight reductions.

Quoting dare100em (Reply 92):
Not much else could be done except maybe the lowering or lifting of the main deck.

Why do you think they would want to? I personally don't see the benefit but would be interested in your idea.

Quoting KarelXWB (Reply 93):
Currently the OEW is speculated at 190 tonne, i.e. heavier than the 77W.

Cool, I have not seen anything compelling yet. If true then we do have a dilemma regarding the MSP.

tortugamon
 
dare100em
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RE: 777X Updated Information And Developments Part 11

Tue Jun 30, 2015 8:43 am

Quoting tortugamon (Reply 94):
Why do you think they would want to? I personally don't see the benefit but would be interested in your idea.

It was just an example what was still left to change but still use the same outer fuse/structure. In case of a 767max this would allow for 8-abreast by lowering the main deck. In the case of the 777X it doesen't make much sense.
 
dynamicsguy
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RE: 777X Updated Information And Developments Part 11

Tue Jun 30, 2015 10:55 am

Quoting tortugamon (Reply 84):
sidewalls is the other thing but I see that as an interior and not the furse, per se.
Quoting dare100em (Reply 92):
I’m not sure the internal widening will leave the fuse total unchanged but it’s true that it can’t really chance structural aspects.

The change to the sidewalls is more structure than interiors. They have to reduce the section height of the fuselage frames. This structural change is where the wider cabin comes from.
 
Egerton
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RE: 777X Updated Information And Developments Part 11

Tue Jun 30, 2015 11:49 am

Quoting KarelXWB (Reply 93):
Currently the OEW is speculated at 190 tonne, i.e. heavier than the 77W.

These weights are beginning to confuse me, and much more than usual.

In Seeking Alpha on 16th December 2014, they say: The operational empty weight for the Boeing 777-300ER is 168 (metric) tons and 155 (metric) tons for the Airbus A350-1000.

If the 777-9 OEW is 190 tonnes, my guess of a 20 tonne difference between the light-heavyweight A350-1100 is miles out?

[Edited 2015-06-30 04:51:58]
 
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KarelXWB
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RE: 777X Updated Information And Developments Part 11

Tue Jun 30, 2015 11:52 am

I think the end result will be slightly less than 190 tonne (say 185t), I think you would be looking at an 30 tonne heavier aircraft.
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Egerton
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RE: 777X Updated Information And Developments Part 11

Tue Jun 30, 2015 12:47 pm

Quoting KarelXWB (Reply 98):
I think the end result will be slightly less than 190 tonne (say 185t), I think you would be looking at an 30 tonne heavier aircraft.

Thanks, KarelXWB. If things end up like this, then it makes me wonder if the 777X project is also encountering a spot of bother, like I wondered the same about GE Aircraft?

And it seems Congress has not authorised additional lending by the US Export-Import Bank? Not that this will make any real difference as the ordinary commercial banking system can do this sort of thing? Hopefully, the UK and EU will stop their version of the US Ex-Im from lending cheaply to overseas airlines and their funders, but deny the same terms for Airbus's home airlines? They are both stupid non-tarriff barriers to fair trade.

[Edited 2015-06-30 05:49:21]

[Edited 2015-06-30 06:30:30]
 
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KarelXWB
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RE: 777X Updated Information And Developments Part 11

Wed Jul 01, 2015 10:00 pm

The 777X list price has been increased by 2.9%.

- 777-8X: $360.5 => $371.0 million
- 777-9X: $388.7 => $400.0 million

http://www.boeing.com/company/about-bca/
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Matt6461
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RE: 777X Updated Information And Developments Part 11

Wed Jul 01, 2015 11:13 pm

Quoting tortugamon (Reply 88):
Some have speculated that the OEW could be less than the 77W as the wing will be substantially lighter and the stretch is small.
Quoting ThReaTeN (Reply 89):
while the OEW figure on Wikipedia (415,000 lbs) was (perhaps intentionally) released as too high

The 777-9's OEW will certainly be higher than 77W's. I can't provide a link to this but behind Leeham's paywall, Bjorn/Ferpe told me in a comment that Randy from Boeing quoted him a 407,000lb OEW for 779. So that's probably the floor for OEW, 415,000 wouldn't be unreasonable.

While CFRP will help with weight, we have to consider the fundamentals of wing design as well: span and area-dependent weight. A rule of thumb is that weights are 40% span-dependent and 60% area. Breaking these out:

-Span-dependent weight rises with (1) cube of span and (2) ultimate load. Effective span is increasing by ~8% (230/213 - the tips aren't fully loaded). By cubic escalation that causes ~25% span weight delta. The ultimate load is also increasing with the longer, heavier fuselage. The stretch is ~3.5% (238/230) but fuse weight increases more than linearly due to bending moment of longer fuse. Total span-dependent delta should be ~30%, thus span-dependent contributes ~12% wing weight delta.

-Wing area is increasing by ~10%. That's a ~6% wing weight delta.

-Total wing weight delta, before CFRP, would be ~18% on this calculation.

-If CFRP saves 10% of weight, total wing weight delta (.9*1.18) is ~6%. If wings are 40% of OEW, OEW delta is ~2.4%.

-If fuselage+floor beams+furnishings is 40% of OEW, and this increases by 4-5%, that's another ~2% OEW delta.

-Between wings and fuse, basic fundamentals would predict ~4% OEW delta. Much higher if CFRP doesn't quite save 10% of weight.

-GE9X will probably be heavier than GE90-115B, even with lower thrust. Its cruise thrust is around equal, but will have a bigger fan and much heavier core to achieve 62 OPR.

-Considering center wing box stays aluminium, empennage size is increasing, and engines should be heavier, total OEW delta should significantly exceed the 4% laid out above. Plus reinforcing the fuselage for 6,000ft pressure and thinner sidewalls will cost weight.

Quoting tortugamon (Reply 94):
If true then we do have a dilemma regarding the MSP

I bet Boeing is setting MSP for more realistic pax loads. With 350 pax @225lbs, a 146,000 MSP still leaves room for 67,000lbs of cargo. At 139.5ft3 usable volume per LD3, 11lbs/ft3 cargo, that would allow for 40LD3's. The 77W's higher MSP comes into play only when you're carrying 500+ pax with few bags and a lot of cargo in the belly. Having a higher MSP would require heavier wing spars, probably just not worth it.

[Edited 2015-07-01 16:16:04]

[Edited 2015-07-01 16:20:33]
 
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Matt6461
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RE: 777X Updated Information And Developments Part 11

Wed Jul 01, 2015 11:32 pm

To follow on from the previous post re 779 vs. 77W weight...

Despite the weight delta, the 779 will still have better aerodymanic performance:

-Induced drag is proportional to Lift^2/Span^2. Span is increasing by ~8%, empty weight increasing by around that amount or slightly less. But at average mission weight, 779's weight delta will only be half of empty weight delta because MTOW isn't changing. Thus induced drag at equal FL will be slightly lower for 779 despite higher weight.

-Parasitic drag will decrease. Total wetted area increases by ~5% between wings and fuselage, but the 10% greater wing area will mean air is ~10% less dense at initial cruise FL. Thus Dp will decrease despite greater wetted area.

-One thing I am trying to understand, might put up a question in TechOps: Boeing has, in the past, touted the 777X's "thin wing." A thinner wing contributes lower Dp but the general trend in airfoil design is towards increased thickness to save on wing bending weight - this is the raison d'etre of supercritical airfoils. If Boeing's statements re thin wing are genuine, then they have reaped some Dp benefit out of the thinner wing that compensates for higher structural weight. That would further explain why 777X will be so fuel efficient despite being heavier than 77W and A35J. Does anyone have insight into why/how Boeing will efficiently make the 777X's wing thinner? (assuming the wing will be thinner, I haven't seen this mentioned much lately)
 
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seabosdca
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RE: 777X Updated Information And Developments Part 11

Wed Jul 01, 2015 11:44 pm

Quoting Matt6461 (Reply 101):
407,000lb OEW for 779

= 185 t. Nicely done, Karel.

Quoting Matt6461 (Reply 101):
I bet Boeing is setting MSP for more realistic pax loads.

They have shown that they would rather keep MTOW and MZFW down even if it limits the airframe's ability to accommodate very high density configurations. The exit limit will be only 475, well below the 777-300ER's limit of 550.

An airline with the 350-ish-passenger configurations most 777-9Xs will have would have to have dense cargo to reach a payload over 66 t. Not impossible at all, but probably a sacrifice worth making compared to increasing weight enough to increase MZFW and MSP further.
 
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Matt6461
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RE: 777X Updated Information And Developments Part 11

Wed Jul 01, 2015 11:48 pm

Quoting seabosdca (Reply 103):
= 185 t. Nicely done, Karel.

Ha I think Karel was on the same thread in the Leeham premium section.  
 
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b777900
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RE: 777X Updated Information And Developments Part 11

Sun Jul 05, 2015 9:10 am

So 2020 will be the first year of operation? Any chance any sooner like 2017 or 2018?
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dynamicsguy
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RE: 777X Updated Information And Developments Part 11

Sun Jul 05, 2015 10:09 am

Quoting b777900 (Reply 105):
So 2020 will be the first year of operation? Any chance any sooner like 2017 or 2018?

No. Simply too much engineering work and too much capital equipment to be acquired to compress the schedule substantially.
 
Max Q
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RE: 777X Updated Information And Developments Part 11

Sun Jul 05, 2015 10:19 am

Still would like to know what sort of control and logic will operate the wing fold mechanism ?


Anyone know ?
The best contribution to safety is a competent Pilot.


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OldAeroGuy
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RE: 777X Updated Information And Developments Part 11

Sun Jul 05, 2015 12:56 pm

Quoting Max Q (Reply 107):
Still would like to know what sort of control and logic will operate the wing fold mechanism ?

I believe it will be something like this.

Tip fold/extend is always a manual operation, controlled by a lever on the flight deck.

GPS is used to provide configuration warning.

For Takeoff, if the airplane moves on to the runway and Tip Extend has not been selected, the Master Caution/Warning is activated and an appropriate EICAS message appears.

If the airplane is on the runway without the tips extended/locked and GPS speed exceeds X kt, the Master Caution/Warning is activated and an appropriate EICAS message appears.

On Landing, if the airplane is on the runway/taxiway with GPS speed below Y kt, and Tip Fold has not been selected, the Master/Caution Warning is activated and an appropriate EICAS message appears.

[Edited 2015-07-05 05:59:24]

[Edited 2015-07-05 06:27:33]
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NAV30
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RE: 777X Updated Information And Developments Part 11

Sun Jul 05, 2015 1:17 pm

Quoting seabosdca (Reply 103):
An airline with the 350-ish-passenger configurations most 777-9Xs will have

All the publicity I've seen so far says that Boeing are aiming for 400-plus passengers on the 779X? Presumably in the hope of eventually pretty well putting the A380 out of business?

[Edited 2015-07-05 06:28:26]
 
PhoenixVIP
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RE: 777X Updated Information And Developments Part 11

Sun Jul 05, 2015 1:44 pm

Quoting NAV30 (Reply 109):

Its Sunday night and our Mickey Mouse economics comes out of the dark!.

All the publicity I see Airbus are aiming for 600 plus passengers on the A380? Presumably in the hope of eventually pretty well putting the 777X out of business?

Sad and unsubstantiated comments as usuals.

Quoting b777900 (Reply 105):
So 2020 will be the first year of operation? Any chance any sooner like 2017 or 2018?

We're already halfway through 2015. That's not possible. Boeing also have quite a lot of time with this aircraft. They have this segment to themselves until at least the A350-1000 picks up speed. Don't rush the aircraft and make it excellent just like the 777-300ER.
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Boeing778X
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RE: 777X Updated Information And Developments Part 11

Sun Jul 05, 2015 10:22 pm

Quoting NAV30 (Reply 109):
All the publicity I've seen so far says that Boeing are aiming for 400-plus passengers on the 779X? Presumably in the hope of eventually pretty well putting the A380 out of business?

The A380s problems go beyond the 777-9, the most fundamental being the fact that it has not sold in significant numbers besides to EK in the last several years.

This is a topic for another time, but in a nutshell, the A380 needs to be stretched and NEOed (with A350 styled wings, please!) to counter. I admit, it's still relevant for the right missions, but without the changes, the 777-9 will be all the more attractive.

Quoting PhoenixVIP (Reply 111):
All the publicity I see Airbus are aiming for 600 plus passengers on the A380? Presumably in the hope of eventually pretty well putting the 777X out of business?

The 777X is not going anywhere, I'd just accept that. Regardless of what Airbus does, the 777-9 is shaping out to be one of the most powerful rising players in the airline industry. The launch of the 777X was the most successful aircraft launch in history, and it has the reliability, safety and popularity of it's predecessors to back it up.

An A380-900neo is a logical move, but it'll still be a niche aircraft. The A380, by definition, is a niche plane, like the 777-200LR. I'm sure the ME3s, SQ, maybe CX would buy them in numbers, but who else?

Quoting b777900 (Reply 105):
So 2020 will be the first year of operation? Any chance any sooner like 2017 or 2018?

2020 is the EIS target for the -9, and 2021 for the -8.

The prototype and test fleet assembly would probably need to be underway in order for a 2017 EIS, but that's not happening. 2018, probably not, but if, and only if development goes flawlessly and everything goes as planned, maybe 3Q/4Q 2019, at the bare earliest.

The 737 MAX EIS was bumped from 4Q to 3Q 2017, so anything can happen.
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spiah
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RE: 777X Updated Information And Developments Part 11

Sun Jul 05, 2015 11:32 pm

Quoting Boeing778X (Reply 112):
The prototype and test fleet assembly would probably need to be underway in order for a 2017 EIS, but that's not happening. 2018, probably not, but if, and only if development goes flawlessly and everything goes as planned, maybe 3Q/4Q 2019, at the bare earliest.

I'll have to second the doubt on 2017/18. There is absolutely no way the plane will be coming out earlier than 2019, and even then that's a stretch. Through the grapevine I understand everything is moving along at a great pace, but for a 2017 intro, things that are to be finished in 2 years would have to be done tomorrow, and that's just not realistic.


Really excited to see how the wing factory shapes up. It's quite a sight.
 
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Stitch
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RE: 777X Updated Information And Developments Part 11

Mon Jul 06, 2015 12:01 am

Quoting Boeing778X (Reply 112):
The A380s problems go beyond the 777-9, the most fundamental being the fact that it has not sold in significant numbers besides to EK in the last several years.

And yet Emirates holding over half the order book for the 777X, which last scored orders almost a year ago is, of course, just normal service.  
 
jacobin777
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RE: 777X Updated Information And Developments Part 11

Mon Jul 06, 2015 1:51 am

Quoting Stitch (Reply 114):
Quoting Boeing778X (Reply 112):
The A380s problems go beyond the 777-9, the most fundamental being the fact that it has not sold in significant numbers besides to EK in the last several years.

And yet Emirates holding over half the order book for the 777X, which last scored orders almost a year ago is, of course, just normal service.

There really isn't (yet) a major replacement cycle for the B77W/A35JXWB market. Lets see what happens in the next 3-5 years regarding orders between the B77X, A50JXWB and A380. I think we will get a better "feel" for the marketplace between those 3 aforementioned plane types.
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lightsaber
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RE: 777X Updated Information And Developments Part 11

Mon Jul 06, 2015 2:38 am

Quoting LAX772LR (Reply 10):
If its primary purpose is to serve as an ULH platform, then it'll never truly be competitive on a 1-to-1 basis with the A35J, as there's only so much you can do to lighten such a ship without detracting from its ability to hoist heavy loads long distances.

Agreed. The 778 will be a specialized plane like the 77L. This also means as soon as the next generation of ULH aircraft arrive (or the A35J or 779 receive an efficiency or MTOW boost), 778 sales will fall off.

Quoting sunrisevalley (Reply 23):
Tim Clark once described the A35J as a "good" 14hr plane. That will cut it for many carriers but not the operators doing 15hr plus sectors.

The A35J will be a very successful plane. Where the 779 should have an advantage is as a combi thanks to the amazing lower deck volume.

Quoting Jacobin777 (Reply 115):
There really isn't (yet) a major replacement cycle for the B77W/A35JXWB market. Lets see what happens in the next 3-5 years regarding orders between the B77X, A50JXWB and A380. I think we will get a better "feel" for the marketplace between those 3 aforementioned plane types.

I think by the time we have a 'feel' the decision will have been made.

The real unknown is the A380NEO. IMHO if a very efficient one comes out, it will change who buys VLAs. If not offered...

The 779 might be the only VLA offered and on the runs it has a sufficient CASM advantage, it will fill the role the 747, 77W, and A380 once did. I find this topic very interesting. Cargo or pax costs will drive the decision. I fully expect a majority of 777X buyers to also buy the A35J. This will be interesting.

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Max Q
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RE: 777X Updated Information And Developments Part 11

Mon Jul 06, 2015 3:37 am

Quoting OldAeroGuy (Reply 108):
I believe it will be something like this.

Tip fold/extend is always a manual operation, controlled by a lever on the flight deck.

GPS is used to provide configuration warning.

For Takeoff, if the airplane moves on to the runway and Tip Extend has not been selected, the Master Caution/Warning is activated and an appropriate EICAS message appears.

If the airplane is on the runway without the tips extended/locked and GPS speed exceeds X kt, the Master Caution/Warning is activated and an appropriate EICAS message appears.

On Landing, if the airplane is on the runway/taxiway with GPS speed below Y kt, and Tip Fold has not been selected, the Master/Caution Warning is activated and an appropriate EICAS message appears.

Sounds logical, i'm curious to see the actual control switch / lever.


Despite everything you know eventually someone will take off with the wing tips retracted !
The best contribution to safety is a competent Pilot.


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Okcflyer
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RE: 777X Updated Information And Developments Part 11

Mon Jul 06, 2015 3:50 am

I'm sure Boeing test pilots will be the first to do it ... To prove it is safe.
 
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seabosdca
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RE: 777X Updated Information And Developments Part 11

Mon Jul 06, 2015 4:59 am

Quoting Max Q (Reply 117):
Despite everything you know eventually someone will take off with the wing tips retracted !

The tips are a small enough part of the wing area that I expect the aircraft will be able to take off safely even in the worst-case scenario where one tip is retracted, one is not, and an engine is out. I'm curious about the effect this will have on runway length calculations.
 
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DocLightning
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RE: 777X Updated Information And Developments Part 11

Mon Jul 06, 2015 5:09 am

Quoting KarelXWB (Reply 38):
Boeing drops the hybrid laminar flow control drag reduction system:

http://aviationweek.com/commercial-a...ditches-drag-reduction-system-777x

That's interesting. Didn't see that coming. But then again, one of the big challenges to these systems has been making them light enough to be worth their benefit.

Quoting OldAeroGuy (Reply 108):
On Landing, if the airplane is on the runway/taxiway with GPS speed below Y kt, and Tip Fold has not been selected, the Master/Caution Warning is activated and an appropriate EICAS message appears.

The question of exactly when the tips will fold is an interesting one. They need to be folded before the aircraft exits the runway. Perhaps they could be set to begin their folding when the thrust reversers are activated and thrust is advanced?

I've noticed that flight crews often wait until they are well off the runway to stow spoilers and flaps, so I assume that adding a checklist item to be done before exiting the runway could be challenging and might impact the ability of the 77X to use high-speed turnoffs.

I also hope very much that Boeing will be designing this aircraft to be able to fly with the tips retracted, albeit at an efficiency penalty.

I also wonder what the cycle time will be for folding and unfolding. When Tower says "Clear for takeoff, 28L no delays" you don't want to be waiting for the wings to unfold.

It's interesting to think of how the 787 wings were in many ways an evolution of the 777 wing and now the 777 wing will be an evolution of the 787 wing.
-Doc Lightning-

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karadion
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RE: 777X Updated Information And Developments Part 11

Mon Jul 06, 2015 5:20 am

Quoting DocLightning (Reply 120):

Have you seen this document?
http://www.aspireaviation.com/wp-con.../12/777X-airport-compatibility.pdf
It will take 20 seconds for the wingtip to retract or extend. So by the time the plane is about to taxi onto the runway, the pilot should be extending the wingtip. In the opposite situation, the pilot should retract the wingtip once taxiing off the runway.
 
jacobin777
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RE: 777X Updated Information And Developments Part 11

Mon Jul 06, 2015 7:02 am

Quoting lightsaber (Reply 116):

The real unknown is the A380NEO. IMHO if a very efficient one comes out, it will change who buys VLAs. If not offered...

An A388NEO would still have the cargo "problem" whereas an A389NEO wouldn't. If both came out, I would expect the latter to probably sell better (relatively speaking) as it would have fantastic CASM as well as cargo capabilities.

Unfortunately for you lightsaber I still don't see your "Udvar-Hazy Special" happening.  

While the market isn't "huge" for an A38XNEO (just as I've been stating for a decade that the market for the A3XX wasn't going to be too big-certainly less than what Airbus had predicted), I do believe a number of current A388 operators and possibly a few more would purchase an A38XNEO.

Quoting lightsaber (Reply 116):
I fully expect a majority of 777X buyers to also buy the A35J.

Besides NH and EK, it seems that has indeed happened with carriers which have purchased the B77X.
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JoeCanuck
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RE: 777X Updated Information And Developments Part 11

Mon Jul 06, 2015 7:25 am

Quoting OldAeroGuy (Reply 108):
I believe it will be something like this.

I wonder if it would be simpler to design a thrust lever limiter, where it is impossible to push past the power required to taxi without the wingtips extended.
What the...?
 
Max Q
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RE: 777X Updated Information And Developments Part 11

Mon Jul 06, 2015 11:27 pm

Quoting joeCanuck (Reply 123):
I wonder if it would be simpler to design a thrust lever limiter, where it is impossible to push past the power required to taxi without the wingtips extended.

So what happens if this 'thrust limiter' activates at the wrong time ?
Like when you need full thrust.


Not a good idea, better to keep it simple.
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tortugamon
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RE: 777X Updated Information And Developments Part 11

Tue Jul 07, 2015 12:19 am

The VN 789 thread mentions a MoU for 8 778s.

tortugamon
 
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KarelXWB
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RE: 777X Updated Information And Developments Part 11

Tue Jul 07, 2015 7:43 am

Quoting tortugamon (Reply 125):
The VN 789 thread mentions a MoU for 8 778s.

No, they have not signed a MoU.
What we leave behind is not as important as how we've lived.
 
mffoda
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RE: 777X Updated Information And Developments Part 11

Tue Jul 07, 2015 11:17 am

Quoting lightsaber (Reply 116):
Quoting sunrisevalley (Reply 23):
Tim Clark once described the A35J as a "good" 14hr plane. That will cut it for many carriers but not the operators doing 15hr plus sectors.

The A35J will be a very successful plane. Where the 779 should have an advantage is as a combi thanks to the amazing lower deck volume.

Actually, what Clark said was:

"By contrast, Clark sees the Airbus A350-1000 as an aircraft for 10-12 hour missions. “It does not have the legs of the 777X,” he says. "

http://aviationweek.com/commercial-a...on/emirates-sees-major-demand-777x
harder than woodpecker lips...
 
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KarelXWB
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RE: 777X Updated Information And Developments Part 11

Tue Jul 07, 2015 11:20 am

The 10-12 hour was a reference to the original design. The 308t MTOW bump turned the jet into an 14 hour plane.
What we leave behind is not as important as how we've lived.
 
tortugamon
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RE: 777X Updated Information And Developments Part 11

Tue Jul 07, 2015 12:01 pm

Quoting KarelXWB (Reply 126):

I did not say they signed a MoU

tortugamon
 
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rotating14
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RE: 777X Updated Information And Developments Part 11

Tue Jul 07, 2015 12:04 pm

Quoting tortugamon (Reply 125):
Quoting KarelXWB (Reply 126):
http://www.flightglobal.com/news/art...-airlines-nears-777x-order-414343/

While it may not be a Mou at the moment, it will be firm.
 
tortugamon
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RE: 777X Updated Information And Developments Part 11

Tue Jul 07, 2015 4:37 pm

Quoting Matt6461 (Reply 102):
-One thing I am trying to understand, might put up a question in TechOps: Boeing has, in the past, touted the 777X's "thin wing."

Could you see the thinner wing being lighter per m2 of wing area ceteris paribus?

Quoting Jacobin777 (Reply 122):
Besides NH and EK, it seems that has indeed happened with carriers which have purchased the B77X.

I think LH belongs on that list as well. So half the 779 customers have also ordered the A351. Nearly the same is true for the A350-1000 where except for 3 orders for the Air Carabais orders have the A350-1000 airline customers are also 777x customers.

Quoting rotating14 (Reply 130):
While it may not be a Mou at the moment, it will be firm.

I read the articles to mean that VN has largely chosen Boeing at this point but have not settled on the particulars.

VN wants to be a regional powerhouse rivaling SIN and HKG so they will need some direct flights to North America to accomplish this goal. It will be great to see some new ULH routes even if I think these SGN-LAX/SFO/JFK routes seem to be a stretch.

tortugamon
 
astuteman
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RE: 777X Updated Information And Developments Part 11

Tue Jul 07, 2015 7:33 pm

Quoting tortugamon (Reply 131):
Could you see the thinner wing being lighter per m2 of wing area ceteris paribus?

Actually no, because it would need thicker skins to create the same second moment of area as a thicker one in order to withstand the bending moments that will be applied....

Rgds
 
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KarelXWB
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RE: 777X Updated Information And Developments Part 11

Tue Jul 07, 2015 9:03 pm

Quoting tortugamon (Reply 129):
I did not say they signed a MoU

Just making sure we're on the same boat.
What we leave behind is not as important as how we've lived.
 
Okcflyer
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RE: 777X Updated Information And Developments Part 11

Wed Jul 08, 2015 3:04 am

Quoting astuteman (Reply 132):

Quoting tortugamon (Reply 131):
Could you see the thinner wing being lighter per m2 of wing area ceteris paribus?

Actually no, because it would need thicker skins to create the same second moment of area as a thicker one in order to withstand the bending moments that will be applied....

Rgds

Thinner wing shape will have a lower moment of inertia but that doesn't necessarily mean the skin has to be thicker to provide sufficient strength. Although I'm a structural engineer, I'm not professionally familiar with plastic composites. That said, IIRC, composite skin thickness generally has to be thicker than metal equivalent for durability in other load cases such as object impact. I'm also not certain if the materials are isotopic or not, certain thickness may be required in the "in plane" direction (flow path of air) to handle friction / drag as well as torsional loads from the control surfaces. In conclusion, I don't think we can conclude that thinner means heavier just yet.

The higher elasticity of the composite material may also favor a lower moment of inertial to allow for more wing flex for aerodynamic reason as well as ride comfort / turbulence aborsion means.
 
astuteman
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RE: 777X Updated Information And Developments Part 11

Wed Jul 08, 2015 5:13 am

Quoting OKCFlyer (Reply 134):
Although I'm a structural engineer

It also happens to be my engineering discipline (with a specific nautical twist), although I've spent most of my working life in operations management and operational/manufacturing strategy

Quoting OKCFlyer (Reply 134):
In conclusion, I don't think we can conclude that thinner means heavier just yet.

In conclusion, we equally can't conclude that thinner means lighter either, at least not to any meaningful extent.

this might be A-net, but you can't have it both ways.

Quoting OKCFlyer (Reply 134):
That said, IIRC, composite skin thickness generally has to be thicker than metal equivalent for durability in other load cases such as object impact

  
I our specific applications, this is one of the things we've discovered.
And I think it's a primarily reason, along with lightning strike resistance, why CFRP aeronautical structures bring weight benefits that are less than the raw material comparison might otherwise imply.
Still worth doing though.
(not for us, though)

Rgds
 
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TheRedBaron
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RE: 777X Updated Information And Developments Part 11

Wed Jul 08, 2015 5:49 am

At 400 million a piece for a 779 it makes the A380 look like a bargain (provided both get hefty discounts)...

Holy cow !!! it better be a super duper Aircraft....

TRB
The best seat in a Plane is the Jumpseat.
 
Okcflyer
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RE: 777X Updated Information And Developments Part 11

Wed Jul 08, 2015 8:53 am

Quoting astuteman (Reply 135):

Quoting OKCFlyer (Reply 134):
In conclusion, I don't think we can conclude that thinner means heavier just yet.

In conclusion, we equally can't conclude that thinner means lighter either, at least not to any meaningful extent.

Sorry for the confusion as I was not trying to imply it would be lighter by a meaningful extent either. I was just trying to point out minimum thickness may be controlled by other loading case than moment of interia to handle moment / bending loads.

Sounds like a fun career!
 
OldAeroGuy
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RE: 777X Updated Information And Developments Part 11

Wed Jul 08, 2015 4:01 pm

Quoting Matt6461 (Reply 102):
One thing I am trying to understand, might put up a question in TechOps: Boeing has, in the past, touted the 777X's "thin wing."

It's possible the word "thin" was used when the more correct term would have been "slender", ie high aspect ratio. Marketing copy may not reflect accurately the aerodynamic distinction.

In transonic airfoil development, the aim is usually to increase wing sectional thickness (t/c) while maintaining cruise Mach number and/or wing sweep.

Wings with higher t/c are generally lighter for the reasons stated by Astuteman and OKCFlyer, not withstanding the minimum gage consideration raised by OKCFlyer.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
tortugamon
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RE: 777X Updated Information And Developments Part 11

Wed Jul 08, 2015 4:59 pm

Quoting KarelXWB (Reply 100):
- 777-9X: $388.7 => $400.0 million

That's $1 Million per 'seat'!  Wow! A clear indication as to why many airlines chose narrow-body aircraft on a route if they can.

Quoting astuteman (Reply 131):
Quoting OKCFlyer (Reply 133):

Thanks guys, we are lucky to have your contributions.

Quoting KarelXWB (Reply 132):
Just making sure we're on the same boat.

We are! Under no-disillusions here. (at least I don't think so  )

Quoting theredbaron (Reply 135):

At 400 million a piece for a 779 it makes the A380 look like a bargain (provided both get hefty discounts)...

In terms of long haul flying and if airlines used it to its full potential, the A380 is the best bargain in the sky.

That being said I do expect an A380neo to EIS not too long after the 77X and it will certainly come with a price increase in addition to the 5+ years of inflation prices that will be factored in by then as well. The 77X pricing is for a 2021+ model already.

tortugamon
 
astuteman
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RE: 777X Updated Information And Developments Part 11

Wed Jul 08, 2015 5:17 pm

Quoting OldAeroGuy (Reply 137):
It's possible the word "thin" was used when the more correct term would have been "slender", ie high aspect ratio. Marketing copy may not reflect accurately the aerodynamic distinction.

That makes a shedload of sense ....

Quoting tortugamon (Reply 138):
Thanks guys, we are lucky to have your contributions

with the grumpy mood I've been in for last week?   
I'm working on the anger management routine, hill-walking, sex, and alcohol  
Well, 2 out of 3 ain't bad  
Rgds
 
TP313
Posts: 286
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RE: 777X Updated Information And Developments Part 11

Mon Jul 13, 2015 8:11 am

Rumours that the 777X is suffering from "weight gain flu"... (subscription required)

http://leehamnews.com/2015/07/13/boe...freeze-a-bit-heavier-than-planned/
 
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zeke
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RE: 777X Updated Information And Developments Part 11

Mon Jul 13, 2015 8:19 am

Quoting TP313 (Reply 140):

Just check this is not one of these 3 class to 2 class issues again, caused a lot of inaccurate speculation on the 787.
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