Newbiepilot
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 1:06 pm

rheinwaldner wrote:
GulfstreamFive wrote:
Boeing CEO Dennis Muilenberg defines MOM aircraft at a Politico Space event last week in Washington DC
Check out the video half way down the page at about 24:00
https://www.geekwire.com/2018/boeing-ceo-dennis-muilenburg-mars-decade/

He says that a decision is due within one year. And that the question continues to be whether the business case is going to close. So I ask myself: if the business case was not a clear case in all the years since Boeing talks about the 757RS/MOM/NMA, what variable could change that in the next year?


I have posted this before, but perhaps you didn’t notice. A launch means that the airplane has performance numbers, delivery dates and pricing settled in a contract with an airline. Every day the design of the airplane is progressing and is getting more mature. Once the engineers have gotten far enough through the design process, the sales teams will be ready to make those commitments. If the airplane is launched too early in the design process there are too many risks that the final product won’t match the contractual promises (like how the 787 was sold for too little and was very late).

It’s not like the airplane is all on paper and then suddenly at launch they put it in CATIA and get the drafters working. The design process has already started. Launch is all about the customer being ready to commit. The engineering work is already happening. That’s what a program office is, which was created last year. They are the ones moving forward with the design.

So to answer your question:

rheinwaldner wrote:
if the business case was not a clear case in all the years since Boeing talks about the 757RS/MOM/NMA, what variable could change that in the next year?


The design has matured enough to the point where they are ready to contractually commit on price, delivery date, performance numbers and capability of the airplane. In the last two years they were speaking to Airlines and suppliers to start the initial design and set the design requirements.
 
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 1:45 pm

Keesje - What would you say about your A322 Idea? Would that have too much range?

What if NMA is an NSA XL with different wing/wingbox/gear - 7W Oval Fuselage with Xtra Wide LD3-45 in the belly - yes it would possibly weigh more than an A322 but not that much more. Envision sitting in an A320 - then Assume that the sidewalls are 18" farther out (to account for the extra seat and the aisle - hold your hands 18" apart - it's not that much) - that too me is what the NMA/NSA fuselage will be with approximately the same fuselage height as A320 (Maybe 6-12" more) - with Modern Materials this Barrel should not be significantly heavier - A Composite Nose and tail possibly lighter enough to offset any weight increase. Also with same passenger Capacity as your A322 - NMA fuselage could be lighter as it would be significantly shorter.
 
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 2:38 pm

keesje wrote:
I see a strong drive towards a range of 5000NM or even more for NMA. IMO that risks building an aircraft that is way to heavy to be competitive on the bulk of flights. I think it should be optimized, or at least be very efficient for flights of around 2hrs / 1000NM.


If that is where the product is being driven, it is being driven there by the customers. If they wanted a high-capacity short-haul widebody, that is what they would be asking for.
 
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 2:55 pm

Newbiepilot wrote:
rheinwaldner wrote:
GulfstreamFive wrote:
Boeing CEO Dennis Muilenberg defines MOM aircraft at a Politico Space event last week in Washington DC
Check out the video half way down the page at about 24:00
https://www.geekwire.com/2018/boeing-ceo-dennis-muilenburg-mars-decade/

He says that a decision is due within one year. And that the question continues to be whether the business case is going to close. So I ask myself: if the business case was not a clear case in all the years since Boeing talks about the 757RS/MOM/NMA, what variable could change that in the next year?


I have posted this before, but perhaps you didn’t notice. A launch means that the airplane has performance numbers, delivery dates and pricing settled in a contract with an airline. Every day the design of the airplane is progressing and is getting more mature. Once the engineers have gotten far enough through the design process, the sales teams will be ready to make those commitments. If the airplane is launched too early in the design process there are too many risks that the final product won’t match the contractual promises (like how the 787 was sold for too little and was very late).

It’s not like the airplane is all on paper and then suddenly at launch they put it in CATIA and get the drafters working. The design process has already started. Launch is all about the customer being ready to commit. The engineering work is already happening. That’s what a program office is, which was created last year. They are the ones moving forward with the design.

So to answer your question:

rheinwaldner wrote:
if the business case was not a clear case in all the years since Boeing talks about the 757RS/MOM/NMA, what variable could change that in the next year?


The design has matured enough to the point where they are ready to contractually commit on price, delivery date, performance numbers and capability of the airplane. In the last two years they were speaking to Airlines and suppliers to start the initial design and set the design requirements.


When the program office was established last year, there was never consensus on a.net about what a program office was all about. In the IT industry, a program (or programme) office (PO) is not directly involved in what the programme is aiming to create. The PO is more focussed on "how" rather than "what", and in the view os some (including me) the 797 PO was set up to find out how to" build a widebody at single-aisle costs", so was more focussed on everything to do with production.

I would therefore doubt that the 797 PO has produced any design documents or CATIA models. Others may have done that in parallel, but not the PO IMHO!
 
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 3:03 pm

Stitch wrote:
keesje wrote:
I see a strong drive towards a range of 5000NM or even more for NMA. IMO that risks building an aircraft that is way to heavy to be competitive on the bulk of flights. I think it should be optimized, or at least be very efficient for flights of around 2hrs / 1000NM.


If that is where the product is being driven, it is being driven there by the customers. If they wanted a high-capacity short-haul widebody, that is what they would be asking for.


If the 767 operations of the last 30 years mean anything, an average 2 hours is about right. And that includes the ER versions that can do 6000NM. It seems Boeing is pushing the NMA as a 767 replacement. I doubt the average flights lengths of the 757 fleets are higher.

Image

As to what customers are asking for, the only large scale survey I saw, was quickly dismissed here on a.net, because it seems results deviate significantly from what Boeing seems to target. :knockout: http://aviationweek.com/site-files/aviationweek.com/files/uploads/2016/07/09/AI29_pie1.jpeg
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 3:10 pm

Stitch wrote:
keesje wrote:
I see a strong drive towards a range of 5000NM or even more for NMA. IMO that risks building an aircraft that is way to heavy to be competitive on the bulk of flights. I think it should be optimized, or at least be very efficient for flights of around 2hrs / 1000NM.


If that is where the product is being driven, it is being driven there by the customers. If they wanted a high-capacity short-haul widebody, that is what they would be asking for.


The average 787 flight is under 4000nm. 5000nm range is well within 787 territory. If an airline wants an airplane that efficiently operates and is optimized for 5000nm, they probably would be buying 787s. From what i hear about the 797, it is intended for 1000nm-4000nm.
 
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 3:22 pm

Newbiepilot wrote:
rheinwaldner wrote:
if the business case was not a clear case in all the years since Boeing talks about the 757RS/MOM/NMA, what variable could change that in the next year?


The design has matured enough to the point where they are ready to contractually commit on price, delivery date, performance numbers and capability of the airplane. In the last two years they were speaking to Airlines and suppliers to start the initial design and set the design requirements.

That was clear to me. Before an aircraft is launched, the engineering has already been started in order to get solid performance predictions (for the reasons you are mentioning).

But outstanding design clarity was not the reason Muilenburg mentioned. He said the business case needs to close first. In April 2018. I am not sure how far you let engineers design an aircraft, of which you don't know whether the business case will close. Normally (see 787, A350, 7777X) the business case is solid enough so that the CEO does not need to mention it every time less than a year before expected launch. Normally the question regarding the business case is "will it be super or only good?" but in case of the 797 the question is "will it close?".

The wording is so careful imho, that Boeing would be able to bury the NMA without loosing their face.

Beside that they were not talking to airlines for 2 years. I can find references about a 757RS from 2009 in the Internet, so this talk with airlines no lasts already 9 years. So there is still no convincing answer imho, what stars would have to align during the next year, that the conclusion would be different than in all the years before...
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 3:30 pm

keesje wrote:
If the 767 operations of the last 30 years mean anything, an average 2 hours is about right. And that includes the ER versions that can do 6000NM.


Considering how many 767s did TATL and Mainland-Hawaii services in their career, I doubt "two hours" was the average stage length of an average 767.

And choosing a data point that represents the single frame with the highest hours and highest cycles is not, IMO, exactly the most relevant data point to make a claim that this is representative of the entire fleet.


keesje wrote:
It seems Boeing is pushing the NMA as a 767 replacement. I doubt the average flights lengths of the 757 fleets are higher.


They're pushing it as a 767 replacement in terms of capacity, at least. And if the average flight length of a 757 today is two hours, Airbus must be drinking absinthe to think they will sell 1000 frames of their six-hour endurance variant (A321-200LR).


keesje wrote:
As to what customers are asking for, the only large scale survey I saw, was quickly dismissed here on a.net, because it seems results deviate significantly from what Boeing seems to target.


If your argument is about stage length, showing a survey that is only about capacity is not very effective.

Though that survey does show that almost three-fourths of the market want an airframe that seats between 150-250 people which is indeed in the 767's capacity range (CO's two-class BusinessFirst 762s seated 174 and their two-class BusinessFirst 767-400s seated 235).
 
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 3:47 pm

rheinwaldner wrote:
Newbiepilot wrote:
rheinwaldner wrote:
if the business case was not a clear case in all the years since Boeing talks about the 757RS/MOM/NMA, what variable could change that in the next year?


The design has matured enough to the point where they are ready to contractually commit on price, delivery date, performance numbers and capability of the airplane. In the last two years they were speaking to Airlines and suppliers to start the initial design and set the design requirements.

That was clear to me. Before an aircraft is launched, the engineering has already been started in order to get solid performance predictions (for the reasons you are mentioning).

But outstanding design clarity was not the reason Muilenburg mentioned. He said the business case needs to close first. In April 2018. I am not sure how far you let engineers design an aircraft, of which you don't know whether the business case will close. Normally (see 787, A350, 7777X) the business case is solid enough so that the CEO does not need to mention it every time less than a year before expected launch. Normally the question regarding the business case is "will it be super or only good?" but in case of the 797 the question is "will it close?".

The wording is so careful imho, that Boeing would be able to bury the NMA without loosing their face.

Beside that they were not talking to airlines for 2 years. I can find references about a 757RS from 2009 in the Internet, so this talk with airlines no lasts already 9 years. So there is still no convincing answer imho, what stars would have to align during the next year, that the conclusion would be different than in all the years before...


Business case includes the price to build and the price to sell. Boeing has been working hard on keeping the price to build down. Engineers have to keep proceeding with design to get accurrate production costs.

For example will the plane have 45K or 50K engines?
What engine manufacturer or manufacturers will be chosen?
How many spoilers will there be 10, 12, 18...?
Will wingtips fold?
How many tires and axles?
What structure will be composote vs aluminum vs titanium vs steel?

Answering all these questions gets the program office towards a complete enough design so that the pricing can be accurate and close the business case. If the airplane costs too much to build it won't have a business case. The 787 was very inaccurate on cost. It sounds like they are taking their time before launching the 797 to get more engineering work done especially around production cost. The good news is that likely means the time from launch to delivery will be shorter since more work was done up front
 
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 4:45 pm

Newbiepilot wrote:
For example will the plane have 45K or 50K engines?
What engine manufacturer or manufacturers will be chosen?
How many spoilers will there be 10, 12, 18...?
Will wingtips fold?
How many tires and axles?
What structure will be composote vs aluminum vs titanium vs steel?

If the business case is not closed before answering these kind of questions, it must be very close to "not worthwhile". At least I cant remember an aircraft program in the past, where such questions were seen as decisive whether the program would become profitable overall or not.

Newbiepilot wrote:
It sounds like they are taking their time before launching the 797 to get more engineering work done especially around production cost. The good news is that likely means the time from launch to delivery will be shorter since more work was done up front


It sounds not at all like that. You don't validate a business case by designing more upfront. In oder to avoid sunk cost, you try to avoid any effort, that would be lost if the project is a nogo in the end. According to the "shift left" philosophy you aim to find wrong decisions as early as possible. So spending considerable design work into an unvalidated business case would be bad and risky business practice.

Closing the business case means primarily marketing activity, estimate production cost (as you rightfully say), try to estimate as good as possible the resulting market share vs. the production cost vs the development investment minus expected subsidiaries.

I am working in large engineering projects too, and we hardly ever design anything upfront in order to get clarity about the business case. The upfront portion of the total effort is 0...3%. A good business case can be affirmed by a seasoned expert after you explain him the project in five sentences. I have seen huge projects launched, where nearly any expert just by gut feeling predicted that it would not deliver as promised, and they were proven right after some years.
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 4:58 pm

rheinwaldner wrote:
I have seen huge projects launched, where nearly any expert just by gut feeling predicted that it would not deliver as promised, and they were proven right after some years.

And we've all seen A380... and 787... maybe it's time for a different approach...
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 6:33 pm

Revelation wrote:
rheinwaldner wrote:
I have seen huge projects launched, where nearly any expert just by gut feeling predicted that it would not deliver as promised, and they were proven right after some years.

And we've all seen A380... and 787... maybe it's time for a different approach...

The 787 business case before launch was a no brainer. The problem was (and generally is) that the reality tends to differ so much from pre-launch plans, that you better have a hammer business case in order to have whiggle room for the unforeseen.

In case of the 797 Boeing just does not seem to have the confidence in the business case, that they usually have.
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 6:45 pm

rheinwaldner wrote:
Newbiepilot wrote:
For example will the plane have 45K or 50K engines?
What engine manufacturer or manufacturers will be chosen?
How many spoilers will there be 10, 12, 18...?
Will wingtips fold?
How many tires and axles?
What structure will be composote vs aluminum vs titanium vs steel?

If the business case is not closed before answering these kind of questions, it must be very close to "not worthwhile". At least I cant remember an aircraft program in the past, where such questions were seen as decisive whether the program would become profitable overall or not.

Newbiepilot wrote:
It sounds like they are taking their time before launching the 797 to get more engineering work done especially around production cost. The good news is that likely means the time from launch to delivery will be shorter since more work was done up front


It sounds not at all like that. You don't validate a business case by designing more upfront. In oder to avoid sunk cost, you try to avoid any effort, that would be lost if the project is a nogo in the end. According to the "shift left" philosophy you aim to find wrong decisions as early as possible. So spending considerable design work into an unvalidated business case would be bad and risky business practice.

Closing the business case means primarily marketing activity, estimate production cost (as you rightfully say), try to estimate as good as possible the resulting market share vs. the production cost vs the development investment minus expected subsidiaries.

I am working in large engineering projects too, and we hardly ever design anything upfront in order to get clarity about the business case. The upfront portion of the total effort is 0...3%. A good business case can be affirmed by a seasoned expert after you explain him the project in five sentences. I have seen huge projects launched, where nearly any expert just by gut feeling predicted that it would not deliver as promised, and they were proven right after some years.


Pricing, commiting to performance guarantees and delivery dates with only 3% of the work done is probably why the A330neo, A320neo, A380, 767tanker, 787 and 747-8 were all late. Doing 10% or more work up front to fully close the business case may lead to better success meaning smaller deferred production costs, more accurate guarantees and on time deliveries. Boeing is doing work on the plane. Look at how many engineering jobs have been posted by Boeing in their nma program office. They most likely would not be doing that if they didnt think they could close the business case
 
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 6:46 pm

Revelation wrote:
rheinwaldner wrote:
I have seen huge projects launched, where nearly any expert just by gut feeling predicted that it would not deliver as promised, and they were proven right after some years.

And we've all seen A380... and 787... maybe it's time for a different approach...


Companies like Boeing can put 4-5 experts / 100-150 yr experience) in a room that come back with pretty good feasibility / risk analyses within days. If they need longer it's probably higher risk. But you can make/break any business case if required, the future can't be calculated. .
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 7:02 pm

Newbiepilot wrote:
rheinwaldner wrote:
Newbiepilot wrote:
For example will the plane have 45K or 50K engines?
What engine manufacturer or manufacturers will be chosen?
How many spoilers will there be 10, 12, 18...?
Will wingtips fold?
How many tires and axles?
What structure will be composote vs aluminum vs titanium vs steel?

If the business case is not closed before answering these kind of questions, it must be very close to "not worthwhile". At least I cant remember an aircraft program in the past, where such questions were seen as decisive whether the program would become profitable overall or not.

Newbiepilot wrote:
It sounds like they are taking their time before launching the 797 to get more engineering work done especially around production cost. The good news is that likely means the time from launch to delivery will be shorter since more work was done up front


It sounds not at all like that. You don't validate a business case by designing more upfront. In oder to avoid sunk cost, you try to avoid any effort, that would be lost if the project is a nogo in the end. According to the "shift left" philosophy you aim to find wrong decisions as early as possible. So spending considerable design work into an unvalidated business case would be bad and risky business practice.

Closing the business case means primarily marketing activity, estimate production cost (as you rightfully say), try to estimate as good as possible the resulting market share vs. the production cost vs the development investment minus expected subsidiaries.

I am working in large engineering projects too, and we hardly ever design anything upfront in order to get clarity about the business case. The upfront portion of the total effort is 0...3%. A good business case can be affirmed by a seasoned expert after you explain him the project in five sentences. I have seen huge projects launched, where nearly any expert just by gut feeling predicted that it would not deliver as promised, and they were proven right after some years.


Pricing, commiting to performance guarantees and delivery dates with only 3% of the work done is probably why the A330neo, A320neo, A380, 767tanker, 787 and 747-8 were all late. Doing 10% or more work up front to fully close the business case may lead to better success meaning smaller deferred production costs, more accurate guarantees and on time deliveries. Boeing is doing work on the plane. Look at how many engineering jobs have been posted by Boeing in their nma program office. They most likely would not be doing that if they didnt think they could close the business case


The A330NEO is late because of engines
The A320NEO was actually early, so we'll not go there. It has since had engine issues
The A380 flew on time, but they stuffed up the wiring solution via a poorly designed CAD interface.
So I completely challenge your premise that "only 3% of the engineering" is what caused these programmes to have issues.

I'm pretty sure that both OEM's have a huge bank of knowledge to allow them to undertake the parametric modelling necessary to have a first approximation at both performance and cost. (most of us armchair A-net CEO's do it on an excel spreadsheet :) )
Typically if you wait to do all the engineering before you launch the programme, you would put your business at huge risk of a massive multi $Bn bill for nugatory NRE, and delay the launch infeasibly.
It seems more likely to me that increasing numbers of engineers are being deployed in order to try to Man Eng out lower cost solutions for some critical producability factors.
That they need to do that suggests to me that the business case is still somewhat "marginal" and therefore considered too high risk to proceed just now.
But Boeing really want to do it, and are prepared to risk the high level of NRE prior to launch.

Rgds
 
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 7:06 pm

Newbiepilot wrote:
Doing 10% or more work up front to fully close the business case ....

And if it does not close?

I am sorry, but possibly loosing 1-2 billions just to clarify the business case of a potential project is not how it works. That does, once more, not pass the smell test.
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 7:10 pm

rheinwaldner wrote:
Newbiepilot wrote:
Doing 10% or more work up front to fully close the business case ....

And if it does not close?

I am sorry, but possibly loosing 1-2 billions just to clarify the business case of a potential project is not how it works. That does, once more, not pass the smell test.


I suspect they are 95% confident it will close. They wouldnt be showing the airplane to airlines if it wasnt expected to close. Airbus launched the A350 mk1 with a business case that turned out flawed and required a relaunch. Boeing appears to be more cautious and deliberate
 
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 7:15 pm

Newbiepilot wrote:
Stitch wrote:
keesje wrote:
I see a strong drive towards a range of 5000NM or even more for NMA. IMO that risks building an aircraft that is way to heavy to be competitive on the bulk of flights. I think it should be optimized, or at least be very efficient for flights of around 2hrs / 1000NM.


If that is where the product is being driven, it is being driven there by the customers. If they wanted a high-capacity short-haul widebody, that is what they would be asking for.


The average 787 flight is under 4000nm. 5000nm range is well within 787 territory. If an airline wants an airplane that efficiently operates and is optimized for 5000nm, they probably would be buying 787s. From what i hear about the 797, it is intended for 1000nm-4000nm.


The average flight length matters little. Even for the 787-8 it is less than 5000nm. An airline looks at the edges of its route network to find a plane that fits their needs and the utilisation of the fleet. Many current widebodies used on short or medium routes would be sitting idle if not flying them. Say you have an 10 hour route than you want to serve daily. You can try with one frame but you will barely have time for maintenance, so you will probably get 2. Now that you have 2 it would make sense to fly the 10h route and something shorter in addition, so that you have the time for maintenance. So your 2 planes will now fly the 8h mission on one day and probably a 6-7 hour on the next (or maybe 2 3 hour missions). So even if you could use the MoM on those 6-7 hours route or on the 2x3 hours, it would not make economical sense, as your longer ranged wide body will sit one the ground doing nothing. So at least for smaller 767 operators range will be a big topic and if the range is not enough, they might skip the MoM altogether even if it could serve the average route length perfectly.
 
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 7:27 pm

keesje wrote:
Revelation wrote:
rheinwaldner wrote:
I have seen huge projects launched, where nearly any expert just by gut feeling predicted that it would not deliver as promised, and they were proven right after some years.

And we've all seen A380... and 787... maybe it's time for a different approach...


Companies like Boeing can put 4-5 experts / 100-150 yr experience) in a room that come back with pretty good feasibility / risk analyses within days. If they need longer it's probably higher risk. But you can make/break any business case if required, the future can't be calculated. .


I am sorry but airplane design is more than just photoshop sketches. To get accurate performance and capability numbers, pricing, delivery dates and everything else that goes into a 200 page sales contract, you need more than 4 or 5 experts for a few days. That is not how airplanes are designed. The NMA is well beyond the sketching phase. Launch means customer contracts are signed. Rough numbers have way too much risk of failure or conservatism for airlines to sign contacts. This launch is higher risk than simple reengine studies.
 
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 7:31 pm

Newbiepilot wrote:
rheinwaldner wrote:
Newbiepilot wrote:
Doing 10% or more work up front to fully close the business case ....

And if it does not close?

I am sorry, but possibly loosing 1-2 billions just to clarify the business case of a potential project is not how it works. That does, once more, not pass the smell test.


I suspect they are 95% confident it will close. They wouldnt be showing the airplane to airlines if it wasnt expected to close. Airbus launched the A350 mk1 with a business case that turned out flawed and required a relaunch. Boeing appears to be more cautious and deliberate


Airbus went on to sell 800 A330CEO's after that, plus hundreds of XWB's. But that's looking back.

That opinion Boeing appears to be more cautious and deliberate could be easily challenged (764, 753, 783, 748, SC, NSA, Dreamliner, 737-7, 737-9). But that's a different topic.
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 7:54 pm

Newbiepilot wrote:
rheinwaldner wrote:
Newbiepilot wrote:
Doing 10% or more work up front to fully close the business case ....

And if it does not close?

I am sorry, but possibly loosing 1-2 billions just to clarify the business case of a potential project is not how it works. That does, once more, not pass the smell test.


I suspect they are 95% confident it will close.

Muilenburg did not give the impression, that there would be 95% confidence. Boeing would not need the disclaimer "if the business case closes" so often (or at all), if there would be 95% certainty.

In fact 95% confidence is more than enough to launch before tomorrow morning.

To get from 95% to 100% confidence, you actually have to run the project.

Newbiepilot wrote:
They wouldnt be showing the airplane to airlines if it wasnt expected to close.

I am sure Boeing and Airbus all the time show airplanes to airlines with no realistic business plan at all.
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 8:59 pm

rheinwaldner wrote:
Newbiepilot wrote:
rheinwaldner wrote:
And if it does not close?

I am sorry, but possibly loosing 1-2 billions just to clarify the business case of a potential project is not how it works. That does, once more, not pass the smell test.


I suspect they are 95% confident it will close.

Muilenburg did not give the impression, that there would be 95% confidence. Boeing would not need the disclaimer "if the business case closes" so often (or at all), if there would be 95% certainty.

In fact 95% confidence is more than enough to launch before tomorrow morning.

To get from 95% to 100% confidence, you actually have to run the project.

Newbiepilot wrote:
They wouldnt be showing the airplane to airlines if it wasnt expected to close.

I am sure Boeing and Airbus all the time show airplanes to airlines with no realistic business plan at all.


There's airline working groups and evolving iterations. Basic configurations are paperwork, tunneling and more detailed system configurations later on.

https://youtu.be/SmigvHkBQIc

System, material and production technology are under TRL development programs contineously in (subsidized) research with institutes.
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 9:14 pm

Would it be possible and would it be desirable for them to design the MOM/NMA/797 to have a "wettable cargo hold", as in, how airplanes use "wet wings" where the wing skin doubles as the exterior of the fuel tank to save weight and maximize fuel storage volume? I am imagining that the cargo hold could be designed from the beginning so that parts of it could be sealed off and used as fuel tanks with the highest possible efficiency. I know that when they add fuselage tanks for ultra long range versions of other airliners, they typically need to fit the tank within the cargo hold, wasting weight and volume.

For example, for the Asian carriers planning for shorter, higher demand routes, where they want to carry some cargo, give them their slightly larger cargo hold, just subtract some space from the wing fuel tanks. Maybe instead of designing the long-cabin variant to have 4,500nm range with wing tanks, design it to have 4,000nm range, and ability to carry the 265-270 pax bags PLUS ~20,000 lbs air freight. For the US carriers that aren't as interested in cargo but want more range for TATL and South America flights, allow them to seal off parts of the cargo hold to serve as the fuel tanks to achieve the range they need. In an international seating configuration, that same long-cabin airplane probably seats 215-220: if they can carry those pax bags PLUS ~20,000 lbs of fuel under the passengers in the fuselage, that should easily be good to extend the range to ~5,500nm.

5,500nm is good range, in either direction, against winter winds, for US Midwest <> Central Europe or US East Coast <> Southern Europe. It would be a CASM beast on those routes without needing to carry any air freight. For US transcon they would skip the fuselage tanks and they would need to start carrying some freight if they really wanted to maximize their value, but they could also just fly 737-10s if they wanted minimum CASM without carrying freight.

Yes I know that designing the cargo hold as "wettable" and then not using that functionality would be a waste for the asian carriers, and I know that tanking fuel in the fuselage isn't as structurally or aerodynamically efficient as tanking fuel in the wings for the US carriers, but when you have two different markets with distinct use cases for the product, this sort of compromise seems pretty good, no?
 
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 9:52 pm

tunahp wrote:
Would it be possible and would it be desirable for them to design the MOM/NMA/797 to have a "wettable cargo hold", as in, how airplanes use "wet wings" where the wing skin doubles as the exterior of the fuel tank to save weight and maximize fuel storage volume?


I am going to guess that certification regulations do not allow for it on airframe safety issues. And even if they did, the complexity and maintenance involved would make it a guaranteed non-starter. This is why ACTs are used for additional fuel volume.
 
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Re: Boeing 797 Discussion Thread - 2018

Thu Apr 19, 2018 10:27 pm

astuteman wrote:
Typically if you wait to do all the engineering before you launch the programme, you would put your business at huge risk of a massive multi $Bn bill for nugatory NRE, and delay the launch infeasibly.
It seems more likely to me that increasing numbers of engineers are being deployed in order to try to Man Eng out lower cost solutions for some critical producability factors.
That they need to do that suggests to me that the business case is still somewhat "marginal" and therefore considered too high risk to proceed just now.
But Boeing really want to do it, and are prepared to risk the high level of NRE prior to launch.

I agree with all of the above.

It's always been clear that MOM is squeezed from above and below and the business case is marginal a challenge.

I've posted the other ST link a few times now where Boeing is saying they are very focused on "producability factors" in the pre-launch phase.

I agree Boeing really wants to do MOM next and so are willing to spend the high NRE before launch.

From my point of view I wouldn't view that NRE as wasted if the program doesn't launch since I'm sure useful things will be learned, but I can see how a business manager would see it as wasted.

We have a bunch of indications (including Keesje's sources!) that the MOM/NMA/797 program is "a go".

It should be an interesting summer!

rheinwaldner wrote:
Muilenburg did not give the impression, that there would be 95% confidence. Boeing would not need the disclaimer "if the business case closes" so often (or at all), if there would be 95% certainty.

Yet that's exactly what you'd expect a CEO to be saying at this stage of a program.

If he said he was 95% confident and in the end the program didn't launch, he'd be fired.

The program is in "plausible deniability" phase, despite the fact there's many indicators that it's "a go".
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Re: Boeing 797 Discussion Thread - 2018

Fri Apr 20, 2018 1:47 am

seahawk wrote:
The average flight length matters little. Even for the 787-8 it is less than 5000nm. An airline looks at the edges of its route network to find a plane that fits their needs and the utilisation of the fleet. Many current widebodies used on short or medium routes would be sitting idle if not flying them. Say you have an 10 hour route than you want to serve daily. You can try with one frame but you will barely have time for maintenance, so you will probably get 2. Now that you have 2 it would make sense to fly the 10h route and something shorter in addition, so that you have the time for maintenance. So your 2 planes will now fly the 8h mission on one day and probably a 6-7 hour on the next (or maybe 2 3 hour missions). So even if you could use the MoM on those 6-7 hours route or on the 2x3 hours, it would not make economical sense, as your longer ranged wide body will sit one the ground doing nothing. So at least for smaller 767 operators range will be a big topic and if the range is not enough, they might skip the MoM altogether even if it could serve the average route length perfectly.

This is 100% correct. The average flight duration table of the 767 is irrelevant.

Expanding on this by using two examples assuming a 24 hour cycle.

Aircraft A is capable of operating 12 hour maximum flights. In between operating its daily 12 hour flight it could fit a short 2 hour flight.

Aircraft B is only capable of operating 8 hour maximum flights. In between operating its daily 8 hour flight it could fit in a 6 hour flight.

Aircraft A and B both average 7 hour flight duration. Yet aircraft A was purchased for its ability to do a longer 12 hour flights. So you'll find most medium to long haul aircraft will have fairly consistent averages.

As an aircrafts range approaches 20 hours its ability to operate a quick short haul flight in the 24 hour cycle hits zero. The average flight length starts to climb dramatically. But in terms of fleet management they could still rotate aircraft to even out the cycles. So an aircraft might be doing a single 16 hour flight per day and then swap with an aircraft that was doing two 8 hour flights.

If an airlines longest routes were between 10-12 hours and the majority of routes were between 4-8 hours then the NMA would be the ideal single aircraft solution. The A321 solution would require a small subfleet of widebodies for the 10-12 hour routes. A 787-9 solution would not be as cost effective on the shorter 4 hour flights.

If an airline had three aircraft types for example some E170's, A321's and 787's. If their maximum route length was 12 hours with the NMA they could pair it with the CS300 and drop to two aircraft families. The two aircraft are positioned in between the three aircraft solution and cover the same spectrum of flights.
 
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Re: Boeing 797 Discussion Thread - 2018

Fri Apr 20, 2018 2:11 am

Stitch wrote:
tunahp wrote:
Would it be possible and would it be desirable for them to design the MOM/NMA/797 to have a "wettable cargo hold", as in, how airplanes use "wet wings" where the wing skin doubles as the exterior of the fuel tank to save weight and maximize fuel storage volume?


I am going to guess that certification regulations do not allow for it on airframe safety issues. And even if they did, the complexity and maintenance involved would make it a guaranteed non-starter. This is why ACTs are used for additional fuel volume.

Fuel tanks are a bladder with pumps, fuel level sensors, venting provisions, over-fill provisions, and nitrogen innerting. Tanks must be proven to be undamaged if removed, unless contained in a hard frame.

And shaken!

There have been proposals to use the bilge, but not the bilge is so small.

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tunahp
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Re: Boeing 797 Discussion Thread - 2018

Fri Apr 20, 2018 3:26 pm

lightsaber wrote:
Stitch wrote:
tunahp wrote:
Would it be possible and would it be desirable for them to design the MOM/NMA/797 to have a "wettable cargo hold", as in, how airplanes use "wet wings" where the wing skin doubles as the exterior of the fuel tank to save weight and maximize fuel storage volume?


I am going to guess that certification regulations do not allow for it on airframe safety issues. And even if they did, the complexity and maintenance involved would make it a guaranteed non-starter. This is why ACTs are used for additional fuel volume.

Fuel tanks are a bladder with pumps, fuel level sensors, venting provisions, over-fill provisions, and nitrogen innerting. Tanks must be proven to be undamaged if removed, unless contained in a hard frame.

And shaken!

There have been proposals to use the bilge, but not the bilge is so small.

Lightsaber


Hmm so is it feasible or no?
 
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Re: Boeing 797 Discussion Thread - 2018

Fri Apr 20, 2018 4:09 pm

Whilst it is very true that the proposed MOM is squeezed at both ends it's worth looking at what.At the upper end their is the 'In trouble' 338NEO.Such an aircaft could ring its death nell which leaves the 339neo as an orphan.Of course it would also limit the 788 to 5,000nm missions and above.But so what one might ask.It also potentially answers any heavy cargo issues some might have perhaps.

At the other end the A321NEO/A321LR reign supreme at present.So fine to have a go at them.Thus they need to be very careful not to overspec the aircrafts capabilities in this regard.It wouldn't surprise me if the thrust levels don't start at 45klbs as opposed to 50klbs.
 
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Re: Boeing 797 Discussion Thread - 2018

Fri Apr 20, 2018 4:11 pm

tunahp wrote:
Hmm so is it feasible or no?


It's theoretically feasible, but it would add a significant amount of weight and complexity and would be very maintenance-intensive. Take a look at the lower hold of a commercial airliner - it has rollers and cargo locks on the floors and insulation and padding along the walls. You'd have to remove that padding and replace it with a non-permeable covering so the fuel would not escape and that covering would need to be strong enough that it would not be damaged by ULDs and pallets. You'd also have to have provisions for "fuel-tight" bulkheads to segment the hold into fuel cells and cargo cells. You'd also need to make the rollers and locks out of a material that will not corrode when exposed to Jet-A. And you'd need a system to fully flush the hold between uses as a fuel cell and as a cargo cell. And probably a bunch of other things.

In the end, a "wettable hold" would be orders of magnitude more expensive for an airline than using ACTs for no real additional benefit in terms of available fuel volume.
 
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Re: Boeing 797 Discussion Thread - 2018

Fri Apr 20, 2018 4:46 pm

Stitch wrote:
tunahp wrote:
Hmm so is it feasible or no?


It's theoretically feasible, but it would add a significant amount of weight and complexity and would be very maintenance-intensive. Take a look at the lower hold of a commercial airliner - it has rollers and cargo locks on the floors and insulation and padding along the walls. You'd have to remove that padding and replace it with a non-permeable covering so the fuel would not escape and that covering would need to be strong enough that it would not be damaged by ULDs and pallets. You'd also have to have provisions for "fuel-tight" bulkheads to segment the hold into fuel cells and cargo cells. You'd also need to make the rollers and locks out of a material that will not corrode when exposed to Jet-A. And you'd need a system to fully flush the hold between uses as a fuel cell and as a cargo cell. And probably a bunch of other things.

In the end, a "wettable hold" would be orders of magnitude more expensive for an airline than using ACTs for no real additional benefit in terms of available fuel volume.


Awesome insight, thanks.

OK but then I only proposed "wettable cargo hold" because I thought it could be more efficient than ACTs... but is my concept still practical/desirable when using ACTs?

For some reason we don't see many aircraft designed from the beginning for ACT fuel storage. Typically only "ultra long range" or "business jet" variants. But in this case where you have (1) the Asians wanting ~20,000 lbs freight capacity beyond a domestic load of passenger bags and not caring much about range as their missions are <3000nmi, and (2) the US majors not caring about freight capacity beyond international pax bags, but wanting range for TATL and South America, it seems like it would be the most efficient compromise to allow carriers to optimize between freight capacity and fuel capacity.
 
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Re: Boeing 797 Discussion Thread - 2018

Fri Apr 20, 2018 4:52 pm

Depending on the numbers of seats and the number of seats per row in combination with the planed cargo container size, you might not have enough belly space for ACTs and all bags.
 
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Re: Boeing 797 Discussion Thread - 2018

Fri Apr 20, 2018 5:04 pm

tunahp wrote:
Stitch wrote:
tunahp wrote:
Hmm so is it feasible or no?


It's theoretically feasible, but it would add a significant amount of weight and complexity and would be very maintenance-intensive. Take a look at the lower hold of a commercial airliner - it has rollers and cargo locks on the floors and insulation and padding along the walls. You'd have to remove that padding and replace it with a non-permeable covering so the fuel would not escape and that covering would need to be strong enough that it would not be damaged by ULDs and pallets. You'd also have to have provisions for "fuel-tight" bulkheads to segment the hold into fuel cells and cargo cells. You'd also need to make the rollers and locks out of a material that will not corrode when exposed to Jet-A. And you'd need a system to fully flush the hold between uses as a fuel cell and as a cargo cell. And probably a bunch of other things.

In the end, a "wettable hold" would be orders of magnitude more expensive for an airline than using ACTs for no real additional benefit in terms of available fuel volume.


Awesome insight, thanks.

OK but then I only proposed "wettable cargo hold" because I thought it could be more efficient than ACTs... but is my concept still practical/desirable when using ACTs?

For some reason we don't see many aircraft designed from the beginning for ACT fuel storage. Typically only "ultra long range" or "business jet" variants. But in this case where you have (1) the Asians wanting ~20,000 lbs freight capacity beyond a domestic load of passenger bags and not caring much about range as their missions are <3000nmi, and (2) the US majors not caring about freight capacity beyond international pax bags, but wanting range for TATL and South America, it seems like it would be the most efficient compromise to allow carriers to optimize between freight capacity and fuel capacity.


I think the schism between what US carriers want and what Asian carriers want is overblown just a bit. On a practical level revenue is still split far far in favor of passenger revenue over cargo revenue for airlines. So ideally yes, Asian carriers may want more cargo. But if you face off a NMA with an A330neo or 787 and get undercut on airfare I am not sure you can make it up in cargo. Yes a mythical jet that was close in weight and aerodynamic performance but also had more cargo space would be ideal. But the reality is it would be heavier. How much heavier? We don’t really know.
 
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Re: Boeing 797 Discussion Thread - 2018

Fri Apr 20, 2018 6:11 pm

tunahp wrote:
For some reason we don't see many aircraft designed from the beginning for ACT fuel storage. Typically only "ultra long range" or "business jet" variants.


ACTs themselves bring issues. I understand they're quite heavy and a pain to maneuver in the hold. You also need to have to add a plumbing system to the hold to connect the ACTs to the main fuel system. But that is about it in terms of modifications to the hold so it is a lot less work to engineer and implement than a fully "wettable" hold.


tunahp wrote:
But in this case where you have (1) the Asians wanting ~20,000 lbs freight capacity beyond a domestic load of passenger bags and not caring much about range as their missions are <3000nmi, and (2) the US majors not caring about freight capacity beyond international pax bags, but wanting range for TATL and South America, it seems like it would be the most efficient compromise to allow carriers to optimize between freight capacity and fuel capacity.


I am of the understanding that airlines that employ ACTs on their airframes tend to just keep them there, even if they are not needed for a mission. So many A321-200s and 737-900ERs have a single ACT installed to allow them to do cross-country missions, but that tank is not removed when the frames are used on shorter stage lengths around those longer missions.

One advantage that NMA will have is it's wing span and area should be a fair bit larger than a narrowbody, so it's internal fuel volume will be much greater. The wider fuselage rumored would also allow a larger center fuel tank to be fitted. So it's quite possible that NMA will not need ACTs for the longer-end missions as it will be able to tank sufficient fuel volume in the wings and center tank.


seahawk wrote:
Depending on the numbers of seats and the number of seats per row in combination with the planed cargo container size, you might not have enough belly space for ACTs and all bags.


This does appear to be an issue for the A321-200LR, especially when configured with all three optional ACTs. Leeham.net is of the opinion operators would not be able to use AKH containers due to lack of available volume and instead would need to hand-load luggage.

I really do not expect NMA to use the AKH container, if for no other reason it would limit palletized cargo which is probably of import to potential Asian customers. As such, I really think it will use at a minimum the LD2 container and 88/96x125 pallets of the 767.
 
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Re: Boeing 797 Discussion Thread - 2018

Fri Apr 20, 2018 6:51 pm

Stitch wrote:
tunahp wrote:
For some reason we don't see many aircraft designed from the beginning for ACT fuel storage. Typically only "ultra long range" or "business jet" variants.


ACTs themselves bring issues. I understand they're quite heavy and a pain to maneuver in the hold. You also need to have to add a plumbing system to the hold to connect the ACTs to the main fuel system. But that is about it in terms of modifications to the hold so it is a lot less work to engineer and implement than a fully "wettable" hold.


tunahp wrote:
But in this case where you have (1) the Asians wanting ~20,000 lbs freight capacity beyond a domestic load of passenger bags and not caring much about range as their missions are <3000nmi, and (2) the US majors not caring about freight capacity beyond international pax bags, but wanting range for TATL and South America, it seems like it would be the most efficient compromise to allow carriers to optimize between freight capacity and fuel capacity.


I am of the understanding that airlines that employ ACTs on their airframes tend to just keep them there, even if they are not needed for a mission. So many A321-200s and 737-900ERs have a single ACT installed to allow them to do cross-country missions, but that tank is not removed when the frames are used on shorter stage lengths around those longer missions.

One advantage that NMA will have is it's wing span and area should be a fair bit larger than a narrowbody, so it's internal fuel volume will be much greater. The wider fuselage rumored would also allow a larger center fuel tank to be fitted. So it's quite possible that NMA will not need ACTs for the longer-end missions as it will be able to tank sufficient fuel volume in the wings and center tank.


seahawk wrote:
Depending on the numbers of seats and the number of seats per row in combination with the planed cargo container size, you might not have enough belly space for ACTs and all bags.


This does appear to be an issue for the A321-200LR, especially when configured with all three optional ACTs. Leeham.net is of the opinion operators would not be able to use AKH containers due to lack of available volume and instead would need to hand-load luggage.

I really do not expect NMA to use the AKH container, if for no other reason it would limit palletized cargo which is probably of import to potential Asian customers. As such, I really think it will use at a minimum the LD2 container and 88/96x125 pallets of the 767.


On the luggage question...

How much more luggage could you jam into the overheads on a 2-3-2 setup than a 3-3? I would assume you pickup the center bins of a widebody but you are only adding one person per row in economy. I feel like you would almost double the overhead bin space without adding gobs of people.
 
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Re: Boeing 797 Discussion Thread - 2018

Fri Apr 20, 2018 7:05 pm

bigjku wrote:
Stitch wrote:
tunahp wrote:
For some reason we don't see many aircraft designed from the beginning for ACT fuel storage. Typically only "ultra long range" or "business jet" variants.


ACTs themselves bring issues. I understand they're quite heavy and a pain to maneuver in the hold. You also need to have to add a plumbing system to the hold to connect the ACTs to the main fuel system. But that is about it in terms of modifications to the hold so it is a lot less work to engineer and implement than a fully "wettable" hold.


tunahp wrote:
But in this case where you have (1) the Asians wanting ~20,000 lbs freight capacity beyond a domestic load of passenger bags and not caring much about range as their missions are <3000nmi, and (2) the US majors not caring about freight capacity beyond international pax bags, but wanting range for TATL and South America, it seems like it would be the most efficient compromise to allow carriers to optimize between freight capacity and fuel capacity.


I am of the understanding that airlines that employ ACTs on their airframes tend to just keep them there, even if they are not needed for a mission. So many A321-200s and 737-900ERs have a single ACT installed to allow them to do cross-country missions, but that tank is not removed when the frames are used on shorter stage lengths around those longer missions.

One advantage that NMA will have is it's wing span and area should be a fair bit larger than a narrowbody, so it's internal fuel volume will be much greater. The wider fuselage rumored would also allow a larger center fuel tank to be fitted. So it's quite possible that NMA will not need ACTs for the longer-end missions as it will be able to tank sufficient fuel volume in the wings and center tank.


seahawk wrote:
Depending on the numbers of seats and the number of seats per row in combination with the planed cargo container size, you might not have enough belly space for ACTs and all bags.


This does appear to be an issue for the A321-200LR, especially when configured with all three optional ACTs. Leeham.net is of the opinion operators would not be able to use AKH containers due to lack of available volume and instead would need to hand-load luggage.

I really do not expect NMA to use the AKH container, if for no other reason it would limit palletized cargo which is probably of import to potential Asian customers. As such, I really think it will use at a minimum the LD2 container and 88/96x125 pallets of the 767.


On the luggage question...

How much more luggage could you jam into the overheads on a 2-3-2 setup than a 3-3? I would assume you pickup the center bins of a widebody but you are only adding one person per row in economy. I feel like you would almost double the overhead bin space without adding gobs of people.


Yes plus if the hold was sized for a 36" wider LD3-45 (36" wider for the extra Aisle and Seat) you pick up space for at least 7-8 more full sized bags per Container. 2x3x2 makes sense.
 
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Re: Boeing 797 Discussion Thread - 2018

Fri Apr 20, 2018 7:28 pm

Sort of off topic

After the 797 ....... i feel like the fuel efficient plane wars will be over with.

think about it ..... 787 to 747-8i to 737 MAX. Airbus did something similar with the A350, 320 NEOs, 330 NEO, and so on.

What will be next? Planes that travel at the speed of sound but that are much more fuel efficient and can make a profit?

Concord NEO / modern version?
 
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Stitch
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Re: Boeing 797 Discussion Thread - 2018

Fri Apr 20, 2018 7:38 pm

Buffalomatt1027 wrote:
What will be next?


New narrowbody designs to replace the A320 and 737 families.
 
tunahp
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Re: Boeing 797 Discussion Thread - 2018

Sat Apr 21, 2018 2:40 am

bigjku wrote:

On the luggage question...

How much more luggage could you jam into the overheads on a 2-3-2 setup than a 3-3? I would assume you pickup the center bins of a widebody but you are only adding one person per row in economy. I feel like you would almost double the overhead bin space without adding gobs of people.


2-4-2 would seem to be pretty much as good. 2-2 with big bins like Embraer E-Jets has tons of overhead space. The airlines aren't going to vary their carry-on baggage policies by type like "on a 737 you're NOT allowed a carry-on bag, but on a 797 you are".

2-3-2 just seems so crazy to add an aisle for just one more seat, plus there is seating awkwardness when you want to scale up to premium seats. Going from 2-3-2 Economy to 2-2-2 might be good for US-style International Premium Economy class, but not good for US domestic 1st class nor Asian Regional Business Class. If you want acceptable with for US 1st/Asian Regional Business you need to move to 5 across seating... and then what is that? 1-3-1? 2-1-1? Also when talking about lie-flat Intl Business class, such as reverse/herringbone, in the 7-across 767 they have to do only 3 "spines", one spine on one aisle, 2 "spines" on the other aisle.

In comparison, starting from 2-4-2 economy, you can move down to 2-3-2 for International Premium Economy, 2-2-2 for US Domestic 1st/ Asian Regional Business class, and if the A330/A340 if any indication, you should be able to to do 4 "spines" of herringbone seating.

I mean I thought the whole innovation of the NMA was that it was going to have some crazy fuselage geometry where the passenger cabin was going to be outsized relative to the cargo hold. So you could have an 8 across passenger cabin with maybe only 1/2 the cargo capacity per fuselage length vs. 787/777.

Of course all the speculation has been 2-3-2 or if not that, then 2-2-2, so I am sure it will be 2-3-2. I just don't really understand it.
 
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Re: Boeing 797 Discussion Thread - 2018

Sat Apr 21, 2018 5:31 am

Revelation wrote:
rheinwaldner wrote:
Muilenburg did not give the impression, that there would be 95% confidence. Boeing would not need the disclaimer "if the business case closes" so often (or at all), if there would be 95% certainty.

Yet that's exactly what you'd expect a CEO to be saying at this stage of a program.

Only if the stage is still early. But not when launching should be expected soon. I cant remember any other program where the vendor talked all the time about the unsafe business case less than a year before launch. You might remember better but I would be interested in sources that prove your claim (from earlier projects).
Many things are difficult, all things are possible!
 
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Re: Boeing 797 Discussion Thread - 2018

Sat Apr 21, 2018 6:41 am

Stitch wrote:
tunahp wrote:
Hmm so is it feasible or no?


It's theoretically feasible, but it would add a significant amount of weight and complexity and would be very maintenance-intensive. Take a look at the lower hold of a commercial airliner - it has rollers and cargo locks on the floors and insulation and padding along the walls. You'd have to remove that padding and replace it with a non-permeable covering so the fuel would not escape and that covering would need to be strong enough that it would not be damaged by ULDs and pallets. You'd also have to have provisions for "fuel-tight" bulkheads to segment the hold into fuel cells and cargo cells. You'd also need to make the rollers and locks out of a material that will not corrode when exposed to Jet-A. And you'd need a system to fully flush the hold between uses as a fuel cell and as a cargo cell. And probably a bunch of other things.

In the end, a "wettable hold" would be orders of magnitude more expensive for an airline than using ACTs for no real additional benefit in terms of available fuel volume.


Tankage in the wing is divided up by the wing stiffening plates with relatively small holes at the top and bottom dividing the wing into cells. That way in a bank the fuel doesn't race outward while the far wing fuel races inward. It is generally not good to have 20 tons of fuel move 5' sideways. A long tank in the body would have even worst effect unless divided. On climb a half full tank would all be in the back. N2 inerting as well as fumes requires a true tank. Also having fuel at the skid surface in a belly landing is probably prohibited or killed by life safety review.
 
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Re: Boeing 797 Discussion Thread - 2018

Sat Apr 21, 2018 7:38 am

RJMAZ wrote:
If an airlines longest routes were between 10-12 hours and the majority of routes were between 4-8 hours then the NMA would be the ideal single aircraft solution. The A321 solution would require a small subfleet of widebodies for the 10-12 hour routes. A 787-9 solution would not be as cost effective on the shorter 4 hour flights.

If an airline had three aircraft types for example some E170's, A321's and 787's. If their maximum route length was 12 hours with the NMA they could pair it with the CS300 and drop to two aircraft families. The two aircraft are positioned in between the three aircraft solution and cover the same spectrum of flights.

While I agree the average flight length is meaningless and it is the extreme that matter, 12 hours is already something like SFO-PEK or IST-MIA and cover everywhere from India/UAE to the entire Eurasia+Africa continent. And then majority of routes 4-8hours long would describe routes operate from MIA to a large part of the South America. It actually sound more like missions that A333 would be suitable for and also what airlines currently use for this type of mission. Is a "smaller, more efficient A333" what airlines want NMA to be? Even with the extreme being considered I don't think the NMA would need this much range. I don't even know were the 333 capable of this type of mission when it EIS.
 
astuteman
Posts: 6752
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Re: Boeing 797 Discussion Thread - 2018

Sat Apr 21, 2018 8:49 am

JayinKitsap wrote:
Stitch wrote:
tunahp wrote:
Hmm so is it feasible or no?


It's theoretically feasible, but it would add a significant amount of weight and complexity and would be very maintenance-intensive. Take a look at the lower hold of a commercial airliner - it has rollers and cargo locks on the floors and insulation and padding along the walls. You'd have to remove that padding and replace it with a non-permeable covering so the fuel would not escape and that covering would need to be strong enough that it would not be damaged by ULDs and pallets. You'd also have to have provisions for "fuel-tight" bulkheads to segment the hold into fuel cells and cargo cells. You'd also need to make the rollers and locks out of a material that will not corrode when exposed to Jet-A. And you'd need a system to fully flush the hold between uses as a fuel cell and as a cargo cell. And probably a bunch of other things.

In the end, a "wettable hold" would be orders of magnitude more expensive for an airline than using ACTs for no real additional benefit in terms of available fuel volume.


Tankage in the wing is divided up by the wing stiffening plates with relatively small holes at the top and bottom dividing the wing into cells. That way in a bank the fuel doesn't race outward while the far wing fuel races inward. It is generally not good to have 20 tons of fuel move 5' sideways. A long tank in the body would have even worst effect unless divided. On climb a half full tank would all be in the back. N2 inerting as well as fumes requires a true tank. Also having fuel at the skid surface in a belly landing is probably prohibited or killed by life safety review.


Naval Architects call this the "free surface effect" :)

It is what sank the Herald of Free Enterprise :(

As you say, the effects can be catastrophic

Rgds
 
StTim
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Re: Boeing 797 Discussion Thread - 2018

Sat Apr 21, 2018 10:00 am

astuteman wrote:
JayinKitsap wrote:
Stitch wrote:

It's theoretically feasible, but it would add a significant amount of weight and complexity and would be very maintenance-intensive. Take a look at the lower hold of a commercial airliner - it has rollers and cargo locks on the floors and insulation and padding along the walls. You'd have to remove that padding and replace it with a non-permeable covering so the fuel would not escape and that covering would need to be strong enough that it would not be damaged by ULDs and pallets. You'd also have to have provisions for "fuel-tight" bulkheads to segment the hold into fuel cells and cargo cells. You'd also need to make the rollers and locks out of a material that will not corrode when exposed to Jet-A. And you'd need a system to fully flush the hold between uses as a fuel cell and as a cargo cell. And probably a bunch of other things.

In the end, a "wettable hold" would be orders of magnitude more expensive for an airline than using ACTs for no real additional benefit in terms of available fuel volume.


Tankage in the wing is divided up by the wing stiffening plates with relatively small holes at the top and bottom dividing the wing into cells. That way in a bank the fuel doesn't race outward while the far wing fuel races inward. It is generally not good to have 20 tons of fuel move 5' sideways. A long tank in the body would have even worst effect unless divided. On climb a half full tank would all be in the back. N2 inerting as well as fumes requires a true tank. Also having fuel at the skid surface in a belly landing is probably prohibited or killed by life safety review.


Naval Architects call this the "free surface effect" :)

It is what sank the Herald of Free Enterprise :(

As you say, the effects can be catastrophic

Rgds


Yes talk to anyone who drives a road tanker. They are all divided into sub tanks but they still get the secondary shove as the liquid comes forward into the bulkhead.
 
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Qantas94Heavy
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Re: Boeing 797 Discussion Thread - 2018

Sat Apr 21, 2018 10:05 am

tunahp wrote:
2-3-2 just seems so crazy to add an aisle for just one more seat, plus there is seating awkwardness when you want to scale up to premium seats. Going from 2-3-2 Economy to 2-2-2 might be good for US-style International Premium Economy class, but not good for US domestic 1st class nor Asian Regional Business Class. If you want acceptable with for US 1st/Asian Regional Business you need to move to 5 across seating... and then what is that? 1-3-1? 2-1-1? Also when talking about lie-flat Intl Business class, such as reverse/herringbone, in the 7-across 767 they have to do only 3 "spines", one spine on one aisle, 2 "spines" on the other aisle.


I don't think it'll be a big problem.

The technical differences between a 7/8 abreast 797 aircraft have been talked about quite a fair bit, so I'll try to avoid rehashing those.

For a 3-3 narrowbody, there's lots of wasted width in business class, and premium economy is also odd with a 2-3 layout. Boarding times with a narrow aisle will also be an issue.

7 abreast premium economy would be very narrow (8 abreast 797 narrower than A330). It would be even worse than A350 8 abreast, which some have criticised for being not premium enough.

For business class, it's probably best to compare to existing 767 aircraft, which seem to handle it fine:

  • Classic herringbone: A330 already needs 3 abreast, no difference
  • Reverse herringbone: 3 or 4 abreast both work (more angle, less pitch for 3 abreast and vice versa)
    • ex-CO BusinessFirst is 5 abreast full flat on a 767
    • 4 abreast reverse herringbone should be fine: just remove one seat, make the rest wider and increase the angle slightly
    • UA Polaris uses a semi-staggered 3 abreast at greater angle to increase density
  • Staggered seats: works well with a 4 abreast layout -- DL/AA/JL all use this option
  • Classic seats: 5 abreast should work for regional business class
    • NH uses 2-1-2, QF used 1-2-2 on their international 767s before retirement
    • Single seats could be upsold or reserved for frequent fliers

Images of all these 767 options are available here: https://imgur.com/a/BNkP9X0
 
brindabella
Posts: 476
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Re: Boeing 797 Discussion Thread - 2018

Sat Apr 21, 2018 10:46 am

Revelation wrote:
astuteman wrote:
Typically if you wait to do all the engineering before you launch the programme, you would put your business at huge risk of a massive multi $Bn bill for nugatory NRE, and delay the launch infeasibly.
It seems more likely to me that increasing numbers of engineers are being deployed in order to try to Man Eng out lower cost solutions for some critical producability factors.
That they need to do that suggests to me that the business case is still somewhat "marginal" and therefore considered too high risk to proceed just now.
But Boeing really want to do it, and are prepared to risk the high level of NRE prior to launch.

I agree with all of the above.


:checkmark: Seconded.




Revelation wrote:
It's always been clear that MOM is squeezed from above and below and the business case is marginal a challenge.

I've posted the other ST link a few times now where Boeing is saying they are very focused on "producability factors" in the pre-launch phase.

I agree Boeing really wants to do MOM next and so are willing to spend the high NRE before launch.

From my point of view I wouldn't view that NRE as wasted if the program doesn't launch since I'm sure useful things will be learned, but I can see how a business manager would see it as wasted.

We have a bunch of indications (including Keesje's sources!) that the MOM/NMA/797 program is "a go".


However I suspect the Business case has looked OK or good for some time.

Hear me out ... :duck:

IMO there is no other explanation which accounts for Boeing obviously continuing to discuss the project with large and even gigantic airlines.

These are very very serious people and Boeing would be playing with their time & attention at it's own great peril!
My conclusion is that Boeing is also very very serious about the MOM
... but I suspect that Boeing is still hesitating over the "producability factors" issue as above.
And will hesitate until the question is as close to a settled and positive outcome as is possible short of actually building the thing.

Let's recall the situation that which arose for Boeing during the last all-new build.
It became a fair bit more serious than "burnt fingers".

In fact at one stage the 787 industrialisation effort looked rather more like "All hands man the pumps!"

And the "drug-like rush" made it all much, much worse.
Boeing was suddenly holding Contracts involving orders for approaching 1,000 frames.
And those Contracts were all in default.

Which as we all know cost Billions and Billions in penalties not to mention loss of reputation - and especially not to mention the many customers who doubtless then found themselves receiving very welcome phonecalls from one J.Leahy who was only too happy to help!
And many of them are very happy with their A330ceos to this day - and the Airbus people are welcome in the door anytime.

So where Boeing was concerned the massive setback had many lamentable consequences - on top of the tens of Billions of money lost.

There has been a great deal of very positive reaction to the MOM as reported in the Press (DL publicly and repeatedly putting it's hand up so as not to miss out on being a Launch Customer, EG).
All this must be both very welcome to Boeing Management - but it must also be a grim reminder of the 787 financial and industrial meltdown, if such reminder is even needed.

In this circumstance, I would expect Boeing to do exhaustive pre-Launch research.

Sorry Rheinwaldner, I think this one is just too big a potential success - or alternatively, potentially another massive fiasco al la 787.

If Boeing is checking, double-checking and then checking yet again, then that must be expected, IMO.
It is money very well spent, no matter which way the decision goes.


Revelation wrote:
It should be an interesting summer!


Can't wait for Farnborough!

cheers
Billy
 
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keesje
Posts: 11806
Joined: Thu Apr 12, 2001 2:08 am

Re: Boeing 797 Discussion Thread - 2018

Sat Apr 21, 2018 12:54 pm

brindabella wrote:

...

In this circumstance, I would expect Boeing to do exhaustive pre-Launch research.

Sorry Rheinwaldner, I think this one is just too big a potential success - or alternatively, potentially another massive fiasco al la 787.

If Boeing is checking, double-checking and then checking yet again, then that must be expected, IMO.
It is money very well spent, no matter which way the decision goes.

Revelation wrote:
It should be an interesting summer!


Can't wait for Farnborough!

cheers


While I principally agree, you can not analyse this in isolation. That killed the NSA 7 years ago. Before Albaugh & McNerney fully realized
what was happening, Leahy was waving an AA 640 NB LOI in their face & had 1000 NEO's in his pocket.

That was a few deliberate double-checks too far. https://youtu.be/rJzRsodeYes?t=37s, the AA 737 MAX launch "party" was 4 weeks later..

They were so focussed on the Dreamliner they didn't see the one coming in from the left.

Image
"Never mistake motion for action." Ernest Hemingway
 
bigjku
Posts: 1709
Joined: Sat Feb 17, 2007 10:51 pm

Re: Boeing 797 Discussion Thread - 2018

Sat Apr 21, 2018 1:29 pm

I will tell you there are people at Boeing who believe that both the A320neo and 737max should never have been done and that long term both are mistakes to be corrected. Not saying I agree with it but they do have some points when they make their case.
 
frmrCapCadet
Posts: 2302
Joined: Thu May 29, 2008 8:24 pm

Re: Boeing 797 Discussion Thread - 2018

Sat Apr 21, 2018 3:25 pm

Airlines likely have a hand in this. They could be preferring modestly different planes, and Boeing will want to launch with a lot of orders. That slightly blurred picture may make that point.
Buffet: the airline business...has eaten up capital...like..no other (business)
 
Newbiepilot
Posts: 3317
Joined: Tue Aug 30, 2016 10:18 pm

Re: Boeing 797 Discussion Thread - 2018

Sat Apr 21, 2018 3:39 pm

keesje wrote:
brindabella wrote:

...

In this circumstance, I would expect Boeing to do exhaustive pre-Launch research.

Sorry Rheinwaldner, I think this one is just too big a potential success - or alternatively, potentially another massive fiasco al la 787.

If Boeing is checking, double-checking and then checking yet again, then that must be expected, IMO.
It is money very well spent, no matter which way the decision goes.

Revelation wrote:
It should be an interesting summer!


Can't wait for Farnborough!

cheers


While I principally agree, you can not analyse this in isolation. That killed the NSA 7 years ago. Before Albaugh & McNerney fully realized
what was happening, Leahy was waving an AA 640 NB LOI in their face & had 1000 NEO's in his pocket.

That was a few deliberate double-checks too far. https://youtu.be/rJzRsodeYes?t=37s, the AA 737 MAX launch "party" was 4 weeks later..

They were so focussed on the Dreamliner they didn't see the one coming in from the left.


Being that Airbus just shelved the A320plus and is reorganizing their engineering teams, it is unlikely something is coming in from the left. In my opinion now is the time to be careful and deliberate. They don’t want to repeat the mistakes from the A350 launch and relaunch that delayed the program 3 years or the mistakes from the 787 where the airplane was again years late and sales prices were too low.

I see the Airbus fans on this website talking about a marginal business case indicating there is not much of a market and the plane is unlikely to be successful.

I see the Boeing fans on this website supporting a deliberate careful approach to avoid mistakes in the past.

As is typical the two sides will never agree, but personally I can’t wait for Farnborough to see what happens. You can tell what side I am on

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