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mjoelnir
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 5:00 pm

morrisond wrote:
NZ321 wrote:
I don't get the stats... the writing is on the wall. There is a need for a medium capacity jet above A321 to fly short to medium haul routes to replace A330 and 777 that are plying 250-300 seat corridors in the ME and Asia and beyond. It doesn't need long legs. Just needs to hit the sweet spot on short - medium haul (1 hr - 6 hrs). Anything above is an option. 788-789 has it covered as does 77x.


Me too - when I saw the numbers that the XLR could only go to about 3,500NM in Aer Lingus Config (185 Seats) which will probably closer to a typical density going forward, I thought - yes there is a Gap.

Aer Lingus would probably pack something like 280-290 in an 788 and that go up to what - about 5,500 NM at that density?

Something that could take 220-240 in Aer Lingus Density about 4,500NM really would be middle of the Market and serve a lot Trans Atlantic Routes than an XLR will ever be able too.

Actually what really struck from looking at the XLR numbers is that the XLR really needs that new wing with more range and higher MTOW.


Where do you found the numbers that a A321XLR could only go 3500nm in an Aer Lingus configuration? Please share.

In regards to the tiny wings on the XLR. We seem to agree, that adding some weight with a bigger wing would make the A321XLR perhaps slightly more economical.

How do you think you can make a short haul narrowbody more economical? Where do you trim the weight? A really uncomfortable narrow 7 seat across, to keep the fuselage small? Smaller wings to keep the weight down?
I know that Boeing will work magic, but the reality is, they did not find a way up to now.
 
flipdewaf
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 5:17 pm

morrisond wrote:
NZ321 wrote:
I don't get the stats... the writing is on the wall. There is a need for a medium capacity jet above A321 to fly short to medium haul routes to replace A330 and 777 that are plying 250-300 seat corridors in the ME and Asia and beyond. It doesn't need long legs. Just needs to hit the sweet spot on short - medium haul (1 hr - 6 hrs). Anything above is an option. 788-789 has it covered as does 77x.


Me too - when I saw the numbers that the XLR could only go to about 3,500NM in Aer Lingus Config (185 Seats) which will probably closer to a typical density going forward, I thought - yes there is a Gap.
.

Does that mean you also think the 737-10 is only capable of 2450nm in a similar configuration?

Fred


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Revelation
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 6:11 pm

https://leehamnews.com/2020/02/06/boein ... ke-a-poll/ tells us analysts are split on whether or not Boeing will do NMA or FSA, with FSA being described as a 757-200/300 substitute.

It suggests Calhoun is not a fan of NMA, and IMO that alone could be its death knell.

Interesting conclusion to the article:

Aboulafia doesn’t believe Boeing can develop a twin aisle airplane with single aisle operating costs. (LNA’s Aircraft Performance Model and engineering analysis concludes Boeing can.)

Maybe Bjorn is a clapping seal?
Wake up to find out that you are the eyes of the world
The heart has its beaches, its homeland and thoughts of its own
Wake now, discover that you are the song that the morning brings
The heart has its seasons, its evenings and songs of its own
 
TObound
Posts: 781
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 6:22 pm

morrisond wrote:
NZ321 wrote:
I don't get the stats... the writing is on the wall. There is a need for a medium capacity jet above A321 to fly short to medium haul routes to replace A330 and 777 that are plying 250-300 seat corridors in the ME and Asia and beyond. It doesn't need long legs. Just needs to hit the sweet spot on short - medium haul (1 hr - 6 hrs). Anything above is an option. 788-789 has it covered as does 77x.


Me too - when I saw the numbers that the XLR could only go to about 3,500NM in Aer Lingus Config (185 Seats) which will probably closer to a typical density going forward, I thought - yes there is a Gap.

Aer Lingus would probably pack something like 280-290 in an 788 and that go up to what - about 5,500 NM at that density?

Something that could take 220-240 in Aer Lingus Density about 4,500NM really would be middle of the Market and serve a lot Trans Atlantic Routes than an XLR will ever be able too.

Actually what really struck from looking at the XLR numbers is that the XLR really needs that new wing with more range and higher MTOW.


There is a gap. The question is whether it's worth filling. I've maintained all along that the XLR is a compromise. Most airlines want closer to 200 seats and closer to 4000NM in real world (winter winds, full pax payload and maybe little bit of cargo). But the question is, are carriers willling to pay for and field a whole new type that has those capabilities?

Just look at what Are Lingus can do with 3500NM range and consider what happens if Airbus can add another 500NM:

http://www.gcmap.com/mapui?R=3500nm%40d ... =wls&DU=mi

And the problem for Boeing is that Airbus could drop $2 billion over the next 5 years and build a whole new "family" around the 321, with a carbon wing, new landing gear and a stretched 322 seating 200 in the Are Lingus config. That redeveloped 321XLR would reach 4000NM for Aer Lingus, opening up the Carribean. And the 322 would come in close enough to 3500NM. Boeing would have to spend 10x what Airbus did to offer that NMA only to end up with some split of market share and the new Airbus 321 family keeping their margins on the NMA lower. That is terrible for a Boeing investor. No way their board allows that, regardless of what fanboys on here think.
 
TObound
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 6:28 pm

Revelation wrote:
https://leehamnews.com/2020/02/06/boeing-will-proceed-with-nma-or-fsa-take-a-poll/ tells us analysts are split on whether or not Boeing will do NMA or FSA, with FSA being described as a 757-200/300 substitute.

It suggests Calhoun is not a fan of NMA, and IMO that alone could be its death knell.

Interesting conclusion to the article:

Aboulafia doesn’t believe Boeing can develop a twin aisle airplane with single aisle operating costs. (LNA’s Aircraft Performance Model and engineering analysis concludes Boeing can.)

Maybe Bjorn is a clapping seal?


Maybe Boeing can. But is it worthwhile if they don't achieve a CASM and performance advantage that would absolutely let them dominate the space?

They could build a large single aisle family that competes with the 321 and hypothetical 322. Sure they split the market with Airbus. But they make enough to pay the bills and make a healthy return over several thousand sales.

Or they spend tens of billions on the NMA only to steal a limited amount of 321N market share, killing the 330NEO, but also hurting the 787. That's a very risky move. There's entirely the chance that the plane sells well and Boeing still walks away with poorer profits overall.
 
TObound
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 6:30 pm

mjoelnir wrote:
morrisond wrote:
NZ321 wrote:
I don't get the stats... the writing is on the wall. There is a need for a medium capacity jet above A321 to fly short to medium haul routes to replace A330 and 777 that are plying 250-300 seat corridors in the ME and Asia and beyond. It doesn't need long legs. Just needs to hit the sweet spot on short - medium haul (1 hr - 6 hrs). Anything above is an option. 788-789 has it covered as does 77x.


Me too - when I saw the numbers that the XLR could only go to about 3,500NM in Aer Lingus Config (185 Seats) which will probably closer to a typical density going forward, I thought - yes there is a Gap.

Aer Lingus would probably pack something like 280-290 in an 788 and that go up to what - about 5,500 NM at that density?

Something that could take 220-240 in Aer Lingus Density about 4,500NM really would be middle of the Market and serve a lot Trans Atlantic Routes than an XLR will ever be able too.

Actually what really struck from looking at the XLR numbers is that the XLR really needs that new wing with more range and higher MTOW.


Where do you found the numbers that a A321XLR could only go 3500nm in an Aer Lingus configuration? Please share.


He read the blog I posted. This is why I suggested people should read that.
 
TObound
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Re: Boeing CEO: NMA will

Thu Feb 06, 2020 6:35 pm

Revelation wrote:
TObound wrote:
Probably. It's amazing analysis. At least a bit closer to how network planners are looking at these aircraft. You start to see how underestimated the XLR is. And how much of a challenge Boeing faces. Especially if they want to sell a small and cheap widebody as the NMA.

It's not amazing that 757's sun is setting and a plane two generations newer than it can give it a run for its money.

To apply the same critical standards as routinely gets applied to Boeing here, we can validly criticize Airbus for not spending the time to do a RCT till now and being late to the game with winglets.

Lord knows we had enough threads here about A32x not being able to do US transcons against winter winds.

Maybe it'd be more topical to see what challenges XLR faces from NMA?

Image

Ref: https://epsilonaviation.wordpress.com/2 ... decessors/


Airbus absolutely should have done the XLR earlier. Dunno why they even bothered with the LR. But it could be possible they weren't quite confident that engine and airframe PIPs were planning out.

As for NMA impact: kills the LR/XLR, kills the 330N, kills the 788 and surpresses margins on the 321N. Airbus would have to do the rewing and stretch just to protect marketshare. The question is whether all that is worth also killing Boeing's balance sheets. I have my doubts. I think a large single aisle is the lower risk option.
 
flipdewaf
Posts: 3584
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 6:35 pm

Revelation wrote:
https://leehamnews.com/2020/02/06/boeing-will-proceed-with-nma-or-fsa-take-a-poll/ tells us analysts are split on whether or not Boeing will do NMA or FSA, with FSA being described as a 757-200/300 substitute.

It suggests Calhoun is not a fan of NMA, and IMO that alone could be its death knell.

Interesting conclusion to the article:

Aboulafia doesn’t believe Boeing can develop a twin aisle airplane with single aisle operating costs. (LNA’s Aircraft Performance Model and engineering analysis concludes Boeing can.)

Maybe Bjorn is a clapping seal?

Absolutely they can make a twin aisle with single aisle operating costs. Look at my performance model and engineering analysis above and you’ll note the 13%? Per seat fuel use per seat advantage of the single aisle. Take a current 737NG as the ‘standard’ for single aisle economics then use a GTF or LEAP derived engine and stick it on a 767 size airframe and Voila! Straight from the book of how to present info to the public from a B2B business.

Until we know what that analysis is then we may as well say voodoo make it happen, I can’t afford a subscription.

Fred


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morrisond
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 6:37 pm

mjoelnir wrote:
morrisond wrote:
NZ321 wrote:
I don't get the stats... the writing is on the wall. There is a need for a medium capacity jet above A321 to fly short to medium haul routes to replace A330 and 777 that are plying 250-300 seat corridors in the ME and Asia and beyond. It doesn't need long legs. Just needs to hit the sweet spot on short - medium haul (1 hr - 6 hrs). Anything above is an option. 788-789 has it covered as does 77x.


Me too - when I saw the numbers that the XLR could only go to about 3,500NM in Aer Lingus Config (185 Seats) which will probably closer to a typical density going forward, I thought - yes there is a Gap.

Aer Lingus would probably pack something like 280-290 in an 788 and that go up to what - about 5,500 NM at that density?

Something that could take 220-240 in Aer Lingus Density about 4,500NM really would be middle of the Market and serve a lot Trans Atlantic Routes than an XLR will ever be able too.

Actually what really struck from looking at the XLR numbers is that the XLR really needs that new wing with more range and higher MTOW.


Where do you found the numbers that a A321XLR could only go 3500nm in an Aer Lingus configuration? Please share.

In regards to the tiny wings on the XLR. We seem to agree, that adding some weight with a bigger wing would make the A321XLR perhaps slightly more economical.

How do you think you can make a short haul narrowbody more economical? Where do you trim the weight? A really uncomfortable narrow 7 seat across, to keep the fuselage small? Smaller wings to keep the weight down?
I know that Boeing will work magic, but the reality is, they did not find a way up to now.


The XLR numbers were in this Article from the previous page

https://epsilonaviation.wordpress.com/2 ... 321xlr-do/

I'm assuming the 7W cross section is 737 tight in Y with pretty narrow aisles - about 186" Wide and somewhere between 165-170" tall. Y+ could be quite comfortable at 2x2x2 with wider aisles to facilitate flow. I would also assume a relatively small wing - 41M extended 36M folded - call it 115-125T MTOW. With engines getting more and more efficient the fuel fraction as you point out should keep falling.

The danger would be to overbuild as you could be stuck with something too capable halfway through the production life of the frame (that point maybe around 2040).

We all know why they paused the NMA decision - it most likely would have been launched by now if the MAX debacle had never happened.
Last edited by morrisond on Thu Feb 06, 2020 6:40 pm, edited 1 time in total.
 
flipdewaf
Posts: 3584
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 6:38 pm

Revelation wrote:
https://leehamnews.com/2020/02/06/boeing-will-proceed-with-nma-or-fsa-take-a-poll/ tells us analysts are split on whether or not Boeing will do NMA or FSA, with FSA being described as a 757-200/300 substitute.

It suggests Calhoun is not a fan of NMA, and IMO that alone could be its death knell.

Interesting conclusion to the article:

Aboulafia doesn’t believe Boeing can develop a twin aisle airplane with single aisle operating costs. (LNA’s Aircraft Performance Model and engineering analysis concludes Boeing can.)

Maybe Bjorn is a clapping seal?

Absolutely they can make a twin aisle with single aisle operating costs. Look at my performance model and engineering analysis above and you’ll note the 13%? Per seat fuel use per seat advantage of the single aisle. Take a current 737NG as the ‘standard’ for single aisle economics then use a GTF or LEAP derived engine and stick it on a 767 size airframe and Voila! Straight from the book of how to present info to the public from a B2B business.

Until we know what that analysis is then we may as well say voodoo make it happen, I can’t afford a subscription.

Fred


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morrisond
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Re: Boeing CEO: NMA will

Thu Feb 06, 2020 6:43 pm

flipdewaf wrote:
morrisond wrote:
NZ321 wrote:
I don't get the stats... the writing is on the wall. There is a need for a medium capacity jet above A321 to fly short to medium haul routes to replace A330 and 777 that are plying 250-300 seat corridors in the ME and Asia and beyond. It doesn't need long legs. Just needs to hit the sweet spot on short - medium haul (1 hr - 6 hrs). Anything above is an option. 788-789 has it covered as does 77x.


Me too - when I saw the numbers that the XLR could only go to about 3,500NM in Aer Lingus Config (185 Seats) which will probably closer to a typical density going forward, I thought - yes there is a Gap.
.

Does that mean you also think the 737-10 is only capable of 2450nm in a similar configuration?

Fred


Sent from my iPhone using Tapatalk


Quite possibly - Although I haven't seen the numbers - but that may be reality.
 
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 6:44 pm

There is definitely a gap between narrowbodies and wide bodies, and it is there because of physics and regulations, and no amount of fancy engineering will overcome it. The jump from 6 abreast/single aisle to 7 abreast/twin aisle means adding too much cross section for the gain in capacity. So you either make a very long single aisle or go to 8 abreast or more. The 7 abreast will always struggle to be economically viable. And making a short to medium range wide body does not appear to be worth the tremendous cost to develop it; by the time it is done the operating costs will not be enough less than the 787 to justify it. So Boeing should just go for the 737 replacement, maybe with two different wings so as to be able to offer a true 757 replacement as well. The reason they could not close the business case for the NMA is that there just is no technology on the horizon that will make 7 abreast competitive.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
morrisond
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 6:46 pm

TObound wrote:
morrisond wrote:
NZ321 wrote:
I don't get the stats... the writing is on the wall. There is a need for a medium capacity jet above A321 to fly short to medium haul routes to replace A330 and 777 that are plying 250-300 seat corridors in the ME and Asia and beyond. It doesn't need long legs. Just needs to hit the sweet spot on short - medium haul (1 hr - 6 hrs). Anything above is an option. 788-789 has it covered as does 77x.


Me too - when I saw the numbers that the XLR could only go to about 3,500NM in Aer Lingus Config (185 Seats) which will probably closer to a typical density going forward, I thought - yes there is a Gap.

Aer Lingus would probably pack something like 280-290 in an 788 and that go up to what - about 5,500 NM at that density?

Something that could take 220-240 in Aer Lingus Density about 4,500NM really would be middle of the Market and serve a lot Trans Atlantic Routes than an XLR will ever be able too.

Actually what really struck from looking at the XLR numbers is that the XLR really needs that new wing with more range and higher MTOW.


There is a gap. The question is whether it's worth filling. I've maintained all along that the XLR is a compromise. Most airlines want closer to 200 seats and closer to 4000NM in real world (winter winds, full pax payload and maybe little bit of cargo). But the question is, are carriers willling to pay for and field a whole new type that has those capabilities?

Just look at what Are Lingus can do with 3500NM range and consider what happens if Airbus can add another 500NM:

http://www.gcmap.com/mapui?R=3500nm%40d ... =wls&DU=mi

And the problem for Boeing is that Airbus could drop $2 billion over the next 5 years and build a whole new "family" around the 321, with a carbon wing, new landing gear and a stretched 322 seating 200 in the Are Lingus config. That redeveloped 321XLR would reach 4000NM for Aer Lingus, opening up the Carribean. And the 322 would come in close enough to 3500NM. Boeing would have to spend 10x what Airbus did to offer that NMA only to end up with some split of market share and the new Airbus 321 family keeping their margins on the NMA lower. That is terrible for a Boeing investor. No way their board allows that, regardless of what fanboys on here think.


That is great strategy especially if Boeing sticks with a 6W solution there is no need to do a new fuselage. However it most likely cost a lot more than $2B - it could be more in the $5-7 B range.

If Boeing goes clean sheet anyways the tight light 7W could almost cause Airbus to start from scratch to compete.
 
flipdewaf
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 6:59 pm

morrisond wrote:
flipdewaf wrote:
morrisond wrote:

Me too - when I saw the numbers that the XLR could only go to about 3,500NM in Aer Lingus Config (185 Seats) which will probably closer to a typical density going forward, I thought - yes there is a Gap.
.

Does that mean you also think the 737-10 is only capable of 2450nm in a similar configuration?

Fred


Sent from my iPhone using Tapatalk


Quite possibly - Although I haven't seen the numbers - but that may be reality.

The 737-10 is only capable of 2450nm in a Aer Lingus type configuration.

There. You can see the numbers so it must be so...

Fred


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morrisond
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Re: Boeing CEO: NMA will

Thu Feb 06, 2020 7:10 pm

flipdewaf wrote:
Revelation wrote:
https://leehamnews.com/2020/02/06/boeing-will-proceed-with-nma-or-fsa-take-a-poll/ tells us analysts are split on whether or not Boeing will do NMA or FSA, with FSA being described as a 757-200/300 substitute.

It suggests Calhoun is not a fan of NMA, and IMO that alone could be its death knell.

Interesting conclusion to the article:

Aboulafia doesn’t believe Boeing can develop a twin aisle airplane with single aisle operating costs. (LNA’s Aircraft Performance Model and engineering analysis concludes Boeing can.)

Maybe Bjorn is a clapping seal?

Absolutely they can make a twin aisle with single aisle operating costs. Look at my performance model and engineering analysis above and you’ll note the 13%? Per seat fuel use per seat advantage of the single aisle. Take a current 737NG as the ‘standard’ for single aisle economics then use a GTF or LEAP derived engine and stick it on a 767 size airframe and Voila! Straight from the book of how to present info to the public from a B2B business.

Until we know what that analysis is then we may as well say voodoo make it happen, I can’t afford a subscription.

Fred


Sent from my iPhone using Tapatalk


Hi Fred - I'll have to wait to see your great analysis on the previous page as my work Computer blocks it. However you are comparing a 737 sized Fuselage to an 767 sized one. That is a Massive difference.

The 737 is 156"H x 148"W for an area of 18,133sq", the 767 is 213"H x 198"W = 33,123sq" - an increase of 83% for only 16.7% more Y seats. No wonder the economics don't work.

Assuming the NMA is 6W most are assuming it has a bigger cross section than an A320 which is 163" H x 156"W for a cross section of 19,971sq" so NMA a bit bigger say 166"H x 160"W for 20,860sq".

Now compare that to a tight light 7W at 170"H and 186"W or 24,884sq" - only 19.3% more for 16.7% more Y seats, and up to 50% more in the front.

Yes seat comfort would not be comparable - but it's hard to see Boeing not making a bigger 6W to be able to stretch it and also keeping a 7W as tight as possible to keep it efficient - no need to make it bigger to stretch it.

What I have been arguing for years is that the difference is not that big.

What happens when you re-run your model with an 166x160" 6W vs 170"x186" 7W? as Opposed to 737 vs 767?
 
morrisond
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Re: Boeing CEO: NMA will

Thu Feb 06, 2020 7:12 pm

flipdewaf wrote:
morrisond wrote:
flipdewaf wrote:
Does that mean you also think the 737-10 is only capable of 2450nm in a similar configuration?

Fred


Sent from my iPhone using Tapatalk


Quite possibly - Although I haven't seen the numbers - but that may be reality.

The 737-10 is only capable of 2450nm in a Aer Lingus type configuration.

There. You can see the numbers so it must be so...

Fred


Sent from my iPhone using Tapatalk


That makes sense. If NMA isn't done or FSA means 5W Brazil project we could see an -10 ER with more thrust and a MTOW bump to close the Gap (somewhat) to the XLR. I doubt they could get to 3,500NM but 3,000NM might be possible.
 
flipdewaf
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 7:16 pm

morrisond wrote:

If Boeing goes clean sheet anyways the tight light 7W could almost cause Airbus to start from scratch to compete.


Indeed, and they could compete with a less tight but significantly lighter 6W. So airbus could offer a more comfortable and cheaper to operate aircraft.

It doesn’t matter how often you you repeat the trope of tight light 7w, until you show how it’s possible it’s a pipe dream and I will continue to call you out on it.

Fred



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flipdewaf
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 7:22 pm

morrisond wrote:
flipdewaf wrote:
Revelation wrote:
https://leehamnews.com/2020/02/06/boeing-will-proceed-with-nma-or-fsa-take-a-poll/ tells us analysts are split on whether or not Boeing will do NMA or FSA, with FSA being described as a 757-200/300 substitute.

It suggests Calhoun is not a fan of NMA, and IMO that alone could be its death knell.

Interesting conclusion to the article:


Maybe Bjorn is a clapping seal?

Absolutely they can make a twin aisle with single aisle operating costs. Look at my performance model and engineering analysis above and you’ll note the 13%? Per seat fuel use per seat advantage of the single aisle. Take a current 737NG as the ‘standard’ for single aisle economics then use a GTF or LEAP derived engine and stick it on a 767 size airframe and Voila! Straight from the book of how to present info to the public from a B2B business.

Until we know what that analysis is then we may as well say voodoo make it happen, I can’t afford a subscription.

Fred


Sent from my iPhone using Tapatalk


Hi Fred - I'll have to wait to see your great analysis on the previous page as my work Computer blocks it. However you are comparing a 737 sized Fuselage to an 767 sized one. That is a Massive difference.

The 737 is 156"H x 148"W for an area of 18,133sq", the 767 is 213"H x 198"W = 33,123sq" - an increase of 83% for only 16.7% more Y seats. No wonder the economics don't work.

Assuming the NMA is 6W most are assuming it has a bigger cross section than an A320 which is 163" H x 156"W for a cross section of 19,971sq" so NMA a bit bigger say 166"H x 160"W for 20,860sq".

Now compare that to a tight light 7W at 170"H and 186"W or 24,884sq" - only 19.3% more for 16.7% more Y seats, and up to 50% more in the front.

Yes seat comfort would not be comparable - but it's hard to see Boeing not making a bigger 6W to be able to stretch it and also keeping a 7W as tight as possible to keep it efficient - no need to make it bigger to stretch it.

What I have been arguing for years is that the difference is not that big.

What happens when you re-run your model with an 166x160" 6W vs 170"x186" 7W? as Opposed to 737 vs 767?

I think I used A320 numbers but I will re run the analysis tomorrow and make sure the seat Widths are comparable.

I will also add some weight to the analysis of the WB to counter the ovoid shape too and reduce the surface area accordingly.

Fred


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Amiga500
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 7:25 pm

Revelation wrote:
Aboulafia doesn’t believe Boeing can develop a twin aisle airplane with single aisle operating costs. (LNA’s Aircraft Performance Model and engineering analysis concludes Boeing can.)

Maybe Bjorn is a clapping seal?


You've said this twice - misrepresenting what I said both times. I let the first one go, but will pull you here.

I said:

Only the clapping seals thought 7AB with a magic fuselage was realistic.

There was a bit more rationality to a shorter range 8AB, but that completely ignored the costs sunk into the 787 and the inflexibility of the 8AB vis-a-vis the A321.


A 7AB approach is not realistic and the supporters of that are in the clapping seal category.

Do LNA base their analysis on a 7AB or an 8AB?
 
morrisond
Posts: 2731
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing CEO: NMA will

Thu Feb 06, 2020 8:10 pm

flipdewaf wrote:
morrisond wrote:
flipdewaf wrote:
Absolutely they can make a twin aisle with single aisle operating costs. Look at my performance model and engineering analysis above and you’ll note the 13%? Per seat fuel use per seat advantage of the single aisle. Take a current 737NG as the ‘standard’ for single aisle economics then use a GTF or LEAP derived engine and stick it on a 767 size airframe and Voila! Straight from the book of how to present info to the public from a B2B business.

Until we know what that analysis is then we may as well say voodoo make it happen, I can’t afford a subscription.

Fred


Sent from my iPhone using Tapatalk


Hi Fred - I'll have to wait to see your great analysis on the previous page as my work Computer blocks it. However you are comparing a 737 sized Fuselage to an 767 sized one. That is a Massive difference.

The 737 is 156"H x 148"W for an area of 18,133sq", the 767 is 213"H x 198"W = 33,123sq" - an increase of 83% for only 16.7% more Y seats. No wonder the economics don't work.

Assuming the NMA is 6W most are assuming it has a bigger cross section than an A320 which is 163" H x 156"W for a cross section of 19,971sq" so NMA a bit bigger say 166"H x 160"W for 20,860sq".

Now compare that to a tight light 7W at 170"H and 186"W or 24,884sq" - only 19.3% more for 16.7% more Y seats, and up to 50% more in the front.

Yes seat comfort would not be comparable - but it's hard to see Boeing not making a bigger 6W to be able to stretch it and also keeping a 7W as tight as possible to keep it efficient - no need to make it bigger to stretch it.

What I have been arguing for years is that the difference is not that big.

What happens when you re-run your model with an 166x160" 6W vs 170"x186" 7W? as Opposed to 737 vs 767?

I think I used A320 numbers but I will re run the analysis tomorrow and make sure the seat Widths are comparable.

I will also add some weight to the analysis of the WB to counter the ovoid shape too and reduce the surface area accordingly.

Fred


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Thanks for putting in the effort - let's make this fun. I have no idea if your software can do it but if you can do the Ostrower Double Circle shape that would be appreciated.
 
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Re: Boeing CEO: NMA will

Thu Feb 06, 2020 8:47 pm

morrisond wrote:
flipdewaf wrote:
Revelation wrote:
https://leehamnews.com/2020/02/06/boeing-will-proceed-with-nma-or-fsa-take-a-poll/ tells us analysts are split on whether or not Boeing will do NMA or FSA, with FSA being described as a 757-200/300 substitute.

It suggests Calhoun is not a fan of NMA, and IMO that alone could be its death knell.

Interesting conclusion to the article:


Maybe Bjorn is a clapping seal?

Absolutely they can make a twin aisle with single aisle operating costs. Look at my performance model and engineering analysis above and you’ll note the 13%? Per seat fuel use per seat advantage of the single aisle. Take a current 737NG as the ‘standard’ for single aisle economics then use a GTF or LEAP derived engine and stick it on a 767 size airframe and Voila! Straight from the book of how to present info to the public from a B2B business.

Until we know what that analysis is then we may as well say voodoo make it happen, I can’t afford a subscription.

Fred


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Hi Fred - I'll have to wait to see your great analysis on the previous page as my work Computer blocks it. However you are comparing a 737 sized Fuselage to an 767 sized one. That is a Massive difference.

The 737 is 156"H x 148"W for an area of 18,133sq", the 767 is 213"H x 198"W = 33,123sq" - an increase of 83% for only 16.7% more Y seats. No wonder the economics don't work.

Assuming the NMA is 6W most are assuming it has a bigger cross section than an A320 which is 163" H x 156"W for a cross section of 19,971sq" so NMA a bit bigger say 166"H x 160"W for 20,860sq".

Now compare that to a tight light 7W at 170"H and 186"W or 24,884sq" - only 19.3% more for 16.7% more Y seats, and up to 50% more in the front.

Yes seat comfort would not be comparable - but it's hard to see Boeing not making a bigger 6W to be able to stretch it and also keeping a 7W as tight as possible to keep it efficient - no need to make it bigger to stretch it.

What I have been arguing for years is that the difference is not that big.

What happens when you re-run your model with an 166x160" 6W vs 170"x186" 7W? as Opposed to 737 vs 767?

The 767 has an average outside dim of 202" , so 186" is a dramatic improvement even without the flattening of the lower lobe. The 767 is a brick compared to a new design. It's like a DC-9-15 compared to an E-175.
Plus the whole logic is to ditch the freight and exploit that advantage. Just like the A321 xlr will do, primarily pax payload.
As far as the 767-400 goes, I can see the logic in a re-engine since it has 18" longer gear than the -300. A re-wing or adding FBW sounds like an expensive project, plus stringent recertification. So, I don't see that.
 
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 10:00 pm

Revelation wrote:
https://leehamnews.com/2020/02/06/boeing-will-proceed-with-nma-or-fsa-take-a-poll/ tells us analysts are split on whether or not Boeing will do NMA or FSA, with FSA being described as a 757-200/300 substitute. It suggests Calhoun is not a fan of NMA, and IMO that alone could be its death knell.


At this point I would not be at all surprised if the Board of Directors is not a fan of NMA.

I still believe Boeing should focus on a 45m / (50m) / 55m narrowbody with a fuselage diameter of around 4.5 meters. This would allow for 2+3+2 in a very-high-density charter configuration with seat "comfort" similar to an eight-abreast 767, but Exit Limits might only allow that on the smaller (45m / 50m) variants and would be too limiting for a mainline operator to employ, so by default they would be forced to use a more comfortable 3+3 config with a wider aisle to improve loading / unloading / cabin service.

If they want to call that FSA, more power to them.
 
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 10:40 pm

Stitch wrote:
Revelation wrote:
https://leehamnews.com/2020/02/06/boeing-will-proceed-with-nma-or-fsa-take-a-poll/ tells us analysts are split on whether or not Boeing will do NMA or FSA, with FSA being described as a 757-200/300 substitute. It suggests Calhoun is not a fan of NMA, and IMO that alone could be its death knell.


At this point I would not be at all surprised if the Board of Directors is not a fan of NMA.

I still believe Boeing should focus on a 45m / (50m) / 55m narrowbody with a fuselage diameter of around 4.5 meters. This would allow for 2+3+2 in a very-high-density charter configuration with seat "comfort" similar to an eight-abreast 767, but Exit Limits might only allow that on the smaller (45m / 50m) variants and would be too limiting for a mainline operator to employ, so by default they would be forced to use a more comfortable 3+3 config with a wider aisle to improve loading / unloading / cabin service.

If they want to call that FSA, more power to them.


What they call it is irrelevant. Airlines will model out how this thing works against their other options and see if it adds value. The challenge for Boeing is that value for one operator doesn't constitute value for another. Adding an extra aisle to improve turn times is only relevant to short haul operators. But adding an extra turn only justifies a rather limited premium (especially when widebody vs. narrowbody costs are considered) and is entirely irrelevant to operators using that airplane for long haul.

The fundamental problem here is that Boeing is trying to compete in two markets at the same time. It's trying to kill the 321 and also to offer a small medium haul twin aisle. It's easy to do well building a large narrow body. But building a widebody that also won't do solid damage to the 787? That's hard. But maybe Boeing's sold enough 787 that they can take the hit...
 
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Thu Feb 06, 2020 11:54 pm

Amiga500 wrote:
Do LNA base their analysis on a 7AB or an 8AB?

Yes, of course, 7AB is what NMA is.

8AB NMA is an a.net invention, I've never seen any aviation media outlet refer to NMA as anything other than 7AB.
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 5:58 am

Stitch wrote:
Revelation wrote:
https://leehamnews.com/2020/02/06/boeing-will-proceed-with-nma-or-fsa-take-a-poll/ tells us analysts are split on whether or not Boeing will do NMA or FSA, with FSA being described as a 757-200/300 substitute. It suggests Calhoun is not a fan of NMA, and IMO that alone could be its death knell.


At this point I would not be at all surprised if the Board of Directors is not a fan of NMA.

I still believe Boeing should focus on a 45m / (50m) / 55m narrowbody with a fuselage diameter of around 4.5 meters. This would allow for 2+3+2 in a very-high-density charter configuration with seat "comfort" similar to an eight-abreast 767, but Exit Limits might only allow that on the smaller (45m / 50m) variants and would be too limiting for a mainline operator to employ, so by default they would be forced to use a more comfortable 3+3 config with a wider aisle to improve loading / unloading / cabin service.

If they want to call that FSA, more power to them.


I think Boeing should do nothing. No new plane in the 2020ies. It is time to make money.
 
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 10:32 am

Revelation wrote:
Amiga500 wrote:
Do LNA base their analysis on a 7AB or an 8AB?

Yes, of course, 7AB is what NMA is.

8AB NMA is an a.net invention, I've never seen any aviation media outlet refer to NMA as anything other than 7AB.


Well, then their fuselage modelling needs an awful lot of work and/or they are drinking the kool-aid.

There is no such thing as a "tight light 7AB". Boeing try their ovoid fuselage and the B check intervals would probably be <3 months or so. No airline is gonna swallow that.
 
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 1:47 pm

I haven't seen this link posted upthread, and I have to wonder if this is the direct reason for Boeing taking a step back; it is too late anyway:
https://www.anna.aero/2019/12/04/united-airlines-orders-50-a321xlrs-to-replace-757s-to-europe/

So I think Boeing have now conceded that ~80% of the Replacement market for 757 / 767 will go to the A321LR or the A321XLR.
Since they are anyway late to the party, might as well bring something truly next gen before showing up.

My guess: The new NMA will pioneer One pilot only operation.
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 2:12 pm

Amiga500 wrote:
Revelation wrote:
Amiga500 wrote:
Do LNA base their analysis on a 7AB or an 8AB?

Yes, of course, 7AB is what NMA is.

8AB NMA is an a.net invention, I've never seen any aviation media outlet refer to NMA as anything other than 7AB.


Well, then their fuselage modelling needs an awful lot of work and/or they are drinking the kool-aid.

There is no such thing as a "tight light 7AB". Boeing try their ovoid fuselage and the B check intervals would probably be <3 months or so. No airline is gonna swallow that.


But it's probably not an avoid - It's more like two circles intersecting at one point - see this https://jonostrower.com/2018/04/toddler ... -fuselage/
 
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 2:20 pm

morrisond wrote:
Amiga500 wrote:
Revelation wrote:
Yes, of course, 7AB is what NMA is.

8AB NMA is an a.net invention, I've never seen any aviation media outlet refer to NMA as anything other than 7AB.


Well, then their fuselage modelling needs an awful lot of work and/or they are drinking the kool-aid.

There is no such thing as a "tight light 7AB". Boeing try their ovoid fuselage and the B check intervals would probably be <3 months or so. No airline is gonna swallow that.


But it's probably not an avoid - It's more like two circles intersecting at one point - see this https://jonostrower.com/2018/04/toddler ... -fuselage/

That wouldn't help. Double bubble requires the section with the largest radius to be more than half a circle to work.
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 2:35 pm

Revelation wrote:
Amiga500 wrote:
Do LNA base their analysis on a 7AB or an 8AB?

Yes, of course, 7AB is what NMA is.

8AB NMA is an a.net invention, I've never seen any aviation media outlet refer to NMA as anything other than 7AB.


This is probably true, but also probably invented because too many other respected members have said a 7 just won't work.
ps - I have always, from first tryout, thought the 8 abreast 330 was close in comfort to a 7 abreast 767 (my favorite)
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 2:52 pm

speedygonzales wrote:
morrisond wrote:
Amiga500 wrote:

Well, then their fuselage modelling needs an awful lot of work and/or they are drinking the kool-aid.

There is no such thing as a "tight light 7AB". Boeing try their ovoid fuselage and the B check intervals would probably be <3 months or so. No airline is gonna swallow that.


But it's probably not an avoid - It's more like two circles intersecting at one point - see this https://jonostrower.com/2018/04/toddler ... -fuselage/

That wouldn't help. Double bubble requires the section with the largest radius to be more than half a circle to work.


I never said it was a Double bubble. Boeing was rumoured to use something similar for NSA back in 2011 - I think with the Computing power and tools of today they will have figured out a way to do it with not too much of a weight penalty.

You always have to remember for a given capacity if you go 7W you save a lot in length and especially can save a lot in the front if you are comparing a 2x2 design to a 2x2x2 design.

For example - lets assume that the large NMA has seating for 234. 24 in Domestic Business Class up front at 38" pitch and 210 in the back at 31" pitch. The simplistic (ignoring things like Lavs) cabin length of an 6W NMA would be 109'5".

A 7W NMA would be 90'2". That is almost 20' shorter. That is a lot. Plus you could argue with the wider fuselage you have more space for lavs and galleys saving some space there - call it 3' in total - so that would put it at over 20'.

I can't see the Ostrower shape taking significantly more structure per seat (although I know it will be more) than what is gained by losing over 20' of fuselage.

Even if it is heavier - it's not that big of a weight penalty.

Here is a great article looking at taking an A320 Fuselage and making it out of Carbon. They put the total fuselage structure at 4,547 KG and if they built it out of Carbon they would save about 1,200KG.

So even if an 7W NMA Carbon is heavier per seat - say 1,000KG than a 20' longer 6W A320 series Aluminum tube- that is not a lot and you are only talking about 1% of the mass of the plane difference. With Carbon the difference may be negligible.

https://www.dlr.de/fa/Portaldata/17/Res ... srw_10.pdf
 
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 3:45 pm

Amiga500 wrote:
Revelation wrote:
Amiga500 wrote:
Do LNA base their analysis on a 7AB or an 8AB?

Yes, of course, 7AB is what NMA is.

8AB NMA is an a.net invention, I've never seen any aviation media outlet refer to NMA as anything other than 7AB.


Well, then their fuselage modelling needs an awful lot of work and/or they are drinking the kool-aid.

There is no such thing as a "tight light 7AB". Boeing try their ovoid fuselage and the B check intervals would probably be <3 months or so. No airline is gonna swallow that.

You've been poo-pooing the oval fuse for five years now ( viewtopic.php?t=597733#p9386171 ) yet we have no evidence that Boeing has ever described NMA as anything other than a seven across 'hybrid' cross section.

Interesting old article quotes LNA's Bjorn Fehrm:

The raw appeal of an elliptical fuselage shape is clear: for the same amount of wetted area – the portion of the hull in contact with the external airflow – a purely circular fuselage usually can't carry as many seats. A lower wetted area for the elliptical fuselage also means less drag.

Another consideration is the length of the fuselage. A six-abreast cabin in a narrowbody fuselage for 250 passengers would result in an excessively long cabin, causing slow and inefficient boarding and deboarding periods, he says.

The optimal seating for a 7M7-sized aircraft is instead a seven-abreast cabin, he adds. But achieving the narrowbody-like economics is only possible with an elliptical fuselage, not a circular shape with greater drag.

There are, however, drawbacks that must be considered. The geometric advantages of the elliptical shape have always been known, but concerns about pressurisation have forced manufacturers of large aircraft to use circular or double-bubble cross-sections.

Any pressurised vessel seeks to reshape the containment into a circle anyway, so any non-circular shape must be strengthened to resist these forces. Adding layers of strengthening increases the weight of the fuselage, leading designers to favour circular cross-sections.

But Fehrm points to a major innovation of the last decade that may overcome the concerns about pressurisation. Aircraft fuselages can now be made from composite material, such as the carbonfibre reinforced plastic (CFRP) used for the fuselage and wing skins of the 787. Adapting such materials to an aircraft with 5,000nm range should not be a technological stretch for the 7M7, which would enter service more than a decade after the Dreamliner.


Ref: https://www.flightglobal.com/analysis-w ... 67.article

So, we get it, you're no fan of the reasoning, but referring to others as koolaid drinkers and clapping seals comes across as unwarranted arrogance.
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 3:57 pm

The reasoning is wrong, because the load distribution caused by the geometry does not change with the material used to build the fuselage. The relative difference between both designs using the same material remains quite static. Sure you could do a CFRP ovid fuselage that is competitive to a conventional metal fuselage, but that is not an effective solution for a new plane.
 
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 4:02 pm

seahawk wrote:
I think Boeing should do nothing. No new plane in the 2020ies. It is time to make money.


I do agree with you, they still have around 4500 737 MAX orders to deliver, but it will also cost them (a lot?) of money to restart the production of the MAX, at least that’s what I think, and if I’m correct a few 737 MAX part suppliers have gone bankrupt because of Boeing temporarily stopping the 737 MAX production. And they still need to deliver other aircraft types. Boeing has big problems that they need to resolve, and it isn’t easy to resolve these problems. What Boeing should do in the 2020s in my opinion, and I don’t want to start a fanboy war here, they should redesign the flight control logic to be like the A220 cockpit, maybe with active side sticks, for their next aircraft in the 2030s. It seems like the NMA is going to be cancelled in favour of the NSA in my opinion.
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 4:09 pm

seahawk wrote:
The reasoning is wrong, because the load distribution caused by the geometry does not change with the material used to build the fuselage. The relative difference between both designs using the same material remains quite static. Sure you could do a CFRP ovid fuselage that is competitive to a conventional metal fuselage, but that is not an effective solution for a new plane.



Would you care to add some reasoning as to why it's not that effective?
 
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Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 4:14 pm

morrisond wrote:
seahawk wrote:
The reasoning is wrong, because the load distribution caused by the geometry does not change with the material used to build the fuselage. The relative difference between both designs using the same material remains quite static. Sure you could do a CFRP ovid fuselage that is competitive to a conventional metal fuselage, but that is not an effective solution for a new plane.



Would you care to add some reasoning as to why it's not that effective?


That’s not what Seahawk said.

Even if it was true that one could save those amounts (the expectations on component and system level savings are different) then that amount would apply equally to both narrow body and wide body and therefore is immaterial to the debate.

Fres


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PS. Analysis ongoing!
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Re: Boeing CEO: NMA will

Fri Feb 07, 2020 4:30 pm

flipdewaf wrote:
morrisond wrote:
seahawk wrote:
The reasoning is wrong, because the load distribution caused by the geometry does not change with the material used to build the fuselage. The relative difference between both designs using the same material remains quite static. Sure you could do a CFRP ovid fuselage that is competitive to a conventional metal fuselage, but that is not an effective solution for a new plane.



Would you care to add some reasoning as to why it's not that effective?


That’s not what Seahawk said.

Even if it was true that one could save those amounts (the expectations on component and system level savings are different) then that amount would apply equally to both narrow body and wide body and therefore is immaterial to the debate.

Fres


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PS. Analysis ongoing!


Thanks on the Analysis.

It's not immaterial to the debate if Boeing's entry in the space is an Carbon 7W vs Airbus stretching the A320 and rewinging it. The fuselage weight difference may be negligible per seat.

Take an A320 Fuselage that is about 4,500KG if that article is right. Build it out of Carbon so it looses 1,200kg and reduce it in length by 20% to get a remaining weight of about 3,000KG.

The 7W Ovalish cross section could be 50% more per meter (taking it back to 4,500KG) of fuselage length ( I think you suggested this number before) for a cross section that is about 24.6% more. That sounds more than reasonable. You would think they could shave a bit off that number with the Ostrower design.

That is why I keep saying that if Boeing does launch a cross section like this - it almost forces Airbus to a clean sheet as who wouldn't want a twin aisle with almost no disadvantage? They could build a new 6W but it really wouldn't save you much weight as the bare fuselage is such a small fraction of the MTOW.
 
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 4:45 pm

morrisond wrote:
seahawk wrote:
The reasoning is wrong, because the load distribution caused by the geometry does not change with the material used to build the fuselage. The relative difference between both designs using the same material remains quite static. Sure you could do a CFRP ovid fuselage that is competitive to a conventional metal fuselage, but that is not an effective solution for a new plane.


Would you care to add some reasoning as to why it's not that effective?


Because your new design would be inferior to a circular or double bubble design using the same construction methods. In addition the basic geometric disadvantage of the 7 abreast seating stays with you. Sure this might be the most efficient 7 abreast design, if you do not want to have a cargo carrying capacity, but the overall design is still less efficient than a conventional 6 or 8 abreast.

So in the end you move to the most modern fuselage construction technique to get you fuselage weight down by 25% compared to a old style metal tube and then you give up 30% of this due to your ovid shape and probably more than the rest due to your ineffective 7 abreast seating configuration.

So all other new designs using the same fuselage construction methods will or better could enjoy a design advantage over your design.
 
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Re: Boeing CEO: NMA will

Fri Feb 07, 2020 4:51 pm

morrisond wrote:
flipdewaf wrote:
morrisond wrote:


Would you care to add some reasoning as to why it's not that effective?


That’s not what Seahawk said.

Even if it was true that one could save those amounts (the expectations on component and system level savings are different) then that amount would apply equally to both narrow body and wide body and therefore is immaterial to the debate.

Fres


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PS. Analysis ongoing!


Thanks on the Analysis.

It's not immaterial to the debate if Boeing's entry in the space is an Carbon 7W vs Airbus stretching the A320 and rewinging it. The fuselage weight difference may be negligible per seat.

Take an A320 Fuselage that is about 4,500KG if that article is right. Build it out of Carbon so it looses 1,200kg and reduce it in length by 20% to get a remaining weight of about 3,000KG.

The 7W Ovalish cross section could be 50% more per meter (taking it back to 4,500KG) of fuselage length ( I think you suggested this number before) for a cross section that is about 24.6% more. That sounds more than reasonable. You would think they could shave a bit off that number with the Ostrower design.

That is why I keep saying that if Boeing does launch a cross section like this - it almost forces Airbus to a clean sheet as who wouldn't want a twin aisle with almost no disadvantage? They could build a new 6W but it really wouldn't save you much weight as the bare fuselage is such a small fraction of the MTOW.


To see the weight advantage of carbon at an aircraft level you need only look at the aircraft that are already in existence and remotely comparable. B789 Vs A339
77L vs A351. Carbon doesn't seem to bring much weight advantage...

Fred
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Re: Boeing CEO: NMA will

Fri Feb 07, 2020 5:05 pm

flipdewaf wrote:
morrisond wrote:
flipdewaf wrote:

That’s not what Seahawk said.

Even if it was true that one could save those amounts (the expectations on component and system level savings are different) then that amount would apply equally to both narrow body and wide body and therefore is immaterial to the debate.

Fres


Sent from my iPhone using Tapatalk

PS. Analysis ongoing!


Thanks on the Analysis.

It's not immaterial to the debate if Boeing's entry in the space is an Carbon 7W vs Airbus stretching the A320 and rewinging it. The fuselage weight difference may be negligible per seat.

Take an A320 Fuselage that is about 4,500KG if that article is right. Build it out of Carbon so it looses 1,200kg and reduce it in length by 20% to get a remaining weight of about 3,000KG.

The 7W Ovalish cross section could be 50% more per meter (taking it back to 4,500KG) of fuselage length ( I think you suggested this number before) for a cross section that is about 24.6% more. That sounds more than reasonable. You would think they could shave a bit off that number with the Ostrower design.

That is why I keep saying that if Boeing does launch a cross section like this - it almost forces Airbus to a clean sheet as who wouldn't want a twin aisle with almost no disadvantage? They could build a new 6W but it really wouldn't save you much weight as the bare fuselage is such a small fraction of the MTOW.


To see the weight advantage of carbon at an aircraft level you need only look at the aircraft that are already in existence and remotely comparable. B789 Vs A339
77L vs A351. Carbon doesn't seem to bring much weight advantage...

Fred


This times 1 million. Why aren't more people saying this in aviation? Where is the benefit to composite structure? Can someone please show?
 
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 5:13 pm

There is a huge benefit for the fuselage structure, just that the fuselage alone contributes not that much to the overall empty weight. For an A320 it is just 4,5-4,6 metric tons which is 11% of the OEW. So even a reduction of the fuselage weight by 25%, just gives you an OEW reduction of ~2,5%.
 
Amiga500
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 6:04 pm

Revelation wrote:
You've been poo-pooing the oval fuse for five years now ( viewtopic.php?t=597733#p9386171 ) yet we have no evidence that Boeing has ever described NMA as anything other than a seven across 'hybrid' cross section.


Having been involved in stress & FaDT of CSeries fuselage, which has 3 different radii and is a *very* mild interpretation of what is being proposed, I know the ____ing thing won't work.
Take that whatever way you want.
I can guarantee a metallic fuselage of that cross section isn't going to work.

Unless CFRP is a magic bullet - implemented with very extreme anisotropic layups, which then bring their own problems - the weight will be prohibitive.


The far better solution is going 8AB - copy the A300 fuselage, then trade off shrinking the keel and crown radii ever so slightly while increasing the radii of the two sides - balancing wetted area against fuselage weight. But IMO that trade-off won't go far, you'll not reduce area much before weight growth is prohibitive.


But having the keel radii so different as to eliminate underfloor cargo in a fuselage wide enough for 7AB is only ever going to end in copious amounts of tears. A re-winged and stretched A322 would decimate a 7AB NMA on operating costs from below and would leave the way clear for Airbus to replace the A330 with a shortened range 8AB that would do similar to the NMA as A330 has done to 767. That is the uncomfortable truth of 7AB.
 
Amiga500
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Re: Boeing CEO: NMA will

Fri Feb 07, 2020 6:10 pm

SteelChair wrote:
This times 1 million. Why aren't more people saying this in aviation? Where is the benefit to composite structure? Can someone please show?


Wing t/c ratio can drop without the spar structure becoming heavier.

This means more aerodynamically efficient solutions.

So even though on the face of it CFRP doesn't reduce wing weight (and increase performance that way), it does enable improved aerodynamic performance.


Obviously, crack inspection intervals for CFRP aren't anything like metallics as each lamina is effectively a crack stopper. Of course, there are other considerations like delaminations.
 
Amiga500
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 6:12 pm

seahawk wrote:
There is a huge benefit for the fuselage structure, just that the fuselage alone contributes not that much to the overall empty weight. For an A320 it is just 4,5-4,6 metric tons which is 11% of the OEW. So even a reduction of the fuselage weight by 25%, just gives you an OEW reduction of ~2,5%.


There is benefit on larger planes.

But not so much on smaller aircraft as laminate thickness has to be large enough to deal with impact damage satisfactorily. So that concern dominates hoop stress meaning you can't go as thin as you would otherwise.

Carbon Nano Fibre (CNF) infused resins should help with impact damage and may enable thinner layups for fuselage designs in future.

But consistently mixing (and measuring the consistency) the resin with CNF is still problematic I gather.
 
DenverTed
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 6:13 pm

Comparing a 3-3 with containers to a 2-3-2 with the same container, about a 160" fuselage at 55m versus 192" fuselage at 50m. So 10% more skin for the 2-3-2, but you get an extra aisle and two more aisle seats. Plus there must be some structural savings for a less slender proportion. And for an equal landing gear height, the 2-3-2 has a better rotation angle for 6,000 ft runways. So, I think one could bend the economic case either way with various assumptions, and one may work better depending on specific conditions.
 
Amiga500
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 6:15 pm

DenverTed wrote:
Comparing a 3-3 with containers to a 2-3-2 with the same container, about a 160" fuselage at 55m versus 192" fuselage at 50m. So 10% more skin for the 2-3-2, but you get an extra aisle and two more aisle seats. Plus there must be some structural savings for a less slender proportion. And for an equal landing gear height, the 2-3-2 has a better rotation angle for 6,000 ft runways. So, I think one could bend the economic case either way with various assumptions, and one may work better depending on specific conditions.


Aisles don't pay fares.
 
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 6:29 pm

Amiga500 wrote:
Revelation wrote:
You've been poo-pooing the oval fuse for five years now ( viewtopic.php?t=597733#p9386171 ) yet we have no evidence that Boeing has ever described NMA as anything other than a seven across 'hybrid' cross section.

Having been involved in stress & FaDT of CSeries fuselage, which has 3 different radii and is a *very* mild interpretation of what is being proposed, I know the ____ing thing won't work.
Take that whatever way you want.

The way I take it is you probably aren't evaluating the same design Boeing is, or you are probably aren't applying the same criteria for acceptance.

Regardless, Calhoun does not seem to be a NMA fan and has kicked the can down the road.

Given the regime change my best guess is we see no NMA at all and we see no NSA proposal for ~five years.
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morrisond
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 6:52 pm

seahawk wrote:
morrisond wrote:
seahawk wrote:
The reasoning is wrong, because the load distribution caused by the geometry does not change with the material used to build the fuselage. The relative difference between both designs using the same material remains quite static. Sure you could do a CFRP ovid fuselage that is competitive to a conventional metal fuselage, but that is not an effective solution for a new plane.


Would you care to add some reasoning as to why it's not that effective?


Because your new design would be inferior to a circular or double bubble design using the same construction methods. In addition the basic geometric disadvantage of the 7 abreast seating stays with you. Sure this might be the most efficient 7 abreast design, if you do not want to have a cargo carrying capacity, but the overall design is still less efficient than a conventional 6 or 8 abreast.

So in the end you move to the most modern fuselage construction technique to get you fuselage weight down by 25% compared to a old style metal tube and then you give up 30% of this due to your ovid shape and probably more than the rest due to your ineffective 7 abreast seating configuration.

So all other new designs using the same fuselage construction methods will or better could enjoy a design advantage over your design.


I get it - but no one is talking about no cargo carrying capacity - I think most assume it would be a XL LD3-45.

Yes - if you are competing with a clean sheet 6W - but how much longer and heavier would it have to get for the same capacity - it looks like 20% more length as I calculated above - that is a lot and as others have pointed out it means things like heavier longer gear - much stronger wingbox, etc.. As I showed above a Carbon 7W fuselage could be 50% heavier than an Carbon 6W A320 series per meter and your fuselage weight wouldn't change.

This shouldn't be that much either as due to the overly thick fuselage skins which would add stiffness means you can save weight elsewhere. The difference would be minimal either plus or minus.

Boeing is most likely looking at Competing with the Airbus A320 Fuselage in Aluminum in an lengthened A322 version. Yes 8W could be more efficient but that is way too big and even harder to make efficient with a given container size.

The 7W wins over the A320 as you can stretch the 7W more. Plus given that fuselage weight is such a minimal part of an aircraft - it's not really a handicap for an eventual 737 successor with smaller wing/wingbox/gear/engines. Which of course brings massive economy of scale which NMA would never get as a standalone 8W program.

The cross section really needs to be shared with NSA - and as I showed above it doesn't really seem like that much of a disadvantage to be 7W.

It may not be 7W but it almost definitely won't be 8W and it seems like it's a wash with 6W - with 7W having more growth possible.

Then assuming FSA (Future SMALL Airplane) is the next Boeing Brazil project (which takes on short range under 3,000nm missions in an 5W design up to 180 Y seats), they then have NMA/NSA in 7W (Middle Sized Airplane smallest 200Y at about 4,000NM and largest 320Y at 5,500NM), and the Large passenger Aircraft is Variants on the 787 - Small, Medium and Large.

I think it would be amazing if the 777X makes it to 2030 as a Passenger Aircraft - but it will have a place as the large freighter for a long time as 747 winds down and Boeing uses the factory space for NMA.

This whole strategy fits in with what Boeing has been predicting for years - Frequency over Capacity as I can see NMA in 7W replacing a lot of 787/330 missions.
 
flipdewaf
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Re: Boeing CEO: NMA will "start with a clean sheet of paper again"

Fri Feb 07, 2020 7:02 pm

Amiga500 wrote:
SteelChair wrote:
This times 1 million. Why aren't more people saying this in aviation? Where is the benefit to composite structure? Can someone please show?


Wing t/c ratio can drop without the spar structure becoming heavier.

This means more aerodynamically efficient solutions.

So even though on the face of it CFRP doesn't reduce wing weight (and increase performance that way), it does enable improved aerodynamic performance.


My understanding (structures was always my weakest area) is that effectively the higher (and more tailorable) Young’s modulus of CFRP means that you can get a structure less likely to buckle in the top surface at increased compression->thinner wing->increased Mcrit.


Amiga500 wrote:
seahawk wrote:
There is a huge benefit for the fuselage structure, just that the fuselage alone contributes not that much to the overall empty weight. For an A320 it is just 4,5-4,6 metric tons which is 11% of the OEW. So even a reduction of the fuselage weight by 25%, just gives you an OEW reduction of ~2,5%.


There is benefit on larger planes.

But not so much on smaller aircraft as laminate thickness has to be large enough to deal with impact damage satisfactorily. So that concern dominates hoop stress meaning you can't go as thin as you would otherwise.


My take on this (and feel free to correct me) is that if you get to the level where CFRP is limited by impact resistance and so in theory you could exploit that additional required thickness by doing crazy shapes you would actually be better just to not do a crazy shape and use a more appropriate material.

Aren’t the properties of CFRP that give it the ability to make thinner, longer wings as opposed to reducing weight the same properties that would allow a longer thinner fuselage at the same pressure differential before becoming bending moment dominated? I.e. suit a very long narrow body...

Fred





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morrisond
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Re: Boeing CEO: NMA will

Fri Feb 07, 2020 7:09 pm

flipdewaf wrote:
Aren’t the properties of CFRP that give it the ability to make thinner, longer wings as opposed to reducing weight the same properties that would allow a longer thinner fuselage at the same pressure differential before becoming bending moment dominated? I.e. suit a very long narrow body...

Fred

Sent from my iPhone using Tapatalk


Besides the ability to do crazy shapes with not much of a penalty - yes that would be another benefit. But how much longer? Could you really go much beyond 753 length for ergonomic reasons without widening the aisle too much and then you might as well go 7W?

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