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727glasair
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 6:37 pm

Ok. I have read all your thoughtful comments....makes a lot of sense.

But there is a big "bottom line" that seems to be ignored:

1) A SINGLE aisle plane can have 6 across seating
2) With TWO aisles, the 767 has just 7 across
3) A VERY slightly wider fuselage would seat 8 across
4) Therefore, this design has left a LOT of seating and profitability on the table....
 
jupiter2
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 6:55 pm

PSAatSAN4Ever wrote:
I'm surprised that no one has mentioned the LD2 carriers in relation to the 767 yet.

The 767 is too narrow by a few inches to fit two of them in the cargo hold side-by-side. That obviously hasn't stopped it from becoming the workhorse in many cargo fleets, but it has been mentioned many times years ago here at a.net that had it been able to do this, it would have sold even more successfully.

If I recall correctly, Airbus designed the A330 and A340 to be wide enough for this task, which they do.

I doubt we will ever see a narrow "wide-body" like the 767 again, simply for this reason. However, in terms of comfort, either seven-across or eight-across is heaven - everything in two's.


Most carriers got around the LD2/LD3 by using LD8 containers. They were built to the width of the 767 cargo hold, no space wasted.
 
jupiter2
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 6:57 pm

727glasair wrote:
Ok. I have read all your thoughtful comments....makes a lot of sense.

But there is a big "bottom line" that seems to be ignored:

1) A SINGLE aisle plane can have 6 across seating
2) With TWO aisles, the 767 has just 7 across
3) A VERY slightly wider fuselage would seat 8 across
4) Therefore, this design has left a LOT of seating and profitability on the table....


And yet there are over 1200 orders for it..... go figure :scratchchin:
 
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c933103
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 6:59 pm

WayexTDI wrote:
c933103 wrote:
AZa346 wrote:
Could an operator put in a 4 aisle 4 layout or that would be illegal?? Besides the obvious unconfort of when the window guy would have to get up! Just curious!
Of course this would also mean longer turnarounds as boarding wouldn't be as dlfast as in a twin aisle... but that may not be such an issue for a plane that does trans Atlantic flights, as that would mean a couple of rotations per day!

iirc things like Tu-114 in Soviet once used that?

From memory, the FAA & EASA do not allow having to go over more than 2 seats to reach the aisle; hence the 3x3 layouts in narrowbodies, 3x3x3 or 2x5x2 or 3x4x3 in widebodies.
No more than 3 seats between aisle and window, no more than 5 seats between aisles.

It was not a requirement back then see viewtopic.php?t=174695 for British
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 7:04 pm

The lack if time history in this thread is driving me nuts. Entry into service years:
a300 1974
767-200 1982
A310 1983
767-300ER 1986
A333 1994
A332 1998

The A310 was launched as the 767 was destroying the A300 market. The 767-300 only trailed by 3 years.

The A332 launch is important as it brought in the MTOW increase, as well as significant engine PIPs.

Both the A300 and 767 use hand me down 747 engines, so neither had the advantage of custom engines.

The A330 had a significantly more advanced engine. In particular the T700 and, at first, PW4168. (People forget it was the PW4175 Pratt botched). The GE offering always struggled, for good reason.

The A330 was also a next generation wing. Just as the 767 was over the A300. That is still happening! It takes accumulating new technology for 8 to 15 years to move a wing forward a generation. Engines take longer..

Lightsaber
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1989worstyear
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 7:14 pm

lightsaber wrote:
The lack if time history in this thread is driving me nuts. Entry into service years:
a300 1974
767-200 1982
A310 1983
767-300ER 1986
A333 1994
A332 1998

The A310 was launched as the 767 was destroying the A300 market. The 767-300 only trailed by 3 years.

The A332 launch is important as it brought in the MTOW increase, as well as significant engine PIPs.

Both the A300 and 767 use hand me down 747 engines, so neither had the advantage of custom engines.

The A330 had a significantly more advanced engine. In particular the T700 and, at first, PW4168. (People forget it was the PW4175 Pratt botched). The GE offering always struggled, for good reason.

The A330 was also a next generation wing. Just as the 767 was over the A300. That is still happening! It takes accumulating new technology for 8 to 15 years to move a wing forward a generation. Engines take longer..

Lightsaber


I don't see it happening now. The NEO wing is an augmentation of the original '94 design.
Stuck at age 15 thanks to the certification date of the A320-200 and my parents' decision to postpone having a kid by 3 years. At least there's Dignitas...
 
rjmf22
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 7:24 pm

airzona11 wrote:
1989worstyear wrote:
WayexTDI wrote:
What 1988 EIS??? The 767 entered into service in 1982 and the A330 in 1994.

Can you realize that there is life after 1988???


What I'm saying is, the post-1987 technology of the A330 ensured its success. The 767 was too early and that's why the orders dried up 20 years ago.


The 767 is still successful. It owns the widebody market for its size. The A330 is larger and for different missions.


The 767 is the perfect plane for TATL markats. I almost feel as if the A330 compares with the 777 better than the 767
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tropical
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 7:29 pm

DarthLobster wrote:
The 767 is still being produced, the 757 is not. The 767 has outsold the 757 by nearly 200 units. Why does everyone still act like the 757 is god's gift to aviation?

Just my own perception of course but I always got the impression that the 757 is so revered amongst airplane enthusiasts because of its raw power/ performance.

Of course, airlines take a far more pragmatic approach to evaluating an aircraft model, so just because the 757 can impressively outperform all other a/c in certain hot & high missions, it does not mean it is the best model for 90% of a typical airline’s overall portfolio of routes..

As a crude analogy, I see it a bit like a car hire company that has two car types in their fleet for the same hire price with similar levels of legroom, safety features and passenger comfort: Golf GTIs and Toyota Prius. Of course most customers are going to prefer the far superior performance and speed of the Golf GTI (or similar American hot-hatch make). But the car hire company will be primarily concerned with the economics so the humble and less glamorous Prius might look far more appealing in their eyes.
 
Gangurru
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 7:38 pm

Weatherwatcher1 wrote:
The A300 and A310 were 8 abreast and cabin width didn’t make those planes great sellers.


It’s also worth remembering that in the 1970s and 1980s Airbus establishing itself in the aviation market. It lacked the prescence of today. As a child of the 1970s, spotting an Airbus on the tarmac was quite a thrill.

Also, the market was more fragmented and Airbus was competing with McDonnell Douglas, Lockheed and, lastly, Boeing.

Airline fleets and orders were also a lot smaller. Orders of only 4 or 5 aircraft were common back then.
 
WayexTDI
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 8:16 pm

c933103 wrote:
WayexTDI wrote:
c933103 wrote:
iirc things like Tu-114 in Soviet once used that?

From memory, the FAA & EASA do not allow having to go over more than 2 seats to reach the aisle; hence the 3x3 layouts in narrowbodies, 3x3x3 or 2x5x2 or 3x4x3 in widebodies.
No more than 3 seats between aisle and window, no more than 5 seats between aisles.

It was not a requirement back then see viewtopic.php?t=174695 for British

For whatever reason, I understood the original question as "nowadays", not 50 years ago.
 
EBiafore99
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 8:33 pm

tropical wrote:
DarthLobster wrote:
The 767 is still being produced, the 757 is not. The 767 has outsold the 757 by nearly 200 units. Why does everyone still act like the 757 is god's gift to aviation?

Just my own perception of course but I always got the impression that the 757 is so revered amongst airplane enthusiasts because of its raw power/ performance.

Of course, airlines take a far more pragmatic approach to evaluating an aircraft model, so just because the 757 can impressively outperform all other a/c in certain hot & high missions, it does not mean it is the best model for 90% of a typical airline’s overall portfolio of routes..

As a crude analogy, I see it a bit like a car hire company that has two car types in their fleet for the same hire price with similar levels of legroom, safety features and passenger comfort: Golf GTIs and Toyota Prius. Of course most customers are going to prefer the far superior performance and speed of the Golf GTI (or similar American hot-hatch make). But the car hire company will be primarily concerned with the economics so the humble and less glamorous Prius might look far more appealing in their eyes.


Totally get it. Recently flew a 753 DTW-LAX and 739 LAX-DTW. IMO, I know the aircraft is older, but the take-off on a 757 is awesome.

Also when I read articles about the 757, my perception is the aircraft was too early for its time. Many airlines didn't know what to do with the aircraft per se. With the advent of TATL use, it seems the 757 has found a niche...which I believe is one of the leading factors for the 797.
 
Kilopond
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 9:18 pm

727glasair wrote:
[...]2) In hindsight, would a slightly larger 8-across fuselage design have been smarter?


You are kidding, aren´t you? The A330 absolutely killed the B767. Well, if you don´t count certain gentlemen´s agreement or crony B767 orders, that is.
 
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lightsaber
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 9:29 pm

tropical wrote:
DarthLobster wrote:
The 767 is still being produced, the 757 is not. The 767 has outsold the 757 by nearly 200 units. Why does everyone still act like the 757 is god's gift to aviation?

Just my own perception of course but I always got the impression that the 757 is so revered amongst airplane enthusiasts because of its raw power/ performance.

Of course, airlines take a far more pragmatic approach to evaluating an aircraft model, so just because the 757 can impressively outperform all other a/c in certain hot & high missions, it does not mean it is the best model for 90% of a typical airline’s overall portfolio of routes..

As a crude analogy, I see it a bit like a car hire company that has two car types in their fleet for the same hire price with similar levels of legroom, safety features and passenger comfort: Golf GTIs and Toyota Prius. Of course most customers are going to prefer the far superior performance and speed of the Golf GTI (or similar American hot-hatch make). But the car hire company will be primarily concerned with the economics so the humble and less glamorous Prius might look far more appealing in their eyes.

Great analogy. Everything is cost based. IMHO, everything must go to CFRP wings as underside laminar flow is easier and the weight savings. The botched 787 EIS scared designs away from CFRP. Now it is the going forward, except for low production volumes (business jets).

Airlines expand if they pick the most economical aircraft. Right now TATL and EU to India is begging for a lower cost per flight aircraft. The A321LR is great and I like the xLR proposal, but look at the low payloads required to make them work (payload/range chart).

I see one more 7-across as today, 8 across is too similar in costs to 9 across and that great cargo capability.

7-across has more drag for a given altitude vs. 6-across or 8-across. Convieniently, it is more structurally efficient for long lengths (ovoid is less efficient than circular, I realize that). So it will just have to have a wing optimized for the mission.

Hint:. The A320 cruise is too low for today's designs. It suffers an 11% drag penalty for flying so low (through dense air). Now this requires more efficient cabin pressurization such as the 787 or A220.

Oh wait, known tech... Tech that save 3% in fuel burn versus an A330/A320/737/767 before we discuss the other stuff (I included the anti-iceing advantage as why design separately?).

I keep noticing people assume constant cruise altitude. I don't. I worked a smaller A330 forever ago that was based on a higher cruise. Do not assume higher cruise will not happen. If a new design comes out that benefits, it is trivial to assign requirements to fly at the new levels.

Note:. I'm in R&D. Stuff I designed 24 years ago is just entering service, so I cannot help but look at the current designs as obsolete.

For small widebodies, folding wingtips are a huge deal. 7 to 9 across. It is cheap to add floors to buildings, so I fully expect the passengers per hectare to keep increasing. It is now 25% higher than what I was taught in college was the limit. :spin:

It is amazing the 767 has no production end in sight. It forced Airbus to almost completely abandon their prior 8-across concept.

Lightsaber
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lightsaber
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 9:54 pm

Kilopond wrote:
727glasair wrote:
[...]2) In hindsight, would a slightly larger 8-across fuselage design have been smarter?


You are kidding, aren´t you? The A330 absolutely killed the B767. Well, if you don´t count certain gentlemen´s agreement or crony B767 orders, that is.

Errr... Not at first. It wasn't until 15 years after the 767 entered the fleet that the A330 killed it. You do realize all aircraft are expected to only have 15 year sales lives? The A330 had far more efficient wings, engines, and subsystems. Yes, a good cross section. The 767 wouldn't be competitive today. But back then there wasn't the automation we have today to make any cross section you want economically.

Today 8-across isn't economical vs. 9-across Meh, technology moves on.

I could design a business case for:
5-across
6-across
7-across
9-across
10-across
17-across (double deck).

Someone else can do 3&4 across. I put in too much tech for those sizings.

9-across is best 320 to 360 seats (3-class). That is too expensive. For 7-across, I would go 250 to 300.

Why yes, I see the 787 migrating to the -10 and never understood the A358 concept being pitched seriously. I also want to see the deal Kuwait received on A338s, I don't understand buying them. (I look at A332s as overdue freight conversions). Read the Prius analogy. Not every route has decent yield for 9-across. 6-across has structural limits for fuel carrying (gear space) that the inefficient 7-across gets for free.

I'd love to engineer in a world where just the cross section mattered. :no:

Look at the difference in a widebody wingbox versus a narrowbody. Now, if you accept 8-across will always be punted from the market by 9-across, how do you design for economical range?

I went out of my way to prove to myself that the 7-across advocates here on a.net we're just wrong. In doing my deep dive, I became a 7-across advocate if cargo and TPAC range were not part of the concept.

There is a narrow optimal range for any cross section. E.g., my 17-across double decker has a HUGE minimum range to beat the competition. Over 70% of the current widebody missions will be more economical with a single deck aircraft. :cry2:

9 and 10 across must forfeit the bottom 40% to 60% of the market to 6-across and 7-across. Oh well... Just my back of the envelope estimates. About half of that the 7-across has enough of an advantage to sell. Note:. Below 1,500nm is narrowbody territory. I'll let someone else inform STC. ;). The broad range depends on cargo yield assumptions. Right now there is a surplus of belly space on too many routes. That will change as 6 and 7 across take over more routes. However, we won't be in balance for 15+ years no matter how much I like certain cross sections.

Lightsaber
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longhauler
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 9:59 pm

c933103 wrote:
AZa346 wrote:
iirc things like Tu-114 in Soviet once used that?

I can't find any record of that. The TU-114 was always 6 abreast in Y and 4 abreast in F.

There was, however, a customer of the Trident that opted for a 7 abreast, single aisle version. Thankfully, only one customer! (Channel Airways).
Just because I stopped arguing, doesn't mean I think you are right. It just means I gave up!
 
1989worstyear
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 10:11 pm

lightsaber wrote:
Kilopond wrote:
727glasair wrote:
[...]2) In hindsight, would a slightly larger 8-across fuselage design have been smarter?


You are kidding, aren´t you? The A330 absolutely killed the B767. Well, if you don´t count certain gentlemen´s agreement or crony B767 orders, that is.

Errr... Not at first. It wasn't until 15 years after the 767 entered the fleet that the A330 killed it. You do realize all aircraft are expected to only have 15 year sales lives? The A330 had far more efficient wings, engines, and subsystems. Yes, a good cross section. The 767 wouldn't be competitive today. But back then there wasn't the automation we have today to make any cross section you want economically.

Today 8-across isn't economical vs. 9-across Meh, technology moves on.

I could design a business case for:
5-across
6-across
7-across
9-across
10-across
17-across (double deck).

Someone else can do 3&4 across. I put in too much tech for those sizings.

9-across is best 320 to 360 seats (3-class). That is too expensive. For 7-across, I would go 250 to 300.

Why yes, I see the 787 migrating to the -10 and never understood the A358 concept being pitched seriously. I also want to see the deal Kuwait received on A338s, I don't understand buying them. (I look at A332s as overdue freight conversions). Read the Prius analogy. Not every route has decent yield for 9-across. 6-across has structural limits for fuel carrying (gear space) that the inefficient 7-across gets for free.

I'd love to engineer in a world where just the cross section mattered. :no:

Look at the difference in a widebody wingbox versus a narrowbody. Now, if you accept 8-across will always be punted from the market by 9-across, how do you design for economical range?

I went out of my way to prove to myself that the 7-across advocates here on a.net we're just wrong. In doing my deep dive, I became a 7-across advocate if cargo and TPAC range were not part of the concept.

There is a narrow optimal range for any cross section. E.g., my 17-across double decker has a HUGE minimum range to beat the competition. Over 70% of the current widebody missions will be more economical with a single deck aircraft. :cry2:

9 and 10 across must forfeit the bottom 40% to 60% of the market to 6-across and 7-across. Oh well... Just my back of the envelope estimates. About half of that the 7-across has enough of an advantage to sell. Note:. Below 1,500nm is narrowbody territory. I'll let someone else inform STC. ;). The broad range depends on cargo yield assumptions. Right now there is a surplus of belly space on too many routes. That will change as 6 and 7 across take over more routes. However, we won't be in balance for 15+ years no matter how much I like certain cross sections.

Lightsaber


I thought the A330 was still competitive against the 787?

1994 subsystems are still modern, but not '82.
Stuck at age 15 thanks to the certification date of the A320-200 and my parents' decision to postpone having a kid by 3 years. At least there's Dignitas...
 
1989worstyear
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 10:17 pm

Kilopond wrote:
727glasair wrote:
[...]2) In hindsight, would a slightly larger 8-across fuselage design have been smarter?


You are kidding, aren´t you? The A330 absolutely killed the B767. Well, if you don´t count certain gentlemen´s agreement or crony B767 orders, that is.


So what you're saying is - the 767 was doomed regardless of cross section because of the 1982 EIS.
Stuck at age 15 thanks to the certification date of the A320-200 and my parents' decision to postpone having a kid by 3 years. At least there's Dignitas...
 
Bricktop
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 10:18 pm

SteelChair wrote:
Its a shame they never offered newer generation engines on it. Boeing was focused on the too heavy, too much range 787.

Yeah, to date they have only sold a paltry 1,400 787s. Epic Fail for sure.

But back on topic, it's clear that most posters here agree with me that the 767 is a dream from a passenger's POV. I still look out for it on TATL but it's getting rarer sadly.
 
airzona11
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 11:06 pm

1989worstyear wrote:
Kilopond wrote:
727glasair wrote:
[...]2) In hindsight, would a slightly larger 8-across fuselage design have been smarter?


You are kidding, aren´t you? The A330 absolutely killed the B767. Well, if you don´t count certain gentlemen´s agreement or crony B767 orders, that is.


So what you're saying is - the 767 was doomed regardless of cross section because of the 1982 EIS.


How are any of these points reality? 767 profitable, still profitable, still in production, still making airlines money. 763s do not match up to A332s or A333s. 767s and A330s are apples and oranges. A330+777 is what you are confusing.
 
SteelChair
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 11:09 pm

Bricktop wrote:
SteelChair wrote:
Its a shame they never offered newer generation engines on it. Boeing was focused on the too heavy, too much range 787.

Yeah, to date they have only sold a paltry 1,400 787s. Epic Fail for sure.

But back on topic, it's clear that most posters here agree with me that the 767 is a dream from a passenger's POV. I still look out for it on TATL but it's getting rarer sadly.


Whoa. Who said the 787 was a failure? I said it was too big and too heavy. I didn't say "for this market segment," but I assumed a reader would understand that. Let me spell it out: the 787 is too big and too heavy to be a true 767 replacement aircraft, thus NMA.
 
SteelChair
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Re: Boeing 767: Fuselage size always limited profitability??

Wed May 08, 2019 11:15 pm

airzona11 wrote:
1989worstyear wrote:
Kilopond wrote:

You are kidding, aren´t you? The A330 absolutely killed the B767. Well, if you don´t count certain gentlemen´s agreement or crony B767 orders, that is.


So what you're saying is - the 767 was doomed regardless of cross section because of the 1982 EIS.


How are any of these points reality? 767 profitable, still profitable, still in production, still making airlines money. 763s do not match up to A332s or A333s. 767s and A330s are apples and oranges. A330+777 is what you are confusing.


I agree with this. ...its an urban legend that the 330 killed the 767. Fake news. But its repeated over and over. They are very different categories of aircraft. 8ab vs 7ab
 
LH707330
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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 12:59 am

lightsaber wrote:
Great analogy. Everything is cost based. IMHO, everything must go to CFRP wings as underside laminar flow is easier and the weight savings. The botched 787 EIS scared designs away from CFRP. Now it is the going forward, except for low production volumes (business jets).

Airlines expand if they pick the most economical aircraft. Right now TATL and EU to India is begging for a lower cost per flight aircraft. The A321LR is great and I like the xLR proposal, but look at the low payloads required to make them work (payload/range chart).

I see one more 7-across as today, 8 across is too similar in costs to 9 across and that great cargo capability.

7-across has more drag for a given altitude vs. 6-across or 8-across. Convieniently, it is more structurally efficient for long lengths (ovoid is less efficient than circular, I realize that). So it will just have to have a wing optimized for the mission.

Hint:. The A320 cruise is too low for today's designs. It suffers an 11% drag penalty for flying so low (through dense air). Now this requires more efficient cabin pressurization such as the 787 or A220.

Oh wait, known tech... Tech that save 3% in fuel burn versus an A330/A320/737/767 before we discuss the other stuff (I included the anti-iceing advantage as why design separately?).

I keep noticing people assume constant cruise altitude. I don't. I worked a smaller A330 forever ago that was based on a higher cruise. Do not assume higher cruise will not happen. If a new design comes out that benefits, it is trivial to assign requirements to fly at the new levels.

Note:. I'm in R&D. Stuff I designed 24 years ago is just entering service, so I cannot help but look at the current designs as obsolete.

For small widebodies, folding wingtips are a huge deal. 7 to 9 across. It is cheap to add floors to buildings, so I fully expect the passengers per hectare to keep increasing. It is now 25% higher than what I was taught in college was the limit. :spin:

It is amazing the 767 has no production end in sight. It forced Airbus to almost completely abandon their prior 8-across concept.

Lightsaber


Thanks for the exhaustive response, couple questions:

1. Why do you say the 320 cruises too low? You referring to its FL390 service ceiling, or some other factor that keeps it at a lower altitude?
2. Regarding 8 across being too close to 9 across, what properties make that so? I'd think at optimum fineness ratios, there should still be a gap in optimum architecture between, say, an A330 and 787 cross-section. Between the 339 and 789, which fuselage makes more sense?
 
krisyyz
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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 1:43 am

Boeing played around with the 767 design, making it bigger before airlines told them just build a new plane, the 777.

This is one of my favourite av docs that mentions the process:
https://youtu.be/0oyWZjdXxlw

KrisYYZ
 
JayinKitsap
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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 5:56 am

One of the best ways to compare is to look at the freighters, the key metric is cost per pound moved. Here 767's are outselling the A330F by like 10-1. With passenger the 330, 350, 777, and 787 did kill the orders, now in service planes are selling quite well for freighter conversions.

The 330, 350, 777, and 787 all have much longer ranges than anything before, it probably doesn't pencil out to do 7ab in a comparable range capability now. But 7ab designed for a range of 5,000 miles looks quite viable. It would take an 8ab designed for a similar range to compete, but that adds 30 to 35 seats to each.
 
WIederling
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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 7:11 am

lightsaber wrote:
The 7-across held until the MTOW increase that came in for the A332 (combined with significant engine PIPs). Suddenly, the A333 was far more competitive TATL. As the payload range curve broadened out nicely (5200nm full pax). Before then, the A333 just didn't have enough surplus range for volume sales.


A332 was introduced when that "magic range" was reached for the shortened version.
A333 and 763 are how much apart capacity wise?

( only with the advent of the 764 do we see a size match to the A332 _not_ the A333.)
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Spiderguy252
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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 8:45 am

PatrickZ80 wrote:
As a freighter, for a very long time the 767 was the best medium-sized aircraft on the market. It was small enough to be put on relatively thin routes where a larger aircraft would be too big. The A330 freighter was developed much later than the 767 and it was bigger, meaning more empty floor space on thin routes. Therefor with anything less than a full load the A330 was less economical than the 767. Same goes for the 777 freighter which is again one step newer and bigger than the A330. But it's easily too big, empty floor space doesn't make money.


Don't forget that the A330F is a dog in the range stakes - it barely has legs to do TATL.
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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 11:57 am

1989worstyear wrote:
lightsaber wrote:
Kilopond wrote:

You are kidding, aren´t you? The A330 absolutely killed the B767. Well, if you don´t count certain gentlemen´s agreement or crony B767 orders, that is.

Errr... Not at first. It wasn't until 15 years after the 767 entered the fleet that the A330 killed it. You do realize all aircraft are expected to only have 15 year sales lives? The A330 had far more efficient wings, engines, and subsystems. Yes, a good cross section. The 767 wouldn't be competitive today. But back then there wasn't the automation we have today to make any cross section you want economically.

Today 8-across isn't economical vs. 9-across Meh, technology moves on.

I could design a business case for:
5-across
6-across
7-across
9-across
10-across
17-across (double deck).

Someone else can do 3&4 across. I put in too much tech for those sizings.

9-across is best 320 to 360 seats (3-class). That is too expensive. For 7-across, I would go 250 to 300.

Why yes, I see the 787 migrating to the -10 and never understood the A358 concept being pitched seriously. I also want to see the deal Kuwait received on A338s, I don't understand buying them. (I look at A332s as overdue freight conversions). Read the Prius analogy. Not every route has decent yield for 9-across. 6-across has structural limits for fuel carrying (gear space) that the inefficient 7-across gets for free.

I'd love to engineer in a world where just the cross section mattered. :no:

Look at the difference in a widebody wingbox versus a narrowbody. Now, if you accept 8-across will always be punted from the market by 9-across, how do you design for economical range?

I went out of my way to prove to myself that the 7-across advocates here on a.net we're just wrong. In doing my deep dive, I became a 7-across advocate if cargo and TPAC range were not part of the concept.

There is a narrow optimal range for any cross section. E.g., my 17-across double decker has a HUGE minimum range to beat the competition. Over 70% of the current widebody missions will be more economical with a single deck aircraft. :cry2:

9 and 10 across must forfeit the bottom 40% to 60% of the market to 6-across and 7-across. Oh well... Just my back of the envelope estimates. About half of that the 7-across has enough of an advantage to sell. Note:. Below 1,500nm is narrowbody territory. I'll let someone else inform STC. ;). The broad range depends on cargo yield assumptions. Right now there is a surplus of belly space on too many routes. That will change as 6 and 7 across take over more routes. However, we won't be in balance for 15+ years no matter how much I like certain cross sections.

Lightsaber


I thought the A330 was still competitive against the 787?

1994 subsystems are still modern, but not '82.

The A330 sales have struggled ever since the 787 production ramp. Unfortunately the types manufactured days are on the wane. It is the 717 of widebodies.

The NMA, if launched, will finish off the A330. There is no doubt the 767 subsystems are out of date. So are the 737, A330, A320, and 77W. Meh .. we have the A220, 787, A350, and 777X. There is never a rapid transition in a capital intensive industry.

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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 12:13 pm

I traveled on a few 767 aircraft 2-4-2 config, extremely tight and not much space for crew with trolleys.
 
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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 1:55 pm

I always thought it was a bit narrow considering the first class layouts. When the initial deliveries occurred (United was first, and lets not forget DL's project 767 where the employees paid for the plane..) the plane was not ETOPS certified, so it was put into domestic use. AA flew them out of ORD for example domestically. Many of the original pre-ETOPS planes were 2-2-2 in F, but once the mid 80s rolled around, and they became certified, many changed the F layout to 2-1-2 to fit the sleeper seats for intl flights.

The strangest layout I ever saw was Air Canada's 2-2-1 layout:
Image
 
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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 2:29 pm

lightsaber wrote:
7-across has more drag for a given altitude vs. 6-across or 8-across. Convieniently, it is more structurally efficient for long lengths (ovoid is less efficient than circular, I realize that). So it will just have to have a wing optimized for the mission.

I went out of my way to prove to myself that the 7-across advocates here on a.net we're just wrong. In doing my deep dive, I became a 7-across advocate if cargo and TPAC range were not part of the concept.


I don't know what kinda factors for the pressure hull you used - and I don't know what they'd need to be.

I *do* know that the CSeries has a complex curvature on the fuselage cross-section, with 3 different radii/centrepoint combinations. One of these combinations has a radii/centrepoint combination that results in a section of the fuselage (cross-section) having a curvature that is from a wider fuselage than it would be taller. It was near the floor beam area - and still - it caused no end of problems.

I would think (based on what happened in detail design and DaDT analysis), the difficult of ramping that concept up to encompass the majority of the fuselage cross section is probably being underestimated.


Way back in the day in uni we had a look at the Dolphin lifting body aircraft and how we could tweak it. If I recall right (and that's a big ask given how many years ago it is now), I think we had evidence for a structural factor of around 1.25-1.5x on a circular fuselage. Obviously the Dolphin is much wider and less structurally efficient than a 7ab ovoid, but I'd think your still looking at a factor of >1.1.

I'll see if I can dig it out - it might be around somewhere on a HD at home.
 
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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 2:56 pm

Amiga500 wrote:

I *do* know that the CSeries has a complex curvature on the fuselage cross-section, with 3 different radii/centrepoint combinations. One of these combinations has a radii/centrepoint combination that results in a section of the fuselage (cross-section) having a curvature that is from a wider fuselage than it would be taller. It was near the floor beam area - and still - it caused no end of problems.

I would think (based on what happened in detail design and DaDT analysis), the difficult of ramping that concept up to encompass the majority of the fuselage cross section is probably being underestimated.

There has been a step change in the quality of automated machine tools over the last few years. It started with the automated friction welders (compressors), CFRP weaving, 3D printing, to complex sheet metal work.

At this time weaving the barrel out of CFRP would be trivial. The era where the 787 pushed the limits of CFRP design is long gone.

I respectfully disagree. Partially as I work for an aerospace company that realized late the step change available to us today. What was hard 5 years ago is easy today for the right team. The way I designed aircraft 5 years ago is obsolete. I've seen prototypes go together the new way and there is no turning back. I do not like having another of my skill sets become worthless, but that is that, I will adapt. Besides, I'm friends with the people who will teach everyone. ;) Amazing the advantage of buying people drinks. :spin:

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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 3:05 pm

It's not manufacturing that was the problem (after all, CSeries fuse is otherwise pretty conventional construction, just newer alloys), it was stress concentrations.


I've a prototype ALM flame arrestor sitting on my desk from quite a few years ago now - (literally) physically impossible to build ~15 years ago. Easy peasy now. Such is the way of things.
 
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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 3:23 pm

Amiga500 wrote:
It's not manufacturing that was the problem (after all, CSeries fuse is otherwise pretty conventional construction, just newer alloys), it was stress concentrations.


I've a prototype ALM flame arrestor sitting on my desk from quite a few years ago now - (literally) physically impossible to build ~15 years ago. Easy peasy now. Such is the way of things.

We can agree that good stress engineers are required. That is why Boeing has whole departments and they outsource to my employer despite us charging them huge multiples. Bwaaa haaa ha.

We hired those excellent ex-Douglas engineers in bulk and they have been doing prototypes for decades and mentored the next generation.

We're debating over perhaps $50 million in added engineering time. :yawn:

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Amiga500
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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 3:30 pm

A pencil can only be sharpened so much.

I'd expect there to be a decent factor on weight in comparison to a circular (or vertical ovoid) equivalent.
 
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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 3:45 pm

Looking at 30 rows of 8x versus 34.2 rows of 7x, I get about 5000 square feet for 8x and 5150 square feet or 7x. But then the nose and tailcone will be bigger for the 8, so add 250 square feet for 8x, so the 8x has more skin for the same pax. And the frontal area is bigger by about 20% which seems like it might have an impact. Then the shorter 8x aircraft will need a larger tail with more surface and weight. But the 8x has a larger cargo hold.
I'm always making the case that the most efficient aircraft for 210 to 240 seats for quick turns and upselling aisle seats is a 35 row to 40 row 2-2-2 aircraft. Slightly wider than the 757, with a length of about 170' between the 752 and 753.
 
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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 5:00 pm

DenverTed wrote:
Looking at 30 rows of 8x versus 34.2 rows of 7x, I get about 5000 square feet for 8x and 5150 square feet or 7x. But then the nose and tailcone will be bigger for the 8, so add 250 square feet for 8x, so the 8x has more skin for the same pax. And the frontal area is bigger by about 20% which seems like it might have an impact. Then the shorter 8x aircraft will need a larger tail with more surface and weight. But the 8x has a larger cargo hold.
I'm always making the case that the most efficient aircraft for 210 to 240 seats for quick turns and upselling aisle seats is a 35 row to 40 row 2-2-2 aircraft. Slightly wider than the 757, with a length of about 170' between the 752 and 753.

You have good numbers. The issue with 8x is one gets 9x for a pair of LD3. Cargo is granular. Either fit the plallets and LD3 or... Not.

Wider makes galley, gear, center fuel tank and water closet placement easier. For 9-across, Airbus and Boeing already have their designs. For 6-across, I cannot put in a modern high AR eing and have the fuel volume.

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Re: Boeing 767: Fuselage size always limited profitability??

Thu May 09, 2019 6:05 pm

There is a huge amount of tooling for aluminum hulls, keeping the same radii and staying circular makes all this equipment work for a whole bunch of models. Airbus has kept the A320 and A300 hull cross sections for all of their models except the A350 and A380. Boeing did the huge investment for the 777, the 767, the 747, and the 737 hull tooling. But with the 787 barrel method only the mandrel needs to be changed to do a new cross section and it may be oval or basically almost any shape that has positive curvature at all locations. Maximum size needs to be established for the 'lathe' and the autoclave. That is a design freedom not available before.

What looks like a flat oval structurally could have a 'hinge' at the window line with tapered ribs, thin at the windows, relatively deep at the crown. In the lower half it is the old school double bubble part circle stayed by the floor beams. A double wall could be done with the pressure hull on the interior of the frame, making the exterior skin much more damage tolerant and keeping all the condensation inside. The void is filled with a foam that also serves as a permanent mandrel for the outside wall. Buried double wall FRP ductwork is made all the time, it can handle truck loads over it with only 3 feet of cover. Switching mandrel size has almost no time difference as a mandrel needs to be installed anyway.

The 797 could use this quite effectively, the height is controlled by the headroom over the aisle plus what is needed for the wingbox. The under floor yes will be smaller than a 767 but a bit taller than the current 737, the inner shell below would allow for easy use of belt loaders.

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