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FrenchPotatoEye
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Re: Boeing 777X - Updated Information And Developments

Fri Nov 24, 2017 5:25 pm

Some pretty renderings of the folding wingtips here:

https://twitter.com/StratAero/status/933762857551921152

They almost look like A350-style sharklets when in the upright position.

Can the jet fly with one of these removed, like how it can be done with winglets, for example?
 
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seahawk
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Re: Boeing 777X - Updated Information And Developments

Fri Nov 24, 2017 5:35 pm

Most likely yes. Maybe they can even fly with them in the upright position.
 
StTim
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Re: Boeing 777X - Updated Information And Developments

Fri Nov 24, 2017 5:46 pm

There would be some significant extra drag if they were to fly in the upright position.
 
OldAeroGuy
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Re: Boeing 777X - Updated Information And Developments

Fri Nov 24, 2017 7:37 pm

seahawk wrote:
Most likely yes. Maybe they can even fly with them in the upright position.


Won't fly in the folded position, not structurally possible. While the folded tip will "lock" on the ground to resist side winds it won't meet flight load requirements.

Very sleek installation though. Notice the locking pen holes in the "tabs" that appear below the wing in the folded position. The tip locking mechanism is all internal with no external fairing required.

Provides induced drag reduction without a parasite drag increase. Aero sealing in the tab/hinge is an interesting problem. Wonder how that is addressed.

Wonder if MMEL (or ferry flight) dispatch will be handled with a damaged tip removed and the other side also removed or with the undamaged tip locked in place at the gate and special ground handling/taxi rules applied.
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Re: Boeing 777X - Updated Information And Developments

Fri Nov 24, 2017 8:52 pm

I personally think that folding wingtips are one of the game changers in aircraft design. Real-estate is becoming quite precious at major airports. I expect future terminals to be multi story to provide the flow through and the 777X will be the first of many folding wingtip planes.

They next will either be the MoM or a narrowbody. The advantage of moving more p

Matt6461 wrote:
Probably what the FAA recognizes is that when a 777X is flying close to MTOW and/or field/altitude/heat limitations on takeoff performance, failure of the wingtips would cause it to miss the safety margin for V2 (most likely) or balanced field length. Without the tips, L/D is significantly lower, meaning climb gradient with OEI is significantly lower, meaning you hit the wall. That's a catastrophe.

If that's the case, then Boeing could still earnestly claim that, for example, a 777X with total tip failure (or loss) could ferry from a location for repairs, so long as it was far under MTOW and/or takeoff performance constraints.

The wingtips will be locked in place other than at the gate. There will be fail safes to prevent actuation.

We haven't had a Navy plane suddenly fold wings since 1957 and that was a improperly manufactured structural member in a F2H-3 Banshee. But there were similar crashes in the 1950s due to mis-manufactured structural members of non-folding aircraft.

https://en.wikipedia.org/wiki/List_of_a ... l_failures


iamlucky13 wrote:

Actual failure of the tips is certified against by the static test.

The main concern is takeoff without the wingtips in the flight position and properly locked.

Testing on folding mechanisms is strict. Due to that 1957 failure and a paranoia, the criteria and process will be enforced. If the wingtips are not locked, it will be impossible to ignore.

To others:
I personally do not understand all the concern. If postern here knew what went into certifying an arresting hook, they would understand folding wingtips are not taken for granted. Testing must be completed. Computer models design the components and verify plausibility, but this is a mechanism that will be on the iron bird. There will be dozens of tests on the iron bird to verify the safety features work. Wingtips will be uncoupled, have numerous failure modes tested.

Then they will be verified on the test aircraft. I'll fly on the 777X when given the opportunity.

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StTim
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Re: Boeing 777X - Updated Information And Developments

Fri Nov 24, 2017 9:10 pm

lightsaber wrote:
Real-estate is becoming quite precious at major airports.

LIghtsaber


It isn't only major airports. LTN has many gates that fit the B737/A320 box but very few for B757 size. This to me will lead many new frames to have devices to reduce on the ground wing span.
 
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Re: Boeing 777X - Updated Information And Developments

Fri Nov 24, 2017 10:25 pm

StTim wrote:
lightsaber wrote:
Real-estate is becoming quite precious at major airports.

LIghtsaber


It isn't only major airports. LTN has many gates that fit the B737/A320 box but very few for B757 size. This to me will lead many new frames to have devices to reduce on the ground wing span.


I would imagine there are some interesting studies sitting around at Boeing on the potential market for MOM if it can fold its wings and fit in a 737 box.
 
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Re: Boeing 777X - Updated Information And Developments

Fri Nov 24, 2017 10:28 pm

Why is there so much fear that a folding could fail? Slats and flaps are large aerodynamic surfaces held to their actuation devices (tracks) by just a few pins and these devices are as well held to the wing through a few pins. The slave interfaces of the flaps also feature quite often a hinge. These numerous movable surfaces have an outstanding safety record. When was the last time that a slat or a flap departed from an airborne Boeing?
 
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Re: Boeing 777X - Updated Information And Developments

Fri Nov 24, 2017 10:51 pm

tomcat wrote:
Why is there so much fear that a folding could fail? Slats and flaps are large aerodynamic surfaces held to their actuation devices (tracks) by just a few pins and these devices are as well held to the wing through a few pins. The slave interfaces of the flaps also feature quite often a hinge. These numerous movable surfaces have an outstanding safety record. When was the last time that a slat or a flap departed from an airborne Boeing?


Agree, how long should they be? 4? maybe 4 meters? if less they can just fold down and the lock problem is solved in mid air.
 
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Re: Boeing 777X - Updated Information And Developments

Sat Nov 25, 2017 1:35 am

tomcat wrote:
Why is there so much fear that a folding could fail? Slats and flaps are large aerodynamic surfaces held to their actuation devices (tracks) by just a few pins and these devices are as well held to the wing through a few pins. The slave interfaces of the flaps also feature quite often a hinge. These numerous movable surfaces have an outstanding safety record. When was the last time that a slat or a flap departed from an airborne Boeing?


Great point. And not to mention used every day around the world on military jets. It is not new technology, in any way shape or form. I think the biggest constraint is weight and if it impacts performance negatively. Safety concerns are not really rooted in reality.
 
uta999
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Re: Boeing 777X - Updated Information And Developments

Sat Nov 25, 2017 8:50 am

As a matter of interest, what would be the aerodynamic and control effect (if any), of one breaking off in flight? Would the crew need to retract the other one, or could it just be left down? Wouldn't it then generate too much lift, especially during the approach?
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Re: Boeing 777X - Updated Information And Developments

Sat Nov 25, 2017 9:36 am

Lufthansa new business class seat for B777-9

https://www.ausbt.com.au/photos-lufthan ... s-revealed
 
mjoelnir
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Re: Boeing 777X - Updated Information And Developments

Sat Nov 25, 2017 11:52 am

tomcat wrote:
Why is there so much fear that a folding could fail? Slats and flaps are large aerodynamic surfaces held to their actuation devices (tracks) by just a few pins and these devices are as well held to the wing through a few pins. The slave interfaces of the flaps also feature quite often a hinge. These numerous movable surfaces have an outstanding safety record. When was the last time that a slat or a flap departed from an airborne Boeing?


What fear? There seem to be more posters reassuring us that they will not fail, than posters declaring that they will fail.
I think the discussion rather turns around what an affect a failure would have. like not being able to extend or fold them on the ground or if you could fly the frame with one missing.
 
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Re: Boeing 777X - Updated Information And Developments

Sat Nov 25, 2017 12:43 pm

mjoelnir wrote:
tomcat wrote:
Why is there so much fear that a folding could fail? Slats and flaps are large aerodynamic surfaces held to their actuation devices (tracks) by just a few pins and these devices are as well held to the wing through a few pins. The slave interfaces of the flaps also feature quite often a hinge. These numerous movable surfaces have an outstanding safety record. When was the last time that a slat or a flap departed from an airborne Boeing?


What fear? There seem to be more posters reassuring us that they will not fail, than posters declaring that they will fail.
I think the discussion rather turns around what an affect a failure would have. like not being able to extend or fold them on the ground or if you could fly the frame with one missing.


Regarding the effect of the loss of one of these wingtip could have I don't think that it's anything new to manage in terms of design of systems and structure as long as double failure scenarios don't need to be taken into account. If a winglet (folding type or not) fails beyond V1, there will be plenty of excess thrust available to compensate any drag increase or lift loss because it is assumed that both engines will be operating. There will also be sufficient roll and yaw control authority because 1) the aircraft will have been designed for it and 2) this scenario is probably already well covered by other failure scenarios (like an engine failure).

If dual failures need to be considered in case of the failure of a wingtip (like simultaneous failures of one wingtip and one engine), it would make the design of the aircraft a bit more complex and it could result to increase slightly the thrust requirements compared to current designs. In the end of the day, Boeing would simply design to comply with this requirement which would make the aircraft slightly more costly but as long as the benefits of the folding wingtips are greater than the regulatory burden, these folding wingtips are a given.

Note that when the loss of a component may be catastrophic, it is designed in such a way that the probability of loosing it is low enough to exclude this scenario. Where necessary, the design will also take into account bird strike cases to ensure that the residual strength of a given component and its attachments after a bird strike will be sufficient to avoid the departure of this component.
 
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Re: Boeing 777X - Updated Information And Developments

Sat Nov 25, 2017 2:51 pm

What I learned from material engineering courses is that a connection is manufactured to be sufficiently more robust than what are connected. So if a bird, or any foreign object, strikes the wing of a plane on takeoff, the effect should roughly be similar to a plane with fixed winglets, and one with a folding wingtip.

The success of these folding wingtips will ultimately lead to downsizing of aircraft wingspans on the ground. I imagine a 787 utilizing Code C gates down in 20 years.
 
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Re: Boeing 777X - Updated Information And Developments

Sat Nov 25, 2017 3:24 pm

mjoelnir wrote:
I think the discussion rather turns around what an affect a failure would have. like not being able to extend or fold them on the ground or if you could fly the frame with one missing.


To answer more specifically to this question, the worst case would be to apply the same criteria as to a jammed slat or flap. The delays incurred due to such jammings are pretty rare. Note the the 77X will have 3 flaps on each wing compared to 2 on the current 777 generation (I don't know about the number of slats). It means 4 additional flap mechanisms on the aircraft. Nobody appears to question the impact of these additional mechanism on the dispatch reliability of the 77X. So I wouldn't worry to much about the other 2 extra mechanisms related to the folding wingtips. They are a bit different than the usual mechanisms, but it doesn't seem impossible to make them highly reliable. Just thinking about it, there are also numerous hinges and rotary actuation devices for the cargo and passenger doors, the landing gear doors and for the landing gears themselves. All these doors also involve their own sealing devices.
 
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Re: Boeing 777X - Updated Information And Developments

Sat Nov 25, 2017 3:27 pm

fcogafa wrote:
Lufthansa new business class seat for B777-9

https://www.ausbt.com.au/photos-lufthan ... s-revealed


Did you catch the size of those cabin windows in the LH 777-x mock up? They look bigger than the 787s! I suspect they are not accurate, but I hope they are!
 
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Re: Boeing 777X - Updated Information And Developments

Sun Nov 26, 2017 7:01 pm

Planesmart wrote:
What if the wing tips are in the folded position when landing due to a malfunction, the landing is aborted, and full power required? In this scenario, will crosswinds also be a greater issue?


If you look at the design you will understand that there is no possible way other than structural failure for the wingtips to fold when they are under load. The load places a friction lock on the locking pins, so they cannot be retracted in flight. The failure mode would be a failure of extension prior to takeoff, in which case the procedure would be to not proceed with takeoff.

The mechanism for the wingtip is much simpler than the mechanisms for the various forms of flaps and ailerons found on airplanes and yet nobody bites their nails about those failing.
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JAAlbert
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Re: Boeing 777X - Updated Information And Developments

Sun Nov 26, 2017 8:18 pm

It seems to me that folding wingtips would be a great addition to most aircraft, particularly at an airport like LAX where every plane faces a tight squeeze pulling up to and away from the gates. The ability to squeeze a 757, 767 or 330 into a smaller gate seems advantageous and with the wing strikes that happen from time to time having a bit more space to maneuver makes sense.

I can't wait to see my first 777-9 (or 8) at the gate with the tips folded!
 
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Re: Boeing 777X - Updated Information And Developments

Sun Nov 26, 2017 9:20 pm

KarelXWB wrote:
The FAA proposes special conditions for the 777X family.

https://www.federalregister.gov/documen ... g-wingtips

http://aviationweek.com/commercial-avia ... g-wingtips tells us:

The FAA issues special conditions when the airworthiness regulations “do not contain adequate or appropriate safety standards because of a novel or unusual design feature.” Although Boeing is applying for certification of the 777X under an amended type certificate based on the existing 777, the wing-fold feature that extends and retracts the last 12 ft. of the aircraft’s all-new composite wing is not covered by existing regulations.

And for those who got nervous when they read the word "catastrophic",

Boeing points out that when it classifies hazards for aircraft events as part of its design-standards safety process, any extremely improbable aircraft-level failure of a critical system automatically defaults to being classified as “catastrophic.” Such systems include flight controls or brakes. The company says this extreme classification is used “to drive the appropriate high-integrity system architectures, design redundancies, and safety features to preclude such events.”

“This same safety and certification methodology was used with our new folding wingtip to ensure a robust systems architecture with mechanical and electrical redundancy, high-integrity control and monitoring architecture, and structural fail-safe load paths from wingtip to fixed wing” Boeing adds.

The article goes through a lot more about how the wingtips will be tested.
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Re: Boeing 777X - Updated Information And Developments

Sun Nov 26, 2017 10:06 pm

JAAlbert wrote:
It seems to me that folding wingtips would be a great addition to most aircraft, particularly at an airport like LAX where every plane faces a tight squeeze pulling up to and away from the gates. The ability to squeeze a 757, 767 or 330 into a smaller gate seems advantageous and with the wing strikes that happen from time to time having a bit more space to maneuver makes sense.

I can't wait to see my first 777-9 (or 8) at the gate with the tips folded!



Well, 787 and A330ceo have to lose 9m in wingspan to be able to fit into smaller gates. It means they would have folding wingtips that are longer than the ones 777X. How long would the folding tips have to be before it becomes unfeasible? (in terms of design, weight, and maintenance)
 
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Re: Boeing 777X - Updated Information And Developments

Sun Nov 26, 2017 10:49 pm

Eyad89 wrote:
Well, 787 and A330ceo have to lose 9m in wingspan to be able to fit into smaller gates. It means they would have folding wingtips that are longer than the ones 777X. How long would the folding tips have to be before it becomes unfeasible? (in terms of design, weight, and maintenance)


While never introduced into service, the 777-200's folding wingtips were 6.5m long. However, at that length they included control surfaces and that raised the weight and complexity a fair bit over those on the 777X, which do not include control surfaces.
 
carlokiii
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 1:04 am

Eyad89 wrote:

Well, 787 and A330ceo have to lose 9m in wingspan to be able to fit into smaller gates. It means they would have folding wingtips that are longer than the ones 777X. How long would the folding tips have to be before it becomes unfeasible? (in terms of design, weight, and maintenance)

Both planes need just about 8m off their wings to fit in 767-sized gates, which Boeing thought was doable enough to actually offer chopped wings in the 787-3 version.

The 777X loses 7m with its wings folded, half a meter more on each side wouldn't be impossible to achieve. Though folding 11% of the 777X wings would be less complex than folding 15% of the A330/787's wings.
 
Eyad89
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 3:43 am

Yeah, but the whole idea made sense for 777X because they wanted a longer span for better performance. 787, on the other hand, would just do it to be able to fit into smaller gates, as the span would remain the same. Is it worth it?
 
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 4:52 am

Ultimately, the maximum viable folding length will be the first control surface and/or fuel tankage, whichever comes first on that particular wing.
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 10:16 am

The GE9X is ready for its first flight.

Image
https://twitter.com/rupaharia/status/935076206579519488
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 10:59 am

KarelXWB wrote:
The GE9X is ready for it's first flight.

Holy cow! It's for sure an optical illusion but it really looks huge... :wideeyed:
 
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 11:01 am

Some details in this Aviation Week article: http://aviationweek.com/commercial-avia ... ied-flight

Impressive, that's the one word which springs to mind!
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 12:17 pm

N14AZ wrote:
KarelXWB wrote:
The GE9X is ready for it's first flight.

Holy cow! It's for sure an optical illusion but it really looks huge... :wideeyed:


I'm not sure it is an optical illusion. I think it really is that big.

What I find impressive is how small the core looks behind that enormous fan.
 
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 12:34 pm

This is really WOW, when is the first flight of the engine?
 
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 12:59 pm

Slash787 wrote:
When the 787's were having their test flights, I wrote on the Boeing FB page that put a 787 flight deck in a 777 and now after 7 years it is actually happening.


It's not entirely the same flight deck. For example, the 777X uses touch screen monitors in the cockpit. The 787 does not.

FrenchPotatoEye wrote:
Some pretty renderings of the folding wingtips here:


Those renders were captured from this video BTW: https://twitter.com/BoeingAirplanes/sta ... 6301138944
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holzmann
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 1:54 pm

Does anyone have a brief comparison (differences, pros/cons) of the GE9X vs. GE90-115B?
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 2:22 pm

holzmann wrote:
Does anyone have a brief comparison (differences, pros/cons) of the GE9X vs. GE90-115B?

Not exactly a comparison, but is brief:

Image

Not so brief coverage: viewtopic.php?t=771715
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 2:38 pm

It would be handy to see a side on view of the engine on the test bed for comparison also.

But first impression, wow! Huge engine.
 
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 2:51 pm

Compared to the CF6-80 next to it, the GE9X cowl is extremely thick (not sure why)- lots of drag
 
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 2:53 pm

The GE9X is ready for it's first flight.

Holy cow! It's for sure an optical illusion but it really looks huge... :wideeyed:

I'm not sure it is an optical illusion. I think it really is that big.

That's what HE said! :biggrin:

kurtverbose wrote:
What I find impressive is how small the core looks behind that enormous fan.

Yes, and also the picture I just posted in #2583 also gives an idea of how small the core is.

There must have been some interesting trade studies over less compressor stages vs bigger core.

I'd guess that they'd be better off with less stages (shorter engine weighs less) but then again my guess looks to be wrong.
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 2:55 pm

KarelXWB wrote:
It's not entirely the same flight deck. For example, the 777X uses touch screen monitors in the cockpit. The 787 does not.


I know its not entirely the same flight deck, but its something which happened which I predicted.
 
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 4:57 pm

Apologies for what may be a very ignorant question: will the engine for the 777X (9) be larger than the current 77W engine? Will the 777-8 and 9 share the same engine? Is there a comparison chart somewhere?
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Stitch
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 5:03 pm

VC10er wrote:
Apologies for what may be a very ignorant question: will the engine for the 777X (9) be larger than the current 77W engine? Will the 777-8 and 9 share the same engine? Is there a comparison chart somewhere?


The GE9X will have a 134" fan compared to the 123" fan of the GE90-11xB and the 777-8 and 777-9 will have the same engine.
 
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 5:10 pm

VC10er wrote:
Apologies for what may be a very ignorant question: will the engine for the 777X (9) be larger than the current 77W engine?

Yes. GE90-115 fan is 128 inches, GE9x is 132 inches.

Will the 777-8 and 9 share the same engine?

Yes. Might be a software de-rate like GE90-115 vs GE90-110.

Is there a comparison chart somewhere?

I couldn't find one. I think the reality is that there is a captive audience so not much of a motivation for the marketing team to make such a chart.
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 5:12 pm

Stitch wrote:
VC10er wrote:
Apologies for what may be a very ignorant question: will the engine for the 777X (9) be larger than the current 77W engine? Will the 777-8 and 9 share the same engine? Is there a comparison chart somewhere?


The GE9X will have a 134" fan compared to the 123" fan of the GE90-11xB and the 777-8 and 777-9 will have the same engine.

You may be right, but https://www.ge.com/stories/aviation-ge9x currently gives us 132 inches not 134.
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 5:51 pm

Revelation wrote:
Stitch wrote:
The GE9X will have a 134" fan compared to the 123" fan of the GE90-11xB and the 777-8 and 777-9 will have the same engine.

You may be right, but https://www.ge.com/stories/aviation-ge9x currently gives us 132 inches not 134.


I went with the Wiki article which says 134", but they're measuring the fan case, but then so is the 2013 Paris presentation that gives the fan case as 132". The original fan was the same 128" diameter as the GE90-11xB, but GE has been pushing it up as they finalize the design so I'm guessing it's ~134" now as that is what the latest GE data says.
 
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 6:03 pm

Haven't they had to up the output from that originally envisaged?
 
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 6:14 pm

Revelation wrote:
I'd guess that they'd be better off with less stages (shorter engine weighs less) but then again my guess looks to be wrong.


Higher bypass ratio increases power density in the core. ( aided by higher pressure ratio.)?

I've seen a trade off diagram somewhere that presented optimal bypass ratio as a function of core efficiencies.
at one time back then a BPR of 1:1.5 was optimum as power extraction in the core was much lower.
( a virtual beer for the person who finds that diagramm ( afair done by some guy from RR ) )
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Stitch
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 6:28 pm

StTim wrote:
Haven't they had to up the output from that originally envisaged?


MTOW has risen to match that of the LR777 at 351,000kg so thrust has been increased as well (now to 105,000 pounds) to compensate.
 
holzmann
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 6:59 pm

I read somewhere (here) that GE has come in overweight on the engine. Is this true? How much of a setback is this for the 777X program?
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Stitch
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 7:05 pm

holzmann wrote:
I read somewhere (here) that GE has come in overweight on the engine. Is this true? How much of a setback is this for the 777X program?


Well there is this thread - viewtopic.php?t=1379051 - where GE notes the GE9X will be a bit heavier than the GE90, but that is not surprising considering the larger fan.
 
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Revelation
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 7:19 pm

Stitch wrote:
holzmann wrote:
I read somewhere (here) that GE has come in overweight on the engine. Is this true? How much of a setback is this for the 777X program?


Well there is this thread - viewtopic.php?t=1379051 - where GE notes the GE9X will be a bit heavier than the GE90, but that is not surprising considering the larger fan.

Thanks for the pointer.

My favorite quote from that thread:

Slide wrote:
All of these things can be true with respect to the GE90: 1) 9X is heavier, 2) 9X delivers less thrust, 3) 9X is more fuel efficient, 4) 777X as a whole is more fuel efficient.

Weight is an important metric, but there's many cases where you'll accept additional weight for other improvements, such as higher pressure ratio, or longer wings with better L/D, etc.

Also thanks for the info on fan diameter vs case diameter.
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redflyer
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 7:36 pm

kurtverbose wrote:
N14AZ wrote:
KarelXWB wrote:
The GE9X is ready for it's first flight.

Holy cow! It's for sure an optical illusion but it really looks huge... :wideeyed:


I'm not sure it is an optical illusion. I think it really is that big.

What I find impressive is how small the core looks behind that enormous fan.


As others have pointed out, the diameter is only a few inches more than the GE90. However, what might be giving it the illusion of being really bigger is the fact that the fan on the 9X has fewer blades than its predecessor.
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AndyW35
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Re: Boeing 777X - Updated Information And Developments

Mon Nov 27, 2017 9:31 pm

The cowl looks very thick, is that because it needs to be for containment purposes due to the fan blades being so big, hence more kinetic energy?

I am no expert though.

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