Boeing 797 Discussion Thread - 2018

keesje · Fri Oct 13, 2017 4:09 pm

RJMAZ wrote:
I made it myself.

a brother

Some good considerations in there.

Polot · Fri Oct 13, 2017 5:10 pm

mjoelnir wrote:
Every now existing wide body uses containers, is really somebody believing that if the 797 will come it will be without containers? I do not know about the LD3-45, it could be a new size special to the 797.
Apart from that, I believe Airbus could counter with a new "A310" not that bird, but a new frame in that form factor.

I doubt Airbus would counter with a new frame, unless the 797 comes out the gate a roaring success. The market size for 2 all new frames in this market is very questionable. I suspect Airbus will stick with their neo plus plus idea and focus on beating the 797 on the lower end of the market and concede the upper end for now until they ready to evaluate the long term future of the A330neo.

RJMAZ · Fri Oct 13, 2017 10:24 pm

Another cross section idea using a simple circular fuselage for a tight 8 abreast.

30cm narrower than the A330 tube and 30cm wider than the 767 comfortable 7AB. Using the narrower LD2 containers allows them to sit slightly lower down as you can see in the image.

Note the height is actually less than the double bubble 767 fuselage.

The weights and sizes from the previously image would still be applicable.

Boeing778X · Fri Oct 13, 2017 10:50 pm

Seems like the MoM is a done deal. I'm hearing rumblings of further details coming, and a few sources have even said the 797 may actually be launched formally at Dubai next month.

Not ready to put money on that just yet, but the 797 seems to be beyond just a concept at this point regardless

The issue I'm curious about is the technology incorporated into this aircraft, and how it will affect further products down the road. Obviously, it's heavily influenced by the 787, but it is my belief that the technology is getting to the point where an NSA 737 replacement may start to be viable, or at least, the development of it.

AAlaxfan · Fri Oct 13, 2017 10:52 pm

RJMAZ wrote:

Another cross section idea using a simple circular fuselage for a tight 8 abreast.

30cm narrower than the A330 tube and 30cm wider than the 767 comfortable 7AB. Using the narrower LD2 containers allows them to sit slightly lower down as you can see in the image.

Note the height is actually less than the double bubble 767 fuselage.

The weights and sizes from the previously image would still be applicable.

Is there a rule that says you have to have 2" armrests. If you go 1.5" on the aisle and window seats on the outer seats and 1.5"s on both the armrests for the aisle seats on the set of 4 inner seats you can have 18" seats all across.

RJMAZ · Sat Oct 14, 2017 12:21 am

AAlaxfan wrote:
Is there a rule that says you have to have 2" armrests. If you go 1.5" on the aisle and window seats on the outer seats and 1.5"s on both the armrests for the aisle seats on the set of 4 inner seats you can have 18" seats all across.

You could do that but you don't gain any extra shoulder room. Either way the seats and aisle width are the same as a 737.

Being a short widebody you could knock an inch off each aisle. Boarding would still be fairly quick.

parapente · Sat Oct 14, 2017 10:32 am

We are at the beginning of a revolution in gas turbines with gearing.The fact that P&W are doing their best to muck it up for themselves should not blindside the obvious advantages that it confers.Their GTF has a fairly conservative gearing.
The next gen will rotate slower and have a further increase in bypass.
The next gen (797 -50klbs thrust) will also be considerably bigger.Thus the fan diameter will be huge.
IMHO this will put a considerable strain on using the classic conventional (low wing)aircraft design.The wings have to be suboptimal due to wing bend for engine ground clearance/and or an MLG that is much longer/heavier than necessary.

Their may be a point coming where they will need to look at a high wing design that will -at a stroke -eliminate both these major issues.

CRHoward · Sat Oct 14, 2017 1:58 pm

I am very curious to find out if Boeing's initial statement that the 797 would be 7Y seating was a ruse. If they do go with 8Y, the a330neo will be squeezed by the 797 from below just as it is by the 787 from above. I don't understand why Airbus is waiting. Their current projects of the a350-1000 and neo upgrades are just about complete. They have the resources and talent to get a new clean sheet aircraft to the market and they are letting Boeing get to the market first. A market that may not be big enough for two. Saying time is on their side doesn't make it so.

Eyad89 · Sat Oct 14, 2017 2:45 pm

RJMAZ wrote:
Stitch wrote:
Scores of thousands of kilograms less weight is what justifies it.

The 787-8 has an OEM OEW of 118,000kg. I expect MoM to come in around the 85,000 kilogram mark (around a 767-300ER). That is over 50,000 kilograms lighter and that is going to be huge in terms of trip fuel savings. That will also allow engines designed around 50,000 pounds of thrust to be used, as opposed to the 787's, which are designed around 75,000 pounds.

Something along the lines of this?

Interesting proposal indeed. I have some questions though?

- you proposed a 797-8 that has 200 seats in a 2 class configuration. If we look at 762, we will find it to be able to seat 216 in a 2 class configuration. Thing is, 762 is 1.5m longer, but it would also have one less passenger per row. I guess 797-8 on your proposed dimensions would hit 230 passengers.

- your proposed 797-10 would be 58m long with 8 seats per row. That is the exact size of A338/A332. But you assumed that it would be lighter by 35t or 41%. That’s a lot. Composite materials wouldn’t do that much alone. How smaller did you make its wings, and how smaller is its MTOW?

Intersting proposal though. I still wonder about the wing span and area that you proposed.

Boeing778X · Sat Oct 14, 2017 2:49 pm

CRHoward wrote:
I am very curious to find out if Boeing's initial statement that the 797 would be 7Y seating was a ruse. If they do go with 8Y, the a330neo will be squeezed by the 797 from below just as it is by the 787 from above. I don't understand why Airbus is waiting. Their current projects of the a350-1000 and neo upgrades are just about complete. They have the resources and talent to get a new clean sheet aircraft to the market and they are letting Boeing get to the market first. A market that may not be big enough for two. Saying time is on their side doesn't make it so.

Airbus in convinced they won the MoM market already with the A321neo/A321LR. They can also stretch, rewing and reengine the A321neo if they wanted to.

Revelation · Sat Oct 14, 2017 3:07 pm

parapente wrote:
We are at the beginning of a revolution in gas turbines with gearing.The fact that P&W are doing their best to muck it up for themselves should not blindside the obvious advantages that it confers.Their GTF has a fairly conservative gearing.
The next gen will rotate slower and have a further increase in bypass.
The next gen (797 -50klbs thrust) will also be considerably bigger.Thus the fan diameter will be huge.
IMHO this will put a considerable strain on using the classic conventional (low wing)aircraft design.The wings have to be suboptimal due to wing bend for engine ground clearance/and or an MLG that is much longer/heavier than necessary.

Their may be a point coming where they will need to look at a high wing design that will -at a stroke -eliminate both these major issues.

Interesting timing on your comments.

Pratt & Whitney Successfully Tests Next-Generation Pure Power® Geared Turbofan™ Technology as Part of FAA Sustainability Program ( a non copyrighted press release ) says:

Pratt & Whitney, a division of United Technologies Corp. (NYSE:UTX), recently completed more than 175 hours of ground testing of a next-generation Geared Turbofan (GTF) engine propulsor technology as part of the Federal Aviation Administration's (FAA) Continuous Lower Energy, Emissions and Noise (CLEEN) program, an FAA NextGen initiative to accelerate the development of environmentally-friendly aircraft technologies.
...
The demonstrator used an existing development engine from a certified Geared TurboFan product to validate the performance capability of a second-generation, ultra-high bypass fan design. The engine successfully operated in a design space never before demonstrated with significantly fewer lower-pressure ratio blades than the current production engine, and a shorter duct inlet. The rig and engine tests are expected to demonstrate a suite of technologies that will help reduce fuel burn by an additional 2 percent.

So we're moving forward as time is marching on. Since they're using an existing engine as a "mule" it's not a huge "leap" in technology, but PW at least is gaining a better understanding of the design space.

seahawk · Sat Oct 14, 2017 4:11 pm

Engine makers are gearing up for the MoM.

CRHoward · Sat Oct 14, 2017 4:11 pm

boe778x wrote:

Airbus in convinced they won the MoM market already with the A321neo/A321LR. They can also stretch, rewing and reengine the A321neo if they wanted to.

I agree but that is short sighted. When the next generation of narrow body aircraft arrives the lower end of the MoM will be up for grabs again and it will again go to the first to market.

texl1649 · Sat Oct 14, 2017 4:12 pm

It is interesting and obviously the trend, but we can almost be certain Boeing won't launch a new model dependant on a new Pratt engine. [url]The Aurora D8, however, is now a design to which Boeing owns the IP rights[/url]. Though this aircraft certainly isn't going to simply be enlarged/produced, I think it's likely the patent portfolio of concepts/applications is a big reason why Boeing ponied up for Aurora. Of some note is that, yes, in the 'double bubble' D8 there were support braces running top to bottom.

https://www.nasa.gov/content/the-double-bubble-d8-0

keesje · Sat Oct 14, 2017 4:37 pm

A 797 won't show up at the gate before 2025. That means A has some time to see, review, discuss and position.

Newbiepilot · Sat Oct 14, 2017 5:13 pm

Boeing778X wrote:
Seems like the MoM is a done deal. I'm hearing rumblings of further details coming, and a few sources have even said the 797 may actually be launched formally at Dubai next month.

Not ready to put money on that just yet, but the 797 seems to be beyond just a concept at this point regardless

The issue I'm curious about is the technology incorporated into this aircraft, and how it will affect further products down the road. Obviously, it's heavily influenced by the 787, but it is my belief that the technology is getting to the point where an NSA 737 replacement may start to be viable, or at least, the development of it.

I think Dubai is still too early for a launch. They will probably launch with a half dozen airlines committing to it, and I think it is too early for that.

Stitch · Sat Oct 14, 2017 6:14 pm

Newbiepilot wrote:
I think Dubai is still too early for a launch. They will probably launch with a half dozen airlines committing to it, and I think it is too early for that.

Agreed Dubai doesn't really make any sense. The 777X launched there because ME airlines were by far the largest customers for the type. Unless flydubai plans to take the first couple of years of production, to me it seems much more likely that a launch would be Farnborough 2018 or Paris 2019.

Boeing778X · Sat Oct 14, 2017 6:37 pm

Newbiepilot wrote:
Boeing778X wrote:
Seems like the MoM is a done deal. I'm hearing rumblings of further details coming, and a few sources have even said the 797 may actually be launched formally at Dubai next month.

Not ready to put money on that just yet, but the 797 seems to be beyond just a concept at this point regardless

The issue I'm curious about is the technology incorporated into this aircraft, and how it will affect further products down the road. Obviously, it's heavily influenced by the 787, but it is my belief that the technology is getting to the point where an NSA 737 replacement may start to be viable, or at least, the development of it.

I think Dubai is still too early for a launch. They will probably launch with a half dozen airlines committing to it, and I think it is too early for that.

Agreed, but it's going to be soon. And considering the nature of the aircraft, I think 6 launch customers off the bat could be met very easily.

Norwegian has expressed their great interested in the type, they'd be one of the first. 757 and 767s in service beyond 2020, especially within the US3s are other areas to watch, and AA is a prime potential customer, IMHO. Something above the A321neo and below the A330-200/787-8 fills that perfectly.

lightsaber · Sat Oct 14, 2017 7:08 pm

Parapente,
The GTF is a game changer. Pratt's processes are out of date and they don't know it.

.

The Pratt MoM proposal would use a 3.5:1 gearbox that allows a more efficient and higher pressure ratio low compressor. It also allows a more efficient low turbine.

The PW1500G was optimized for a 1.5 hour mission and the PW1100G for 2 hours. At the longer MoM missions, I fully expect a 4 stage low turbine to enable a higher bypass ratio. This creates a plane, if combined with 8-across cross section, would be competitive on 3+ hour missions.

I expect a CFRP folding wingtip wing. But what wingspan? Before fold. The less fold,the more fuel...

AAlaxfan wrote:
RJMAZ wrote:

Another cross section idea using a simple circular fuselage for a tight 8 abreast.

30cm narrower than the A330 tube and 30cm wider than the 767 comfortable 7AB. Using the narrower LD2 containers allows them to sit slightly lower down as you can see in the image.

Note the height is actually less than the double bubble 767 fuselage.

The weights and sizes from the previously image would still be applicable.

Is there a rule that says you have to have 2" armrests. If you go 1.5" on the aisle and window seats on the outer seats and 1.5"s on both the armrests for the aisle seats on the set of 4 inner seats you can have 18" seats all across.

I like this concept. It makes far more sense to me than 7 across.

Lightsaber

neutrino · Sat Oct 14, 2017 7:16 pm

keesje wrote:
A 797 won't show up at the gate before 2025. That means A has some time to see, review, discuss and position.

The key is how much time they will take "to see, review, discuss and position". One year? Four years Eight years? Who knows!

Newbiepilot · Sat Oct 14, 2017 8:49 pm

neutrino wrote:
keesje wrote:
A 797 won't show up at the gate before 2025. That means A has some time to see, review, discuss and position.

The key is how much time they will take "to see, review, discuss and position". One year? Four years Eight years? Who knows!

It is hard to know. The A350/A330neo response to the 787 took a very long time.

I think it will be interesting to see how the market changes. I'm excited to see a 797 starting to become more serious.

keesje · Sat Oct 14, 2017 9:02 pm

It reminds of 2010. Everybody was focussing on the Boeing NSA that was going to change everything.

Airbus pre-empted with the NEO & quickly sold 1000. At that stage Boeing couldn't start a 7 year development process no more.

Newbiepilot · Sat Oct 14, 2017 9:25 pm

keesje wrote:
It reminds of 2010. Everybody was focussing on the Boeing NSA that was going to change everything.

Airbus pre-empted with the NEO & quickly sold 1000. At that stage Boeing couldn't start a 7 year development process no more.

It also reminds me of 2003 when Airbus was focused 4 engines 4 long haul with the A340 and A380 and took years to conclude they needed an all new twin engine airplane rather than refreshing their existing planes to respond to the 787.

keesje · Sat Oct 14, 2017 10:33 pm

Newbiepilot wrote:
keesje wrote:
It reminds of 2010. Everybody was focussing on the Boeing NSA that was going to change everything.

Airbus pre-empted with the NEO & quickly sold 1000. At that stage Boeing couldn't start a 7 year development process no more.

It also reminds me of 2003 when Airbus was focused 4 engines 4 long haul with the A340 and A380 and took years to conclude they needed an all new twin engine airplane rather than refreshing their existing planes to respond to the 787.

Correct and the 1000 existing A330s sold since 2003 perfectly fit into these memories.

PlanesNTrains · Sun Oct 15, 2017 2:57 am

keesje wrote:
Newbiepilot wrote:
keesje wrote:
It reminds of 2010. Everybody was focussing on the Boeing NSA that was going to change everything.

Airbus pre-empted with the NEO & quickly sold 1000. At that stage Boeing couldn't start a 7 year development process no more.

It also reminds me of 2003 when Airbus was focused 4 engines 4 long haul with the A340 and A380 and took years to conclude they needed an all new twin engine airplane rather than refreshing their existing planes to respond to the 787.

Correct and the 1000 existing A330s sold since 2003 perfectly fit into these memories.

Sure, just not this thread.

seahawk · Sun Oct 15, 2017 3:10 am

I do not believe they will use folding wings. It will be a category D aircraft anyway and 52m should be enough.

DaufuskieGuy · Sun Oct 15, 2017 4:41 am

[/quote]

I think Dubai is still too early for a launch. They will probably launch with a half dozen airlines committing to it, and I think it is too early for that.[/quote]

Agreed, but it's going to be soon. And considering the nature of the aircraft, I think 6 launch customers off the bat could be met very easily.

Norwegian has expressed their great interested in the type, they'd be one of the first. 757 and 767s in service beyond 2020, especially within the US3s are other areas to watch, and AA is a prime potential customer, IMHO. Something above the A321neo and below the A330-200/787-8 fills that perfectly.[/quote]

i'd think ua and dl are just as likely given their sizable and aging 757/767 (and 777A for ua) fleets that are running just the transcon, tatl, hawaii and hub to hub routes the 797 is designed for

ikramerica · Sun Oct 15, 2017 5:00 am

The problem with 8Y is it makes the 797 either too big (capacity) for its mission or too short and stubby like the 762 and A310, which is suboptimal.

These proposals show that the A330/A300 and 767 are too wide by today's cram the pax in standards. Your choice is a size between the 2 for 8Y, or one between the A320 and 767 at 7Y. The latter allows for a more optimal length when sized for the capacity the 797 is slotted for. It also allows for more containers per pax than a stubby 8Y.

william · Sun Oct 15, 2017 5:04 am

RJMAZ wrote:
That cross section provides perfect loading under pressure. Similar to an ATR72. It provides 90% of the advantages of an oval design in terms of surface area and none of the disadvantages. An oval design simply wont work and will always be trying to form a circle under pressure. So it would need to be either super thick and heavy or have a support column in the middle of the cabin.

8 wide is more efficient too than 7 abreast making it worth having the second Aisle.

The fuselage height is only 4.5metres high so the shortest design at 46metres long is actually more slender than a 767-200 and a 787-8. The cabin length would be the same as the A321. But with 8 vs 6 seats in the width that still has 33% more seats in full economy. So it has to be fairly short for an 8 abreast cabin.

I'd expect the 797-8 version to be fairly niche. As the shortest version of any family usually has the worst CASM. I calculate its CASM would actually be similar to a 787-8. So the only advantage would be total trip cost.

The 797-9 would carry more passengers with very little increase in trip cost. So it's CASM would now beat all of the widebody aircraft on medium haul routes across the atlantic.

The 797-10 carries even more passengers with only a further tiny increase in trip costs. Its CASM would now reach narrowbody territory. Its structual weight per seat would equal the A321 with 75% more seats for 75% more weight. So under 1000nm there would be no cost penalty to upsize congested routes.

Return of the domestic widebody?

ikramerica · Sun Oct 15, 2017 5:15 am

4.8m wide, 5.15m tall. If you are going to use the less spacious LD2, you need more of them. 7y gives you 1/7th more container space.

DaufuskieGuy · Sun Oct 15, 2017 5:51 am

ikramerica wrote:
The problem with 8Y is it makes the 797 either too big (capacity) for its mission or too short and stubby like the 762 and A310, which is suboptimal.

These proposals show that the A330/A300 and 767 are too wide by today's cram the pax in standards. Your choice is a size between the 2 for 8Y, or one between the A320 and 767 at 7Y. The latter allows for a more optimal length when sized for the capacity the 797 is slotted for. It also allows for more containers per pax than a stubby 8Y.

desirable airports like LGA, DCA, LAX, SFO, SEA, BOS etc. are going to have great difficulty expanding (and in some cases will never expand) so the only solution will be to upguage. Plus hub to hub routes, Hawaii/FL routes, anywhere a 753 is deployed is a good route for the 797

WIederling · Sun Oct 15, 2017 8:17 am

Newbiepilot wrote:
It also reminds me of 2003 when Airbus was focused 4 engines 4 long haul with the A340 and A380 and took years to conclude they needed an all new twin engine airplane rather than refreshing their existing planes to respond to the 787.

Yes, It took Airbus ages to realize that you can't counter a meme driven hype(er) object with "real, down to earth" hardware.
IMU the same could be said about Twin vs Quad. ( see the A340-300 vs 777-200ER topic. )
Boeing ( American companies in general ) appear to be much better at creating perfect PR storms.

The XWB was less of an answer to the 787 than an attack on the 777 range.
Final answer to the 787 was to have the A330 slog on ( due to the PR intrinsic 787 project issues successfully at that )

Newbiepilot · Sun Oct 15, 2017 10:51 am

Regardless of what the 797 is, I expect Airbus will find a way to respond. We have a thread for that topic already

viewtopic.php?t=1374459

I expect Boeing has already thought about how Airbus can respond. That might be why the airplane is looking to be bigger than a A321/757 and go after 767s, 787s and A330s that aren't being used near their MTOW.

RJMAZ · Sun Oct 15, 2017 11:08 am

[quote="Eyad89"]your proposed 797-10 would be 58m long with 8 seats per row. That is the exact size of A338/A332. But you assumed that it would be lighter by 35t or 41%. That’s a lot. Composite materials wouldn’t do that much alone. How smaller did you make its wings, and how smaller is its MTOW?.[/quote]
The A330 carries 139,000litres of fuel.

The A310 and this 797 carries only 60,000 litres.

That is an extra 60T of fuel to lift. That's required a huge wing in size and volume to lift and carry that much fuel. The landing gear then needs to be stronger and heavier. The engines need to much bigger and heavier to produce the extra thrust. That is where the extra 35T has gone.

The wings are designed to lift a certain weight. The A310 wings which are 44m can lift 165T which is more than the weight of this aircraft.

enzo011 · Sun Oct 15, 2017 11:29 am

Newbiepilot wrote:
It also reminds me of 2003 when Airbus was focused 4 engines 4 long haul with the A340 and A380 and took years to conclude they needed an all new twin engine airplane rather than refreshing their existing planes to respond to the 787.

Wasn't that the Virgin Atlantic slogan? You seem to either want to rewrite a bit of history or just not remembering what happened at that time. Airbus couldn't respond to the 787 in a timely fashion as they were busy with trying to get the A380 ready for production and service. There isn't a infinite amount of resources at either Boeing or Airbus to respond to the competition. So while we would like either company to just quickly respond when the competition launches a new model or design it may not always be possible.

morrisond · Sun Oct 15, 2017 12:33 pm

RJMAZ wrote:
Stitch wrote:
Scores of thousands of kilograms less weight is what justifies it.

The 787-8 has an OEM OEW of 118,000kg. I expect MoM to come in around the 85,000 kilogram mark (around a 767-300ER). That is over 50,000 kilograms lighter and that is going to be huge in terms of trip fuel savings. That will also allow engines designed around 50,000 pounds of thrust to be used, as opposed to the 787's, which are designed around 75,000 pounds.

Something along the lines of this?

RJMAZ - That's a beautiful diagram - however your diagram is misrepresenting how wide an LD3-45 actually is and how much wasted space there would be in the cargo hold with an 8W fuselage and an LD3-45.

Redraw your diagram in 7W with a proper LD3-45 Width (they are only 95" Wide across at the top - 62" at the bottom and 45" Tall) and then you will have what I think the 797 will be - less than 190" wide and less than 170" tall. Yours is way to close to the 787, and the 787 cross section is to close to the 777.

I think many are overthinking the Seating Capacity of the 797. I think you have to think of it in Single Aisle Terms - If an A321 is 230-240 in Sardine Class - the 797 would be 270-280 in sardine configuration, same length (or a little shorter to keep weight down) but 1 seat wider.

If an AA 321 V3 is 16 Business, 18 Y+ and 153 Y = 187 total - the 797 would be 20-24 Business(depending on 2x1x2 or 2x2x2), 21 Y+ and 179 Y = about 220 Total - or about 270 in sardine class.

mjoelnir · Sun Oct 15, 2017 12:36 pm

enzo011 wrote:
Newbiepilot wrote:
It also reminds me of 2003 when Airbus was focused 4 engines 4 long haul with the A340 and A380 and took years to conclude they needed an all new twin engine airplane rather than refreshing their existing planes to respond to the 787.

Wasn't that the Virgin Atlantic slogan? You seem to either want to rewrite a bit of history or just not remembering what happened at that time. Airbus couldn't respond to the 787 in a timely fashion as they were busy with trying to get the A380 ready for production and service. There isn't a infinite amount of resources at either Boeing or Airbus to respond to the competition. So while we would like either company to just quickly respond when the competition launches a new model or design it may not always be possible.

Airbus response to the 787 at that time was selling heaps of A330, there was no need for a panic response.

RJMAZ · Sun Oct 15, 2017 1:22 pm

morrisond wrote:
I think many are overthinking the Seating Capacity of the 797. I think you have to think of it in Single Aisle Terms - If an A321 is 230-240 in Sardine Class - the 797 would be 270-280 in sardine configuration, same length (or a little shorter to keep weight down) but 1 seat wider.

If an AA 321 V3 is 16 Business, 18 Y+ and 153 Y = 187 total - the 797 would be 20-24 Business(depending on 2x1x2 or 2x2x2), 21 Y+ and 179 Y = about 220 Total - or about 270 in sardine class.

The 797-8 would have the same cabin length as the A321. 8 abreast vs 6 abreast is 33% more seats. Your calculations all use 7 abreast.

So if you want to compare an A321 in 240 seat in 28 pitch sardine config the 797-8 would be 320 seats.

The 797-9 would be 384 seats. 8 extra rows of 8.

The 797-10 would be 448 seats. 8 extra rows of 8. Think about that many passengers flying a short 500nm trip.

Let's compare 3 class.
AA 321 V3 is 16 Business, 18 Y+ and 153 Y = 187 total.

The 797-8 would be 24 business 24 Y+ and 204Y =252

797-9 would be 30 business. 32 Y+ and 236Y = 298

797-10 would be 36 business, 40Y+ and 268Y = 344 seats

lightsaber · Sun Oct 15, 2017 1:55 pm

mjoelnir wrote:
enzo011 wrote:
Newbiepilot wrote:
It also reminds me of 2003 when Airbus was focused 4 engines 4 long haul with the A340 and A380 and took years to conclude they needed an all new twin engine airplane rather than refreshing their existing planes to respond to the 787.

Wasn't that the Virgin Atlantic slogan? You seem to either want to rewrite a bit of history or just not remembering what happened at that time. Airbus couldn't respond to the 787 in a timely fashion as they were busy with trying to get the A380 ready for production and service. There isn't a infinite amount of resources at either Boeing or Airbus to respond to the competition. So while we would like either company to just quickly respond when the competition launches a new model or design it may not always be possible.

Airbus response to the 787 at that time was selling heaps of A330, there was no need for a panic response.

The issue is the 7+ year time lag to respond. Airbus took too long and A330 deliveries tapered off earlier than expected (prior to full A350 production ramp). While the A330 is a great design, its time has come. Airbus gave Boeing time to solve their problems and develop the 787-10. If Boeing hadn't lacked definition on the 787 (seriously, the most critical dimension is wingbox length and Mitsubishi delivered a wingbox within specification/drawing 1cm smaller than Boeing expected... And the wing/body join going multiple tons over plan). You cannot expect a competitor to fail. Airbus was lucky.

Lightsaber

neutrino · Sun Oct 15, 2017 2:03 pm

enzo011 wrote:
Newbiepilot wrote:
It also reminds me of 2003 when Airbus was focused 4 engines 4 long haul with the A340 and A380 and took years to conclude they needed an all new twin engine airplane rather than refreshing their existing planes to respond to the 787.

Wasn't that the Virgin Atlantic slogan? You seem to either want to rewrite a bit of history or just not remembering what happened at that time. Airbus couldn't respond to the 787 in a timely fashion as they were busy with trying to get the A380 ready for production and service. There isn't a infinite amount of resources at either Boeing or Airbus to respond to the competition. So while we would like either company to just quickly respond when the competition launches a new model or design it may not always be possible.

Actually, it looks like you are the one trying "to rewrite a bit of history" or maybe you are just plain forgetful, or something else.....
That slogan originated from Airbus. Virgin simply adopted it. Hope this is now clear to you. If not, Mr Google can help further. Cheers.

c933103 · Sun Oct 15, 2017 2:15 pm

RJMAZ wrote:
The 797-8 would have the same cabin length as the A321. 8 abreast vs 6 abreast is 33% more seats. Your calculations all use 7 abreast.

So if you want to compare an A321 in 240 seat in 28 pitch sardine config the 797-8 would be 320 seats.

The 797-9 would be 384 seats. 8 extra rows of 8.

The 797-10 would be 448 seats. 8 extra rows of 8. Think about that many passengers flying a short 500nm trip.

Let's compare 3 class.
AA 321 V3 is 16 Business, 18 Y+ and 153 Y = 187 total.

The 797-8 would be 24 business 24 Y+ and 204Y =252

797-9 would be 30 business. 32 Y+ and 236Y = 298

797-10 would be 36 business, 40Y+ and 268Y = 344 seats

That would probably be too much capacity to what have been proposed, hence most likely it won't go to 8-abreast, and could instead be 7-abreast. As a widebody it could also start at a length shorter than A321

parapente · Sun Oct 15, 2017 2:19 pm

Yes they were lucky Lightsaber.Getting a 'free'5 years due to Boeing problems was lucky.But note it (330) was and is a good product,that also helped.
Where they were smart IMHO was blindsiding everybody when finally (mark3?) when they accepted the sales the 788(9) had already got and switched their aim to the aging 772er (and latterly the 773er).It is true they hoped that they could get away with a 350 shrink (wrong) but what were they supposed to do?The required engine for the 330Neo has only now come into existence.
Whether this will be too little too late or manage to keep a %age of that market who knows.They seem to be doing 'ok' so far but early days.

Oddly enough (looking at all these slimline X8 abreast ideas).I think they are probably more appropriate for Airbus (330 replacement) in about 5 + years time rather than Boeing!

As has been said ( and hell Airbus actually offered a stretched 322 15 odd years ago) Airbus can get to (one class) 250 pax with a 322 and most likely use the existing engine (developed).Not an area they need to build a new aircraft for right now,

CHI87LG · Sun Oct 15, 2017 2:29 pm

I just hope Boeing has learned from the past 30 years that the middle-range model never does particularly well. Don't launch three planes. Make a big and a little 797, and then make a bigger one later.

ikramerica · Sun Oct 15, 2017 2:35 pm

morrisond wrote:
RJMAZ wrote:
Stitch wrote:
Scores of thousands of kilograms less weight is what justifies it.

The 787-8 has an OEM OEW of 118,000kg. I expect MoM to come in around the 85,000 kilogram mark (around a 767-300ER). That is over 50,000 kilograms lighter and that is going to be huge in terms of trip fuel savings. That will also allow engines designed around 50,000 pounds of thrust to be used, as opposed to the 787's, which are designed around 75,000 pounds.

Something along the lines of this?

RJMAZ - That's a beautiful diagram - however your diagram is misrepresenting how wide an LD3-45 actually is and how much wasted space there would be in the cargo hold with an 8W fuselage and an LD3-45.

Redraw your diagram in 7W with a proper LD3-45 Width (they are only 95" Wide across at the top - 62" at the bottom and 45" Tall) and then you will have what I think the 797 will be - less than 190" wide and less than 170" tall. Yours is way to close to the 787, and the 787 cross section is to close to the 777.

I think many are overthinking the Seating Capacity of the 797. I think you have to think of it in Single Aisle Terms - If an A321 is 230-240 in Sardine Class - the 797 would be 270-280 in sardine configuration, same length (or a little shorter to keep weight down) but 1 seat wider.

If an AA 321 V3 is 16 Business, 18 Y+ and 153 Y = 187 total - the 797 would be 20-24 Business(depending on 2x1x2 or 2x2x2), 21 Y+ and 179 Y = about 220 Total - or about 270 in sardine class.

The LD3-45 is not efficient in a wide body. The LD2 is almost as much capacity and the double version LD8 is nearly double. An LD8 hold can also accommodate a single LD3 or an LD3-45 in the same space, as well as standard height and width wide body pallets. The 797 would be crippled as a large regional aircraft in many parts of the world if limited to LD3-45 and short pallets.

morrisond · Sun Oct 15, 2017 3:16 pm

Here is a good graphic of what the 797 cross section will more likely be - compared to those above and below. I think this is pretty much on the money.

https://s.yimg.com/fz/api/res/1.2/iaCbn ... 9x1024.png

WIederling · Sun Oct 15, 2017 4:14 pm

morrisond wrote:
Here is a good graphic of what the 797 cross section will more likely be - compared to those above and below. I think this is pretty much on the money.

https://s.yimg.com/fz/api/res/1.2/iaCbn ... 9x1024.png

That is a .5m delta in length of major axis. to keep the form the floor has to take ~2.5..3t/m compression force
( cabin height 6000', cruise level ~36k' ) with a design layout for "no buckling"
( quite a bit heavier than the same forces in tension.)

morrisond · Sun Oct 15, 2017 4:59 pm

As has been pointed out many times a Composite barrel in this size class has excess strength due to have to account for impact loads. It may have the extra strength needed for an oval.

WIederling · Sun Oct 15, 2017 5:15 pm

morrisond wrote:
As has been pointed out many times a Composite barrel in this size class has excess strength due to have to account for impact loads. It may have the extra strength needed for an oval.

".. pointed out many times a Composite barrel .."

oh, sure.
Hoop stresses are of no importance here. ( though circumferential skin tension is ~14..15t/m )
What is important is the forces that need to be brought to bear to keep the oval form.

a thin walled cylinder does have no form stability. pressurized it will turn round what ever oblong you start with.

mjoelnir · Sun Oct 15, 2017 6:52 pm

lightsaber wrote:
mjoelnir wrote:
enzo011 wrote:

Wasn't that the Virgin Atlantic slogan? You seem to either want to rewrite a bit of history or just not remembering what happened at that time. Airbus couldn't respond to the 787 in a timely fashion as they were busy with trying to get the A380 ready for production and service. There isn't a infinite amount of resources at either Boeing or Airbus to respond to the competition. So while we would like either company to just quickly respond when the competition launches a new model or design it may not always be possible.

Airbus response to the 787 at that time was selling heaps of A330, there was no need for a panic response.

The issue is the 7+ year time lag to respond. Airbus took too long and A330 deliveries tapered off earlier than expected (prior to full A350 production ramp). While the A330 is a great design, its time has come. Airbus gave Boeing time to solve their problems and develop the 787-10. If Boeing hadn't lacked definition on the 787 (seriously, the most critical dimension is wingbox length and Mitsubishi delivered a wingbox within specification/drawing 1cm smaller than Boeing expected... And the wing/body join going multiple tons over plan). You cannot expect a competitor to fail. Airbus was lucky.

Lightsaber

You should not look at one side only. Boeing was similar lucky. Airbus had it's fuck up with the production start of the A380, that took a few years engineering capacity from any other program at Airbus at that time. Without that we could possible look at a fully ramped A350 program by now. On the other hand the A350 today profited from further advances in engine technology, so chance is, that negative and positive developments just could cancel out. All the time Airbus has been the under dog and increasing market share through the years.

ikramerica · Sun Oct 15, 2017 7:12 pm

morrisond wrote:
Here is a good graphic of what the 797 cross section will more likely be - compared to those above and below. I think this is pretty much on the money.

https://s.yimg.com/fz/api/res/1.2/iaCbn ... 9x1024.png

No way. It will be round or taller than long. It's not going to be wider than tall. Further there is no need to be 5m wide at 7Y with 17.2" seats and sculpted side walls. A modern design could be almost 1 foot narrower than the 767.

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