User avatar
keesje
Posts: 10219
Joined: Thu Apr 12, 2001 2:08 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 1:05 am

If Boeing goes for a flat 2-3-2 cross section, a bigger flat container design might be considerated retaining commonality with the widely used AKH / LD3-45 series. A container that fits A320's but can use the extra space of a wider NMA fuselage too, opening up extra revenue potential for Cargo.

Image

Oersonally I think the chances of a twin aisle NMA have shrunken over the last half year.
"Never mistake motion for action." Ernest Hemingway
 
User avatar
ikolkyo
Posts: 1509
Joined: Tue Nov 05, 2013 8:43 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 1:07 am

keesje wrote:
If Boeing goes for a flat 2-3-2 cross section, a bigger flat container design might be considerated retaining commonality with the widely used AKH / LD3-45 series. A container that fits A320's but can use the extra space of a wider NMA fuselage too, opening up extra revenue potential for Cargo.

Image

Oersonally I think the chances of a twin aisle NMA have shrunken over the last half year.


Why do you keep saying it won't be a twin aisle? Airlines have said they wanted a twin aisle and airlines have shown interest in early proposals of a twin aisle aircraft.
 
User avatar
keesje
Posts: 10219
Joined: Thu Apr 12, 2001 2:08 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 1:37 am

ikolkyo wrote:
keesje wrote:
If Boeing goes for a flat 2-3-2 cross section, a bigger flat container design might be considerated retaining commonality with the widely used AKH / LD3-45 series. A container that fits A320's but can use the extra space of a wider NMA fuselage too, opening up extra revenue potential

Personally I think the chances of a twin aisle NMA have shrunken over the last half year.


Why do you keep saying it won't be a twin aisle? Airlines have said they wanted a twin aisle and airlines have shown interest in early proposals of a twin aisle aircraft.


Because under ~260 seats a twin aisles is heavier / less efficient than a single aisle. In the end airlines put the money where their mouth is. A bigger twin aisle doesn't address the segment the airlines indicate.
"Never mistake motion for action." Ernest Hemingway
 
Newbiepilot
Posts: 2078
Joined: Tue Aug 30, 2016 10:18 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 3:36 am

keesje wrote:
If Boeing goes for a flat 2-3-2 cross section, a bigger flat container design might be considerated retaining commonality with the widely used AKH / LD3-45 series. A container that fits A320's but can use the extra space of a wider NMA fuselage too, opening up extra revenue potential for Cargo.

Image

Oersonally I think the chances of a twin aisle NMA have shrunken over the last half year.


We had a whole thread dedicated to your expandable AKH LD3-45 and the clear consensus was that it is a bad idea that adds weight and will likely break:

viewtopic.php?t=1365951

We also are repetitively hearing from a Boeing themselves that their concept is a small widebody.

Are you trying to cast shade over that concept before it even gets launched? Is that because you favor A321s?
 
NateGreat
Posts: 38
Joined: Thu Sep 28, 2017 6:02 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 4:47 am

I’m too lazy to read through everything, but will the 797 be a single-aisle or twin-aisle plane?
 
User avatar
EA CO AS
Posts: 14226
Joined: Wed Nov 14, 2001 8:54 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 4:52 am

NateGreat wrote:
I’m too lazy to read through everything, but will the 797 be a single-aisle or twin-aisle plane?


My money is still on a single aisle, right in the space between the 757-200 and 757-300; 225-245 in a two class configuration with 4500-5000nm range.
"In this present crisis, government is not the solution to our problem - government IS the problem." - Ronald Reagan

Comments made here are my own and are not intended to represent the official position of Alaska Air Group
 
User avatar
william
Posts: 2018
Joined: Thu Jun 10, 1999 1:31 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 5:03 am

NateGreat wrote:
I’m too lazy to read through everything, but will the 797 be a single-aisle or twin-aisle plane?


Proposed to be a twin aisle.
 
NateGreat
Posts: 38
Joined: Thu Sep 28, 2017 6:02 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 5:19 am

william wrote:
NateGreat wrote:
I’m too lazy to read through everything, but will the 797 be a single-aisle or twin-aisle plane?


Proposed to be a twin aisle.

So, basically a 767-sized Dreamliner?
 
ikramerica
Posts: 14293
Joined: Mon May 23, 2005 9:33 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 5:32 am

Despite how "widely used" the -45 is, it's barely bigger than 1 real LD3 and far shorter. If it can't hold 2x LD3 side by side, the 797 will hold 2x LD2 like the 767, which can also hold 1 LD3 or LD3-45 or a standard height pallet.
Of all the things to worry about... the Wookie has no pants.
 
User avatar
Slug71
Posts: 572
Joined: Wed Jan 04, 2017 6:08 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 5:41 am

NateGreat wrote:
william wrote:
NateGreat wrote:
I’m too lazy to read through everything, but will the 797 be a single-aisle or twin-aisle plane?


Proposed to be a twin aisle.

So, basically a 767-sized Dreamliner?


Pretty much. I wouldn't be surprised if the 767 is restarted though. Makes the most sense as far as cost goes.
 
RJMAZ
Posts: 214
Joined: Sat Jul 09, 2016 2:54 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 6:53 am

keesje wrote:
If Boeing goes for a flat 2-3-2 cross section, a bigger flat container design might be considerated retaining commonality with the widely used AKH / LD3-45 series.

If they plan on selling 1000+ aircraft they would just introduce a new container like the 767. The extra weight to make it extendable while remaining bomb proof would be too much.

Basically they would go with a 45inch height LD6 or LD8 container down from their original 64inch height.

The LD6 is two LD3's joined together.
The LD8 is two LD2's joined together.

LD8-45 would suit an oval 7 abreast
LD6-45 would suit an oval 8 abreast.

Your design is half way between the two.
 
RJMAZ
Posts: 214
Joined: Sat Jul 09, 2016 2:54 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 7:22 am

NateGreat wrote:
I’m too lazy to read through everything, but will the 797 be a single-aisle or twin-aisle plane?

It will definitely be twin aisle. There has been multiple industry reports confirming this in other threads. Widebody with narrowbody economics has been quoted many times. Empty weight per passenger will have to be within 10% of an A320 or 737-8. Only one widebody aircraft has come close to that, the Airbus A300.

If I was a gambling man it will be nearly identical to the A300 is every dimension. Scaled down to maybe 95-96% and fully composite with the latest engines. The empty weight, fuel weight and max takeoff weight would be equal or slightly less than the A300.

So a tight 8 abreast perfectly circular fuselage. The LD3's in the A330 use all of the height under the cabin floor. So a slightly scaled down cross section would have less height for the container. They would then use narrower 767 LD2's. The LD2's can then sit slightly lower down in the fuselage to allow the cabin floor to be same spot.

The A300 has a cabin area of 215m2 at 88T empty weight. So we're looking at a cabin area of 200m2 at 80T empty as the average point of the MOM family.
 
parapente
Posts: 1937
Joined: Tue Mar 28, 2006 10:42 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 7:42 am

There seems to be NMA (new midrange aircraft)MOM (middle of market).NSA (new small/single aisle aircraft).Possibly more!
All depends on the thinking at the time.Someone linked an article to one of the threads recently that suggested that Boeing were going cold on the midrange aircraft and going back to a more classic NSA proposal but others in the article disagreed.So really hard to know quite what will emerge and or when frankly.
One gets a very firm impression - including from Boeing - that the mom/midrange proposal is/was for an aircraft seating between 250-270 pax with a range up to 5,500 nm.This would require engines in the (max) 50klbs class.Clearly an all new GTF engine.We know all 3 manufacturers are working on this .Either by what they have done,what they are doing or whom they have bought.
From what has been released/patents it is nearly certain this would be an ovoid fuse of twin aisle probably (but not certain) at 2x3x2 economy (2x2x2biz?)config.
The big question is how much market there is in this space over the next 30 years.Answers on a postcard!Nobody knows!we even hear of potential stop gap 767 orders.
If they 'back off' this route on the basis that it is 'too much aircraft ' and that the 737 cannot go on for ever then it is far more likely they would go for a single aisle solution i.e. The NSA.
Think that's a summary.
Oh and Airbus are sitting on their hands.But discussing paper 'plus and plus/plus' with clients which are upgrades (unknown) of the A320.
 
AirbusMDCFAN
Posts: 368
Joined: Sun Nov 27, 2016 10:51 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 8:18 am

Saudi Arabia has been identified is 1 possible fit for the 797, and the heavily traveled Jeddah - Riyadh route

Source/Link: https://www.bloomberg.com/news/articles ... ew-797-jet
 
parapente
Posts: 1937
Joined: Tue Mar 28, 2006 10:42 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 9:04 am

Articles in Reuters also read very bullishly.Positive noises from most parts of the globe now.All seem settled on a 220-270 pax with a squashed (their word) cabin cross section.Boeing talking about learnings from existing programs and manufacturing issues.It is probably a 'slam dunk' now with increasingly positive noises leading to a Farnbrough launch.
It has to be said that it does fit very well between the Max10 and the 788 in terms of both pax and range.Getting the price right will be the key.
 
WIederling
Posts: 4368
Joined: Sun Sep 13, 2015 2:15 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 9:26 am

william wrote:
For the uptemth time the airline have said they want a widebody.


customers invariably tell their wishes in scope of solutions they know.
Few can think abstract enough to not go that path.

So if you build what your customers want you get yesteryears airplane with maybe a bit modern stuff added.
IMU the 737 NG is the perfect example.

If you want to be better at your job of fulfilling your customer needs you
first have to back trace what kind of wish has really been made.
From there you can go forward and take newest tech and be really creative in designing
a fitting product.
That will not be what the customer envisioned but it will present what the customers needs.

here you have to ask : what properties make them want a WB layout?
Murphy is an optimist
 
brindabella
Posts: 234
Joined: Fri Apr 30, 2010 10:38 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 10:19 am

[quote="morrisond"

... In reality they may be forced to do two different fuselage widths ala 757/767 and then maybe they do go 8w on MOM and due a pure 6W NSA.


Hurry up and wait.

I[/quote]

My thoughts for a while has been for the recapitulation of the 757/767 development; but here having 8w MOM and 6w NSA.
With the aim again of saving say 30% due to commonality.
So having in mind that the MOM is substantially at least an A338 replacement for short-medium range (where the A300/A330 started, really),
it is interesting to see RJMAZ, iamlucky13 and yourself working on the MOM being directly competitive with the A321LR.

A task that I had assigned .to the NSA(!).

Thanks to you all,

cheers Bill

PS -but one last thing for you all - how about some graphics of fuse x-sections to go with the words?
Billy
 
User avatar
keesje
Posts: 10219
Joined: Thu Apr 12, 2001 2:08 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 10:41 am

I think Airbus would totally applaud Boeing investing in a big 797:

- 240-280 seats
- 2-3-2 cross section
- up to 5500NM range
- with the dying LD6 as cargo option,
- first flight 2024

Image

They would rule the huge segment 120-240 seat up to 4000NM for the foreseeable future, just enhancing / expanding the existing products for their existing customer base.
Last edited by keesje on Sun Nov 12, 2017 10:42 am, edited 1 time in total.
"Never mistake motion for action." Ernest Hemingway
 
Eyad89
Posts: 243
Joined: Fri Sep 02, 2016 10:47 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 10:43 am

RJMAZ wrote:
Widebody with narrowbody economics has been quoted many times.



That's the quote that I can't really understand. How's that even possible? whatever they use to improve the performance of a widebody can also be used to improve the performance of a nerrowbody. narrobody aircraft will always be ahead. Unless they are comparing a new widebody with an ancient narrowbody.
 
RJMAZ
Posts: 214
Joined: Sat Jul 09, 2016 2:54 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 11:09 am

Eyad89 wrote:
That's the quote that I can't really understand. How's that even possible? whatever they use to improve the performance of a widebody can also be used to improve the performance of a nerrowbody. narrobody aircraft will always be ahead. Unless they are comparing a new widebody with an ancient narrowbody.

It is very easy to achieve. A widebody can easily match the latest narrowbody aircraft in fuel burn per passenger. The key is per passenger. The extra fuel burn matches the extra passengers.

Nearly all widebody aircraft have been built to travel twice as far as an average narrowbody. So to carry twice as many passengers it needs four to five times as much fuel. The whole plane has to be heavier to carry all that weight. So on a short trip its flying with half fuel and lots of dead weight. This is the only reason these widebody aircraft can't match the economics of a narrowbody.

There has only ever been one widebody aircraft built light with similar range to a narrowbody. That is the Airbus A300. Even though it is 30 years old it is lighter per passenger than most of the current generation narrow bodies. We didn't have as much congestion back then. A new version would sell like hotcakes.
 
User avatar
keesje
Posts: 10219
Joined: Thu Apr 12, 2001 2:08 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 11:14 am

My thoughts for a while has been for the recapitulation of the 757/767 development; but here having 8w MOM and 6w NSA.
With the aim again of saving say 30% due to commonality.
So having in mind that the MOM is substantially at least an A338 replacement for short-medium range (where the A300/A330 started, really),
it is interesting to see RJMAZ, iamlucky13 and yourself working on the MOM being directly competitive with the A321LR.

A task that I had assigned .to the NSA(!).

Thanks to you all,

cheers Bill

PS -but one last thing for you all - how about some graphics of fuse x-sections to go with the words?


Image
"Never mistake motion for action." Ernest Hemingway
 
Jayafe
Posts: 583
Joined: Mon Jun 26, 2017 3:12 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 11:15 am

Eyad89 wrote:
RJMAZ wrote:
Widebody with narrowbody economics has been quoted many times.



That's the quote that I can't really understand. How's that even possible? whatever they use to improve the performance of a widebody can also be used to improve the performance of a nerrowbody. narrobody aircraft will always be ahead. Unless they are comparing a new widebody with an ancient narrowbody.


It's not, that's the trick (and the reason why it's still no more than powerpoint presentations. A long way ahead, if it ever happens...
 
Eyad89
Posts: 243
Joined: Fri Sep 02, 2016 10:47 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 11:47 am

RJMAZ wrote:
Eyad89 wrote:
That's the quote that I can't really understand. How's that even possible? whatever they use to improve the performance of a widebody can also be used to improve the performance of a nerrowbody. narrobody aircraft will always be ahead. Unless they are comparing a new widebody with an ancient narrowbody.

It is very easy to achieve. A widebody can easily match the latest narrowbody aircraft in fuel burn per passenger. The key is per passenger. The extra fuel burn matches the extra passengers.

Nearly all widebody aircraft have been built to travel twice as far as an average narrowbody. So to carry twice as many passengers it needs four to five times as much fuel. The whole plane has to be heavier to carry all that weight. So on a short trip its flying with half fuel and lots of dead weight. This is the only reason these widebody aircraft can't match the economics of a narrowbody.

There has only ever been one widebody aircraft built light with similar range to a narrowbody. That is the Airbus A300. Even though it is 30 years old it is lighter per passenger than most of the current generation narrow bodies. We didn't have as much congestion back then. A new version would sell like hotcakes.


Why compare A300 to current widebodies? We all agree that current widebodies are optimized for long flights. The question is: how good can a widebody that's optimized for short flights be when compared to narrowbodies. Then you need to compare A300 to A321 and see what you get for weight per passenger.

A300: OEW = 88,000 kg
default 2-class configuration: 247 seats
weight per passenger = 88t/247 = 356kg

A321: OEW = 48,000
default 2-class configuration: 185 seats
weight per passenger = 48t/185 = 259kg

The A300 is heavier per passenger by 37% !!

Now both planes here are old designs. A brand new A300 from Boeing would be lighter for sure, but so would a brand new A321 from Boeing. Narrowbodies will always be ahead in terms of weight per passenger as long as you apply the same level of weight reduction and optimization for both.
Last edited by Eyad89 on Sun Nov 12, 2017 11:49 am, edited 1 time in total.
 
RJMAZ
Posts: 214
Joined: Sat Jul 09, 2016 2:54 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 11:48 am

brindabella wrote:
My thoughts for a while has been for the recapitulation of the 757/767 development; but here having 8w MOM and 6w NSA.
With the aim again of saving say 30% due to commonality.
So having in mind that the MOM is substantially at least an A338 replacement for short-medium range (where the A300/A330 started, really),
it is interesting to see RJMAZ, iamlucky13 and yourself working on the MOM being directly competitive with the A321LR.

A task that I had assigned .to the NSA(!).

Thanks to you all,

cheers Bill

PS -but one last thing for you all - how about some graphics of fuse x-sections to go with the words?

Circular 8 abreast cross section.
Image


And the double bubble oval with lengths and ranges. Probably knock 5% off the ranges if it was made as a circular 8 abreast due to the extra drag.
Image

In regards to the NSA.

The 737 replacement NSA will probably look very similar in size to the current 737. It will just be lighter, using new manufacturing techniques.

The advantages of weight reduction is much bigger than you expect. A 10% reduction in empty weight by just changing to new materials is fairly realistic. This would reduce fuel burn by at least 5% due to fuel burn reducing the lighter the plane becomes. The total takeoff weight is now much lighter with the same amount of passengers as you have less fuel weight and less empty weight.

This has a knock on effect that you could now make the wing, engines and landing gear smaller and lighter as you are taking off at a lower weight. This happens when you optimise the design. So that 10% initial weight reduction will end up being more. So the 737-8 sized replacement will most likely be lighter, have a smaller wing, less internal fuel and lower thrust engines. All while flying the same number of passengers the same distance. So a big improvement in CASM.

The 6 abreast, lightweight and short ranged optimised design allows it to easily beat any potential CS500. You could not make a single wing family that could compete with both the CS500 and A321LR. That's why the MOM will sit slightly above the the medium range A321 and the NSA will sit just above the CS500.
 
parapente
Posts: 1937
Joined: Tue Mar 28, 2006 10:42 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 12:02 pm

When either manufacturer embarks on a brand new $10bn+ project they have to try (as best they can) to look up to 30 years into the future.Hardly easy,particularly in times of rapid change.Not a job I would relish!
It takes approx 10 years to develop,test and ramp up to full manufacturing speed.You need another 10 min years to get your investment back (of course it depends on costs and volume of sales).All being well you have a further 10+ years of printing money.Of course the accountants don't spread finance this way but it is crude way.
Obviously the further you look into the future the less certain you can be.This can be terrible-but sometimes changes 'come to you' .So you really don't want to be betting on those last years.
As for the 797 as it appears it will be (i.e. 220-270 pax one class with a max range of 5,500 nm -note max).
Well aircraft 'like'this have been around.A300,A310,B757-200/300 and 767-200 and of course 300 (er).So there is an historical legacy of 3,000 odd jets.So they are not invirgin territory.But that's the past/recent present.
Boeing can see the A321NEO with up to 240 seats doing well and they can see the 250 seats at up to 7,000nm loosing sales (heavy shrinks).
So it is hardly stupid to pop something in the middle once again.
Then you have the LCC market.Using Airbus as an example it's gone from A319 to A320 to A321 (even out to 240 seats.
So if that very solid trend continues -what next??.We know single aisles get really hard on turnaround after 230-240 seats.In 15-20 years might This type of a/c not be the new LCC of choice?
Not saying it will but it might.
 
Eyad89
Posts: 243
Joined: Fri Sep 02, 2016 10:47 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 12:02 pm

RJMAZ wrote:
brindabella wrote:
My thoughts for a while has been for the recapitulation of the 757/767 development; but here having 8w MOM and 6w NSA.
With the aim again of saving say 30% due to commonality.
So having in mind that the MOM is substantially at least an A338 replacement for short-medium range (where the A300/A330 started, really),
it is interesting to see RJMAZ, iamlucky13 and yourself working on the MOM being directly competitive with the A321LR.

A task that I had assigned .to the NSA(!).

Thanks to you all,

cheers Bill

PS -but one last thing for you all - how about some graphics of fuse x-sections to go with the words?

Circular 8 abreast cross section.
Image


And the double bubble oval with lengths and ranges. Probably knock 5% off the ranges if it was made as a circular 8 abreast due to the extra drag.
Image

In regards to the NSA.

The 737 replacement NSA will probably look very similar in size to the current 737. It will just be lighter, using new manufacturing techniques.

The advantages of weight reduction is much bigger than you expect. A 10% reduction in empty weight by just changing to new materials is fairly realistic. This would reduce fuel burn by at least 5% over the same trip. The total takeoff weight is now much lighter with the same amount of passengers as you have less fuel weight and less empty weight.

This has a knock on effect that you could now make the wing, engines and landing gear smaller and lighter as you are taking off at a lower weight. This happens when you optimise the design. So that 10% initial weight reduction will end up being more. So the 737-8 sized replacement will most likely be lighter, have a smaller wing, less internal fuel and lower thrust engines. All while flying the same number of passengers the same distance. So a big improvement in CASM.



In reference to the post that I just made, the current A321 would be much lighter per passenger than the proposed 797 in that photo. How can 797 stand a chance against the economics of narrowbodies then?

This 797 weight per passenger = 80,000/230 = 347 kg/passenger
That is 34% heavier per passenger than the current A321, imagine how bigger this difference can get if A321 was a brand new design that is made of CFRP. Oh, and I did not use a very dense configuration for the A321.

Speaking form a CASM point of view as you suggested, I don't get why Boeing would go for a widebody MOM. It would be at a clear disadvantage.
Last edited by Eyad89 on Sun Nov 12, 2017 12:19 pm, edited 3 times in total.
 
User avatar
Btblue
Posts: 649
Joined: Thu Mar 18, 2004 4:57 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 12:14 pm

A variety of sources claim Boeing can produce a twin aisle aircraft with single aisle economics. If Boeing can do that, then surely airlines must be asking what the economic possibilities are for single aisle jet, of similar size to the 757-200/300 that is lighter?
 
RJMAZ
Posts: 214
Joined: Sat Jul 09, 2016 2:54 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 12:44 pm

Eyad89 wrote:
In reference to the post that I just made, the current A321 would be much lighter per passenger than the proposed 797 in that photo. How can 797 stand a chance against the economics of narrowbodies then?

You are not using realistic seating comparisons.

The 797-10 in that photo is the same length as a A330-200, but with a 5metre wide cabin. That is a massive 250m2 of cabin space.

The A321 has only 127m2 which is roughly half.

The A321 is 50T. The 797-10 at 80T is much lighter per cabin area.

In all economy 28" pitch you'd have over 400 seats in that 797-10. Compare that to 240 in the A321.

The 797-10 would beat narrowbody on CASM, flying the same range. It would be used for short thick routes to replace narrowbody flights 2 into 1. It would most likely have a higher density seating.

The 797-9 would match narrow bodies on CASM but fly slightly further. Great for transatlantic where narrow bodies are payload limited.

The 797-8 would have worse CASM than a narrowbody but still beat the larger widebody. It would make a great medium to long haul aircraft on thin routes. It would generally have more spacious seating and more business class seats. It even has enough range to fly from: Asia to Europe. Australia to Japan, western Europe to deeper in the USA. East coast US to deeper into Europe. The ME3 from its hubs can still cover all of Asia and Europe with the 797-8. So it could open up many secondary cities as its 30% smaller than a 787-8.
 
User avatar
william
Posts: 2018
Joined: Thu Jun 10, 1999 1:31 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 1:06 pm

Eyad89 wrote:
RJMAZ wrote:
Eyad89 wrote:
That's the quote that I can't really understand. How's that even possible? whatever they use to improve the performance of a widebody can also be used to improve the performance of a nerrowbody. narrobody aircraft will always be ahead. Unless they are comparing a new widebody with an ancient narrowbody.

It is very easy to achieve. A widebody can easily match the latest narrowbody aircraft in fuel burn per passenger. The key is per passenger. The extra fuel burn matches the extra passengers.

Nearly all widebody aircraft have been built to travel twice as far as an average narrowbody. So to carry twice as many passengers it needs four to five times as much fuel. The whole plane has to be heavier to carry all that weight. So on a short trip its flying with half fuel and lots of dead weight. This is the only reason these widebody aircraft can't match the economics of a narrowbody.

There has only ever been one widebody aircraft built light with similar range to a narrowbody. That is the Airbus A300. Even though it is 30 years old it is lighter per passenger than most of the current generation narrow bodies. We didn't have as much congestion back then. A new version would sell like hotcakes.


Why compare A300 to current widebodies? We all agree that current widebodies are optimized for long flights. The question is: how good can a widebody that's optimized for short flights be when compared to narrowbodies. Then you need to compare A300 to A321 and see what you get for weight per passenger.

A300: OEW = 88,000 kg
default 2-class configuration: 247 seats
weight per passenger = 88t/247 = 356kg

A321: OEW = 48,000
default 2-class configuration: 185 seats
weight per passenger = 48t/185 = 259kg

The A300 is heavier per passenger by 37% !!

Now both planes here are old designs. A brand new A300 from Boeing would be lighter for sure, but so would a brand new A321 from Boeing. Narrowbodies will always be ahead in terms of weight per passenger as long as you apply the same level of weight reduction and optimization for both.


Nice summary, the return of the domestic widebody that will sell well in Asia and the USA. Your summary of the 737 situation is interesting too. It would explain why Boeing passed on the CS when given the oppurtunity to buy it. Next gen NB will be out probably 10-15 years and one can start clean with slate family of aircraft.
 
User avatar
william
Posts: 2018
Joined: Thu Jun 10, 1999 1:31 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 1:10 pm

WIederling wrote:
william wrote:
For the uptemth time the airline have said they want a widebody.


customers invariably tell their wishes in scope of solutions they know.
Few can think abstract enough to not go that path.

So if you build what your customers want you get yesteryears airplane with maybe a bit modern stuff added.
IMU the 737 NG is the perfect example.

If you want to be better at your job of fulfilling your customer needs you
first have to back trace what kind of wish has really been made.
From there you can go forward and take newest tech and be really creative in designing
a fitting product.
That will not be what the customer envisioned but it will present what the customers needs.

here you have to ask : what properties make them want a WB layout?


What you state is true to a certain point. One may think he or she knows more than the customer but its the customer who is doing the buying. If one cannot achieve NB economics in a WB its best to tell the customer that and move on to the NB MOM. However, Boeing has yet to tell the airlines "no". There are articles in which the airlines have told Boeing they are not interested in a Boeing A321 for a MOM.
 
User avatar
keesje
Posts: 10219
Joined: Thu Apr 12, 2001 2:08 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 1:56 pm

Btblue wrote:
A variety of sources claim Boeing can produce a twin aisle aircraft with single aisle economics. If Boeing can do that, then surely airlines must be asking what the economic possibilities are for single aisle jet, of similar size to the 757-200/300 that is lighter?


Boeing might as well proceed developing a VLA with twin aisle economics and a NB with regional economics.

I think a A330-900 vs. 787-9 (moonshot) review demonstrates we shouldn't fly blind on PR promises from an OEM.

There are articles in which the airlines have told Boeing they are not interested in a Boeing A321 for a MOM


Which articles? Boeing has been scrambling to find an A321 answer for years and the airlines' orderbooks tell more than moderately objective articles quoting them.
"Never mistake motion for action." Ernest Hemingway
 
User avatar
seahawk
Posts: 5694
Joined: Fri May 27, 2005 1:29 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 2:10 pm

Sale numbers favour the moonshot...
 
Eyad89
Posts: 243
Joined: Fri Sep 02, 2016 10:47 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 2:15 pm

RJMAZ wrote:

You are not using realistic seating comparisons.

The 797-10 in that photo is the same length as a A330-200, but with a 5metre wide cabin. That is a massive 250m2 of cabin space.

The A321 has only 127m2 which is roughly half.

The A321 is 50T. The 797-10 at 80T is much lighter per cabin area.

In all economy 28" pitch you'd have over 400 seats in that 797-10. Compare that to 240 in the A321.

The 797-10 would beat narrowbody on CASM, flying the same range. It would be used for short thick routes to replace narrowbody flights 2 into 1. It would most likely have a higher density seating.

The 797-9 would match narrow bodies on CASM but fly slightly further. Great for transatlantic where narrow bodies are payload limited.

The 797-8 would have worse CASM than a narrowbody but still beat the larger widebody. It would make a great medium to long haul aircraft on thin routes. It would generally have more spacious seating and more business class seats. It even has enough range to fly from: Asia to Europe. Australia to Japan, western Europe to deeper in the USA. East coast US to deeper into Europe. The ME3 from its hubs can still cover all of Asia and Europe with the 797-8. So it could open up many secondary cities as its 30% smaller than a 787-8.



Oh no, the seating I used are from real airlines who operate A321. I only used the A321 with 185 seats. Many airlines already fly much more than 185 in their A321s.

Comparing cabin area between 797 and a narrowbody does not make sense, simply because 797 has two aisles. So a considerable portion of its area will be wasted in that extra aisle. The area you calculated for 787-10 is not all usable. It is more fair if we stick to comparing realistic seating configuration.

797-10 has an OEW of 85000 kg, and A321 has Almost HALF that OEW at 48000kg. To be more exact, that’s 56% of the weight of 797-10. Basically, the only way for 797-10 to match weight per passenger of A321 is if A321 offers 56% of 797-10 seats. That means A321 has only to offer 145 seats for this to be true. That is less than even what A320 offers.

Basic math shows that 797-10 cannot even beat current A320 when it comes to weight per passenger, how can you say it even beats A321? It just does not make sense in numbers.

More importantly, we are comparing 797-10 to the A320 family. They are not CFRP planes. Remeber, Boeing is designing a CFRP planes. Imagine how bigger this difference would get.
 
User avatar
par13del
Posts: 7347
Joined: Sun Dec 18, 2005 9:14 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 2:29 pm

The issue with widebody versus narrow body is not whether the widebody is heavier or has a greater weight per pax, it is whether the benefits it brings out-weighs the negatives and how much Boeing can reduce the differential. So far everyone is quick to point out the negative, how about the positives. Widebody a/c are abused on short range runs on a daily basis, whether positioning flights or to add temporary capacity, if these are all loss making flights then yes, a dedicated widebody a/c for those flights would be an economic disaster, but do we know if that is true?
 
Newbiepilot
Posts: 2078
Joined: Tue Aug 30, 2016 10:18 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 2:36 pm

keesje wrote:
I think Airbus would totally applaud Boeing investing in a big 797:

- 240-280 seats
- 2-3-2 cross section
- up to 5500NM range
- with the dying LD6 as cargo option,
- first flight 2024

Image

They would rule the huge segment 120-240 seat up to 4000NM for the foreseeable future, just enhancing / expanding the existing products for their existing customer base.


I commend you for finding a way to spin this in a positive direction for Airbus even if the cargo container discussion is kind of silly.

First of all, 57% market share for the A320neo based on backlog is not ruling a huge segment. The 737MAX has 43% of the backlog for the MAX vs NEO so those planes are very competitive. Airbus hasn't publicly said much about new developments for the A321 beyond the LR versions which is only a 7,000lbs MTOW boost, which isn't that much of a change. They keep reiterating it is their MoM plane and are happy with that. Their opinion might change now that the 737-10 is launched and if a NMA gets launched.

A widebody as discussed would severely impact the A330neo. Many A330s are flying regional routes and a new plane optimized for shorter missions would have implications on the A330neo since it would be squeezed from above by the 787 payload/efficiency in longer missions and the NMA from below.

I am excited to see what a new plane would bring. I don't think Airbus is applauding at all since they will be forced to respond.
 
User avatar
lightsaber
Moderator
Posts: 13132
Joined: Wed Jan 19, 2005 10:55 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 2:45 pm

seahawk wrote:
That plane would not even be able to take the luggage from the pax in a eco heavy configuration. And if you start hand loading the baggage, the fast turn around promised by the twin aisle is gone.

The 2-4-2 twin will have a longer cargo hold than the 767 thanks to modern design tools. So it will easily have enough cargo room. Oh, the tail will be hand loaded, but hand loading the tail in an all Y configuration isn't a big deal time wise.

Do recall the 767 lacked a modern fly by wire system. That required the center of gravity be far ahead of the center of lift. With fly by wire, the landing gear will be better placed allowing more cargo room and the tail can be more filled with bags.

Of course, I expect a modern additive manufacturing rear bulkhead, so we should expect another row or so of seating. I also expect a plane heavily optimized for use without crew rests or provisions to add them. Oh, Perhaps copy Airbus with a bunk under the cockpit, but that would be it.

With folding wingtips, the wingbox will be optimized for not only weight, but maximizing cargo. The wings will hold the fuel (perhaps some in the center, perhaps not, I would bet for a later MTOW increase a la A332).

I can say the 2-3-2 will not happen. The 2-4-2 as proposed (inch narrower isles, 1/2 inch narrower seats) is certain. People will not pay for a luxurious Y. It is also more practical configuration for J.

Lightsaber

May I hope for a 2-3-2 Y+? :hyper: Now that should please everyone! For Y+ will be at the old school fares while offering a bit more width, legroom, and hopefully catering than the old school Y.

I had hopes to hear more news by now...

Lightsaber
You only have the first amendment with the 2nd. If you're not going to offend someone with what you say, you don't have the 1st.
 
User avatar
lightsaber
Moderator
Posts: 13132
Joined: Wed Jan 19, 2005 10:55 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 2:52 pm

par13del wrote:
The issue with widebody versus narrow body is not whether the widebody is heavier or has a greater weight per pax, it is whether the benefits it brings out-weighs the negatives and how much Boeing can reduce the differential. So far everyone is quick to point out the negative, how about the positives. Widebody a/c are abused on short range runs on a daily basis, whether positioning flights or to add temporary capacity, if these are all loss making flights then yes, a dedicated widebody a/c for those flights would be an economic disaster, but do we know if that is true?

Just to expand:
1. The widebody will add weight for a wing more efficient in cruise.
2. The widebody will have higher bypass engines that are optimized for longer cruise (climb fuel burn penalty due to weight and low spool off optimum mach # more due to larger fan). Engines will also cost more per cycle, but less per hour for maintenance.
3. The widebody carries extra weight for the width. Just as a longer bridge is heavier per foot, so is a wider plane heavier per foot of width.

The 797 will have poor economics on less than 3 hour runs. But I expect it to be optimized well for 3 hour runs.

I'm still not certain on a widebody for the 797, but I'm warming up to the idea.

Lightsaber
You only have the first amendment with the 2nd. If you're not going to offend someone with what you say, you don't have the 1st.
 
User avatar
keesje
Posts: 10219
Joined: Thu Apr 12, 2001 2:08 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 4:16 pm

Eyad89 wrote:
RJMAZ wrote:

You are not using realistic seating comparisons.

The 797-10 in that photo is the same length as a A330-200, but with a 5metre wide cabin. That is a massive 250m2 of cabin space.

The A321 has only 127m2 which is roughly half.

The A321 is 50T. The 797-10 at 80T is much lighter per cabin area.

In all economy 28" pitch you'd have over 400 seats in that 797-10. Compare that to 240 in the A321.

The 797-10 would beat narrowbody on CASM, flying the same range. It would be used for short thick routes to replace narrowbody flights 2 into 1. It would most likely have a higher density seating.

The 797-9 would match narrow bodies on CASM but fly slightly further. Great for transatlantic where narrow bodies are payload limited.

The 797-8 would have worse CASM than a narrowbody but still beat the larger widebody. It would make a great medium to long haul aircraft on thin routes. It would generally have more spacious seating and more business class seats. It even has enough range to fly from: Asia to Europe. Australia to Japan, western Europe to deeper in the USA. East coast US to deeper into Europe. The ME3 from its hubs can still cover all of Asia and Europe with the 797-8. So it could open up many secondary cities as its 30% smaller than a 787-8.



Oh no, the seating I used are from real airlines who operate A321. I only used the A321 with 185 seats. Many airlines already fly much more than 185 in their A321s.

Comparing cabin area between 797 and a narrowbody does not make sense, simply because 797 has two aisles. So a considerable portion of its area will be wasted in that extra aisle. The area you calculated for 787-10 is not all usable. It is more fair if we stick to comparing realistic seating configuration.

797-10 has an OEW of 85000 kg, and A321 has Almost HALF that OEW at 48000kg. To be more exact, that’s 56% of the weight of 797-10. Basically, the only way for 797-10 to match weight per passenger of A321 is if A321 offers 56% of 797-10 seats. That means A321 has only to offer 145 seats for this to be true. That is less than even what A320 offers.

Basic math shows that 797-10 cannot even beat current A320 when it comes to weight per passenger, how can you say it even beats A321? It just does not make sense in numbers.

More importantly, we are comparing 797-10 to the A320 family. They are not CFRP planes. Remeber, Boeing is designing a CFRP planes. Imagine how bigger this difference would get.


Years ago I guestimated a stretched, rewinged A321 would weigh 55-56t OEW. It would be a 4-5 row stretch. While it doesn't exist, few doubt it's doable with existing technology.

http://www.cardatabase.net/modifiedairlinerphotos/search/photo_search.php?id=00015369

Skilled Boeing analysts and engineers wouldn't have a problem deriving basic specs, costs, performance without having to know the details. As was reported, Airbus hasn't been sitting on it's hands and could pre-empt again soon.

https://leehamnews.com/2017/05/10/airbus-can-kill-boeing-797/
"Never mistake motion for action." Ernest Hemingway
 
User avatar
KarelXWB
Moderator
Posts: 25527
Joined: Sun Jul 15, 2012 6:13 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 4:23 pm

Newbiepilot wrote:
I don't think Airbus is applauding at all since they will be forced to respond.


I'm not entirely convinced Airbus will be "forced" to respond. It's not unthinkable that Airbus could give the MOM market away to Boeing, and focuses on other areas of the aviation market.
What we leave behind is not as important as how we've lived.
 
User avatar
Revelation
Topic Author
Posts: 16456
Joined: Wed Feb 09, 2005 9:37 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 6:26 pm

Bloomberg ( https://www.bloomberg.com/news/articles ... ew-797-jet ) has an article about how the 797 might play out in Saudi's fleet. Not much news in the article, IMHO, but does give us the CEO's view of where the program currently is:

Boeing has been holding talks with possible customers on how it should build the aircraft, which would be the company’s first all-new design since the 787 Dreamliner, said commercial airplanes chief Kevin McAllister. The company is studying whether there’s enough of a business case to justify the development costs.

Customers have got a really good idea what they’re looking for,” he said. “I think the middle of the market will be a terrific aircraft. We like how it’s shaping up, we’re just down to a spot where we want to put some structure around getting the right business plan.

No surprise to many of us, it's far from a slam-dunk in terms of the business plan.
The gun is NOT a precious symbol of freedom
It is a deadly cancer on American society
Those who believe otherwise are consumed by an ideology
That is impervious to evidence
 
User avatar
KarelXWB
Moderator
Posts: 25527
Joined: Sun Jul 15, 2012 6:13 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 7:57 pm

Revelation wrote:
No surprise to many of us, it's far from a slam-dunk in terms of the business plan.


Indeed. Boeing has been talking about "getting the right business plan" for years.

One might wonder why Boeing and Airbus always wait so long to launch a new aircraft, up until the point they have no other choice.
What we leave behind is not as important as how we've lived.
 
DfwRevolution
Posts: 8985
Joined: Sat Jan 09, 2010 7:31 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 8:09 pm

KarelXWB wrote:
One might wonder why Boeing and Airbus always wait so long to launch a new aircraft, up until the point they have no other choice.


Are you being sarcastic?

Launching an all-new airplane program is a massive decision that will consume tens of billions of dollars and commit the business to a strategy for the next quarter century. For many board members and executives, it's the biggest vote they will make in their entire career and not one to be taken lightly. They cannot be wrong.
I have a three post per topic limit. You're welcome to have the last word.
 
User avatar
KarelXWB
Moderator
Posts: 25527
Joined: Sun Jul 15, 2012 6:13 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 8:12 pm

DfwRevolution wrote:
Launching an all-new airplane program is a massive decision that will consume tens of billions of dollars and commit the business to a strategy for the next quarter century. For many board members and executives, it's the biggest vote they will make in their entire career and not one to be taken lightly. They cannot be wrong.


And yet many people argue that A350/777X/A330neo/MOM should have been launched earlier. At some point the aircraft may arrive too late on the market, like the 757-300.
What we leave behind is not as important as how we've lived.
 
User avatar
keesje
Posts: 10219
Joined: Thu Apr 12, 2001 2:08 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 8:14 pm

Image

If the lower fuselage would be just a bit higher, circular, it would be lighter and it could optionally take the same LD3 containers / pallets as the 787, 777 and A350s. If it has high BPR engines, it would have high main landing gears anyway.

:wink2:
"Never mistake motion for action." Ernest Hemingway
 
NateGreat
Posts: 38
Joined: Thu Sep 28, 2017 6:02 pm

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 8:35 pm

[photoid][/photoid]
keesje wrote:
Image

If the lower fuselage would be just a bit higher, circular, it would be lighter and it could optionally take the same LD3 containers / pallets as the 787, 777 and A350s. If it has high BPR engines, it would have high main landing gears anyway.

:wink2:

Where did you find that graphic? Did Boeing make that?
 
User avatar
Stitch
Posts: 24631
Joined: Wed Jul 06, 2005 4:26 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 9:08 pm

KarelXWB wrote:
And yet many people argue that A350/777X/A330neo/MOM should have been launched earlier. At some point the aircraft may arrive too late on the market, like the 757-300.


Well the 757-300 was a derivative of an existing design developed for high-traffic routes and introduced shortly before a worldwide crash in passenger traffic due to factors including 9/11 and SARS.

The 787 and A350 both landed right in the sweet spot of the 200-300 seat replacement market currently filled with the 767-300, 777-200, A330-200, A330-300 and A340-300.

The A330-800 and A330-900 probably were launched too late, but they were also low-risk reactionary moves to the failure of the A350-800 as an A332/A333 replacement, which risked the 787 taking the majority of that replacement market.

The 777X is a high-risk reactionary move to the A350-1000 and one could argue Boeing could have offered it earlier than they did, but the 777-300ER was still selling quite well due to performance, economics and availability until the mid-2010s and that is when Boeing pulled the trigger.
 
RJMAZ
Posts: 214
Joined: Sat Jul 09, 2016 2:54 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 9:18 pm

Eyad89 wrote:
Oh no, the seating I used are from real airlines who operate A321. I only used the A321 with 185 seats. Many airlines already fly much more than 185 in their A321s.

Comparing cabin area between 797 and a narrowbody does not make sense, simply because 797 has two aisles. So a considerable portion of its area will be wasted in that extra aisle. The area you calculated for 787-10 is not all usable. It is more fair if we stick to comparing realistic seating configuration.

797-10 has an OEW of 85000 kg, and A321 has Almost HALF that OEW at 48000kg. To be more exact, that’s 56% of the weight of 797-10. Basically, the only way for 797-10 to match weight per passenger of A321 is if A321 offers 56% of 797-10 seats. That means A321 has only to offer 145 seats for this to be true. That is less than even what A320 offers.

Basic math shows that 797-10 cannot even beat current A320 when it comes to weight per passenger, how can you say it even beats A321? It just does not make sense in numbers.

More importantly, we are comparing 797-10 to the A320 family. They are not CFRP planes. Remeber, Boeing is designing a CFRP planes. Imagine how bigger this difference would get.

Wrong wrong wrong.

I am the person that made both graphics. So I can tell you now you aren't comparing similar seat density. I calculated those seat values with lower seat density than all of the narrowbody comparisons you have looked at. We're talking a lie flat business class in my graphic. No narrowbody offers this. The 797-10 being the shortest range would not require lie flat seats, but I kept density consistent across all three models.

Both widebody designs have aisles that are narrower than the A320. With 8 abreast you effectively have two 4 abreast cabins so the aisle can be narrower like a 4 abreast regional. You must calculate aisle area per seat.

With 17.5inch economy seats you are looking at two 16inch aisles on the oval 797 design vs one 22inch aisle in the A320. With 18inch wide seats the A320 has a 19inch aisle and the 797 would require tight 14inch aisles.

Let's compare with the 17.5inch seats.
797 32inch of aisle for 8 seats = 4" per seat
A320 22inch of aisle for 6 seats = 3.66" per seat

So the 797 only has 10% extra aisle area per seat, far from double. This is why 8 abreast is superior to 7 abreast options as the extra aisle is worth it.

The 797-10 has the same 45m cabin length as the A330-200 both with 8 abreast. Most A332 are fitted with a long haul cabin, where as the 797-10 would be used for short haul. Expect well over 300+ seats in the 797-10.

Now let's compare using the exact same recliner business class seats that the narrowbody aircraft use.

https://www.seatguru.com/airlines/Ameri ... 21_V3.php#

This A321 has 187 seats only 8.5% business class.
Business: 16 recliner 4 rows 21" wide, 36" pitch
Economy: 171 with 30 rows average 32" pitch

The 797-10 with 8.5% business has 350 seats
Business: 30 seats 5 rows 2-2-2, 21" wide, 36" pitch
Economy: 320 seats 40 rows with 32" pitch.

797-10: 85T with 350 seats = 242kg per seat
A321LR - 50.8T with 187 seats = 271kg per seat

As you can see the 797-10 smashes every single narrowbody made. Even a carbon fibre wing on the 737 or A321 families would not help them. Empty weight per passenger is the most important factor for short range CASM. In fact it is even more important than engine efficiency. Engine efficiency becomes the most important at much longer ranges.

Now that you can see my I am right you might try and counter saying my empty weights are too low. Look up the A300 weights. My design is 5% narrower but 8% longer cabin, so similar structural volume. So the 5% reduction comes from using composites. If anything 85T is conservative.
Last edited by RJMAZ on Sun Nov 12, 2017 9:32 pm, edited 1 time in total.
 
RJMAZ
Posts: 214
Joined: Sat Jul 09, 2016 2:54 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 9:28 pm

keesje wrote:
If the lower fuselage would be just a bit higher, circular, it would be lighter and it could optionally take the same LD3 containers / pallets as the 787, 777 and A350s. If it has high BPR engines, it would have high main landing gears anyway.

Image
Here is the A330 circular cross section with LD3 containers. Look how tight it is and how high the floor has to be. You want the floor lower so the widest point is at elbow level. Considering my 8 abreast 797-10 is a foot narrower than the A330 even if it was full circular you could not fit LD3's. The floor would have to be at the 50% mark, so the widest point of the cabin would be at floor level.

Using LD2's which are the same height but narrower than the LD3 would allow them to sit slightly lower down in the fuselage. But still that would require a fully circular fuselage. I actually think this is the most likely cross section 8ab, 5m cabin width, circular fuselage with LD2's.

If you want an oval design you can only use LD3-45's. Or maybe a custom container the same height as an LD3-45 but slightly wider. This would be highly likely if they plan on building 1000+.

I'd say 60% chance of circular 8ab with ld2's. 35% chance of oval double bubble, and 5% pure oval. 0% chance of 7ab as it cant reach narrowbody casm. 0% chance of 6ab as it can't reach the passenger requirement for upgauging short thick narrowbody routes. It would need 757-300 length.
Last edited by RJMAZ on Sun Nov 12, 2017 9:43 pm, edited 1 time in total.
 
User avatar
keesje
Posts: 10219
Joined: Thu Apr 12, 2001 2:08 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 9:42 pm

I think it's about the money. This aircraft maybe won't burn less, misses out on cargo and can't flexibly be used on slightly longer routes. Maybe the cheaper, directly available 2-4-2 A330 fuselage ain't so bad. But most of all, 2-4-2 of some lenght seem not to cover most of the market inbetween 737 and 787.
"Never mistake motion for action." Ernest Hemingway
 
RJMAZ
Posts: 214
Joined: Sat Jul 09, 2016 2:54 am

Re: Boeing officially forms program office to flesh out 797 plans

Sun Nov 12, 2017 10:12 pm

keesje wrote:
I think it's about the money. This aircraft maybe won't burn less, misses out on cargo and can't flexibly be used on slightly longer routes. Maybe the cheaper, directly available 2-4-2 A330 fuselage ain't so bad. But most of all, 2-4-2 of some lenght seem not to cover most of the market inbetween 737 and 787.

I don't think it misses out on cargo at all even if it uses LD3-45's. The 797 is much longer, the shortest 797-8 is still longer than the A321.

The A319, A320 and A321 can fit 5, 7 and 10 LD3-45 containers. The A321LR has three aux tanks allowing only 7 containers.

My oval 797-8, 9 and 10 design would have 9, 13 and 17 ld3-45 containers.

That is just as much cargo space per passenger than the A320 family and much more space than the A321LR with its aux tanks.

If a custom container is made that is 25% wider it would have far more cargo than any narrowbody.

The shortest 797-8 being lighter but having the same max takeoff weight it has a fair bit of excess payload capacity. If a premium low density seating option is used they could even fit an aux fuel tank making a 797-8LR. This would push range up towards 6000nm. It would be a niche aircraft for long and thin routes that lots of members here love.

Who is online

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

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

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

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

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

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

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos