jagraham
Posts: 215
Joined: Sun Jul 17, 2016 11:10 pm

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

Wed Dec 06, 2017 10:13 pm

JustSomeDood wrote:
seahawk wrote:
Imho the big problem is that there seem to be 2 camps of interested airline when it comes to range. One looks at something with around 3000nm range, the other at something at 5000nm+ as a 763ER replacement.

The problem is both seem to prefer a similar seat number, yet with very different cabin space requirements. The problem is that the longer ranged variant is also the one needing more cabin space, so that there is easy trade-off possible.


I won't be so sure of that, the Asian/Indian carriers that want 3000nm people-haulers are also the sort of carriers where adding frequency isn't really an option. If B is thinking of committing to a clean-sheet wide body design anyways. It might be pertinent for them to design and market the stretch as a replacement of 2 narrowbodies (i.e 320-340 seats in low-J narrowbody configuration), and lop off enough frames to satisfy EU/US range requirements to avoid cannibalizing on 787 sales.


Which Asian / Indian carriers are we talking about? The ones who can buy more than 100 airplanes have already loaded up on narrowbodies.

For the record, I think range on a 797 should top out at 5000 nm. And perhaps be a bit less. Because when you get above 5000 nm, you have to carry enough fuel - and have enough takeoff power - that the difference between a 5000+ nm plane and a shrunken 789 (they should really shrink the 789 and end the 788 they make now) is not enough to warrant the development expense. Except perhaps taking the 3rd spar out of the wing. Which is still a 787 of some sort
 
jagraham
Posts: 215
Joined: Sun Jul 17, 2016 11:10 pm

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

Wed Dec 06, 2017 10:22 pm

Stitch wrote:
jagraham wrote:
3000 nm is the exact distance from JFK to LHR. Still air. No reserves. A plane designed for 3000 nm pax and bags only will be very marginal - see Leeham's analysis of the A321LR carrying 206 pax between JFK and LHR. Also, lie-flat seats have become a competitive feature over the Atlantic and only the ULCCs will fly across the Atlantic without lie-flat seats now.


And that appears to be where the contention is.

The US3 and EU LCCs appear to want 5000nm so they can do TATL.

The Asian, Indian and Chinese appear to want 3000-3500nm as it nicely covers their part of the world. 3000nm would also be perfect for Australian domestic and Trans-Taz.



I think the same plane will do fine for both. Except the 5000nm needs to be about 4500nm.

The US and EU airlines for the most part will fly less dense. The current 763 files about 220 this way and the A332 flies about 240. With the newer lie flat seats.

The Asian, Indian, and Chinese will pack them in. An A332 over there will have 290 to 350 people on it.

That's 5000 to 11000 extra kg for the Far East carriers. Should lop off about 500 to 1000 nm.
 
fcogafa
Posts: 1036
Joined: Fri May 16, 2008 4:37 pm

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

Wed Dec 06, 2017 11:06 pm

Spirit Aerosystems are upgrading their facility and hope to be a contractor for the 797

https://www.flightglobal.com/news/artic ... on-443938/
 
jagraham
Posts: 215
Joined: Sun Jul 17, 2016 11:10 pm

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

Wed Dec 06, 2017 11:32 pm

Newbiepilot wrote:
Polot wrote:
Newbiepilot wrote:

A high value and low value don’t tell the whole story. A 767-300ER with useable life left (under around 30K cycles and 80K hours) has seen its value on the used market jump. That type of plane may be worth $15M-20M or more. If used prices hold due to freighter demand, it may be worthwhile to buy a new one with the intention of only flying it for 6-12 years and then selling to ATSG/ABX/Atlas/UPS/SF etc. Before Amazon and its partners bought 40+ Used 767-300ERs, the same plane may have been worth $10M or less and the idea of buying new and selling after 6-12 years was less attractive.

Its current popularity is actually reflected in the that post. Look at the high (newest frame) estimated market value for the pax 767-300ER. Now look one line down at the high estimated value of the larger, more expensive, 777-200ER. That is because of the current desirability of lightly used 763s for freighter conversion. The newest pax 763ER is of similar age to the newest pax 77E.


Good point. I didn’t notice that the high value 767-300ER is worth more than the bigger 777-200ER. That is a big clue on why the 767 passenger production may get restarted and also there is interest in this capacity segment that the MOM is targeting.


A "cheap" enhancement for the 767 would be to put GEnx2 engines on the 764. The extra height of the landing gear allows for a drop in installation. The GEnx2 is only 300 lb heavier than a RB211, so the wing should be able to take it. The 764 has a 777 flightdeck so talking to a GEnx2 should be a breeze. And it's easier to shrink an aircraft than to grow it. Only problem is that the 764 gets quite close to a 788 that way.
 
User avatar
NeBaNi
Posts: 141
Joined: Sun Dec 20, 2009 10:45 am

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

Thu Dec 07, 2017 1:03 am

keesje wrote:
A few months I posted this, to illustrate the enormous improvements that R&D has brought us over the last 40 years

Resulting in top notch design and innovation, combining better costs and environmental friendly technology to safeguard our earth for future generations.

Image

Now indications are the 1981 one might already be the top notch technology needed for a sustainable solution .

A testament to excellence, foresight & innovation in aerospace. Fantastic :cloudnine:

Don't inhale unless accessary

And once again, I'll repeat my answer to you the last time you posted this:
Literally all of the "green" designs in the pic you posted are NOT envisioned to enter into service next decade. They were designed with the technology (assumptions/ predictions) of 2030s in mind.
So why are you trying to mislead with that picture?
 
RJMAZ
Posts: 282
Joined: Sat Jul 09, 2016 2:54 am

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

Thu Dec 07, 2017 2:20 am

jagraham wrote:
A "cheap" enhancement for the 767 would be to put GEnx2 engines on the 764. The extra height of the landing gear allows for a drop in installation. The GEnx2 is only 300 lb heavier than a RB211, so the wing should be able to take it.

Genx2 is WAY bigger

763 engine - 3900kg - 86" fan - 50klb thrust
764 engine - 4400kg - 93" fan - 59klb thrust
Genx2 - 5600kg - 105" fan - 66klb thrust

The A330NEO actually burns more fuel on a trip below 1000nm compared to the older A330CEO. The NEO weighs 5T more empty. The same thing would happen with the 767 using genx2. You would be better off keeping the current light engines as a lot of the trips would be around 1000nm.

There are no engines available in the size/weight/thrust range required. If Boeing wanted a new engine, Rolls-Royce could deliver the quickest with its Trent 1500. This was planned for the A340NEO.

A scaled down genx would be ideal but it would need to be a clean sheet design. Simply putting a smaller fan on the genx2b67 wouldn't save much weight as the core would be the same.
 
2175301
Posts: 1045
Joined: Wed May 16, 2007 11:19 am

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

Thu Dec 07, 2017 3:23 am

LockheedBBD wrote:
Leeham says that the NMA is being pushed back to 2027: https://leehamnews.com/2017/12/04/boein ... 7-sources/

Now we have another decade on this thread to speculate! :white: :tombstone:



Not really: I don't know who is really surprised by this. In reality saying it will take 10 years to develop and certify an aircraft is reasonable.

As for the speculation on what it will look like and key features... We will know that when they announce it; which could easily be within a year.

Have a great day,
 
2175301
Posts: 1045
Joined: Wed May 16, 2007 11:19 am

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

Thu Dec 07, 2017 5:41 am

There seems to be an endless debate about narrow-body vs wide-body and various trade offs; and of course how Airbus could respond (which has it's own thread).

It is my understanding that one of the commonly stated problems with an 8 abreast 2 isle wide-body extreme oval (no or minimum cargo) is that the extra reinforcement in the floors, structure, and walls needed to keep the shape at altitude with the aircraft pressurized (with the cabin being pushed towards a circle). That common argument is that the weight required for such reinforcement outweighs the advantages.

On the "Airbus weighs response if Boeing launches new mid-market model" thread I posted what to me (as an engineer) is an obvious answer to that on November 25.

"What IF... Boeing comes up with an 8 abreast carbon fiber ovoid with periodic vertical reinforcements down the center to keep the carbon fiber hull weight down. Not great for cargo; but would be great for passengers service. I'm betting that they are at least looking at that; and if that is their final proposal I have no idea how Airbus responds except to duplicate the base design."

Putting some more thought into that... I realizes just how beneficial using center-line vertical (normally in tension) reinforcement could be. Here are some further thoughts on how it could be done:

First. In order to support various cabin arrangements there could be a series of vertical anchor "pin points" running most of the length of the aircraft. Say every meter, perhaps every 2 meters. The design of the extreme oval fuselage would be such that a vertical reinforcement is only needed perhaps every 3 or 6 meters (or whatever). That way you only need some of the points in service so you can have full width access in the other areas; and that a vertical reinforcement member could fail without jeopardizing the aircraft.

Second: This would likely not be as simple as a cable with pinned ends. But a more elegant flatter panel with 2 upper and 2 lower pins; such that failure of an individual pin would shift the load to the other pin - making vertical reinforcement members more difficult to fail.

Third. The vertical reinforcement member could have vertical supports for the floor - minimizing floor structure weight in the areas where these vertical structures exist.

This should save a lot of weight compared to a no vertical reinforcement extreme oval design, while maintaining cabin layout flexibility.

There are other valid ideas on this forum related to large wings, and perhaps putting baggage behind passengers in a special area (with the required separation wall) to lengthen the design (which could also increase the extreme oval shape.

It will be interesting to see what is finally proposed. But, this idea makes engineering sense...

Have a great day,
 
jagraham
Posts: 215
Joined: Sun Jul 17, 2016 11:10 pm

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

Thu Dec 07, 2017 6:42 am

RJMAZ wrote:
jagraham wrote:
A "cheap" enhancement for the 767 would be to put GEnx2 engines on the 764. The extra height of the landing gear allows for a drop in installation. The GEnx2 is only 300 lb heavier than a RB211, so the wing should be able to take it.

Genx2 is WAY bigger

763 engine - 3900kg - 86" fan - 50klb thrust
764 engine - 4400kg - 93" fan - 59klb thrust
Genx2 - 5600kg - 105" fan - 66klb thrust

The A330NEO actually burns more fuel on a trip below 1000nm compared to the older A330CEO. The NEO weighs 5T more empty. The same thing would happen with the 767 using genx2. You would be better off keeping the current light engines as a lot of the trips would be around 1000nm.

There are no engines available in the size/weight/thrust range required. If Boeing wanted a new engine, Rolls-Royce could deliver the quickest with its Trent 1500. This was planned for the A340NEO.

A scaled down genx would be ideal but it would need to be a clean sheet design. Simply putting a smaller fan on the genx2b67 wouldn't save much weight as the core would be the same.


A - Compare the GEnx2 to RR211-524 weight wise. Not the GE CF6
B - I was concerned with weight when I referenced the RB211. The 767 wing was strengthened to accept the RB211 rather late in the program when BA insisted on that engine
C - As far as fan diameter, the Pratt 4000-94 is used on the 767-300. The GEnx2 fan is 11 inches bigger than the Pratt 4000 fan. The 764 gear is 18 inches taller than the 763 gear. So the GEnx2 should fit the 764 just fine. Not the 763.
D - There is indeed a possibility (considering the A332 to A338 experience, quite likely) that at some short ranges the original 764 might be more efficient than a '764MAX'.
 
RJMAZ
Posts: 282
Joined: Sat Jul 09, 2016 2:54 am

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

Thu Dec 07, 2017 7:16 am

jagraham wrote:
A - Compare the GEnx2 to RR211-524 weight wise. Not the GE CF6

The RR211-524 is even lighter.
Weight 4,300kg. 86.3" fan diameter 60klb thrust.

That is 80% of the weight and diameter of the genX. If the 767-400 needed a longer nose gear to go from 86" to 94" then it is highly doubtful a 105" will fit.

The engines are closer to the main landing gear than the nose gear. The 19" taller nose gear only gives 9" or so of extra clearance at the engines. The genx2 would need to be lifted close to the wing like the 737MAX to fit the 767 even with the taller 764 nose gear.

It would have absolutely no chance of fitting with the 763 nose gear. The genX2 would need to be scaled down 90% atleast to be a good fit.

https://en.m.wikipedia.org/wiki/Rolls-Royce_RB211
 
parapente
Posts: 1989
Joined: Tue Mar 28, 2006 10:42 pm

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

Thu Dec 07, 2017 8:19 am

Interesting post 2175301.You may well be right concerning the need for vertical posts.At least on the main deck-they may be able to transfer the loads outwards using the floor to allow normal containers below.But..
According to all published sources they are going for a X7 abreast (ovoid) fuse.Perhaps this is one of the reasons.A X7 ovoid can be achieved without structural (vertical) strengthening whereas a wider x8 can't.
 
User avatar
Revelation
Topic Author
Posts: 16648
Joined: Wed Feb 09, 2005 9:37 pm

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

Thu Dec 07, 2017 11:45 am

jagraham wrote:
RJMAZ wrote:
jagraham wrote:
A "cheap" enhancement for the 767 would be to put GEnx2 engines on the 764. The extra height of the landing gear allows for a drop in installation. The GEnx2 is only 300 lb heavier than a RB211, so the wing should be able to take it.

Genx2 is WAY bigger

763 engine - 3900kg - 86" fan - 50klb thrust
764 engine - 4400kg - 93" fan - 59klb thrust
Genx2 - 5600kg - 105" fan - 66klb thrust

The A330NEO actually burns more fuel on a trip below 1000nm compared to the older A330CEO. The NEO weighs 5T more empty. The same thing would happen with the 767 using genx2. You would be better off keeping the current light engines as a lot of the trips would be around 1000nm.

There are no engines available in the size/weight/thrust range required. If Boeing wanted a new engine, Rolls-Royce could deliver the quickest with its Trent 1500. This was planned for the A340NEO.

A scaled down genx would be ideal but it would need to be a clean sheet design. Simply putting a smaller fan on the genx2b67 wouldn't save much weight as the core would be the same.


A - Compare the GEnx2 to RR211-524 weight wise. Not the GE CF6
B - I was concerned with weight when I referenced the RB211. The 767 wing was strengthened to accept the RB211 rather late in the program when BA insisted on that engine
C - As far as fan diameter, the Pratt 4000-94 is used on the 767-300. The GEnx2 fan is 11 inches bigger than the Pratt 4000 fan. The 764 gear is 18 inches taller than the 763 gear. So the GEnx2 should fit the 764 just fine. Not the 763.
D - There is indeed a possibility (considering the A332 to A338 experience, quite likely) that at some short ranges the original 764 might be more efficient than a '764MAX'.

Behold the son of Frankentanker, Frankenliner! :bigthumbsup:

Nice thought exercise, but in the end, we're still talking about investing large sums of money to build something that only sells if you can build it for small sums of money.
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
 
RJMAZ
Posts: 282
Joined: Sat Jul 09, 2016 2:54 am

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

Thu Dec 07, 2017 12:57 pm

jagraham wrote:
Stitch wrote:
jagraham wrote:
3000 nm is the exact distance from JFK to LHR. Still air. No reserves. A plane designed for 3000 nm pax and bags only will be very marginal - see Leeham's analysis of the A321LR carrying 206 pax between JFK and LHR. Also, lie-flat seats have become a competitive feature over the Atlantic and only the ULCCs will fly across the Atlantic without lie-flat seats now.


And that appears to be where the contention is.

The US3 and EU LCCs appear to want 5000nm so they can do TATL.

The Asian, Indian and Chinese appear to want 3000-3500nm as it nicely covers their part of the world. 3000nm would also be perfect for Australian domestic and Trans-Taz.



I think the same plane will do fine for both. Except the 5000nm needs to be about 4500nm.

The US and EU airlines for the most part will fly less dense. The current 763 files about 220 this way and the A332 flies about 240. With the newer lie flat seats.

The Asian, Indian, and Chinese will pack them in. An A332 over there will have 290 to 350 people on it.

That's 5000 to 11000 extra kg for the Far East carriers. Should lop off about 500 to 1000 nm.

Everyone usually quotes wikipedia range.

The ranges listed are usually with a light payload in ideal conditions traveling with the wind.

Subtract 500nm for divert fuel.
Subtract 10% by carrying a normal payload.
Subtract 10% for when travelling westbound.
Subtract 10% if you are operating from hot/high airports.

A 787-10 fully loaded out of a hot middle east airport will struggle to fly 4500nm even though wikipedia lists 6430nm.

Same deal with Air Asia's A330 fleet with their 9abreast cabin. Range is around two thirds of the wikipedia range.

So in the case of the MOM it would need a 5000nm wikipedia range to do decent transatlantic. This would be for the shortest long range model. Fully loaded west bound that would be around 3500nm realistic.

Berlin to New York is 3450nm
Paris to New York is 3200nm
London to New York is 3000nm

The stretched shorter ranged model probably won't be able to do transatlantic with a decent payload.

Japan to Los Angeles is 4750nm.
Japan to Sydney is 4250nm.
I could see Japan buying hundreds of the short ranged stretched version for domestic use. They would probably try and push the long ranged model pretty far.
 
User avatar
keesje
Posts: 10327
Joined: Thu Apr 12, 2001 2:08 am

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

Thu Dec 07, 2017 3:01 pm

Drag, weight, maintenance costs and required engine power so far showed a strong relation with fuselage cross section. lets a assume for a minute that won't go away because of groundbreaking new technological magic. :boxedin:

At that stage expanding on a NB concept decreasing some of it inherent disadvantage might be a feasible option.
1 Wide aisle seems more effective than 2 narrow ones. Overall operating costs could be kept down.

Image

Optimal wings, engines, landing gears could be developped to make it competitive both in the 180 seat 1000NM and 240 seat 4500NM segment.

The time a wide body compromise (A330, 767) could work in both segments effectively is probably behind us.

Image
"Never mistake motion for action." Ernest Hemingway
 
WIederling
Posts: 4669
Joined: Sun Sep 13, 2015 2:15 pm

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

Thu Dec 07, 2017 4:08 pm

rheinwaldner wrote:
Newbiepilot wrote:
I don’t see am A320.5 hurting the backlog of 4000 planes to build.

I also dont see the backlog endangered. The A320.5 (and the CS500, that you forgot) could endanger the future 737 backlog. Note: I said, could. I have no idea whether Airbus will build these two new variants. Even only the possibility that they "could" should be considered by the Boeing strategy. Therefore my forecast is, that the MOM will not come in a way, that leaves the 737 space undefended.


Airbus expects to deliver better than every second A320fam as A321 airframe in the near future.
When ever an A320.5 can reach the market the gravity of the A320fam demand will have moved right into the A321 window.
About as usefull as doing an A318NEO. i.e. will not happen.

Remember A319 used to be more than 50% of deliveries that moved to strongly A320 dominated deliveries .... next year in Jerusalem: 50+% A321 :-)
The large range step up from CEO to NEO engines has accelerated that process.
Murphy is an optimist
 
morrisond
Posts: 305
Joined: Thu Jan 07, 2010 12:22 am

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

Thu Dec 07, 2017 4:11 pm

Keesje - What about including the Leeham MOM7 image as well - 178" H x 194"W
 
Newbiepilot
Posts: 2166
Joined: Tue Aug 30, 2016 10:18 pm

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

Thu Dec 07, 2017 7:50 pm

keesje wrote:
Drag, weight, maintenance costs and required engine power so far showed a strong relation with fuselage cross section. lets a assume for a minute that won't go away because of groundbreaking new technological magic. :boxedin:

At that stage expanding on a NB concept decreasing some of it inherent disadvantage might be a feasible option.
1 Wide aisle seems more effective than 2 narrow ones. Overall operating costs could be kept down.

Image

Optimal wings, engines, landing gears could be developped to make it competitive both in the 180 seat 1000NM and 240 seat 4500NM segment.

The time a wide body compromise (A330, 767) could work in both segments effectively is probably behind us.

Image


Do you have any analysis to support the statement that wide single aisle keeps the operating costs down? I thought you waived the white flag regarding the structure efficiency comment. I don't understand why this is better than 7 abreast. If you are going to make the plane wider, why not add an extra seat per row?
 
User avatar
william
Posts: 2103
Joined: Thu Jun 10, 1999 1:31 pm

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

Thu Dec 07, 2017 8:19 pm

2175301 wrote:
There seems to be an endless debate about narrow-body vs wide-body and various trade offs; and of course how Airbus could respond (which has it's own thread).

It is my understanding that one of the commonly stated problems with an 8 abreast 2 isle wide-body extreme oval (no or minimum cargo) is that the extra reinforcement in the floors, structure, and walls needed to keep the shape at altitude with the aircraft pressurized (with the cabin being pushed towards a circle). That common argument is that the weight required for such reinforcement outweighs the advantages.

On the "Airbus weighs response if Boeing launches new mid-market model" thread I posted what to me (as an engineer) is an obvious answer to that on November 25.

"What IF... Boeing comes up with an 8 abreast carbon fiber ovoid with periodic vertical reinforcements down the center to keep the carbon fiber hull weight down. Not great for cargo; but would be great for passengers service. I'm betting that they are at least looking at that; and if that is their final proposal I have no idea how Airbus responds except to duplicate the base design."

Putting some more thought into that... I realizes just how beneficial using center-line vertical (normally in tension) reinforcement could be. Here are some further thoughts on how it could be done:

First. In order to support various cabin arrangements there could be a series of vertical anchor "pin points" running most of the length of the aircraft. Say every meter, perhaps every 2 meters. The design of the extreme oval fuselage would be such that a vertical reinforcement is only needed perhaps every 3 or 6 meters (or whatever). That way you only need some of the points in service so you can have full width access in the other areas; and that a vertical reinforcement member could fail without jeopardizing the aircraft.

Second: This would likely not be as simple as a cable with pinned ends. But a more elegant flatter panel with 2 upper and 2 lower pins; such that failure of an individual pin would shift the load to the other pin - making vertical reinforcement members more difficult to fail.

Third. The vertical reinforcement member could have vertical supports for the floor - minimizing floor structure weight in the areas where these vertical structures exist.

This should save a lot of weight compared to a no vertical reinforcement extreme oval design, while maintaining cabin layout flexibility.

There are other valid ideas on this forum related to large wings, and perhaps putting baggage behind passengers in a special area (with the required separation wall) to lengthen the design (which could also increase the extreme oval shape.

It will be interesting to see what is finally proposed. But, this idea makes engineering sense...

Have a great day,


Well detailed post. I don't think the airframe is the issue. I think the powerplants are the issue, thus the delay in service date.
 
TranscendZac
Posts: 54
Joined: Sat Jun 13, 2015 12:50 pm

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

Fri Dec 08, 2017 12:27 am

jagraham wrote:
RJMAZ wrote:
jagraham wrote:
A "cheap" enhancement for the 767 would be to put GEnx2 engines on the 764. The extra height of the landing gear allows for a drop in installation. The GEnx2 is only 300 lb heavier than a RB211, so the wing should be able to take it.

Genx2 is WAY bigger

763 engine - 3900kg - 86" fan - 50klb thrust
764 engine - 4400kg - 93" fan - 59klb thrust
Genx2 - 5600kg - 105" fan - 66klb thrust

The A330NEO actually burns more fuel on a trip below 1000nm compared to the older A330CEO. The NEO weighs 5T more empty. The same thing would happen with the 767 using genx2. You would be better off keeping the current light engines as a lot of the trips would be around 1000nm.

There are no engines available in the size/weight/thrust range required. If Boeing wanted a new engine, Rolls-Royce could deliver the quickest with its Trent 1500. This was planned for the A340NEO.

A scaled down genx would be ideal but it would need to be a clean sheet design. Simply putting a smaller fan on the genx2b67 wouldn't save much weight as the core would be the same.


A - Compare the GEnx2 to RR211-524 weight wise. Not the GE CF6
B - I was concerned with weight when I referenced the RB211. The 767 wing was strengthened to accept the RB211 rather late in the program when BA insisted on that engine
C - As far as fan diameter, the Pratt 4000-94 is used on the 767-300. The GEnx2 fan is 11 inches bigger than the Pratt 4000 fan. The 764 gear is 18 inches taller than the 763 gear. So the GEnx2 should fit the 764 just fine. Not the 763.
D - There is indeed a possibility (considering the A332 to A338 experience, quite likely) that at some short ranges the original 764 might be more efficient than a '764MAX'.

The 764 uses the 93” fan CF6 derivative with 63,000lbs of thrust. It would likely not need significant work to hang larger engines.

With that said, Boeing is not going to use a 767 as the basis for the 797. It’s too old, too heavy, and too large for the role. The 797 is probably going to bridge the 752/3 and on the high side pax wise the 762/763.
Zac
 
User avatar
keesje
Posts: 10327
Joined: Thu Apr 12, 2001 2:08 am

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

Fri Dec 08, 2017 12:38 am

Newbiepilot wrote:
keesje wrote:
Drag, weight, maintenance costs and required engine power so far showed a strong relation with fuselage cross section. lets a assume for a minute that won't go away because of groundbreaking new technological magic. :boxedin:

At that stage expanding on a NB concept decreasing some of it inherent disadvantage might be a feasible option.
1 Wide aisle seems more effective than 2 narrow ones. Overall operating costs could be kept down.

Image

Optimal wings, engines, landing gears could be developped to make it competitive both in the 180 seat 1000NM and 240 seat 4500NM segment.

The time a wide body compromise (A330, 767) could work in both segments effectively is probably behind us.

Image


Do you have any analysis to support the statement that wide single aisle keeps the operating costs down? I thought you waived the white flag regarding the structure efficiency comment. I don't understand why this is better than 7 abreast. If you are going to make the plane wider, why not add an extra seat per row?


Yes, an extra seat increases the loads. http://www.airliners.net/forum/viewtopic.php?f=3&t=1362655&start=750#p19987987
Please provide a detailed analyses why you believe a 7 abreast twin aisle is as structurally efficient as a single aisle below ~ 275 seats.
"Never mistake motion for action." Ernest Hemingway
 
RJMAZ
Posts: 282
Joined: Sat Jul 09, 2016 2:54 am

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

Fri Dec 08, 2017 2:13 am

keesje wrote:
Please provide a detailed analyses why you believe a 7 abreast twin aisle is as structurally efficient as a single aisle below ~ 275 seats.

We have thoroughly been over this.

We have done empty weight per passenger using identical cabins.
We have done empty weight per cabin area.
We have done empty weight per usable seating area taking into account aisle width.

The widebody proved to be just as structurally efficient.

In addition to this. Once an aircraft gets too long and skinny the weight per extra metre increases. For example going from 35m to 40m may add 3T of structure. But going from 50m to 55m might add 6T of extra structure.

The DC-8 and 757 show this massive weight gains for the added length. Nearly 1000kg per added metre.

The 737 shows 500-600kg per added metre.
The A318 to A320 added 510kg per metre.

A 762 to 763 added 950kg per metre.
The A332 to A333 has a low 450kg per extra metre.

To think an extra 1T of fuselage structure can get you 2mtres of A330 fuselage for 16 seats. Where as the same 1T on the 757 gets only 6 seats and half the cargo volume.

This is why your long skinny 6 abreast is pretty much a 757-300NEO

The A310 weighs 20% more empty and has 20% more cabin area than the 753. It can also board in nearly half the time and fly 50% further. That is definitely more structurally efficient.

The A300 weights 37% more but has 42% more cabin area. Both the A300 and A310 use wider seats too than the 757. If you used the same seats width as the 757 the A3XX could be 5% narrower and lighter.

This is why the Boeing MOM will most likely be a tight 8AB aircraft. With a A310 style long range model and a A300 style people mover. These are definitely not too big. This is well in the middle of market zone.

Obviously a 7AB isn't that efficient. That extra aisle for only one seat. So you would be better off going to a short 8AB if you want the most weight efficient option going over 270 seats.
 
jagraham
Posts: 215
Joined: Sun Jul 17, 2016 11:10 pm

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

Fri Dec 08, 2017 4:58 am

RJMAZ wrote:
jagraham wrote:
A - Compare the GEnx2 to RR211-524 weight wise. Not the GE CF6

The RR211-524 is even lighter.
Weight 4,300kg. 86.3" fan diameter 60klb thrust.

That is 80% of the weight and diameter of the genX. If the 767-400 needed a longer nose gear to go from 86" to 94" then it is highly doubtful a 105" will fit.

The engines are closer to the main landing gear than the nose gear. The 19" taller nose gear only gives 9" or so of extra clearance at the engines. The genx2 would need to be lifted close to the wing like the 737MAX to fit the 767 even with the taller 764 nose gear.

It would have absolutely no chance of fitting with the 763 nose gear. The genX2 would need to be scaled down 90% atleast to be a good fit.

https://en.m.wikipedia.org/wiki/Rolls-Royce_RB211


From EASA (Pratt 6000, page 4)
https://www.easa.europa.eu/system/files ... 062005.pdf

The following customer supplied equipment are not part of the basic engine weight: integrated drive
generator (IDG); hydraulic pump, filter and pressure switch; one high pressure valve; pressure regulating
valve; intermediate pressure check valve; nacelle inlet cowl /P2T2 probe mount; fan cowls and
associated hardware; thrust reverser assembly including activation system, attachment hardware and
associated electrical harnesses; common nozzle assembly including aft pylon fairing and attachment
hardware; forward engine mount, rear engine mount, and attachment hardware.
The engine build-up
(EBU) includes: IDG cooling system components; inlet anti-icing valve and ducts; environmental control
system bleed air ducts; electrical harnesses; starter, starter air valve, and ducting; mass fuel flow meter;
fire detection system.

From EASA (Rolls RB211 524 and RB211-22 certification)


TCDS No.:E.062
RB211-524 & -22B SERIES

Issue: 01
Date:
19 May 2017
TE.CERT.
00052
-
001 © European Aviation Safety Agency,
2017
. All rights reserved. ISO9001 Certified.
Page 9 of 23
Proprietary document. Copies are not controlled.
Confirm revision status through the EASA
-
Internet/Intranet.
An agency of the European Union

5.
Dry Weight
engine model dry weight

RB211-22B-02 5410 kg (1)

RB211-524B3-02, RB211-524B4-D-02 5057 kg (2)

RB211-524B2-19, RB211-524B-02,
RB211-524B-19, RB211-524B-B-02 5060 kg (2)

RB211-524D4-19, RB211-524D4-39, 5078 kg (2)
RB211-524D4-B-19, RB211-524D4-B-39,
RB211-524D4X-19, RB211-524D4X-B-19

RB211-524C2-19, 524C2-B-19 5080 kg (2)

RB211-524G2-19, RB211-524G3-19 5775 kg (3)

RB211-524G2-T-19, RB211-524G3-T-19 5688 kg (3)

RB211-524H-36 5775 kg (3)

RB211-524H2-19 5790 kg (3)

RB211-524H-T-36 5688 kg (3)

RB211-524H2-T-19 5703 kg (3)

------------------------------------------------------------------------

Basic engine weight does not include some heavy and necessary structures. The table above is the dry weight per EASA
 
User avatar
seabosdca
Posts: 5296
Joined: Sat Sep 01, 2007 8:33 am

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

Fri Dec 08, 2017 5:30 am

RJMAZ wrote:
The A310 weighs 20% more empty and has 20% more cabin area than the 753. It can also board in nearly half the time and fly 50% further. That is definitely more structurally efficient.


And yet none of that has translated into better real-world financial performance. The A310 is done except for a few stragglers in low-utilization cargo service, while every 753 ever built remains in high-utilization passenger service and operators cling ferociously to their frames. How much of that is because the A310 has oversized engines that use more like 50% more fuel than those on the 753, and how much is because of the A310's undersized wing and generally spotty aerodynamics (by modern standards), I don't know.
 
jagraham
Posts: 215
Joined: Sun Jul 17, 2016 11:10 pm

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

Fri Dec 08, 2017 5:39 am

 
jagraham
Posts: 215
Joined: Sun Jul 17, 2016 11:10 pm

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

Fri Dec 08, 2017 5:55 am

RJMAZ wrote:
jagraham wrote:
Stitch wrote:

And that appears to be where the contention is.

The US3 and EU LCCs appear to want 5000nm so they can do TATL.

The Asian, Indian and Chinese appear to want 3000-3500nm as it nicely covers their part of the world. 3000nm would also be perfect for Australian domestic and Trans-Taz.



I think the same plane will do fine for both. Except the 5000nm needs to be about 4500nm.

The US and EU airlines for the most part will fly less dense. The current 763 files about 220 this way and the A332 flies about 240. With the newer lie flat seats.

The Asian, Indian, and Chinese will pack them in. An A332 over there will have 290 to 350 people on it.

That's 5000 to 11000 extra kg for the Far East carriers. Should lop off about 500 to 1000 nm.

Everyone usually quotes wikipedia range.

The ranges listed are usually with a light payload in ideal conditions traveling with the wind.

Subtract 500nm for divert fuel.
Subtract 10% by carrying a normal payload.
Subtract 10% for when travelling westbound.
Subtract 10% if you are operating from hot/high airports.

A 787-10 fully loaded out of a hot middle east airport will struggle to fly 4500nm even though wikipedia lists 6430nm.

Same deal with Air Asia's A330 fleet with their 9abreast cabin. Range is around two thirds of the wikipedia range.

So in the case of the MOM it would need a 5000nm wikipedia range to do decent transatlantic. This would be for the shortest long range model. Fully loaded west bound that would be around 3500nm realistic.

Berlin to New York is 3450nm
Paris to New York is 3200nm
London to New York is 3000nm

The stretched shorter ranged model probably won't be able to do transatlantic with a decent payload.

Japan to Los Angeles is 4750nm.
Japan to Sydney is 4250nm.
I could see Japan buying hundreds of the short ranged stretched version for domestic use. They would probably try and push the long ranged model pretty far.



Airliner ranges are specified pax / bags, no cargo. At MTOW (after pax / bags, fuel up to MTOW). Boeing seems to have gone to Airbus' 95kg / pax definition. That's definitely light for real world, but it eliminates one variable.

I believe the following

1) Natural growth in passenger traffic for transatlantic routes will push the standard TATL model to 789 or A333 size
2) While I think the 787-10 will do a bit better than 4500 nm fully loaded in the Middle East, anybody who needs normal (not extreme) 4750nm+ range is in 787-10 territory. The 797 doesn't have to meet that need.
3) The stretched model must do TATL; that is what interests the like of BA, LH, and UA
4) It's all about the engine. And the engine weight. This is also where the primary program risk is. From a program management standpoint, I would do a trijet, use LEAP-1Bs (737MAX) and thereby eliminate the risk for about 3000 lb extra weight (versus 2 GTF 40000 lb engines). But I put my bet on Boeing pushing GE (and maybe Pratt) to get the LEAP 1A (or GTF) in the low 40Ks thrust wise. And do the rest with the wing.
 
jagraham
Posts: 215
Joined: Sun Jul 17, 2016 11:10 pm

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

Fri Dec 08, 2017 6:28 am

TranscendZac wrote:
jagraham wrote:
RJMAZ wrote:
Genx2 is WAY bigger

763 engine - 3900kg - 86" fan - 50klb thrust
764 engine - 4400kg - 93" fan - 59klb thrust
Genx2 - 5600kg - 105" fan - 66klb thrust

The A330NEO actually burns more fuel on a trip below 1000nm compared to the older A330CEO. The NEO weighs 5T more empty. The same thing would happen with the 767 using genx2. You would be better off keeping the current light engines as a lot of the trips would be around 1000nm.

There are no engines available in the size/weight/thrust range required. If Boeing wanted a new engine, Rolls-Royce could deliver the quickest with its Trent 1500. This was planned for the A340NEO.

A scaled down genx would be ideal but it would need to be a clean sheet design. Simply putting a smaller fan on the genx2b67 wouldn't save much weight as the core would be the same.


A - Compare the GEnx2 to RR211-524 weight wise. Not the GE CF6
B - I was concerned with weight when I referenced the RB211. The 767 wing was strengthened to accept the RB211 rather late in the program when BA insisted on that engine
C - As far as fan diameter, the Pratt 4000-94 is used on the 767-300. The GEnx2 fan is 11 inches bigger than the Pratt 4000 fan. The 764 gear is 18 inches taller than the 763 gear. So the GEnx2 should fit the 764 just fine. Not the 763.
D - There is indeed a possibility (considering the A332 to A338 experience, quite likely) that at some short ranges the original 764 might be more efficient than a '764MAX'.

The 764 uses the 93” fan CF6 derivative with 63,000lbs of thrust. It would likely not need significant work to hang larger engines.

With that said, Boeing is not going to use a 767 as the basis for the 797. It’s too old, too heavy, and too large for the role. The 797 is probably going to bridge the 752/3 and on the high side pax wise the 762/763.


The weight thing is interesting. 764 OEW is 229000 lb. A332 OEW is between 265000 and 266000 lb depending on engine. 788 OEW is 264500.

So the 767 is old indeed. But not particularly heavy. Of course the A332 has bigger engines except for GE (both are CF6-80E) and flies farther. And the 788 flies much farther and has much heavier engines. Backing the engines out (CF6-80E, 9500 lb dry weight, GEnx1, 13500 lb dry weight) puts the 764 at 210000 lb without its engines, the A332 at 246000 lb without its engines, and the 788 at 245500 without its engines. The A332 is set up for 241200 lb of fuel, the 788 for 223400 lb of fuel, and the 764 for 161700 lb of fuel. Or 60000 to 80000 lb less fuel. It would get close to a wash without the fuel structure. But the fuel structure is there. About 35000 extra lb for either the A332 or the 788 versus the 764.

In conclusion, the 764 weight should not be a major impediment. The wing, on the other hand . . .
 
parapente
Posts: 1989
Joined: Tue Mar 28, 2006 10:42 pm

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

Fri Dec 08, 2017 8:38 am

What will Boeing be putting up as 'the competition' when planning a MOM?
Right now I guess it would be the 240 seat A321NEO/206 seater (2class) LR.
Neither smack in the middle of the MOM circle.
But they are aware of a 'plus' and a 'plus plus' versions of the A321NEO.
We don't know what they are-but Boeing will.
We guess they are a smaller stretch (250 pax) and a larger stretch (270 pax) and if the 4,500-5,000 range target is to be met then a new carbon wing.
We assume both would use very similar engines.
So is the most economical design an ovoid twin aisle X7 fuse or an ovoid twin aisle X8 fuse?
We have also recently read that they accept that 'ovoid' restricts use of optimised containers in hold -period.
Their mantra is 'wide bodied comfort with narrow bodied economics'.
Which solution offers the best meeting of this concept and beating of any competition?
We can see from a generation ago what happens when you pitch a single aisle stretch (757-300) against an optimised X8 twin aisle (A310).
The 757-300 wins.See above.
So why would that change now? All things being equal.
 
User avatar
keesje
Posts: 10327
Joined: Thu Apr 12, 2001 2:08 am

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

Fri Dec 08, 2017 10:18 am

RJMAZ wrote:
This is why your long skinny 6 abreast is pretty much a 757-300NEO


? Nope. The A320 has already a wider fuselage than 737/757 and the concept above adds 10-12 inch. Combined that's a lot over a 757/737.

https://lh3.googleusercontent.com/-XSZq70Ph0nw/WgLiQGz3xnI/AAAAAAAADOs/lnQC79nMhpA9CUBJqwlmIcpOhhyenSKlACLcBGAs/s1600/Boeing%252520MoM%252520NMA%252520NSA%252520A321%252520keesje%252520Airbus%252520Design%252520Engine%252520Wing%252520737_zpscrrkvmms.jpg

Your rules of thumb are off here. Compare the same age same seat capacity Boeing 753 and 762 and even then the sub optimal 753 is much lighter.

We have to be carefull with seatcounts. They are often carefully selected to support a preset conclusion and seriously influence all kinds of "per seat" figures. Nothing to do with real operations. If possible I try to find full economy class figuration's at 30 inch. But then even you are comparing 16.6" wide A330 9 abreast figures with A380 19" wide seats.
"Never mistake motion for action." Ernest Hemingway
 
Eyad89
Posts: 278
Joined: Fri Sep 02, 2016 10:47 pm

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

Fri Dec 08, 2017 12:08 pm

keesje wrote:
RJMAZ wrote:
This is why your long skinny 6 abreast is pretty much a 757-300NEO



Your rules of thumb are off here. Compare the same age same seat capacity Boeing 753 and 762 and even then the sub optimal 753 is much lighter.

We have to be carefull with seatcounts. They are often carefully selected to support a preset conclusion and seriously influence all kinds of "per seat" figures. Nothing to do with real operations. If possible I try to find full economy class figuration's at 30 inch. But then even you are comparing 16.6" wide A330 9 abreast figures with A380 19" wide seats.


Comparing weight per seat only makes sense IMO if both planes were configured in an all-economy class. Otherwise results would be greatly distorted.

Thomas Cook makes this easy for us with their all-economy class configuration for all the following:

753 all economy: 280 seats.
752 all economy: 235 seats.
763 is configured in 8 seats per row in a single class, they have 326 seats installed in there.

So, even when pushing their 763 towards an 8ab, it is still heavier per seat than both 752 and 753 in a similar all-economy class.

752 and 762 have exactly the same range and almost similar seating capacity (if 762 is 7ab), that resulted in 752 getting 9 times the sales of 762 (and the 763 as well).

752: 913 units sold
762: 128 units sold
763: 104 units sold

I still believe 797 would be more attractive as a narrowbody. That's just my opinion, I guess we will see how that goes.
Last edited by Eyad89 on Fri Dec 08, 2017 12:15 pm, edited 1 time in total.
 
RJMAZ
Posts: 282
Joined: Sat Jul 09, 2016 2:54 am

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

Fri Dec 08, 2017 12:12 pm

keesje wrote:
Your rules of thumb are off here. Compare the same age same seat capacity Boeing 753 and 762 and even then the sub optimal 753 is much lighter.

The 767 has nearly double the range. So of course it will be heavier. It has more than twice the fuel capacity compared to the 757. The cabin area isn't that much more.

The A300 has similar range to the 757. So a much closer apple to apple comparison. Both have very similar weights per passenger, per cabin area etc.

parapente wrote:
We can see from a generation ago what happens when you pitch a single aisle stretch (757-300) against an optimised X8 twin aisle (A310).
The 757-300 wins.See above.
So why would that change now? All things being equal.

Only 55 757-300's were built compared to 255 A310's.

The 757-300 performed poorly in nearly every metric. It couldn't fly transatlantic and it was beaten by a 737 on short haul.

The A310 had great CASM on transatlantic when it came out. In fact it probably had the best CASM at the time on medium haul compared to the trijets and the 762. The 767-300ER was probably the only aircraft that was competitive. However the A310 being much smaller opened many new thin routes. Just like the A321LR plans to do. In the 1980's the global market was small but 255 aircraft was still impressive for a 15 year run. That would be 1000+ aircraft today in terms of market percentage.

The larger A330 killed the A310. The A330 had even better CASM on a transatlantic flights as it was designed for medium haul. With the same engine tech the larger plane is usually more efficient.

As the A330 has now grown into a heavy long haul aircraft a dedicated shorter ranged aircraft now has a chance.
Last edited by RJMAZ on Fri Dec 08, 2017 12:30 pm, edited 1 time in total.
 
Eyad89
Posts: 278
Joined: Fri Sep 02, 2016 10:47 pm

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

Fri Dec 08, 2017 12:30 pm

RJMAZ wrote:

The 767 has nearly double the range. So of course it will be heavier. It has more than twice the fuel capacity compared to the 757. The cabin area isn't that much more.

The A300 has similar range to the 757. So a much closer apple to apple comparison. Both have very similar weights per passenger, per cabin area etc.




Well, 767-300 has the exact range as 752, it is the 767-300ER that has almost double the range, and the extra range for the ER is really what made it the most successful 767 variant. It shows clearly here how airlines preferred the 757 over 767 if they were not looking for range.

An all economy A300 would seat around 325 passengers, that is still heavier per passenger than 752 and 753 in a similar configuration.
 
RJMAZ
Posts: 282
Joined: Sat Jul 09, 2016 2:54 am

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

Fri Dec 08, 2017 12:54 pm

Eyad89 wrote:
Well, 767-300 has the exact range as 752, it is 767-300ER that has almost double the range, and the extra range is really what made it the most successful 767 variant.

An all economy A300 would seat around 325 passengers, that is still heavier per passenger than 752 and 753 in a similar configuration.

The non ER 767's aren't a fair comparison. They still have the heavy large wing and structure used on the extended range models. They really just have the centre fuel tank removed and the maximum takeoff weight reduced on paper.

The A300 has 361 seats with 30" pitch. Full economy. Dozens of aircraft had this config. Monarch airlines for example here is their seat map. Seats are only half an inch narrower and similar boarding times.

https://www.seatmaestro.com/wp-content/ ... 0-603r.pdf

A300 - 361 seats 88,600kg = 245kg
757-300 - 276 seats 64300kg = 233kg

So the A300 is 5% heavier per passenger which is excellent conidering the A300 has 20% greater range.

If the A300 was optimised to have the same range ad the 753 it would be lighter. As it would only need to carry two thirds of the fuel.

We have been over this already in extreme detail at the start of this thread. Every counter argument has already been debunked.
 
Newbiepilot
Posts: 2166
Joined: Tue Aug 30, 2016 10:18 pm

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

Fri Dec 08, 2017 12:59 pm

keesje wrote:

Yes, an extra seat increases the loads. http://www.airliners.net/forum/viewtopic.php?f=3&t=1362655&start=750#p19987987
Please provide a detailed analyses why you believe a 7 abreast twin aisle is as structurally efficient as a single aisle below ~ 275 seats.


Nice propaganda technique trying to turn this on me lacking credibility and then citing yourself as a source.

I don’t know what the best design is, but you keep saying again and again (perhaps the propaganda technique is ad nauseam) that narrowbody is better. I have seen these pictures pitching a wide narrowbody again and again and again, yet don’t provide any facts supporting your claim that a narrowbody is better for Boeing. I think all you are doing is trying to discredit what Boeing is working on since all the rumors from them is that they are looking at a small widebody.

I like where RJMAZ is going with his points. The problem is that we can’t look at empty weights of various airplanes to optimize the fuselage since MTOW, wing, engines, etc changes as well. The 767 wing is 50% larger than the 767 to support a higher takeoff weight and is where the majority of the weight is coming from, not the fuselage.
 
Eyad89
Posts: 278
Joined: Fri Sep 02, 2016 10:47 pm

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

Fri Dec 08, 2017 1:29 pm

RJMAZ wrote:
Eyad89 wrote:
Well, 767-300 has the exact range as 752, it is 767-300ER that has almost double the range, and the extra range is really what made it the most successful 767 variant.

An all economy A300 would seat around 325 passengers, that is still heavier per passenger than 752 and 753 in a similar configuration.

The non ER 767's aren't a fair comparison. They still have the heavy large wing and structure used on the extended range models. They really just have the centre fuel tank removed and the maximum takeoff weight reduced on paper.

The A300 has 361 seats with 30" pitch. Full economy. Dozens of aircraft had this config. Monarch airlines for example here is their seat map. Seats are only half an inch narrower and similar boarding times.

https://www.seatmaestro.com/wp-content/ ... 0-603r.pdf

A300 - 361 seats 88,600kg = 245kg
757-300 - 276 seats 64300kg = 233kg

So the A300 is 5% heavier per passenger which is excellent conidering the A300 has 20% greater range.

If the A300 was optimised to have the same range ad the 753 it would be lighter. As it would only need to carry two thirds of the fuel.

We have been over this already in extreme detail at the start of this thread. Every counter argument has already been debunked.


So you are comparing a 9-abreast A300 (from your link) against a 6-abreast 753? Is that how MOM should be? 16.5 inches 9-abreast? Even with that, 753 was lighter per passenger.

Let's stick to 8-abreat A300, let's assume that would be similar to the all-economy A332 in Thomas Cook with 8-abreast that has 321 seats:

A300: 88,000/321 = 274 kg/passenger
753: 64,000/280 = 228 kg/passenger

That's 20% lighter in 753's favour.

Sure, you would say range isn't the same for both. Then let's use 752 as it has exactly the same range as A300:

752: 58,000/235 = 246 kg/passenger. (A300 can only achieve that if 9-abreast, which is unrealistic for most airlines)

For identical ranges, 752 is 11% lighter per passenger than A300.

and in our previous discussion, we spent our time debating the dimensions of seats and aisles more than anything else lol. Based on numbers, it is still very clear to me that narrowbodies are the ones with the lighter frames per passenger for similar configs. I am sorry, you still have not proven otherwise unless seating config is somehow different. Don't think that was 'debunked' yet.
Last edited by Eyad89 on Fri Dec 08, 2017 1:58 pm, edited 2 times in total.
 
User avatar
Polot
Posts: 7358
Joined: Thu Jul 28, 2011 3:01 pm

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

Fri Dec 08, 2017 1:42 pm

RJMAZ wrote:
Only 55 757-300's were built compared to 255 A310's.

The 757-300 performed poorly in nearly every metric. It couldn't fly transatlantic and it was beaten by a 737 on short haul.

I'd argue timing was the biggest problem with the 757-300. If it had entered service in 1990 instead of 1999 (2 years before the 9/11 downturn, 5 years before 757 end of production) it probably would have been a far larger success (albeit at the expense of some 752 orders). I don't know why you think it was beaten by a 737 on short haul. NW/DL and CO/UA, for example, love the plane and NW executives in the past expressed regret that they did not order more when Boeing was going around asking for a final call of 757 orders.
 
nehalem
Posts: 3
Joined: Fri Dec 08, 2017 1:41 pm

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

Fri Dec 08, 2017 1:52 pm

keesje wrote:
RJMAZ wrote:
This is why your long skinny 6 abreast is pretty much a 757-300NEO


? Nope. The A320 has already a wider fuselage than 737/757 and the concept above adds 10-12 inch. Combined that's a lot over a 757/737.


And that is why Boeing is better off with a dual aisle than a single aisle. At least assuming they go with 737 size seating. Basically 1 30 inch aisle = 2 18 inch aisle - six 1 inch smaller seats. Then you can add in the 7th seat for free(at least in terms of aisle space).
 
JHwk
Posts: 474
Joined: Wed Jan 30, 2013 2:11 am

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

Fri Dec 08, 2017 2:24 pm

parapente wrote:
So is the most economical design an ovoid twin aisle X7 fuse or an ovoid twin aisle X8 fuse?
We have also recently read that they accept that 'ovoid' restricts use of optimised containers in hold -period.

Unless you put LD3's in the back at the main deck elevation, which could also address the "stubby" length at 250-270 passengers. It really comes down to how flattened of an ovoid shape can be economical; nothing really prevents you from going X9 beyond that factor.
 
parapente
Posts: 1989
Joined: Tue Mar 28, 2006 10:42 pm

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

Fri Dec 08, 2017 2:45 pm

I mentioned containers only because I read an article recently (somewhere) where Boeing accepted that this (ovoid) shape would compromise
the size of container (to a narrow body size).One has to assume they believe it is worth it ,ie 'wide body comfort with narrow body economics'.
But you may be right that they may be able to use the main deck for LD3's if required.

What I still find somewhat perverse is the argument here is always between X8 twin and X6 single.Yet Boeing have stated they are going for this terrible idea that can't possibly work -the ovoid X7.
Does nobody think this great and massively experienced company did not research all possible configurations ad nausiam.And look at all possible responses.From the 707 to the 787 which aircraft did they get wrong? I really feel they are owed a little respect here.Is it not possible - just possible that for a mid size mid range aircraft it is exactly right? From what we read certainly some major airline CEO's seem to think so.

Again I recently read that the head of 330 NEO sales states that the reason the 338 isn't selling is that the present 332's are only half way through their life.Well any 332's that aren't using their 6-7knm range won't be replaced by a 338 in 10 years time if this new a/c is about ,that's for sure.
 
bigjku
Posts: 1135
Joined: Sat Feb 17, 2007 10:51 pm

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

Fri Dec 08, 2017 3:43 pm

parapente wrote:
I mentioned containers only because I read an article recently (somewhere) where Boeing accepted that this (ovoid) shape would compromise
the size of container (to a narrow body size).One has to assume they believe it is worth it ,ie 'wide body comfort with narrow body economics'.
But you may be right that they may be able to use the main deck for LD3's if required.

What I still find somewhat perverse is the argument here is always between X8 twin and X6 single.Yet Boeing have stated they are going for this terrible idea that can't possibly work -the ovoid X7.
Does nobody think this great and massively experienced company did not research all possible configurations ad nausiam.And look at all possible responses.From the 707 to the 787 which aircraft did they get wrong? I really feel they are owed a little respect here.Is it not possible - just possible that for a mid size mid range aircraft it is exactly right? From what we read certainly some major airline CEO's seem to think so.

Again I recently read that the head of 330 NEO sales states that the reason the 338 isn't selling is that the present 332's are only half way through their life.Well any 332's that aren't using their 6-7knm range won't be replaced by a 338 in 10 years time if this new a/c is about ,that's for sure.


Where have the actually stated a 7 wide? Like with a link. I haven’t seen them discuss that at all.
 
nehalem
Posts: 3
Joined: Fri Dec 08, 2017 1:41 pm

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

Fri Dec 08, 2017 6:00 pm

keesje wrote:
Drag, weight, maintenance costs and required engine power so far showed a strong relation with fuselage cross section. lets a assume for a minute that won't go away because of groundbreaking new technological magic. :boxedin:

At that stage expanding on a NB concept decreasing some of it inherent disadvantage might be a feasible option.
1 Wide aisle seems more effective than 2 narrow ones. Overall operating costs could be kept down.

Image

Optimal wings, engines, landing gears could be developped to make it competitive both in the 180 seat 1000NM and 240 seat 4500NM segment.

The time a wide body compromise (A330, 767) could work in both segments effectively is probably behind us.

Image


Fuselage width
B737 - 148in
A320 - 156in
NSA/NMA - 168in

It would seem that your proposed NSA/NMA would need magic tech in order to compete with the A320 given the formers larger cross-section.
 
User avatar
keesje
Posts: 10327
Joined: Thu Apr 12, 2001 2:08 am

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

Fri Dec 08, 2017 7:47 pm

nehalem wrote:
keesje wrote:
Drag, weight, maintenance costs and required engine power so far showed a strong relation with fuselage cross section. lets a assume for a minute that won't go away because of groundbreaking new technological magic. :boxedin:

At that stage expanding on a NB concept decreasing some of it inherent disadvantage might be a feasible option.
1 Wide aisle seems more effective than 2 narrow ones. Overall operating costs could be kept down.

Image

Optimal wings, engines, landing gears could be developped to make it competitive both in the 180 seat 1000NM and 240 seat 4500NM segment.

The time a wide body compromise (A330, 767) could work in both segments effectively is probably behind us.

Image


Fuselage width
B737 - 148in
A320 - 156in
NSA/NMA - 168in

It would seem that your proposed NSA/NMA would need magic tech in order to compete with the A320 given the formers larger cross-section.


That is correct, if both would have the same capacity and fly the same mission. However an NMA would have a longer cabin for premium cabins (sleeper seats) or more seats (up to 50 rows) making it heavier (structural efficiency).

A single narrow aisle on 7 hr flights with many people going for the lav, meals being served, people stretching their legs benefits from an aisle where people realistically can pass each other/ trolleys. Also in high density cabins for short flights.
"Never mistake motion for action." Ernest Hemingway
 
User avatar
sassiciai
Posts: 829
Joined: Mon Jan 07, 2013 8:26 pm

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

Fri Dec 08, 2017 8:07 pm

It's really quite amazing to see that this (latest) thread has almost reached 700 posts, and it is still just full of the same wild speculation (at best)

Outside a very small core within Boeing, no-one knows with any degree of certainty what the company is preparing to commit to. A commitment that engages the company for decades, for billions, and will exclude other activities

I pop into this thread from time to time, but all I find are the same shrinking group arguing round and round about the same issues, with no clarity evolving. I for one would advise you all to go visit Christmas Markets and/or have a beer or 3, and lighten up. Single isle/double isle, 6/7/8 abreast, how many doors and LD3 containers - is this really as important to you as you demonstrate?

Boeing doesn't know what it's going to do here yet (if it does anything), so why bother discussing it! Wait till there's a decision!
 
Eyad89
Posts: 278
Joined: Fri Sep 02, 2016 10:47 pm

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

Fri Dec 08, 2017 9:03 pm

sassiciai wrote:



so why bother discussing it!


Because we, as avgeeks, get this biochemical buzz in our brains when talking about such topics. That’s fine. People get this feeling discussing different topics.

Isn’t this why these forums were created for in the first place?
 
SCAT15F
Posts: 718
Joined: Fri Feb 09, 2007 8:34 am

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

Fri Dec 08, 2017 9:12 pm

Where is this "767-400 has taller landing gear to fit the PW4000 94-inch fan" stuff coming from? The taller gear has absolutely NOTHING to do with the engines.

The 767-300 uses exactly the same size engines (93 and 94-inch fans) as the 767-400. The only difference is the thrust rating, and the higher rating is available for the -300 as well.

This is basic information people.
 
User avatar
Revelation
Topic Author
Posts: 16648
Joined: Wed Feb 09, 2005 9:37 pm

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

Fri Dec 08, 2017 9:59 pm

sassiciai wrote:
It's really quite amazing to see that this (latest) thread has almost reached 700 posts, and it is still just full of the same wild speculation (at best)

Outside a very small core within Boeing, no-one knows with any degree of certainty what the company is preparing to commit to. A commitment that engages the company for decades, for billions, and will exclude other activities

I pop into this thread from time to time, but all I find are the same shrinking group arguing round and round about the same issues, with no clarity evolving. I for one would advise you all to go visit Christmas Markets and/or have a beer or 3, and lighten up. Single isle/double isle, 6/7/8 abreast, how many doors and LD3 containers - is this really as important to you as you demonstrate?

Boeing doesn't know what it's going to do here yet (if it does anything), so why bother discussing it! Wait till there's a decision!

I agree that this discussion is circular and distracting, but I don't think a.net needs a "thread ombudsman" to point that out. People wanna chat, let them chat. It is important to them, obviously. People don't want to participate, fine, just don't open the thread. I'm sure if news comes along a new thread will be created. Meanwhile, this is a discussion forum, so discuss away!
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
 
RJMAZ
Posts: 282
Joined: Sat Jul 09, 2016 2:54 am

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

Fri Dec 08, 2017 10:09 pm

parapente wrote:
What I still find somewhat perverse is the argument here is always between X8 twin and X6 single.Yet Boeing have stated they are going for this terrible idea that can't possibly work -the ovoid X7.

The 787 was launched as an 8AB aircraft now its a 9AB with 95% of operators.

The aircraft may launch with a super comfy 7ab with two 20inch aisles and 18inch seats. But airlines will use 15inch aisles and 17inch seats and that allows for exactly an 8th highly profitable seat. As a narrowbody upgauging aircraft on short thick routes trips of 1-2 hours 17inch seats are fine. Even 16.5inch would be fine on such short trips. 16.5" is totally unacceptable on a A330 flying 10 hours.

The long range, shorter length model could fly 8+ hours with 7ab using comfy 18/18.5inch seats. It would be great for premium airlines.

Eyad89 wrote:
and in our previous discussion, we spent our time debating the dimensions of seats and aisles more than anything else lol. Based on numbers, it is still very clear to me that narrowbodies are the ones with the lighter frames per passenger for similar configs. I am sorry, you still have not proven otherwise unless seating config is somehow different. Don't think that was 'debunked' yet.

It was pretty clear to me from the users that posted after the discussion that it was debunked.

I'd honestly appreciate for the sake of everyone else if we didn't fill this thread up again with numbers.

There are no real world examples for a long narrowbody 6ab and a short 8AB that has:
1) Equal range
2) Equal engine technology
3) Equal seat width
4) Equal aisle percentage per seat.

So we have to act crazy and crunch numbers. Calculate area per seat, adjust pitch to compensate for width etc. You always used smaller seats and a higher density cabin to try to prove your argument.

When used with similar area they came out even.
 
heavymetal
Posts: 4490
Joined: Fri May 08, 2015 3:37 am

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

Fri Dec 08, 2017 10:29 pm

RJMAZ wrote:
keesje wrote:
Your rules of thumb are off here. Compare the same age same seat capacity Boeing 753 and 762 and even then the sub optimal 753 is much lighter.

The 767 has nearly double the range. So of course it will be heavier. It has more than twice the fuel capacity compared to the 757. The cabin area isn't that much more.

The A300 has similar range to the 757. So a much closer apple to apple comparison. Both have very similar weights per passenger, per cabin area etc.

parapente wrote:
We can see from a generation ago what happens when you pitch a single aisle stretch (757-300) against an optimised X8 twin aisle (A310).
The 757-300 wins.See above.
So why would that change now? All things being equal.

Only 55 757-300's were built compared to 255 A310's.

The 757-300 performed poorly in nearly every metric. It couldn't fly transatlantic and it was beaten by a 737 on short haul.

The A310 had great CASM on transatlantic when it came out. In fact it probably had the best CASM at the time on medium haul compared to the trijets and the 762. The 767-300ER was probably the only aircraft that was competitive. However the A310 being much smaller opened many new thin routes. Just like the A321LR plans to do. In the 1980's the global market was small but 255 aircraft was still impressive for a 15 year run. That would be 1000+ aircraft today in terms of market percentage.

The larger A330 killed the A310. The A330 had even better CASM on a transatlantic flights as it was designed for medium haul. With the same engine tech the larger plane is usually more efficient.

As the A330 has now grown into a heavy long haul aircraft a dedicated shorter ranged aircraft now has a chance.


Polot wrote:
RJMAZ wrote:
Only 55 757-300's were built compared to 255 A310's.

The 757-300 performed poorly in nearly every metric. It couldn't fly transatlantic and it was beaten by a 737 on short haul.

I'd argue timing was the biggest problem with the 757-300. If it had entered service in 1990 instead of 1999 (2 years before the 9/11 downturn, 5 years before 757 end of production) it probably would have been a far larger success (albeit at the expense of some 752 orders). I don't know why you think it was beaten by a 737 on short haul. NW/DL and CO/UA, for example, love the plane and NW executives in the past expressed regret that they did not order more when Boeing was going around asking for a final call of 757 orders.


Polot is exactly correct here. The 757-300's lack of sales was a function of it's poor timing to market, not it's poor economics. Ask any of the carriers operating it - for the carriers that operate it, its one of, if not the, most profitable narrowbodies thanks to its great economics. I believe it would have outsold the 757-200 over the long run if given the opportunity, much like all of the other upgauge models. Unfortunately 9/11 sealed the 757 family's fate.
 
jagraham
Posts: 215
Joined: Sun Jul 17, 2016 11:10 pm

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

Sat Dec 09, 2017 2:11 am

SCAT15F wrote:
Where is this "767-400 has taller landing gear to fit the PW4000 94-inch fan" stuff coming from? The taller gear has absolutely NOTHING to do with the engines.

The 767-300 uses exactly the same size engines (93 and 94-inch fans) as the 767-400. The only difference is the thrust rating, and the higher rating is available for the -300 as well.

This is basic information people.


I did NOT say that the 764 has taller landing gear to fit the PW4000. For the record, the taller gear allows for adequate rotation with the longer fuselage. So the 764 does not have the 739 problem.

What I did say is that since the 763 can accommodate the PW4000 AND the 764 has 18 inch higher landing gear AND the GEnx-2 has an 11 inch bigger fan than the PW4000, the 764 should be able to accommodate the GEnx-2 without significant changes. While the 763 cannot.
 
User avatar
EA CO AS
Posts: 14255
Joined: Wed Nov 14, 2001 8:54 am

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

Sat Dec 09, 2017 6:53 am

ikramerica wrote:
The 752 did not replace 722s in anybody's fleet. The 757 and 767 replaced 707s and dc8s. The 738 was the in fleet 722 replacement aircraft.


True, but Boeing did specifically design the 757 with the intent of being a 722 replacement; the proposed 757-100 actually, then the 757-200 was obviously a more capable variant that ultimately took all the orders.
"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
 
RJMAZ
Posts: 282
Joined: Sat Jul 09, 2016 2:54 am

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

Sat Dec 09, 2017 6:59 am

[quote="heavymetal"]Polot is exactly correct here. The 757-300's lack of sales was a function of it's poor timing to market, not it's poor economics. Ask any of the carriers operating it - for the carriers that operate it, its one of, if not the, most profitable narrowbodies thanks to its great economics. I believe it would have outsold the 757-200 over the long run if given the opportunity, much like all of the other upgauge models. Unfortunately 9/11 sealed the 757 family's fate.[/quote]
No, that is the biggest load of crap I've ever heard. The 757-300 was a desperate last gasp attempt by Boeing to keep the 757 line going. Sales for the 757 came to a dead stop in 1994 with 12 orders and another 13 orders in 1995. The introduction of the A321 in 1994 is what caused that dead stop. The 737-900 didn't help either.

The 757-300 was a last attempt in 1996 to improve CASM as the A321 could easily match the CASM of the 757-200.

That is 5 years before September 11. The coffin lid was already on and that simply added the last nail.

I doubt a 757-300 style modern version would sell very well today. Unless it could sell 1000+ frames its a bad idea.

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