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Opus99
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 11:23 am

flipdewaf wrote:
VV wrote:
VV wrote:

No there is no plan to increase the MTOW beyond 775,000 lbs.


By the way, it may be important to not change the MTOW target for now even if it is technically possible.

Increasing the MTOW would be the last resort if they absolutely need to meet contractual commitments on payloads or range. It is even possible it would be given as an option to affected customers.

It is more important to maintain the motivation on the design bureau to reduce the aircraft's empty weight.

At this stage, I think Boeing already has an idea whether they would meet the weight target of the aircraft.
Components have been weighed for the four flight test aircraft and the different production airframes. Even complete aircraft have been weighed, albeit with the flight test instruments.

Obviously they are not going to tell us the details.


I'm hoping we see the range creeping up from the 7285 figure. I would like to see Boeing confidently state a Pax+Bags range of closer to the original ~7500 or even up to 7700nm. As it stands it looks a bit like payload could be taking a hit and this bird needs that to be successful I think.

Fred

Range will go above 14,000KM. Boeing website has been stating 13,500 for sometime long time but their press release when BA ordered (FEB 2019) states the range at 14,075KM Although everywhere else states at 13500
 
flipdewaf
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 11:53 am

Opus99 wrote:
flipdewaf wrote:
VV wrote:

By the way, it may be important to not change the MTOW target for now even if it is technically possible.

Increasing the MTOW would be the last resort if they absolutely need to meet contractual commitments on payloads or range. It is even possible it would be given as an option to affected customers.

It is more important to maintain the motivation on the design bureau to reduce the aircraft's empty weight.

At this stage, I think Boeing already has an idea whether they would meet the weight target of the aircraft.
Components have been weighed for the four flight test aircraft and the different production airframes. Even complete aircraft have been weighed, albeit with the flight test instruments.

Obviously they are not going to tell us the details.


I'm hoping we see the range creeping up from the 7285 figure. I would like to see Boeing confidently state a Pax+Bags range of closer to the original ~7500 or even up to 7700nm. As it stands it looks a bit like payload could be taking a hit and this bird needs that to be successful I think.

Fred

Range will go above 14,000KM. Boeing website has been stating 13,500 for sometime long time but their press release when BA ordered (FEB 2019) states the range at 14,075KM Although everywhere else states at 13500


I recall they did have it at 7525nm for a while and then moved it down to 7285, I'm not sure if this coincided with a change in cabin layout and an increase in the standard from 414 to 426 pax 2-class. I would expect the BA config to hold significantly less than either of these figures, probably closer to 300pax. I don't think BA would be putting it near its Maximum Range anyway.

Fred
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GEUltraFan9XGTF
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 12:08 pm

I am optimistically going to say that one the reasons why the 778 is "dying" in pax form is because the 779 will meet the 778 range target with full pax and bags/cargo. It will be a beast. The 778 will still be the basis for an amazing freighter replacement of the 777F.
© 2020. All statements are my own. The use of my statements, including by journalists, YouTube vloggers like "DJ's Aviation", etc. without my written consent is strictly prohibited.
 
flipdewaf
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 12:29 pm

GEUltraFan9XGTF wrote:
I am optimistically going to say that one the reasons why the 778 is "dying" in pax form is because the 779 will meet the 778 range target with full pax and bags/cargo. It will be a beast. The 778 will still be the basis for an amazing freighter replacement of the 777F.
19.3% range increase? They might get 8K out if it if they increase the MTOW to 360t but thats still make believe at this time.

The 777F has a max payload of ~103t out to 4970nm requiring ~100t of fuel.

If the 777XF has an increase of 20t in the empty weight Up to about 165tt then to keep the payload the same the MZFW will have to be about 268t and will need to be 17% less fuel to get to the same range. I don't see 17% improvement being likely. If the Ge9X could be integrated to the current platform then the bulk of the fuel savings could be ported to a platform with higher available weight for fuel/payload (Impact of higher weight engines admittedly not included).

Last post on the matter from me as I realise this is off topic.

Fred
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morrisond
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 2:23 pm

flipdewaf wrote:
GEUltraFan9XGTF wrote:
I am optimistically going to say that one the reasons why the 778 is "dying" in pax form is because the 779 will meet the 778 range target with full pax and bags/cargo. It will be a beast. The 778 will still be the basis for an amazing freighter replacement of the 777F.
19.3% range increase? They might get 8K out if it if they increase the MTOW to 360t but thats still make believe at this time.

The 777F has a max payload of ~103t out to 4970nm requiring ~100t of fuel.

If the 777XF has an increase of 20t in the empty weight Up to about 165tt then to keep the payload the same the MZFW will have to be about 268t and will need to be 17% less fuel to get to the same range. I don't see 17% improvement being likely. If the Ge9X could be integrated to the current platform then the bulk of the fuel savings could be ported to a platform with higher available weight for fuel/payload (Impact of higher weight engines admittedly not included).

Last post on the matter from me as I realise this is off topic.

Fred


Fred - Curious - How do you get a 20T increase in MTOW? Just the length increase?

From a post I made a few weeks ago

""I would agree. I think Boeing probably threw a lot more engineering resources at this bird to get the OEW weight down once they saw how good the A350 was turning out.

If they didn't - then it's their failure. But there isn't much that isn't brand spanking new on this aircraft except for the Outer Mold line, nose and probably lower lobe. It really is a new aircraft and should have been certificated as such.

Everything is basically new.

787 Cockpit/systems (except for 777 Bleed systems)
New Lighter Interior
New WIngBox
New Gear
New Wing
New Tail


I found a neat number on the A320 that the barrel and nose is only 3% of MTOW - say that is about Double on something like an 777 and OEW weight is about 55% of MTOW - so that means that by weight at least 90% of the aircraft/structure was touched.

Boeing uses many of the same tools and Vendors as Airbus. Given another 3-4 years of development time is it not reasonable to assume OEW weight is going to come in a lot better than some of the assumptions on here? I have seen as high as 190T which seems silly.

Wiki now puts it at 177T according to Bjorn Fehrm (March 7, 2019). "Boeing's 777X analyzed, Part 4"

It could be a closer to 170T which could make it's economics even better. The 777W is at 168T (but is that pre the 2016 weight savings program?)

777X is longer - but same MTOW. They could have saved a lot of weight elsewhere - if not - why did they change so many things?"


From reports - the 777X wing is no heavier than 77W and engines are no heavier either. I would have to assume all the systems and tail are lighter. Windows may be heavier in 777X - but the freighter has no windows.

Unless they beefed up the gear for a higher MTOW it has the same dimensions as 77W gear - so 15-20 years newer you would hope it's lighter as well ( I believe it's a new design).
 
VV
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 3:35 pm

Opus99 wrote:
...
Range will go above 14,000KM. Boeing website has been stating 13,500 for sometime long time but their press release when BA ordered (FEB 2019) states the range at 14,075KM Although everywhere else states at 13500


14,000 km = 7,559 nmi ; 13,500 km = 7,289 nmi
Boeing's web site mentions 777-9's range of 7,285 nmi with 426 passengers.

Depending on the payload and OEW you can play around in term of range. Basically with about 300 passengers and an OEW of 407,300 lbs it can go farther than 8,000 nmi equivalent still air distance. Do you need more capability than that? I am not so sure.

Increasing the MTOW (and range) when there is not much competition is just useless.

However, increasing TO thrust rating might be useful for some airports like JNB, BOG, MEX or BOM, depending on the route (the distance) to fly.
For most airlines a TO thrust of 105,000 lb is largely enough.

I plotted a payload range with an OEW of 407,000 lbs. It is using the typical fuel reserve used by "normal" airline for evaluation.
  • contingency fuel: 5% of trip fuel
  • 200 nmi diversion
  • 30 minute hold above alternate
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MileHFL400
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 3:40 pm

Any news on actual flights? When is XY supposed to take to the skies?
Thanks and best Regards
AA
 
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VCVSpotter
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 3:46 pm

MileHFL400 wrote:
Any news on actual flights? When is XY supposed to take to the skies?


According to this post, they estimate sometime in June 2020. As someone who has tracked the 777-9 program heavily, I think that they’re correct.

https://mobile.twitter.com/b777xlovers/ ... 2431974402
https://docs.google.com/spreadsheets/d/ ... edit#gid=0

Just a normal teenager juggling AP classes and airplanes. No biggie • Love the 747 & 777-9 • Farewell BA/KL 744s
 
morrisond
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 4:31 pm

VV wrote:
Opus99 wrote:
...
Range will go above 14,000KM. Boeing website has been stating 13,500 for sometime long time but their press release when BA ordered (FEB 2019) states the range at 14,075KM Although everywhere else states at 13500


14,000 km = 7,559 nmi ; 13,500 km = 7,289 nmi
Boeing's web site mentions 777-9's range of 7,285 nmi with 426 passengers.

Depending on the payload and OEW you can play around in term of range. Basically with about 300 passengers and an OEW of 407,300 lbs it can go farther than 8,000 nmi equivalent still air distance. Do you need more capability than that? I am not so sure.

Increasing the MTOW (and range) when there is not much competition is just useless.

However, increasing TO thrust rating might be useful for some airports like JNB, BOG, MEX or BOM, depending on the route (the distance) to fly.
For most airlines a TO thrust of 105,000 lb is largely enough.

I plotted a payload range with an OEW of 407,000 lbs. It is using the typical fuel reserve used by "normal" airline for evaluation.
  • contingency fuel: 5% of trip fuel
  • 200 nmi diversion
  • 30 minute hold above alternate
Image


185T OEW? Somehow I doubt it will be that Heavy - even Leeham is estimating 177T and many think it could be lighter than that - a lot closer to 170T.

How about rerunning with those specs - it's probably a lot better than 7,285NM with 426 Passengers.
 
flipdewaf
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 5:08 pm

morrisond wrote:
flipdewaf wrote:
GEUltraFan9XGTF wrote:
I am optimistically going to say that one the reasons why the 778 is "dying" in pax form is because the 779 will meet the 778 range target with full pax and bags/cargo. It will be a beast. The 778 will still be the basis for an amazing freighter replacement of the 777F.
19.3% range increase? They might get 8K out if it if they increase the MTOW to 360t but thats still make believe at this time.

The 777F has a max payload of ~103t out to 4970nm requiring ~100t of fuel.

If the 777XF has an increase of 20t in the empty weight Up to about 165tt then to keep the payload the same the MZFW will have to be about 268t and will need to be 17% less fuel to get to the same range. I don't see 17% improvement being likely. If the Ge9X could be integrated to the current platform then the bulk of the fuel savings could be ported to a platform with higher available weight for fuel/payload (Impact of higher weight engines admittedly not included).

Last post on the matter from me as I realise this is off topic.

Fred


Fred - Curious - How do you get a 20T increase in MTOW? Just the length increase?
at 6m longer and 2.2t/m there is 13.2tons. That comparison though is between two PAX A/C so includes relevant things such as furnushins so the realistic difference in weigh outside of what PAX require would give you closer about 1.8t/m giving 10.8t.

the wing span is increased by ~10%. As a cantilevered beam this would result in an increase of span^2 in the required loads carried and as such with similar material would have a weight increase of span^3, the other major wing scaling factors are the MZFW and the T/C. As the Wing appears to cruise at the same speed and fits broadly where the old when went then the T?C can be assumed to be held pretty steady. The MZFW has increased from 237t to 255t (7.6% increase).

With and increase from ~47t wing weight for the base model then we would expect a wing weight in the order odf 67t but as you say there is likely some reduction because of the new materials, likely in the order of 10% giving a wing weight increase of around 11t.

We are at 21.8t so far...

The engines are heavier I believe, not sure on the figure though.

morrisond wrote:
From a post I made a few weeks ago

""I would agree. I think Boeing probably threw a lot more engineering resources at this bird to get the OEW weight down once they saw how good the A350 was turning out.

If they didn't - then it's their failure.

Are you suggesting that they weren't already trying to maximise performance and still leaving things in reserve? Boeing have more sense than using knee jerk reactions to complex engineering programs.

morrisond wrote:
But there isn't much that isn't brand spanking new on this aircraft except for the Outer Mold line, nose and probably lower lobe. It really is a new aircraft and should have been certificated as such.

Everything is basically new.

787 Cockpit/systems (except for 777 Bleed systems)
New Lighter Interior
New WIngBox
New Gear
New Wing
New Tail

Bigger wing/wingbox is the issue here

morrisond wrote:

I found a neat number on the A320 that the barrel and nose is only 3% of MTOW - say that is about Double on something like an 777 and OEW weight is about 55% of MTOW - so that means that by weight at least 90% of the aircraft/structure was touched.

Boeing uses many of the same tools and Vendors as Airbus. Given another 3-4 years of development time is it not reasonable to assume OEW weight is going to come in a lot better than some of the assumptions on here? I have seen as high as 190T which seems silly.

If they are using the same vendors and tools why do they get different physics?

morrisond wrote:

Wiki now puts it at 177T according to Bjorn Fehrm (March 7, 2019). "Boeing's 777X analyzed, Part 4"

It could be a closer to 170T which could make it's economics even better. The 777W is at 168T (but is that pre the 2016 weight savings program?)

777X is longer - but same MTOW. They could have saved a lot of weight elsewhere - if not - why did they change so many things?"

Because as it stood the 777 was going to get eaten alive by the A350.

There two options on the table were:
a. reduce the weight to compete directly with the A350
b. Increase performance within the weight of the current aircraft

Option a leads to more direct competition with the 787 stablemate and and is difficult to the point of a new aircraft being easier. A new component needs fully recertifying but an old one at higher weights needs deomonstrating its good for the higher loads (more analysis)/

Option B allows them to increase the size and take it out of direct competition with the A350 to a certain extent.

thats why many things were changed.

morrisond wrote:


From reports - the 777X wing is no heavier than 77W and engines are no heavier either. I would have to assume all the systems and tail are lighter. Windows may be heavier in 777X - but the freighter has no windows.

Can you post them? Basic strutural engineering would say there's a lot to be made up there, the 787 didn't manage all that much vs the A330.
morrisond wrote:

Unless they beefed up the gear for a higher MTOW it has the same dimensions as 77W gear - so 15-20 years newer you would hope it's lighter as well ( I believe it's a new design).
Were thay bad at landing gear when they did the first?

Fred
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Opus99
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 5:24 pm

Leeham analyses thé 777X particularly the -9 in a four part article that’s behind a paywall. Basically the wing apparently has kept its weight with the 77W. The engine I believe is slightly heavier by about 2.5 tonnes and the extra length of the fuselage adds 2 tonnes and then the only thing that brings the most weight gain is the centre wing box which is still Aluminum and reinforced with titanium if I remember. So I believe that’s what takes it to 177T
 
VV
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 7:38 pm

morrisond wrote:
...
185T OEW? Somehow I doubt it will be that Heavy - even Leeham is estimating 177T and many think it could be lighter than that - a lot closer to 170T.

How about rerunning with those specs - it's probably a lot better than 7,285NM with 426 Passengers.


You believe it or not, it does not matter to me. I stand by my number of 407,300 lb OEW.

an OEW of 177 tonnes (390,000 lb) is way too light in my opinion, but it is up to you which one to believe.

Image
 
Opus99
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 7:45 pm

VV wrote:
morrisond wrote:
...
185T OEW? Somehow I doubt it will be that Heavy - even Leeham is estimating 177T and many think it could be lighter than that - a lot closer to 170T.

How about rerunning with those specs - it's probably a lot better than 7,285NM with 426 Passengers.


You believe it or not, it does not matter to me. I stand by my number of 407,300 lb OEW.

an OEW of 177 tonnes (390,000 lb) is way too light in my opinion, but it is up to you which one to believe.

Image

That means it weighs heavier than a 747-400...damn. If it truly weighs heavier than a 747 then I’m not sure what Boeing think they’re doing
 
VV
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 7:49 pm

Opus99 wrote:
VV wrote:
morrisond wrote:
...
185T OEW? Somehow I doubt it will be that Heavy - even Leeham is estimating 177T and many think it could be lighter than that - a lot closer to 170T.

How about rerunning with those specs - it's probably a lot better than 7,285NM with 426 Passengers.


You believe it or not, it does not matter to me. I stand by my number of 407,300 lb OEW.

an OEW of 177 tonnes (390,000 lb) is way too light in my opinion, but it is up to you which one to believe.

Image

That means it weighs heavier than a 747-400...damn. If it truly weighs heavier than a 747 then I’m not sure what Boeing think they’re doing


Well, maybe so.
 
morrisond
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 8:04 pm

Opus99 wrote:
Leeham analyses thé 777X particularly the -9 in a four part article that’s behind a paywall. Basically the wing apparently has kept its weight with the 77W. The engine I believe is slightly heavier by about 2.5 tonnes and the extra length of the fuselage adds 2 tonnes and then the only thing that brings the most weight gain is the centre wing box which is still Aluminum and reinforced with titanium if I remember. So I believe that’s what takes it to 177T



Then take out weight for the new 787 Style tail, 787 systems/avionics, 787 Interior.

As far as I can recall - The engines did not gain any weight - heavier core offset by lighter Fan.

If it is 185T they failed.
 
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Stitch
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 8:10 pm

177,000kg sounds too light to me.

Last numbers I saw from Leeham.net for the 777-9 was 185,000kg which was "corroborated" by Daniel Tsang. Boeing themselves said the OEW was at 188,000kg at their Post-2014 Design Gate.

The only one I have seen claiming the 777-9 would be overly "light" was Aspire Aviation, who claimed it was 164,000kg at the Post-2014 Design Gate (a figure 24,000kg lower than Boeing's). Aspire did say 188,000kg for a 300-seat four-class Revision E airframe which does match Boeing's P2014 DG numbers, so that could be the configuration Boeing was giving.

And yes, 188,000kg is close to the Boeing OEM OEW of a 747-400ER.
 
morrisond
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 8:12 pm

flipdewaf wrote:
morrisond wrote:
flipdewaf wrote:
19.3% range increase? They might get 8K out if it if they increase the MTOW to 360t but thats still make believe at this time.

The 777F has a max payload of ~103t out to 4970nm requiring ~100t of fuel.

If the 777XF has an increase of 20t in the empty weight Up to about 165tt then to keep the payload the same the MZFW will have to be about 268t and will need to be 17% less fuel to get to the same range. I don't see 17% improvement being likely. If the Ge9X could be integrated to the current platform then the bulk of the fuel savings could be ported to a platform with higher available weight for fuel/payload (Impact of higher weight engines admittedly not included).

Last post on the matter from me as I realise this is off topic.

Fred


Fred - Curious - How do you get a 20T increase in MTOW? Just the length increase?
at 6m longer and 2.2t/m there is 13.2tons. That comparison though is between two PAX A/C so includes relevant things such as furnushins so the realistic difference in weigh outside of what PAX require would give you closer about 1.8t/m giving 10.8t.

the wing span is increased by ~10%. As a cantilevered beam this would result in an increase of span^2 in the required loads carried and as such with similar material would have a weight increase of span^3, the other major wing scaling factors are the MZFW and the T/C. As the Wing appears to cruise at the same speed and fits broadly where the old when went then the T?C can be assumed to be held pretty steady. The MZFW has increased from 237t to 255t (7.6% increase).

With and increase from ~47t wing weight for the base model then we would expect a wing weight in the order odf 67t but as you say there is likely some reduction because of the new materials, likely in the order of 10% giving a wing weight increase of around 11t.

We are at 21.8t so far...

The engines are heavier I believe, not sure on the figure though.

morrisond wrote:
From a post I made a few weeks ago

""I would agree. I think Boeing probably threw a lot more engineering resources at this bird to get the OEW weight down once they saw how good the A350 was turning out.

If they didn't - then it's their failure.

Are you suggesting that they weren't already trying to maximise performance and still leaving things in reserve? Boeing have more sense than using knee jerk reactions to complex engineering programs.

morrisond wrote:
But there isn't much that isn't brand spanking new on this aircraft except for the Outer Mold line, nose and probably lower lobe. It really is a new aircraft and should have been certificated as such.

Everything is basically new.

787 Cockpit/systems (except for 777 Bleed systems)
New Lighter Interior
New WIngBox
New Gear
New Wing
New Tail

Bigger wing/wingbox is the issue here

morrisond wrote:

I found a neat number on the A320 that the barrel and nose is only 3% of MTOW - say that is about Double on something like an 777 and OEW weight is about 55% of MTOW - so that means that by weight at least 90% of the aircraft/structure was touched.

Boeing uses many of the same tools and Vendors as Airbus. Given another 3-4 years of development time is it not reasonable to assume OEW weight is going to come in a lot better than some of the assumptions on here? I have seen as high as 190T which seems silly.

If they are using the same vendors and tools why do they get different physics?

morrisond wrote:

Wiki now puts it at 177T according to Bjorn Fehrm (March 7, 2019). "Boeing's 777X analyzed, Part 4"

It could be a closer to 170T which could make it's economics even better. The 777W is at 168T (but is that pre the 2016 weight savings program?)

777X is longer - but same MTOW. They could have saved a lot of weight elsewhere - if not - why did they change so many things?"

Because as it stood the 777 was going to get eaten alive by the A350.

There two options on the table were:
a. reduce the weight to compete directly with the A350
b. Increase performance within the weight of the current aircraft

Option a leads to more direct competition with the 787 stablemate and and is difficult to the point of a new aircraft being easier. A new component needs fully recertifying but an old one at higher weights needs deomonstrating its good for the higher loads (more analysis)/

Option B allows them to increase the size and take it out of direct competition with the A350 to a certain extent.

thats why many things were changed.

morrisond wrote:


From reports - the 777X wing is no heavier than 77W and engines are no heavier either. I would have to assume all the systems and tail are lighter. Windows may be heavier in 777X - but the freighter has no windows.

Can you post them? Basic strutural engineering would say there's a lot to be made up there, the 787 didn't manage all that much vs the A330.
morrisond wrote:

Unless they beefed up the gear for a higher MTOW it has the same dimensions as 77W gear - so 15-20 years newer you would hope it's lighter as well ( I believe it's a new design).
Were thay bad at landing gear when they did the first?

Fred


See article below.

Wings have been covered above - the Wing Box seems to have gained some weight - but they may a problem with the Japanese Translation as the part Subaru supplies is heavier as it now incorporates the Wheel Wheels - But it should be heavier. But it does use a lot more titanium.

He does talk about its ability to carry a bigger payload than 77W. Many on here were assuming that payload may be lower when they were assuming significantly higher OEW weights.

https://www.flightglobal.com/systems-an ... 38.article
 
morrisond
Posts: 2745
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 8:15 pm

Stitch wrote:
177,000kg sounds too light to me.

Last numbers I saw from Leeham.net for the 777-9 was 185,000kg which was "corroborated" by Daniel Tsang. Boeing themselves said the OEW was at 188,000kg at their Post-2014 Design Gate.

The only one I have seen claiming the 777-9 would be overly "light" was Aspire Aviation, who claimed it was 164,000kg at the Post-2014 Design Gate (a figure 24,000kg lower than Boeing's). Aspire did say 188,000kg for a 300-seat four-class Revision E airframe which does match Boeing's P2014 DG numbers, so that could be the configuration Boeing was giving.

And yes, 188,000kg is close to the Boeing OEM OEW of a 747-400ER.


Leeham says 177T from their article last March.

https://leehamnews.com/2019/03/07/boein ... ed-part-4/

If it really weighs the same as an 744ER than that is really poor design. That basic structure dates from Sliderules and the 1960's.

In 50 years they can't take any weight of the structure? BTW range of base 744 is quoted the same as 779. A 779 would be carrying significantly less fuel to achieve that same range so less structure needed - 350ishT vs 400t MTOW. Avionics/ control systems would be significantly lighter - it's just a little longer and wider wingspan - with about 2% less wing area.

Interior would definitely be lighter on 777x as no stairs, etc..
Last edited by morrisond on Tue May 26, 2020 8:26 pm, edited 1 time in total.
 
Opus99
Posts: 999
Joined: Thu May 30, 2019 10:51 pm

Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 8:17 pm

Stitch wrote:
177,000kg sounds too light to me.

Last numbers I saw from Leeham.net for the 777-9 was 185,000kg which was "corroborated" by Daniel Tsang. Boeing themselves said the OEW was at 188,000kg at their Post-2014 Design Gate.

The only one I have seen claiming the 777-9 would be overly "light" was Aspire Aviation, who claimed it was 164,000kg at the Post-2014 Design Gate (a figure 24,000kg lower than Boeing's). Aspire did say 188,000kg for a 300-seat four-class Revision E airframe which does match Boeing's P2014 DG numbers, so that could be the configuration Boeing was giving.

And yes, 188,000kg is close to the Boeing OEM OEW of a 747-400ER.

Wow. I’m struggling to find out what is making it so heavy, what was the point of carbon fibre here and there if the plane is going to weigh as much as a 747. That’s a shame
 
Opus99
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 8:25 pm

Boeing had to have done something after realising what Airbus were doing. There’s no way they could’ve kept it THAT high. Changes to the engine nacelles from the staggered version to the straight. AL-LI cargo beams instead of AL. That probably can’t get rid of 10 tonnes but come on.
 
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Stitch
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 9:39 pm

morrisond wrote:
Leeham says 177T from their article last March.


I'm not a subscriber, so I can't see the numbers, but I'll accept the value.

Leeham prefers to use "normalized" three-class seating so that would shave a fair bit of weight due to more non-Premium seating (which is significantly lighter than First and Business Class suites) so I could see an 11,000kg reduction (plus any savings Boeing has incorporated since 2014).


morrisond wrote:
If it really weighs the same as an 744ER than that is really poor design. That basic structure dates from Sliderules and the 1960's.


The 777-300ER was only 11,000kg lighter than a 747-400 per Boeing OEM OEWs. Modern frames are a fair bit heavier due to more stringent certification standards since the 1960s. The 777X also had larger and fancier interior fittings (overhead bins, lavatories, galleys) all of which would be certified to much-more recent standards.
 
Opus99
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 9:57 pm

https://seekingalpha.com/article/407122 ... am-matters

Taken from this seeking alpha article from 2017 (behind a paywall) but I'll summarise- (done a bit of investigation)

There is a table that shows the breakdown of the increase in weight compared to the 777-300ER.

Fuselage - 5190 KG increase
Turbofans - 335KG increase
Nacelles - 200KG Increase
Tail Group - 1450 KG Increase
Wing - 6,170 Increase
Folding Mechanism - 2630 Increase
Total - 15,975 increase.

Now if really and truly Boeing were able to keep the wing the same according to Leehams March 2019 analysis which he says was no small feat at all, then that should leave us at about 177T BUT that is if indeed they did, I wonder what his source would have been to confirm they had kept the wing the same weight and if indeed true, I wonder what they might have done to achieve that?

"The wing got larger as well but was now made with a wingbox of Carbon Fiber Reinforced Plastic (CFRP) instead of aluminum. With a 7m longer wingspan (71.8m compared with 64.8m for the 777-200LR/300ER), there was no weight gain. But the fact an 11% longer wing could be kept at the same weight as the donor’s wing, it’s no small achievement."

Quote from Leeham above.
Last edited by Opus99 on Tue May 26, 2020 10:03 pm, edited 1 time in total.
 
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bikerthai
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 10:00 pm

Opus99 wrote:
Wow. I’m struggling to find out what is making it so heavy, what was the point of carbon fibre here and there if the plane is going to weigh as much as a 747. That’s a shame


If you break it down, then the reason is obvious.

The carbon wing did what it supposed to do. It increased the wing span of the plane, thus increasing efficiency. Because the fuselage is still aluminum, Boeing kept the center wing box aluminum to avoid dealing with thermo expansion issues. So they have to increase titanium use probably at the carbon/aluminum interface for galvanic corrosion issues. So increasing span but only a slight inrease in weight seems like a plus.

As for the fuselage. Don't forget they are going for a 6000ft elevation cabin pressure. So comparing it to the weight of a 747 in terms of structural efficiency would be almost like apples and oranges unless you try to factor in the diferential in pressure load and do a linear parrametric ratio to get an approximate 747 fuselage weight at 6000ft pressure.

bt
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JohanTally
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 11:28 pm

Opus99 wrote:
https://seekingalpha.com/article/4071222-boeing-777x-every-kilogram-matters

Taken from this seeking alpha article from 2017 (behind a paywall) but I'll summarise- (done a bit of investigation)

There is a table that shows the breakdown of the increase in weight compared to the 777-300ER.

Fuselage - 5190 KG increase
Turbofans - 335KG increase
Nacelles - 200KG Increase
Tail Group - 1450 KG Increase
Wing - 6,170 Increase
Folding Mechanism - 2630 Increase
Total - 15,975 increase.

Now if really and truly Boeing were able to keep the wing the same according to Leehams March 2019 analysis which he says was no small feat at all, then that should leave us at about 177T BUT that is if indeed they did, I wonder what his source would have been to confirm they had kept the wing the same weight and if indeed true, I wonder what they might have done to achieve that?

"The wing got larger as well but was now made with a wingbox of Carbon Fiber Reinforced Plastic (CFRP) instead of aluminum. With a 7m longer wingspan (71.8m compared with 64.8m for the 777-200LR/300ER), there was no weight gain. But the fact an 11% longer wing could be kept at the same weight as the donor’s wing, it’s no small achievement."

Quote from Leeham above.


Have we heard anything about a reduction in weight by thinning the sidewalls? It would impressive if they shedded weight all while strengthening for the lower cabin altitude. The test flight program seems to be going well so hopefully we get some concrete answers soon.
 
flipdewaf
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 11:37 pm

With 177t empty weight it would take 78t out to ~5000nm and drop about 1t/70nm of payload ability. At 8000nm it has about 36t or just over 300 pax. A 351 takes about 73t to 5900 and drops at 1t/80nm, at 8000nm has 47t available.

Fred


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Opus99
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Re: Boeing 777X Testing/Production Thread - 2020

Tue May 26, 2020 11:59 pm

JohanTally wrote:
Opus99 wrote:
https://seekingalpha.com/article/4071222-boeing-777x-every-kilogram-matters

Taken from this seeking alpha article from 2017 (behind a paywall) but I'll summarise- (done a bit of investigation)

There is a table that shows the breakdown of the increase in weight compared to the 777-300ER.

Fuselage - 5190 KG increase
Turbofans - 335KG increase
Nacelles - 200KG Increase
Tail Group - 1450 KG Increase
Wing - 6,170 Increase
Folding Mechanism - 2630 Increase
Total - 15,975 increase.

Now if really and truly Boeing were able to keep the wing the same according to Leehams March 2019 analysis which he says was no small feat at all, then that should leave us at about 177T BUT that is if indeed they did, I wonder what his source would have been to confirm they had kept the wing the same weight and if indeed true, I wonder what they might have done to achieve that?

"The wing got larger as well but was now made with a wingbox of Carbon Fiber Reinforced Plastic (CFRP) instead of aluminum. With a 7m longer wingspan (71.8m compared with 64.8m for the 777-200LR/300ER), there was no weight gain. But the fact an 11% longer wing could be kept at the same weight as the donor’s wing, it’s no small achievement."

Quote from Leeham above.


Have we heard anything about a reduction in weight by thinning the sidewalls? It would impressive if they shedded weight all while strengthening for the lower cabin altitude. The test flight program seems to be going well so hopefully we get some concrete answers soon.

This is just a theory but I think Boeing took out the 6,000ft lower cabin altitude, now the cabin altitude is definitely lower, but I feel maybe not quite 6,000 anymore so as to save weight, maybe 6500-7000 etc. why do I say that? because the figure has been taken out of all their marketing campaigns for the aircraft, all you hear now is a 'lower cabin altitude' etc. I'm not sure what the 77W cabin altitude is but I assume 8,000ft so even 7,000ft would be a 'lower cabin altitude' and then changing the engine nacelles and then whatever magic they were able to achieve with the wing
 
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Re: Boeing 777X Testing/Production Thread - 2020

Wed May 27, 2020 2:17 am

flipdewaf wrote:
With 177t empty weight it would take 78t out to ~5000nm and drop about 1t/70nm of payload ability. At 8000nm it has about 36t or just over 300 pax. A 351 takes about 73t to 5900 and drops at 1t/80nm, at 8000nm has 47t available.

Fred


Sent from my iPhone using Tapatalk



So what structural, efficiency and aerodynamic magic do you think Airbus was able to pull off to make the A351 so much better than Boeing can with the 777X 4-5 years later using a lot of the same Vendors, Engines with better SFC.

The tube is maybe 5% of the MTOW - the rest is all new and state of the art Aerodynamics.
 
JohanTally
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Re: Boeing 777X Testing/Production Thread - 2020

Wed May 27, 2020 2:36 am

Opus99 wrote:
JohanTally wrote:
Opus99 wrote:
https://seekingalpha.com/article/4071222-boeing-777x-every-kilogram-matters

Taken from this seeking alpha article from 2017 (behind a paywall) but I'll summarise- (done a bit of investigation)

There is a table that shows the breakdown of the increase in weight compared to the 777-300ER.

Fuselage - 5190 KG increase
Turbofans - 335KG increase
Nacelles - 200KG Increase
Tail Group - 1450 KG Increase
Wing - 6,170 Increase
Folding Mechanism - 2630 Increase
Total - 15,975 increase.

Now if really and truly Boeing were able to keep the wing the same according to Leehams March 2019 analysis which he says was no small feat at all, then that should leave us at about 177T BUT that is if indeed they did, I wonder what his source would have been to confirm they had kept the wing the same weight and if indeed true, I wonder what they might have done to achieve that?

"The wing got larger as well but was now made with a wingbox of Carbon Fiber Reinforced Plastic (CFRP) instead of aluminum. With a 7m longer wingspan (71.8m compared with 64.8m for the 777-200LR/300ER), there was no weight gain. But the fact an 11% longer wing could be kept at the same weight as the donor’s wing, it’s no small achievement."

Quote from Leeham above.


Have we heard anything about a reduction in weight by thinning the sidewalls? It would impressive if they shedded weight all while strengthening for the lower cabin altitude. The test flight program seems to be going well so hopefully we get some concrete answers soon.

This is just a theory but I think Boeing took out the 6,000ft lower cabin altitude, now the cabin altitude is definitely lower, but I feel maybe not quite 6,000 anymore so as to save weight, maybe 6500-7000 etc. why do I say that? because the figure has been taken out of all their marketing campaigns for the aircraft, all you hear now is a 'lower cabin altitude' etc. I'm not sure what the 77W cabin altitude is but I assume 8,000ft so even 7,000ft would be a 'lower cabin altitude' and then changing the engine nacelles and then whatever magic they were able to achieve with the wing


That's a good point. Also the barely failed static test could lead to a slightly raised cabin altitude to cheaply resolve the defect.
 
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Stitch
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Re: Boeing 777X Testing/Production Thread - 2020

Wed May 27, 2020 2:56 am

Opus99 wrote:
This is just a theory but I think Boeing took out the 6,000ft lower cabin altitude, now the cabin altitude is definitely lower, but I feel maybe not quite 6,000 anymore so as to save weight, maybe 6500-7000 etc. why do I say that? because the figure has been taken out of all their marketing campaigns for the aircraft, all you hear now is a 'lower cabin altitude' etc. I'm not sure what the 77W cabin altitude is but I assume 8,000ft so even 7,000ft would be a 'lower cabin altitude' and then changing the engine nacelles and then whatever magic they were able to achieve with the wing


The 777 has a cabin altitude of 8000 feet at its maximum service ceiling, but it would normally not operate that high. At standard cruising altitudes, it may very well have a cabin altitude of around 6000 feet already.
 
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bikerthai
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Re: Boeing 777X Testing/Production Thread - 2020

Wed May 27, 2020 4:29 am

JohanTally wrote:
Have we heard anything about a reduction in weight by thinning the sidewalls?


"Thinning of the side wall" is a misnomer. What they did was reduced the frame height at the window belt/shoulder in order to get more seat width space. As any structure designer will tell you, if you reduce the height of your I beam, you will lose stiffness, thus efficiency.

The 6000 ft altitude was not arbitrary. It was backed up with many hours of issobaric chamber testing. Of course, like everything else, it was probably a trade off between the optimum pressure altitude and structure weight.

They can probably play around with the altitude during operation but they will probably not deviate much from it.

morrisond wrote:
So what structural, efficiency and aerodynamic magic do you think Airbus was able to pull off to make the A351 so much better than Boeing can with the 777X 4-5 years later


While the A350 still have the longitudinal splice joint and the 787 does not, both do not have the massive number of stringer fasteners that comes with a co-cured composite panel. The 777-X still have the stringer and shear tie fasteners and a mostly aluminum fuselage, which while may not contribute much to drag, is still less efficient.

Rule of thumb when converting aluminum to graphite composite structure is for the same size structure, you should weight about 2/3 rd as much.

bt
Intelligent seeks knowledge. Enlightened seeks wisdom.
 
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VCVSpotter
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Re: Boeing 777X Testing/Production Thread - 2020

Wed May 27, 2020 4:40 am

777-9 N779XW is scheduled for phase one stability and control testing tomorrow (May 27, 2020) BFI-BFI.

http://kpae.blogspot.com/2020/05/paine- ... ay-26.html
https://docs.google.com/spreadsheets/d/ ... edit#gid=0

Just a normal teenager juggling AP classes and airplanes. No biggie • Love the 747 & 777-9 • Farewell BA/KL 744s
 
flipdewaf
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Re: Boeing 777X Testing/Production Thread - 2020

Wed May 27, 2020 12:04 pm

morrisond wrote:
flipdewaf wrote:
With 177t empty weight it would take 78t out to ~5000nm and drop about 1t/70nm of payload ability. At 8000nm it has about 36t or just over 300 pax. A 351 takes about 73t to 5900 and drops at 1t/80nm, at 8000nm has 47t available.

Fred


Sent from my iPhone using Tapatalk



So what structural, efficiency and aerodynamic magic do you think Airbus was able to pull off to make the A351 so much better than Boeing can with the 777X 4-5 years later using a lot of the same Vendors, Engines with better SFC.

The tube is maybe 5% of the MTOW - the rest is all new and state of the art Aerodynamics.


Well I don't think airbus have employed magic to counter Boeings magic, that's the point.
Airbus A351 - Spec pax-365
Spec Range 8700nm
OWE - 150t
Mission landing weight = 150t + 6t fuel + 5t Pantry +365*0.095 payload = 195675kg, Fuel used = 319000-195675 = 123.325, fuel used per paxnm = 123325/(8700*365) = 0.0388kg/paxnm

By simple breguet we can estimate the fuel use on the 777X spec range mission as 0.372kg/paxnm

If we assume the 777X has at least as good fuel use per paxnm as the A350 then for the 7285 spec mission it would need 0.0372*426*7285 = 115.486t of fuel for the mission.
351.5-115.486 = landing weight of 236.046t If we remove payload weight (426*0.095) and the pantry and reserve as above we get 184.576..

Now... My algorithm for weight estimation actually puts the 779X at 179t so like I mentioned upthread, something fishy is going on.

Would I be surprised to see Boeing come it at 179t? I wouldn't expect the initial examples to maybe but over the long term then yes, but it doesn't seem to fit right when you take in to account the relative range of the spec mission I would expect the previous range north of 7500nm to be more where it should be sitting with regard to the spec mission, I don't understand why it isn't.

By way of reference my weight estimation algorithm puts the [email protected], the [email protected] the [email protected] the [email protected] and the [email protected]

I wont speak more about this here but would carry on in tech ops as that is a more appropriate place.

Fred
Image
 
morrisond
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Re: Boeing 777X Testing/Production Thread - 2020

Wed May 27, 2020 12:12 pm

bikerthai wrote:
morrisond wrote:
So what structural, efficiency and aerodynamic magic do you think Airbus was able to pull off to make the A351 so much better than Boeing can with the 777X 4-5 years later


While the A350 still have the longitudinal splice joint and the 787 does not, both do not have the massive number of stringer fasteners that comes with a co-cured composite panel. The 777-X still have the stringer and shear tie fasteners and a mostly aluminum fuselage, which while may not contribute much to drag, is still less efficient.

Rule of thumb when converting aluminum to graphite composite structure is for the same size structure, you should weight about 2/3 rd as much.

bt


I would agree on the Barrel weight savings. I'll try to find it again - I linked it in the NMA threads but there was study done on an A320 Barrel - The Aluminum barrel was about 3% of MTOW - Carbon saved about 1% of MTOW.

So on an 777 sized aircraft - call that 4T - maybe 6T at the Worst.

A351 is Supposedly 155T OEW and the 777X is what 10% Larger? Something in the Mid 170's is not that hard to believe with 4-5 years more development and engines with better SFC which should offset the fastener drag.

You also have the 77W at 168T vs A351 at 155T which makes sense given there relative size difference. They took a bunch of weight out of the 777 crown in recent years. 787 avionics and interior should save a chunk of weight over 77W.

A351 meets the crash standards at 155T - I really have a hard time believing the 777X will weigh as much as an 744ER.
 
StTim
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Re: Boeing 777X Testing/Production Thread - 2020

Wed May 27, 2020 4:23 pm

morrisond wrote:
bikerthai wrote:
morrisond wrote:
So what structural, efficiency and aerodynamic magic do you think Airbus was able to pull off to make the A351 so much better than Boeing can with the 777X 4-5 years later


While the A350 still have the longitudinal splice joint and the 787 does not, both do not have the massive number of stringer fasteners that comes with a co-cured composite panel. The 777-X still have the stringer and shear tie fasteners and a mostly aluminum fuselage, which while may not contribute much to drag, is still less efficient.

Rule of thumb when converting aluminum to graphite composite structure is for the same size structure, you should weight about 2/3 rd as much.

bt


I would agree on the Barrel weight savings. I'll try to find it again - I linked it in the NMA threads but there was study done on an A320 Barrel - The Aluminum barrel was about 3% of MTOW - Carbon saved about 1% of MTOW.

So on an 777 sized aircraft - call that 4T - maybe 6T at the Worst.

A351 is Supposedly 155T OEW and the 777X is what 10% Larger? Something in the Mid 170's is not that hard to believe with 4-5 years more development and engines with better SFC which should offset the fastener drag.

You also have the 77W at 168T vs A351 at 155T which makes sense given there relative size difference. They took a bunch of weight out of the 777 crown in recent years. 787 avionics and interior should save a chunk of weight over 77W.

A351 meets the crash standards at 155T - I really have a hard time believing the 777X will weigh as much as an 744ER.


I think the whole point of that article was that as the barrel diameter reduces the advantages of carbon fibre also reduce as you need to have more weight of carbon for more than just the basic strength. I seem to remember this was for items such as resistance to ramp rash etc.
 
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Re: Boeing 777X Testing/Production Thread - 2020

Wed May 27, 2020 5:25 pm

777-9 N779XW has filed as BOE1 for phase one stability and control testing. Departing at 11:00AM Pacific, the flight will take them south into Oregon, returning to BFI at 4:01PM.

https://flightaware.com/live/flight/BOE1
https://docs.google.com/spreadsheets/d/ ... edit#gid=0

Just a normal teenager juggling AP classes and airplanes. No biggie • Love the 747 & 777-9 • Farewell BA/KL 744s
 
JayinKitsap
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Re: Boeing 777X Testing/Production Thread - 2020

Wed May 27, 2020 6:17 pm

I think the point of a Testing / Production thread is to get information on the Testing & Production.

Isn't debating for a week the weight of the 777, I suspect Boeing did their best on getting the 777 weight to the lowest practical. Can't that be discussed elsewhere.
 
MileHFL400
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Re: Boeing 777X Testing/Production Thread - 2020

Wed May 27, 2020 7:34 pm

JayinKitsap wrote:
I think the point of a Testing / Production thread is to get information on the Testing & Production.

Isn't debating for a week the weight of the 777, I suspect Boeing did their best on getting the 777 weight to the lowest practical. Can't that be discussed elsewhere.


Agreed
Thanks and best Regards
AA
 
744SPX
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Re: Boeing 777X Testing/Production Thread - 2020

Wed May 27, 2020 9:59 pm

VV wrote:
morrisond wrote:
...


Image


Did anyone notice the wingspan? has it really been increased to almost 239 feet from 235?
 
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MoKa777
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Re: Boeing 777X Testing/Production Thread - 2020

Wed May 27, 2020 11:42 pm

744SPX wrote:
VV wrote:
morrisond wrote:
...


Image


Did anyone notice the wingspan? has it really been increased to almost 239 feet from 235?


Good catch, both the 777X ACAP documents I downloaded (Prelim from 2017 and Revision A from 2018) list it as 235ft 5in.
Never be proud. Always be grateful.
 
JayinKitsap
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Re: Boeing 777X Testing/Production Thread - 2020

Thu May 28, 2020 2:01 am

If really 238'-10" now, it was done before the static test frame. Probably just the spindley tip got longer, might have gained a 1/4% or so.
 
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qf789
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Re: Boeing 777X Testing/Production Thread - 2020

Thu May 28, 2020 5:08 am

Test frame #1 N779XW landing at BFI today

Image

Image

Image

Image

https://twitter.com/AeroimagesChris/sta ... 18624?s=20
Forum Moderator
 
VV
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Re: Boeing 777X Testing/Production Thread - 2020

Thu May 28, 2020 5:33 am

VCVSpotter wrote:
777-9 N779XW has filed as BOE1 for phase one stability and control testing. Departing at 11:00AM Pacific, the flight will take them south into Oregon, returning to BFI at 4:01PM.

https://flightaware.com/live/flight/BOE1


That's a nice roller-coaster ride.

There are several stall speed determination, it seems.
 
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Chipmunk1973
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Re: Boeing 777X Testing/Production Thread - 2020

Thu May 28, 2020 5:42 am

qf789 wrote:
Test frame #1 N779XW landing at BFI today

Image

https://twitter.com/AeroimagesChris/sta ... 18624?s=20

Must of climbed above 35,000ft if you can see the Earth in the background :duck:
Cheers,
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FluidFlow
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Re: Boeing 777X Testing/Production Thread - 2020

Thu May 28, 2020 6:12 am

morrisond wrote:

I would agree on the Barrel weight savings. I'll try to find it again - I linked it in the NMA threads but there was study done on an A320 Barrel - The Aluminum barrel was about 3% of MTOW - Carbon saved about 1% of MTOW.



I think it is important to know, that this is most probably the naked barrel without any installation. A full barrel (seats, galleys, cargo systems, etc.) is way above 3% of MTOW. The increase in weight for the 777X comes also from the fact that you need to install a cabin. There is no good in stretching the cabin and leaving it empty to save weight, as there will also be no revenue generated from this area then. So gaining 6t, for additional 40 seats is only about 150kg per seat, what seems to be about right in my opinion, if you include the fact, that due to the stretch there also needs to be additional strengthening, not only to carry the weight but also to take the moment from the tail.
 
Opus99
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Re: Boeing 777X Testing/Production Thread - 2020

Thu May 28, 2020 9:02 am

VV wrote:
morrisond wrote:
...
185T OEW? Somehow I doubt it will be that Heavy - even Leeham is estimating 177T and many think it could be lighter than that - a lot closer to 170T.

How about rerunning with those specs - it's probably a lot better than 7,285NM with 426 Passengers.


You believe it or not, it does not matter to me. I stand by my number of 407,300 lb OEW.

an OEW of 177 tonnes (390,000 lb) is way too light in my opinion, but it is up to you which one to believe.

Image

I’ve checked the Boeing website and this exact shot lists the wing as 235ft
 
VV
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Re: Boeing 777X Testing/Production Thread - 2020

Thu May 28, 2020 11:18 am

Opus99 wrote:
VV wrote:
morrisond wrote:
...
185T OEW? Somehow I doubt it will be that Heavy - even Leeham is estimating 177T and many think it could be lighter than that - a lot closer to 170T.

How about rerunning with those specs - it's probably a lot better than 7,285NM with 426 Passengers.


You believe it or not, it does not matter to me. I stand by my number of 407,300 lb OEW.

an OEW of 177 tonnes (390,000 lb) is way too light in my opinion, but it is up to you which one to believe.

Image

I’ve checked the Boeing website and this exact shot lists the wing as 235ft


Fortunately I added a time stamp on the picture. Someone put the wrong number prior to October 2019.
 
VV
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Re: Boeing 777X Testing/Production Thread - 2020

Thu May 28, 2020 11:33 am

But even the current picture is still mistaken.
Why is it still 72.8 m??
72.8 m is 238 ft 10 in

235 ft 5 in should be about 71.8 m.
 
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bikerthai
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Re: Boeing 777X Testing/Production Thread - 2020

Thu May 28, 2020 1:54 pm

Wouldn't be surprised if it's a typo error when the number was sent from the Engineering dept to the PR dept. I've seen these metric conversion in the past, but less so with CAD automation.

bt
Intelligent seeks knowledge. Enlightened seeks wisdom.
 
flipdewaf
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Re: Boeing 777X Testing/Production Thread - 2020

Thu May 28, 2020 2:51 pm

Maybe it could be a chance in wingspan in flight vs on the ground, i.e. taking account of the flex? Sounds like a lot though.

Fred
Image
 
Opus99
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Re: Boeing 777X Testing/Production Thread - 2020

Thu May 28, 2020 2:56 pm

VV wrote:
But even the current picture is still mistaken.
Why is it still 72.8 m??
72.8 m is 238 ft 10 in

235 ft 5 in should be about 71.8 m.

They have the correct dimension conversion on the main 777x page

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Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos