This should be a really interesting program to watch. Boeing blew it on the 787 with their botched out sourcing and issues with production so learned a lot (one hopes). They also developed or refined some great tech and have partner companies now with the experience and expertise to take those advances to the 797.

Now comes the fun part, designing the plane to appeal to the largest number of customers given some will want more performance and others just want a CASM monster/people mover.

It is going to be really interesting to watch the competing ideas on this one. Where do you set the range ceiling? There's always that one more mission that some airline will want, but every 100 nm will make the plane heavier. Is there room in the market for multiple fuselage lengths? Make it too short and the A321 will eat its lunch. Make it too long and you're cannibalizing the 787 for shorter missions.

It's an interesting airplane because it could be both a TATL monster and a "kontschaufel" that would replace 757-300s and bring bigger aircraft back to missions that used to be flown with A300s and 767s until those couldn't compete with the A321 and 738/9. I think the right specs are somewhere in this area:

One-class maximum density: ~299 seats, ~4200 nm with full pax/bags
Domestic US style seating: ~249 seats, ~4500 nm with full pax/bags
International (J/Y) style seating: ~199-215 seats, ~4750 nm with full pax/bags

It's very simple. You re-design the 757 in plastic, upgrade the engines and avionics, add FBW and you're done.

Can the basics of the 787 be scaled down to 757 size?

It's going to be a very difficult aircraft to get right isn't it? Too big/heavy, could eat 787 sales, and A330Neo MAY take too many of it's sales to make it as profitable as it could be. Not capable enough, ditto with the A321LR, or inevitable A322. Interesting times ahead. Looking forward to seeing what they come up with.

200-250 pax range 4000-4500nm and CASM at least 10% lower than the A321 neo or 737-10 MAX with equal or lower trip costs.

Do that and you have a winner.

That is moving along quite nicely and looks like a launch will be coming in the next 24 months.

seabosdca wrote:

One-class maximum density: ~299 seats, ~4200 nm with full pax/bags
Domestic US style seating: ~249 seats, ~4500 nm with full pax/bags
International (J/Y) style seating: ~199-215 seats, ~4750 nm with full pax/bags

I like those stats and agree that is a nice slot to put the 797.

ElroyJetson wrote:

200-250 pax range 4000-4500nm and CASM at least 10% lower than the A321 neo or 737-10 MAX with equal or lower trip costs.

Do that and you have a winner.

A widebody with 250 max pax would get eaten alive by the A321 IMO, and if not by the A321 certainly by an A321 stretch. To work as a small widebody it'll have to be bigger than that.

I haven't followed the recent discussions as I should. So sorry for asking- do we already know if it will be a single or twin aisle? I always thought it'll be a single aisle.

seabosdca wrote:

ElroyJetson wrote:

200-250 pax range 4000-4500nm and CASM at least 10% lower than the A321 neo or 737-10 MAX with equal or lower trip costs.

Do that and you have a winner.

A widebody with 250 max pax would get eaten alive by the A321 IMO, and if not by the A321 certainly by an A321 stretch. To work as a small widebody it'll have to be bigger than that.

What exactly do you base that on?

N14AZ.The truth is nobody knows for certain.Perhaps not even Boeing.But all the pronouncements they have made and those 'close to the matter' suggest it is to be an ovoid fuse seating 2X3X2.That shape alone suggests it will be carbon composite (hardly surprising).I think they have spoken of pax numbers 220-270 range.With range up 5knm If am not mistaken.Engines 45/50lbs thrust.Rolls certainly gonna have a go with their geared ultrafan concept.
But others may know better.

N14AZ wrote:

I haven't followed the recent discussions as I should. So sorry for asking- do we already know if it will be a single or twin aisle? I always thought it'll be a single aisle.

Boeing seems to be fixated on what they call "hybrid cross section": a 767-like 7-abreast passenger cabin with narrowbody-like cargo deck designed to fit LD3-45. Hence, it would be a twin aisle. Easy target for the hypothetical "A322" with new wing, engines and stretched A321 fuselage.

timpdx wrote:

seabosdca wrote:

One-class maximum density: ~299 seats, ~4200 nm with full pax/bags
Domestic US style seating: ~249 seats, ~4500 nm with full pax/bags
International (J/Y) style seating: ~199-215 seats, ~4750 nm with full pax/bags

I like those stats and agree that is a nice slot to put the 797.

That is a modern 767-200. And I see no magical way to stop this from having the same problem in costs as a 767-200 compared to a 757-300, when both planes use similar technology levels and as modern engines

BoeingGuy wrote:

seabosdca wrote:

ElroyJetson wrote:

200-250 pax range 4000-4500nm and CASM at least 10% lower than the A321 neo or 737-10 MAX with equal or lower trip costs.

Do that and you have a winner.

A widebody with 250 max pax would get eaten alive by the A321 IMO, and if not by the A321 certainly by an A321 stretch. To work as a small widebody it'll have to be bigger than that.

What exactly do you base that on?

He means a widebody with 200-250 pax would only have a few seats more than A322 at the cost of a considerably heavier weight. CASM wouldn't look so attractive.

2-3-2 is just too difficult to be justified when compared to a 3-3 configuration IMO. Why add another isle for the sake of gaining one seat only? I know 797 would be implementing newer design techniques that would make it highly efficient. But why wouldn't Boeing apply the same advanced methods to get an even more efficient 3-3 MOM?

seahawk wrote:

That is a modern 767-200. And I see no magical way to stop this from having the same problem in costs as a 767-200 compared to a 757-300, when both planes use similar technology levels and as modern engines

I share your skepticism, but Boeing seems to think that it can make a narrow-walled, CFRP-built 7Y oval fuselage with 17" seats (so a bit narrower and considerably less tall than a 767) work at these lower ranges.

The 767-200 was kind of a perfect storm of inefficiency in hindsight. It turned out once it had its proper engines that it was a 6500 nm plane, way more range than anyone needed at that capacity. It was wider than necessary for 7Y and much heavier than necessary to fly the missions it did even when it was young. I believe that a new small widebody could be vastly more competitive than the 767-200. I don't know if it's good enough to take on an A322 with a bigger wing.

seabosdca wrote:

seahawk wrote:

That is a modern 767-200. And I see no magical way to stop this from having the same problem in costs as a 767-200 compared to a 757-300, when both planes use similar technology levels and as modern engines

I share your skepticism, but Boeing seems to think that it can make a narrow-walled, CFRP-built 7Y oval fuselage with 17" seats (so a bit narrower and considerably less tall than a 767) work at these lower ranges.

The 767-200 was kind of a perfect storm of inefficiency in hindsight. It turned out once it had its proper engines that it was a 6500 nm plane, way more range than anyone needed at that capacity. It was wider than necessary for 7Y and much heavier than necessary to fly the missions it did even when it was young. I believe that a new small widebody could be vastly more competitive than the 767-200. I don't know if it's good enough to take on an A322 with a bigger wing.

Sure, being better than 762 would be easy, but it still would face the same basic problems. You add one aisle for one extra seat. And if you go to LD3-45s for cargo, capacity will be tight in a high density configuration. It also means you end up with a wide oval, which is not nice for load bearing and some of the weight saved by this fuselage form will return for strengthening needed to make the form possible. And like the 767 you are facing problems from the single aisle competition but also from a full site 8 abreast solution, which would be heavier and have more drag, but would also add capacity - especially for cargo. I must say I at the moment I would be confident that it is possible to built an 8 abreast plane that would have an operating cost penalty smaller than the capacity advantage it would offer compared to a wide oval 7 abreast.

Boeing can form all the study groups it wants, but, the wing and fuselage are the least of their challenges. The keys to the next generation jets lies with the engine manufacturers. It's therefore of much more interest to follow the developments at RR, Pratt and GE; whatever they come up with will be followed by Boeing and Airbus projects to fit the new engines - not the other way around.

So all these discussions about 6, 7 or 8 abreast, wide- or narrowbody, oval or circular, means nothing. The trick is the engines.

B777LRF wrote:

Boeing can form all the study groups it wants, but, the wing and fuselage are the least of their challenges. The keys to the next generation jets lies with the engine manufacturers. It's therefore of much more interest to follow the developments at RR, Pratt and GE; whatever they come up with will be followed by Boeing and Airbus projects to fit the new engines - not the other way around.

So all these discussions about 6, 7 or 8 abreast, wide- or narrowbody, oval or circular, means nothing. The trick is the engines.

It is true that engine improvements usually holds the highest contribution to the overall efficiency of airliners, but that does not mean we can just ignore weight and drag altogether. They still play their parts.

B777LRF wrote:

Boeing can form all the study groups it wants, but, the wing and fuselage are the least of their challenges. The keys to the next generation jets lies with the engine manufacturers. It's therefore of much more interest to follow the developments at RR, Pratt and GE; whatever they come up with will be followed by Boeing and Airbus projects to fit the new engines - not the other way around.

So all these discussions about 6, 7 or 8 abreast, wide- or narrowbody, oval or circular, means nothing. The trick is the engines.

Engines are important to get the desired efficiency, but you must assume the same efficiency of the engines when looking at the fuselage and wing design.

seahawk wrote:

B777LRF wrote:

Engines are important to get the desired efficiency, but you must assume the same efficiency of the engines when looking at the fuselage and wing design.

Eyad89 wrote:

B777LRF wrote:

It is true that engine improvements usually holds the highest contribution to the overall efficiency of airliners, but that does not mean we can just ignore weight and drag altogether. They still play their parts.

I agree with both of you, but the basic premise of this thread has the issues backwards: It's engines first, then fuselage and wings. If, just for arguments sake, the next big thing in the engine department turns out to be ducted fans which lends itself to mounting on the aft fuselage, then all previous discussions about fuselage dimensions and wing geometry goes out the window.

Engines first; the rest will follow.

Interesting development. Love to see this come to fruition.

Revelation wrote:

Can someone explain the strong progress around 1970
and the following rebound that takes 10 years to recross the 1970 line?

advent of the Wide Body Airliner?

I like the idea of a 757-300 capacity airliner. Oh yeah, it better look prettier than the 757 (sorry but it's not the best aircraft in terms of looks)

My "gestimate" is the MOM response will be single aisle of 144" internal diameter seating 6 abreast. IMO extra width over the 737 fuselage will be used either to increase aisle width to allow easier loading, but some could go to seat width.
I can't see how a twin aisle response can be less than 176" at 7 abreast. I believe a second aisle requires more than one extra seat width to justify the weight of the extra frame to accommodate it.
The same fuselage dimensions might then be used on the NSA.

Ruscoe

Of course, it should be pointed out that the "inefficient" 762 is still rolling off the line 40 years later (in military guise), having never been re-engined even.

B777LRF wrote:

Boeing can form all the study groups it wants, but, the wing and fuselage are the least of their challenges. The keys to the next generation jets lies with the engine manufacturers. It's therefore of much more interest to follow the developments at RR, Pratt and GE; whatever they come up with will be followed by Boeing and Airbus projects to fit the new engines - not the other way around.

So all these discussions about 6, 7 or 8 abreast, wide- or narrowbody, oval or circular, means nothing. The trick is the engines.

There's probably no modern engine optimized in the thrust rating that Boeing would need. Boeing probably already is working with engine manufacturers and I would expect would be able to get at least one to design an all new engine optimized for this airframe and payload requirements. Getting two engine manufacturers to develop new engines would likely be more challenging.

texl1649 wrote:

Of course, it should be pointed out that the "inefficient" 762 is still rolling off the line 40 years later (in military guise), having never been re-engined even.

The 767 was re-engined in the late 1980s when the ER versions came out. The PW4000 is much different than the original JT9D.

Any rumors on development and program costs??

Or usual $2B, $5B, $8B, $12B and finally $25B.

I can see a double isle 2-4-2 layout. Should be quick to load, they can sell half the seats have direct isle access. I know it's not a fan favorite of any of ours but I'd imagine it'd move the needle.

If Boeing were to scale down the exact 787-8/9/10 design, to a 7 abreast, twin aisle with 757 performance, they would be onto a winner.

It would be cheap to develop too.

Newbiepilot wrote:

texl1649 wrote:

Of course, it should be pointed out that the "inefficient" 762 is still rolling off the line 40 years later (in military guise), having never been re-engined even.

The 767 was re-engined in the late 1980s when the ER versions came out. The PW4000 is much different than the original JT9D.

GE's motor was also replaced, although the CF6 update was more evolution than revolution. Rolls also came to the party with the RB211-524H.

ElroyJetson wrote:

200-250 pax range 4000-4500nm and CASM at least 10% lower than the A321 neo or 737-10 MAX with equal or lower trip costs.

Do that and you have a winner.

Agree, they'll have to resist overspecification.

An oval cross section seems a kind of bad-ish idea from a structural weight / costs point of view, compared to a (near) cylindrical one.

Eyad89 wrote:

BoeingGuy wrote:

seabosdca wrote:

A widebody with 250 max pax would get eaten alive by the A321 IMO, and if not by the A321 certainly by an A321 stretch. To work as a small widebody it'll have to be bigger than that.

What exactly do you base that on?

He means a widebody with 200-250 pax would only have a few seats more than A322 at the cost of a considerably heavier weight. CASM wouldn't look so attractive.

2-3-2 is just too difficult to be justified when compared to a 3-3 configuration IMO. Why add another isle for the sake of gaining one seat only? I know 797 would be implementing newer design techniques that would make it highly efficient. But why wouldn't Boeing apply the same advanced methods to get an even more efficient 3-3 MOM?

Cargo.

Easily justified. Airplanes carry more than just passengers.

Channex757 wrote:

Newbiepilot wrote:

texl1649 wrote:

Of course, it should be pointed out that the "inefficient" 762 is still rolling off the line 40 years later (in military guise), having never been re-engined even.

The 767 was re-engined in the late 1980s when the ER versions came out. The PW4000 is much different than the original JT9D.

GE's motor was also replaced, although the CF6 update was more evolution than revolution. Rolls also came to the party with the RB211-524H.

While the names sound similar the CF6-80A to CF6-80C2 was a big shift. The 80C2 introduced FADEC which has a big impact of fuel control and engine controls being electronic. That's a big change.

However the CF6-80C2 hasn't gone through big step improvements since. It's quite outdated compared to the GEnx. The GEnx is likely too big for a 797 airplane, so GE may come up with a new engine in the same or less thrust rating as the old CF6-80A or RB211 engines.

keesje wrote:

ElroyJetson wrote:

200-250 pax range 4000-4500nm and CASM at least 10% lower than the A321 neo or 737-10 MAX with equal or lower trip costs.

Do that and you have a winner.

Agree, they'll have to resist overspecification.

I think 4500-5000nm would be the better outcome.

Example: United is interested, so DEN/FCO. That's 4850nm.

Over the past few years I ventilated I wouldn't be suprized if this becomes a big narrowbody after all. Because useful technology of a small WB can be applied on a bigger (longer) NB too.

Does this look like a WB? Really?



If a single 30 inch aisle counts for two in practice and Boeing indicates full size LD3's / pallets are out of the picture anyway, why the hassle of a twin aisle, 5000NM .

And what if they Boeing does that small WB and Airbus does a big NB, 10t lighter, 10% more efficient two years later? Yes, they can.

Eyad89 wrote:

He means a widebody with 200-250 pax would only have a few seats more than A322 at the cost of a considerably heavier weight. CASM wouldn't look so attractive.

2-3-2 is just too difficult to be justified when compared to a 3-3 configuration IMO. Why add another isle for the sake of gaining one seat only? I know 797 would be implementing newer design techniques that would make it highly efficient. But why wouldn't Boeing apply the same advanced methods to get an even more efficient 3-3 MOM?

If Boeing goes cleansheet will be a tight 8 abreast for sure. The more seats you have the greater the CASM advantage. Its the only way to get the CASM down low enough to smash the narrow body aircraft. 7 abreast would struggle to match the A321 as you pointed out. A 6 abreast MOM wouldn't offer much extra capacity above the A321, if it had extra range(weight) added then it would probably have similar CASM on short trips.

The dimensions and weights of a cleansheet MOM would be within a couple percent of an A300. The A300 is a perfect example showing just how light an 8 abreast widebody can be if optimised for short range.

With composites and new engines the MOM should be lighter and fly further than the 40 year old A300. An A300 size/weight MOM with modern engines would need only 70% of the A300's fuel capacity to fly 4000nm. The max takeoff would be coming down close to 150T. That is really light. About 80% of the seats of the 787-8 but much lighter.

I'd assume two fuselage lengths, with the shorter aircraft having more range.

I still think Boeing will go with a fully optimised lightweight 787 built for short range efficiency. The 787-8 will then get cancelled with free upgrades to the larger long range 787-9 or the efficient short range lightweight version. It would explain the increased rate of production.

Airliners.net spends a lot of time talking about cabin width. A lot of casual aviation fans don't see much more than the interior of an airplane and a paint scheme from afar. I think that might be why there is so much discussion on width of the cabin and efficiencies from 6, 7, 8 etc abreast seating and 17inch vs 18 inch wide seats. What else are you going to think about while on a long flight sitting in economy? Not as many people pay close attention to the exact geometry of the wing, how many spoilers there are, if the flaps are double slotted and how the wing high lift devices work at low speeds to maximize payload.

In the bigger picture, the fuselage structure is just 10-15% of the entire airframe weight. The added weight of a 7 abreast cabin vs 6 abreast is going to be very small. The engineers can optimize the length, width and diameter of the fuselage for the number of passengers they intend to carry. There is lots of flexibility and shorter fuselages have some positive features as well as narrower fuselages.

What I think really maters is payload and that depends on size of the wing and engines chosen. The 787 wing is 3 times the size of the 737 and the engines have almost 3 times as much thrust. That is where there is a huge gap. Splitting the difference in wing area with a 2500 sq ft wing and engines with 50k lbs thrust could allow a smaller version to have close to the range of a 767 and a larger version to have less range but very low CASM on missions under 2500 miles.

A MTOW in the 250-350K range could open up a lot of sales opportunities for the Asian market. The Asian market that we have today barely existed when the A300 and A310 were designed (Beijing's airport had 12 gates when the A300 entered service and now has over 100). The result is that there are A330s, 787s, and 777s being used on flights under 2000 miles all across Asia. These airplanes have overpowered engines and too large of wings to be efficient in this segment compared to a clean sheet design. Even without step changes in engine technology and optimized wing and engine combo could sell very well.

I think we probably will see a widebody design so that the airplane can have enough capacity to compete against an A330neo flying regional flights between the Middle East and India or regionally in East Asia between destinations like SIN, HKG, TPE, PVG, PEK, CAN, ICN, NRT, KIX, HND etc. The Japanese airlines will have a plane better suited for their short haul market while US carriers will have a lower capacity version best suited for point to point transatlantic and Hawaii.

WIederling wrote:

Revelation wrote:

Can someone explain the strong progress around 1970
and the following rebound that takes 10 years to recross the 1970 line?

advent of the Wide Body Airliner?

I'm not sure of the exact data the chart is derived from, but my guess would be the early 1970s were skewed by the advent of the high bypass ratio turbofan and a lot of 747/DC-10/L10 deliveries, which burned much less fuel on a per-seat basis than the previous generation of jetliners. WB deliveries slowed down post-1973 oil crisis, but airlines were still taking delivery of comparatively less-efficient 727s, 737s, DC-9s, etc. through the decade. I also wonder if Concorde's 1976 EIS contributed to the little spike at mid-decade?

I think if they went twin aisle they might go 2-4-2. That would help with the size vs seat count issue that a 7 abreast design encounters and provide more cargo space.

It may be better for Boeing to go narrowbody with a short version 5500nm range and long version 4250nm range. Dimensions similar to the DC-8 Super 60s?

We have to remind ourselves that certain seats have new value to airline sales than they did just a few years ago. They can sell window/aisle seats at a premium versus middle seats (Economy Saver, etc.). Same can be said of bin/luggage space. I think MOM will be designed with this new market reality in mind, hence, it will be a twin-aisle (2+4+2) A300 with modern, optimized wing and engines, LD3 capability, etc. More aisle seats to up-sell, etc.

If Boeing is smart, they should also should develop a single aisle version, a 737 successor, with smaller wing and de-rated engines, at the same time and manufacture them in parallel just as the 757/767 were.

holzmann wrote:

We have to remind ourselves that certain seats have new value to airline sales than they did just a few years ago. They can sell window/aisle seats at a premium versus middle seats (Economy Saver, etc.). Same can be said of bin/luggage space. I think MOM will be designed with this new market reality in mind, hence, it will be a twin-aisle (2+4+2) A300 with modern, optimized wing and engines, LD3 capability, etc. More aisle seats to up-sell, etc.

If Boeing is smart, they should also should develop a single aisle version, a 737 successor, with smaller wing and de-rated engines, at the same time and manufacture them in parallel just as the 757/767 were.

Too early to start producing the 737 replacement. It will be MOM first and then 737 replacement.

I don't understand those who claim that 4500nm range will be perfect. In my opinion that is 1000nm too short. It leaves out a lot of TATL and Intra-Asian routes. If they're going to spend billions on making an all new airliner, designing it with too short range would be a massive waste.

JetBuddy wrote:

I don't understand those who claim that 4500nm range will be perfect. In my opinion that is 1000nm too short. It leaves out a lot of TATL and Intra-Asian routes. If they're going to spend billions on making an all new airliner, designing it with too short range would be a massive waste.

It could be but look at the huge market between the Middle East and India and flights under 6 hours in Asia. If the airframe is too heavy with 5500nm range, it might not have low enough operating costs or acquisitions costs to undercut the A330 in the Asia and Middle Eastern markets.

A plane optimized in 2017 for 4500 miles likely will gain at least 500 miles range by 2030.

A plane optimized in 2017 for 4500 miles likely will gain at least 500 miles range by 2030.