I put some data together on new generation narrowbody aircraft, including a few concepts.

A lot of work because much is unpublished and can only be estimated based out of graphs, drawings and bit and pieces from articles. I did a lot of interpolations, and did checks to see if data / performance isn't to good to be truth, reasonable. OE marketing "brochure" data most serves the goal to make your product looks best, leaving out critical conditions.

There is a lot to be told on assumptions, choices, calculations and estimations. Many variables are customer specified. In case of questions I can share.
- Aircraft types are lined up by single class seat capacity, referenced by available cabin length.


keesje

Row 19 is an overall score, weighing Efficiency 2 as important as Capability & Runway performance.

Pls let me know if you see enhancements. I see small errors myself already Maybe add E195-E2 ?

theres a fly in my soup.

Some of the seat counts are off, A321 singe class high density would be over 218. Examples, JQ @ 230, U2 @ 235 and W6 @ 239

a320fan wrote:

Some of the seat counts are off, A321 singe class high density would be over 218. Examples, JQ @ 230, U2 @ 235 and W6 @ 239

You are right higher seatcounts fly for the A321, but also for the A320 (186), 737-8 (200) and many other types.

LCC's / leisure oprators tend to fly shorter routes, remove / minimize lavatories and galleys as much as possible, fly ultra slim seats and reduce seat pitch to the minimum. Taking these seatcounts as reference tends to create apples & oranges comparisons. So I took a close look at available cabin length. Starting right after the cockpitdoor until the rear bulkhead. Every airline has to put passengers, luggage, galleys, lavatories and cabin crew into that space and it seems a more objective, measurable variable.

Seat pitch also greatly determines seatcount so I took 29-30inch as reference. Some airlines go lower with ultra slim seats 27-28 inch.. I checked for consistency (row 13). For E195 & A220 you get the different scores (4-5 abreast).


keesje

Compared to version 1.2:

Found out C919 cabin is slightly longer than A320NEO, moved it (Column J)
Removed A320Plus Capable, readers convinced me, it makes no sense (heavier, costlier, hurts A321 sales), a lighter, efficiency driven variant remains (Column L)
Added the E195-E2. Despite being a "Regional, it's seat capacity & payload make it a NB alternative for airlines. (Column A)
Members advised to increase 737-7 seatcount to better value it's 2m longer cabin than the A319NEO (Column E,4)
Adjusted installed thrust (Line 7) numbers. Not included in runway perf. Airlines will select thrust. Could include max thrust variant - power/weight ratio (Line 18).

Considering adding a clean sheet Boeing NSA to the table. To see what's realistic / desirable if you would start with a clean sheet today. A basic choice would be to optimize either for the middle of the market or include 240seat/4000NM. It seems you can't miraculously have both in an optimal design, with so many capable competitors.


source : Boeing https://aviationweek.com/sites/default/ ... k=vtNEZoJz

Over the last week I looked at algorithms to calculate range of these NB aircraft. Tried several 1st and 2nd degree functions using MTWO, OE, wing etc.

I used 8 aircraft specs of which I could find the OE (airport guide) payload range diagrams to verify and enhance the evolving algorithm.

Based on this it seems the ranges calculated (row) for "unknow"(by me) aircraft ranges can be calculated with a +/- 100 NM accuracy. Of course I used confirmed ranges where available.

All aircraft are similar configured twins with current generation LEAP & PW1000 engines so that the base for a lot of assumptions.

Seatcount / payload (row 4) were determined as a function of available cabin lenght / seats per row. This includes seats, galleys, lavatories, cabinets space etc. to make it objective.

I plan to score comfort as cabin volume/ passenger, to again include lavatory, bin, galley space as part of passenger comfort.



Column T I tried a ultra efficient NSA for up to 150 seats. In my model, low OEW + high MTOW does wonders for the overall score (row 20).
But that what aircraft builders have known for 100+ years

Oops the old 1.3< the new 1.4..

I noticed that the passenger comfort row is empty. May I suggest an alternate (or additional) metric based on available seat space, e.g., seat pitch and width? From a quick search, one data source for anthropomorphic measurements is here: https://ehs.oregonstate.edu/sites/ehs.oregonstate.edu/files/pdf/ergo/ergonomicsanddesignreferenceguidewhitepaper.pdf
some of the measurements useful to assess seat comfort are at page 13 of that pdf. I'm sure that there will be more detailed data somewhere else, e.g., in the US military.

Keesje,

This is a great database. I may suggest adding a few other items for efficiency scoring:

- Aspect ratio or spanloading, with a preference to spanloading
- Aircraft wetted area, and wetted area per seat. This is difficult to find, but for the Airbus aircraft, you can find the approximate surface areas of each component of the aircraft in the De-Icing and External Cleaning portion of the ACAPS. That will be a reasonable enough approximation.
- Thrust-to-MTOW ratio

heavymetal wrote:

Keesje,

This is a great database. I may suggest adding a few other items for efficiency scoring:

- Aspect ratio or spanloading, with a preference to spanloading
- Aircraft wetted area, and wetted area per seat. This is difficult to find, but for the Airbus aircraft, you can find the approximate surface areas of each component of the aircraft in the De-Icing and External Cleaning portion of the ACAPS. That will be a reasonable enough approximation.
- Thrust-to-MTOW ratio

Thnx heavymetal, as you can see the table is still in progress. It's a bit chaotic. Calculated values I used for reference/interpolations/ calculation need to be restructured.
Aspect ratio is a good one for performance & efficiency interpolations. Wetted area would be a huge effort, the aircraft are quiet close & I assumed all OE's did their jobs cleaning up their aircraft aerodynamically. Interestingly to see how two very different aircraft like E195-E2 and A220-100 get so close in overall performance with the same seatcounts and engines.

Column H & M show the composites wing for the MS-21 payed off in terms of OE, they are very light for big NB's. It also become clear the MS-21-300 has a MTOW issue / limitation, severely restricting range for it's size & market. No doubt there a story behind this & the Irkut is working on it.

IADFCO wrote:

I noticed that the passenger comfort row is empty. May I suggest an alternate (or additional) metric based on available seat space, e.g., seat pitch and width? From a quick search, one data source for anthropomorphic measurements is here: https://ehs.oregonstate.edu/sites/ehs.oregonstate.edu/files/pdf/ergo/ergonomicsanddesignreferenceguidewhitepaper.pdf
some of the measurements useful to assess seat comfort are at page 13 of that pdf. I'm sure that there will be more detailed data somewhere else, e.g., in the US military.

IADFCO, you are right. In practice available seatspace is hard to make objective as an overall comfort score though. For years I've been trying to find an objective, usefull metric viewtopic.php?t=1351701

Seat pitch, seat width are very important, but we see airlines reducing armrest width, narrowing aisles to get there. Or increasing seat-pitch by minimizing lavatories or removing catering/galley. In order to escape marketing tricks & perceptions I'm now considering an all covering, objective new variable: cabin volume per passenger. So instead of available seat space available passenger space.

The advantage is you include available space for seating, your luggage, the toilets and great meal service all in one. I can calculate the cross section of the cabin from the floor up & multiply by the length of the cabin (cockpit door- rear bulkhead). And then divide by the seatcapacity of that cabin. Avoiding a cabin scores more comfortable, if you reduce lavatories/ galleys, or do 1 inch armrests. It weighs in too, if the cabin is low, with small bins & narrow aisles (people bumping your shoulders). Most of all, it seems reasonable objective and easy to determine for a variety of cabins.

I calculated seat count as function of available cabin length already, assuming on a NB a wider cabin seat width doesn't increase seatcount, just comfort. Except when it's a narrower 4 or 5 abreast of course.


https://www.researchgate.net/figure/Dou ... _312520488

Hi keesje, good effort! Would be good to have Payload Max, Landing weight Max, Fuel Max (kg/lb) Seat qty per floor area. Small observation: pax@100kg works for main lines in Y config, C should consider pax@120kg. UULC at high density layout could be considered pax@90kg

I included passenger comfort row 19. To avoid marketing tricking with seat cushion widths, pitches, 1 inch armrests, bumpy narrow aisles, removed /mini lavatories, galley trade-offs etc. I decided for cabin volume per passenger seat. This way large luggagebins, wider aisles, wide armrests, real shoulder space, roomy lavatories and additional cappucino machines are included too for passenger comfort, irrespective of specific airline trade-offs

In the overall score efficiency (row 17) is weighed double.

torontofly wrote:

Hi keesje, good effort! Would be good to have Payload Max, Landing weight Max, Fuel Max (kg/lb) Seat qty per floor area. Small observation: pax@100kg works for main lines in Y config, C should consider pax@120kg. UULC at high density layout could be considered pax@90kg

Thank you Toronto, I'm considering improvements for version 1.6. already. Payload is included in line 14. I stayed away from multi class cabins, because specifications, number of seats, they are really up to the airline and hard to create a credible average for comparisons. A Spirit A321 might carry double the seatcount as an AA transcon one. I strive for objectivity as much as possible .

That's a lot of work Keesje, thanks! Will be following with interest.

Here's my concept of a shared 6-abreast fuselage for the Boeing NSA and NMA:








It uses the circular dimension of the MC-21 fuselage, but with a lower floor to provide an even roomier cabin and most importantly, more width at the limiting head and shoulder height. This will require a new container type. Boeing being one half of the duopoly might be able to push that through. If not, bags it is. It would not be the end of the world, the comfort and flexibility from the extra cabin width that allows a passing aisle is more important in my view.

This fuselage design with the lowered floor will, within the same wetted area of the A320 series, have an aisle wide enough (with 737 wide seats) to pass each other for very fast boarding. In the NMA configuration it would have seat width and a spacious cabin a 321XLR could only dream of.

Personally I think this fuselage concept would be the ticket for Boeing to make a strong come back in the single aisle market. A come back Airbus would struggle to have an answer to. Boeing would have a plane that:
- Shared NMA/NSA cross section.
- Is 28 cm / 13 cm wider than the 757/737 and A320 respectively at comparable wetted area of the latter.
- Flexibility in seat width vs aisle width. (both short haul boarding speed and medium haul seat width comfort possible).
- Very comfortable economy possible vs. only 737 width possible on the small double aisle proposal).
- No floor in compression
- Much more cargo space than on the small double aisle proposal.
- You can than have a plane that has a fuselage advantage the A320 can not match without going cleansheet
- After ramp up will heave a production efficiency advantage.
- Will have state of the human/machine interface from lessons learned from MCAS.
- Have solved your MAX replacement problem, successfully launch a new 3x3 against a 60+/month competitor and cater fore a very decent part of the middle of the market with the NMA version of it.

keesje wrote:

Payload is included in line 14.

I think in the chart we need to distinguish between PLD MAX @ Fuel and PLD @ FUEL MAX. Its a trade off in PLD-Range capabilities based on fuel tankage/MTOW/MLW. Platforms optimized for shorter range will demonstrate better PAX/OEW than LR design for the same PAX count as the latter needs more structure to carry more fuel (eg 195 vs A220-100).

Taxi645 wrote:

Here's my concept of a shared 6-abreast fuselage for the Boeing NSA and NMA:








It uses the circular dimension of the MC-21 fuselage, but with a lower floor to provide an even roomier cabin and most importantly, more width at the limiting head and shoulder height. This will require a new container type. Boeing being one half of the duopoly might be able to push that through. If not, bags it is. It would not be the end of the world, the comfort and flexibility from the extra cabin width that allows a passing aisle is more important in my view.

This fuselage design with the lowered floor will, within the same wetted area of the A320 series, have an aisle wide enough (with 737 wide seats) to pass each other for very fast boarding. In the NMA configuration it would have seat width and a spacious cabin a 321XLR could only dream of.

Personally I think this fuselage concept would be the ticket for Boeing to make a strong come back in the single aisle market. A come back Airbus would struggle to have an answer to. Boeing would have a plane that:
- Shared NMA/NSA cross section.
- Is 28 cm / 13 cm wider than the 757/737 and A320 respectively at comparable wetted area of the latter.
- Flexibility in seat width vs aisle width. (both short haul boarding speed and medium haul seat width comfort possible).
- Very comfortable economy possible vs. only 737 width possible on the small double aisle proposal).
- No floor in compression
- Much more cargo space than on the small double aisle proposal.
- You can than have a plane that has a fuselage advantage the A320 can not match without going cleansheet
- After ramp up will heave a production efficiency advantage.
- Will have state of the human/machine interface from lessons learned from MCAS.
- Have solved your MAX replacement problem, successfully launch a new 3x3 against a 60+/month competitor and cater fore a very decent part of the middle of the market with the NMA version of it.

There's a lot of excel lines not included in the table I used to e.g. model range and calculate cabin volume. For the NSA I coincidently took a similar approach to you, maximum cabin width 3.8m, like the MS-21. For Boeing it will be hard to produce an NSA at price levels lower than the mass produced NEO. So the goal is to clearly set it apart on the performance scores in rows 16-19.

To make the OEW low, a composite wing like the MS-21 really appears to make a difference. Also I specified to keep an NSA "unbeatable" 150-200 seat single class up to 5 hours, limiting MTOW. All assuming there will be some kind of NMA to cover longer, heavier flights. Or a special variant as you suggest.

On container / pallet options, the A320, C919 and MS21 have it. AKH is the defacto standard in Europe and Asia. Asian airlines warned Boeing not having it on an NMA, is a no go for them. I think it is highly likely it will be an option on any new Boeing NSA/NMA. It's always been an burden on the 737, exploited by Airbus.

As you can see (row 20), I succeeded in having the NSA overall score better than competitors. Spacey cabin, low OEW, composites and moderate MTOW/range are the main ingredients..

torontofly wrote:

I think in the chart we need to distinguish between PLD MAX @ Fuel and PLD @ FUEL MAX. Its a trade off in PLD-Range capabilities based on fuel tankage/MTOW/MLW. Platforms optimized for shorter range will demonstrate better PAX/OEW than LR design for the same PAX count as the latter needs more structure to carry more fuel (eg 195 vs A220-100).

On the payload range options I choose to go for a reasonable payload (M-class, 100kg/pass, galley volume, normal 1:50 lavatory rate), to stay away from max fuel tank capacity, structural payload limits, etc. Also for longer flights, usually less seats are in, more galley, everything starts moving, and then it becomes apples & oranges all around and I have to add 60 columns to cover all variants .

On the XLR you can see standard range is relatively low, 3500NM, but remove 40 seats/ 4t, add an ACT and you'll go over 4500NM. That's the case for all these aircraft.

In line 10 the coloured ranges are the ones I could find official payload range/standard reserves, condition graphs for (airport compatibility guides) I used them to verify models for calculating the unkowns.

For version 1.6 I will include NSA Large, slightly larger than A320NEO Plus, slightly shorter tha 737-9.. The perfect 200 seat / 5 CA / full galley/ lavatories variant. Lenght 41,8m? See how low an OEW can realitically be specified still meeting range requirements..

The E195-E2 can seat up to 146 pax in single class @28” pitch and 132 @31” pitch. Don’t know what are the assumptions you are using, but this may be useful.

https://www.embraercommercialaviation.c ... rcial-jet/

Jungleneer wrote:

The E195-E2 can seat up to 146 pax in single class @28” pitch and 132 @31” pitch. Don’t know what are the assumptions you are using, but this may be useful.

https://www.embraercommercialaviation.c ... rcial-jet/

Thanks, I calculated seatcapacity based on available cabin lenght, including galleys, required lavatories, emergency exists, door areas etc. Basically between the cockpitdoor and rear galley backpanel, I mostly used scaled drawings. An effort to make it objective for all aircraft. Official OE brochures usually take you for a ride on seatcounts. They take extreme maximums, leaving out operational airline requirements, to make costs / performance per seat (e.g. CASM) look better, for the less informed public.

It seems my seating and range calculations worked out pretty good for the E195-E2. In the PDF they mention a range of 2600NM with 146 passengers @100kg. I calculated 2713NM with 133 passengers @100kg. Gives a good feeling for the other unknowns in line 10. An official payload range diagram is best, but can't find that for an E195-E2.

10 minutes later : found it! Embraer published -E2 Airport Planning Manual 2 weeks ago
https://www.flyembraer.com/irj/go/km/docs/download_center/Anonymous/Ergonomia/Home%20Page/Documents/APM_E-JetsE2.PDF
including E195-E2 payload range curves (slide 49). For my 13,3t payload the official range IAS conditions is: ..2700Nm!

You can imagine the enormous (and well deserved) boast to my selfconfidence in modelling range based on a few relevant variables. To be honest it only works because all aircraft in the table are same generation, same engine sfc, same configuration platforms.


source: https://www.flyembraer.com/irj/go/km/do ... JetsE2.PDF

As you can see the E195-E2 in my capability score doesn't score very high; 5.9 (line 16) . I guess that's it's fate. For a Regional aircraft 5 hours with 133 people isn't bad at all, contrary! But this is major league NB segment, upping the reference. It's really up to the operators network, how well it fits in. E.g. intra Europe seems ok..

But I believe Azul has their aircraft configured to 137 seats. Therefore, 132 seems a little bit low for a high density. KLM has 132 in dual class cabin.

Jungleneer wrote:

But I believe Azul has their aircraft configured to 137 seats. Therefore, 132 seems a little bit low for a high density. KLM has 132 in dual class cabin.

As you can see I calculated seatcounts, rather than using specific airline cabin examples or in this case Embraer marketing materials. KLM has two classes but uses the same seats and moveable cabin dividers. Business class has other perks (lounge acces, catering, priority boarding etc.). So the seats are all the same. E195-E2 operators KLM (132), Binter (132) and Helvetic (134) seem pretty close to my seat capacity model (133) though. Calculated seat per available cabin lenght (row 13) is kept as a constant, adjusted for seats per row.

Great for the explanation. Seems solid for me.

keesje wrote:

On container / pallet options, the A320, C919 and MS21 have it. AKH is the defacto standard in Europe and Asia. Asian airlines warned Boeing not having it on an NMA, is a no go for them. I think it is highly likely it will be an option on any new Boeing NSA/NMA. It's always been an burden on the 737, exploited by Airbus.

If you want a passing aisle/high comfort NMA option within the A320 wetted area there is no other option than lowering the floor. Anyone who doesn't want the new lower container standard can use bags. My estimate is that the attractiveness of a shared fuselage between a passing aisle NSA/ high comfort NMA within the A320 wetted area would more than offset the disadvantage that some regions will be very reluctant to accept either the new container standard or bags option. I think, long term, you could still get about 50% of the Airbus/Boeing market share and good way to differentiate from just being a slightly newer A320. Something Airbus could do themselves much easier, quicker and cheaper than Boeing. Of course it hard to say for sure from my position what airliners would decide when they have to draw their wallets.

If you want to go to the same passing aisle/comfort levels with the standard container you would indeed need to go up to a ~4.15m fuselage with the accompanying drag and weight. That would make it hard for the NSA to be competitive especially within the 36m wingspan limitation and for the smallest variant. If you can't share the same fuselage cross section between NSA/NMA, you loose economy of scale and flexibility at final assembly, which would make it very hard to gain back market share with a clean sheet against the A320 pumping out 70/month. To me the above approach seems like possibly a good approach for a tiny window of opportunity Boeing could jump through, if you aim wrong you hit the wall.

Taxi645 wrote:

keesje wrote:

On container / pallet options, the A320, C919 and MS21 have it. AKH is the defacto standard in Europe and Asia. Asian airlines warned Boeing not having it on an NMA, is a no go for them. I think it is highly likely it will be an option on any new Boeing NSA/NMA. It's always been an burden on the 737, exploited by Airbus.

If you want a passing aisle/high comfort NMA option within the A320 wetted area there is no other option than lowering the floor. Anyone who doesn't want the new lower container standard can use bags. My estimate is that the attractiveness of a shared fuselage between a passing aisle NSA/ high comfort NMA within the A320 wetted area would more than offset the disadvantage that some regions will be very reluctant to accept either the new container standard or bags option. I think, long term, you could still get about 50% of the Airbus/Boeing market share and good way to differentiate from just being a slightly newer A320. Something Airbus could do themselves much easier, quicker and cheaper than Boeing. Of course it hard to say for sure from my position what airliners would decide when they have to draw their wallets.

If you want to go to the same passing aisle/comfort levels with the standard container you would indeed need to go up to a ~4.15m fuselage with the accompanying drag and weight. That would make it hard for the NSA to be competitive especially within the 36m wingspan limitation and for the smallest variant. If you can't share the same fuselage cross section between NSA/NMA, you loose economy of scale and flexibility at final assembly, which would make it very hard to gain back market share with a clean sheet against the A320 pumping out 70/month. To me the above approach seems like possibly a good approach for a tiny window of opportunity Boeing could jump through, if you aim wrong you hit the wall.

I think Boeing at this stage is all about risk avoidance. Ignoring the AKH standard seems an unacceptable program risk. While Boeing got away with it for decades (because US carriers cargo/ luggage MD80, 717, 727, 737, 757 commonality) things have changed. I think in the next decade more carriers will move on from labor intensive, slow, cargo unfriendly bulk loading processes.

The chances Boeing will not follow the AKH standard for their next NMA/NSA model seem very low. But you never know, they built a reputation now for finding reasons to misread what's written on the wall..

keesje wrote:

Taxi645 wrote:

keesje wrote:

On container / pallet options, the A320, C919 and MS21 have it. AKH is the defacto standard in Europe and Asia. Asian airlines warned Boeing not having it on an NMA, is a no go for them. I think it is highly likely it will be an option on any new Boeing NSA/NMA. It's always been an burden on the 737, exploited by Airbus.

If you want a passing aisle/high comfort NMA option within the A320 wetted area there is no other option than lowering the floor. Anyone who doesn't want the new lower container standard can use bags. My estimate is that the attractiveness of a shared fuselage between a passing aisle NSA/ high comfort NMA within the A320 wetted area would more than offset the disadvantage that some regions will be very reluctant to accept either the new container standard or bags option. I think, long term, you could still get about 50% of the Airbus/Boeing market share and good way to differentiate from just being a slightly newer A320. Something Airbus could do themselves much easier, quicker and cheaper than Boeing. Of course it hard to say for sure from my position what airliners would decide when they have to draw their wallets.

If you want to go to the same passing aisle/comfort levels with the standard container you would indeed need to go up to a ~4.15m fuselage with the accompanying drag and weight. That would make it hard for the NSA to be competitive especially within the 36m wingspan limitation and for the smallest variant. If you can't share the same fuselage cross section between NSA/NMA, you loose economy of scale and flexibility at final assembly, which would make it very hard to gain back market share with a clean sheet against the A320 pumping out 70/month. To me the above approach seems like possibly a good approach for a tiny window of opportunity Boeing could jump through, if you aim wrong you hit the wall.

I think Boeing at this stage is all about risk avoidance. Ignoring the AKH standard seems an unacceptable program risk. While Boeing got away with it for decades (because US carriers cargo/ luggage MD80, 717, 727, 737, 757 commonality) things have changed. I think in the next decade more carriers will move on from labor intensive, slow, cargo unfriendly bulk loading processes.

The chances Boeing will not follow the AKH standard for their next NMA/NSA model seem very low. But you never know, they built a reputation now for finding reasons to misread what's written on the wall..

If they do go for the standard container, I would not be surprised they will go a few cm (2-4) wider than the MC-21. Because of the described side curvature issue with the MC-21 because of the high floor to accommodate the standard container, any 1cm you go larger in diameter almost gives you twice that at the limiting shoulder and head height. So that would mean 4.08-4.10m. Seeing what the MC-21 already accomplished, I don't think you need to go 4.15m to get an acceptable passing aisle.