Real A300, 310, 757, 767 replacement aircraft idea

[keesje]

Hi folks, I put on some ideas on a 200-300 seat medium haul aircraft.

IMO there is a large gab between the A321/737-900ER and the A330-200 / 787 / A350 which are significant larger / heavier, don't fit the gates and are optimized for long haul (including LD3's).

There are a pile of A300/310, 757-200, 757-300, 767-200, 767-300s that need to be replaced in the next decade. Currently offered aircraft don't seem to fit the requirement.

I tried to summarize everything in 1 picture, that should tell it all. What do you think?


http://i191.photobucket.com/albums/z160/keesje_pics/greenliner-1.jpg

[student88]

I think you have too much time on your hands! Great graphics tho!

[Dani]

Well, where do you see a gap? The A321 can go to about 220 passengers, the 787-8 210-280. How do you want to design an aircraft with 230 seats and a OEW (do you mean DOM?) of 72 tons? Boeing is at the moment the leader in lightweight design.

I don't think that airlines want to open another separate type. The trick is fleet commonality, not variety...
Dani

[mighluss]

But... an aircraft designed for long range, is so efficient in short hops? You all know that higher range requires higher MTOW, so bigger engines, that in short hops will be running at a lower regime.

So maybe is logical, a replacement of A300 type, with lower MTOW, so smaller engines running at his designed regime, more efficient in short, but high demand routes...

Or maybe I'm speaking nonsense? :}

Any opininons?

[chornedsnorkack]

I think that a cross-section only slightly wider than A320 and much narrower than B767 is not efficient for 6 abreast. The 2 narrow aisles would not be much help in disembarking, and would take up a lot of space. A single wider aisle would be better. But still problematic on short hops - waste of space. What you could do, however, is to have a plane slightly wider than A320 directed at long and thin routes.

[Jetstream Rider]

2, 2, 2 seating is much better than 3, 3 for longhaul. You get two aisles so get a feeling of space and you only ever have to climb over 1 person to get out of your seat.
Spoke to a chap recently who hated the 747 because of its 3 seats by the window - he much preferred the 2 seats in an A340. Certainly a long way with one aisle does feel a bit cramped.
The 787 could easily be shrunk and I think that is the best option. I do see a missing link though, the 787 is bigger than the 767, so what will fly into the space limited and market limited but profitable routes the 76 flies now? Places like GCM (too small for a 777) and LCA where a 767 is a perfect size all year round? (A330 and 787 seem a bit big, I know Cyprus fly an A330 to LCA, but they are not the world's most profitable).

Edited for spelling.

[keesje]

Thnx for the responses!

In the picture on the right side you can see the Greenliner is a bit wider then the A320.

It has two aisles for short routes & faster (de)boarding; 30% of the middle seat can fold up, as indicated at the picture. That creates about 10 additional cross-over's. when two stairs / gates are used this should really speed up the process and short haul / leisure operations.

The single aisle variant offers superior seat comfort. The middle seat offers an unsurpassed 23 inch (including armrests) and the aisle window seats a still very good 21 (incl armrests) compensating for long flights in a relatively narrow cabin (compared to 767/ 330 / etc). The 757-200s used increasingly transatlantic (Co, NW, AA, DL, US) offers a critical narrow 17 inch with shared armrests..

I think the 787 is a great plane but its 110tons empty weight prevent it from becoming efficient for short haul. As a reference the 757-300 weighs 65 tons, 40 metric tons less then 787-8. That 40 tons equals the weight of ~400 passengers including luggage...

Lets not forget the 787 is a serious 9 abreast widebody that fits easily 330 seats in single class, so about 50% more then a A321 in single class. The 787-3 is still 100 tons and uncompetitive heavy compared to even older generation aircraft like the A300 and 767.

Both the A321 and B787-300 are not transatlantic / medium haul. The 787-8 is very long haul which translates in its high empty weight / installed thrust.

I think an aircraft like the Greenliner would offer significantly lower CASM then 787/ A330/ like aircraft on medium routes were lean passenger operations are more important then cargo.

I think there are at least 1600 757/767/a300/310 that need to be replaced in the next decade. Intra Asia, European and US coast to coast like operations require new fuel efficient aircraft. IMO neither the 737-900ER, A321 or 787-3 do cater for the required growth, range and efficiency.

Contraryto the 737/757 this aircraft can carry the NB containers / pallets used on the a320 series. It's a long fuselage, many should fit in.

[chornedsnorkack]

2, 2, 2 seating is much better than 3, 3 for longhaul. You get two isles so get a feeling of space and you only ever have to climb over 1 person to get out of your seat.

Yes, but the space costs. Boeing 767 has only 1 extra seat compared to 757 in normal economy, but the fuselage width is 127 cm wider (376 and 503 cm) and the frontal drag, skin friction drag, weight and induced drag are accordingly bigger.

30% of the middle seat can fold up, as indicated at the picture. That creates about 10 additional cross-over's. when two stairs / gates are used this should really speed up the process and short haul / leisure operations.

You could do the same on short-hop 767s. Is it done?

The single aisle variant offers superior seat comfort. The middle seat offers an unsurpassed 23 inch (including armrests) and the aisle window seats a still very good 21 (incl armrests) compensating for long flights in a relatively narrow cabin

No, it is not unsurpassed. Greenliner is plainly narrower than Sud-Est Armagnac, which has 470 cm fuselage width (compare A320 at 395 cm and 767 at 503 cm), and is single aisle with 3-3 seating.

[keesje]

All Sud-Est Armagnac were broken up in the fifties. Setting up production would be a hazard and I doubt the range / capasity is sufficient. ;)

Folding up seats on the 767 seem less praticle. Its 3 wide seats in the 767 instead of two narrow ones for a start, apart from that, not to many 767s are used on short haul..

I agree on the frontal area / friction & weight on the 767 vs 757. Thats why I tried to introduce narrow body efficiency with wide-body comfort and twin aisle mobility.

Apart from that I hear the 757-300 offers great CASM but is on the edge regarding stiffness, comfort and (de)boarding. 20 inches additional cross section could do the trick offering new cabin options and operational flexibility without introducing widebodies cost levels.


http://i191.photobucket.com/albums/z160/keesje_pics/greenlinercabin.jpg?t=1196855762

For longhaul a two class configuration seems most feasible. 4 class is possible but likely few routes would be able to support the higher CASM.

[Jetstream Rider]

2,2,2 v's 3,3 - space does indeed cost, but it needs to be weighed against the popularity of the config. If your competitors fly widebodies with 2 aisles and you offer a narrowbody with one, then your aircraft may not be so popular. Its a difficult equation, but given the choice for the same aircraft size I'd go for the 2,2,2.
I fly the 767 on shorthaul routes, and even though it has higher fuel burn than the 757 it does an excellent (profitable) job especially when you add in cargo. From various destinations we carry tons of the stuff. The Airbus 320 family cannot do that, the 757 is limited in that respect and the 787 is too big. There is a gap and it will be interesting to see what will fill it.
The great power of the 767 and the 757 is their flexibility - something the 320 doesn't have. Its up against weight limits and range limits and cargo hold size. For some airlines this isn't an issue, but when the 75 and 76 leave the fleets of some airlines, then something will have to drop. It depends where the airlines want to place their risks - fuel burn or lack of flexibility.

[chornedsnorkack]

Apart from that I hear the 757-300 offers great CASM but is on the edge regarding stiffness, comfort and (de)boarding. 20 inches additional cross section could do the trick offering new cabin options and operational flexibility without introducing widebodies cost levels.

What do the 6 inches of extra width of A320 do regarding stiffness, comfort and boarding? The use of this extra width is at the option of airline - they can offer wider seats than on 737, or extra wide aisle. How does the performance of A321 compare with 737-900 and 757-200? (A321 has a small wing, so it cannot match the MTOW and range of 757, but it does match 737-900.)

[World of Tweed]

Great food for thought on here.

If I may add a few points:

I agree there is a gap in the market for medium size, mid range type. As already stated the B737-8/900 and A321 just don't cut it weight/range when you get up past the 5hr mark. But I think the reason no one has replaced the 757 directly is because even now boeing will admit the 757 is and always was Too heavy for 70% of its routes. i.e. its weight reflects the capability of the aircraft which few operators used more than 30% of its working life.

My operator is curently slowly rolling over from 75/767 to 738 and on the Egyptian routes (ex UK) the 738 is consitently leaving bags behind to lift the weight out of field limited airports. This is unacceptable but will be the future as the accountants love the 737. Personally, once you are past the LCD screens I think its an achaeic deisgn with no business flying in its current guise.

However - the problem as I see it is to be able to design an airframe that is sufficiently light enough in a structural sense to be able to serve the shorter sectors competitively with the 320/737 whilst retaining the performance of the 75/76/310 for the longer sectors.

I don't believe a single design can serve both markets - not with the commercial pressures of the industry at the moment and the 738s and 320s of this world kicking at its heels. The accountants cannot resist them.

My personal view is somewhat simplistic - refurb the current fleet of 757s strip the ETOPS kit out of the a/c (within reason) and install winglets and new engine cores.

An expesive mod but you'll get the aircraft you need as sadly the market for an All in One aircraft is A:too small and B: likely to neither segment justice.

[keesje]

The 6 inches on the 320 vs the 737 do offer significantly higher stiffness for weight, noticeable space / comfort.

I think one of the biggest advantages of the A321 over the 737-900ER is payload range and the ability to carry cargo containers and pallets, while the 737 and 757 can not.

http://www.bandbreed.nl/~cargoguide/assets/uld/Pallet11.gif http://www.bandbreed.nl/~cargoguide/assets/uld/Pallet6.gif

Because the greenliner is just over 60 meters, a lot of them should fit in.

The A321 can't match the 757 range flexibility it is build for / used on high volume trunk routes. Its cargo capability, much lower weight and operating costs was one of the factors that pushed the 757 out of the market.

[chornedsnorkack]

B737 and B757 share a cross-section, but they have a number of differences like cockpit, landing gear and engines.

Suppose that one were to design a plane which has the cross-section and heavy commonality with A321, but bigger wing, engines and MTOW. let´s call them A322 and A323.

The airplane would be heavier than A321 on short hops - but it would have a longer range, and A323 would have good CASM.

Now, do you think that it would be possible to employ A322 profitably in a manner that could compete with A350?

B757 is loved by VIPs like Air Force Two and VIP charters. It has great range and can use small airports - much better range than VIP 737s. It has smaller size than B767-200. Several airlines use 757 for all-business flights - l' Avion has 90 business class seats, Eos has 48 about first class flat beds.

What their problem is is that they cannot offer a good frequency for the business passengers.

So what about having a schedule which intersperses widebodies with large cargo and economy loads and relatively small business class with medium-haul narrowbodies with relatively big business class, little economy and cargo capacity?

[keesje]

chornedsnorkack, i once specified an aircraft like you mention : the A320 enhanced performance with a lenght inbetween 320 and 321, new engines, interior and roof top windows :)

It could offer a bit more range & less capasity the the A321 without real dramatic modifications. Henry Lam (kaktusdigital.com) did a IMO great visual on it:

http://www.cardatabase.net/modifiedairlinerphotos/photos/big/00007055.jpg


However IMO it wouldn't really offer the payload range operational flexibility to be a 757 / 767 / A310 successor..

[Desert Diner]

The problem with your 2+2+2 design is that you are replacing an additional seat for an aisle (empty space). This may sound good but it also represents a 14% reduction in potential revenue for an airline (not a good thing).

The bigger planes have twin aisle due to the greater seat number 2+4+2 or 3+3+3 or even 2+5+2. I am sure some bean counter may be salivating at the option of a 5+5 configuration somewhere.

The sucessor for the planes you mentioned are the twin aisled 787/350 and the 330/777 designs. The short haul routes are most economicaly covered by single aisle (737/32x) designs.

A narow body business+ configuration may make economic sense, but you need the larger size to make money with economy passengers.

[keesje]

Desert Liner, the number aisles is related to safety. So 5-5 would probably never get approved. The 2-2-2 I specified has narrow seats and minimum width aisles. Also the double seats are placed at minimum pitch that wouldn't go well on 4-5 seaters.

The additional cabin provides credible comfort & luggage space for flights up to 9 hours. It's a little bigger, more range, better cargo and more comfortable then the 757s. Combine that with CFRP fuselage + wing and new gen engines and I doubt operators will go for expensive 40 tons /90.000lbs heavier 787's/ A350s, that provide an enormous boost in capasity on top of that. I don't see how that can be an economic solution for the 757/762 sized medium haul replacement markets. It would be great aircraft on the wrong mission.

Side kick: I wouldn't be surprized if Boeing makes a deal with the Japanese to convert the 787-3s orders into 787-8s and move on with the 787-10 instead. A win win it seems.. The 787 simply aint a <5 hr aircraft.. neither are the A330 (ask Qantas) and A350..

http://i191.photobucket.com/albums/z160/keesje_pics/greenlinercaprange.jpg?t=1196860023

[chornedsnorkack]

I think one of the biggest advantages of the A321 over the 737-900ER is payload range and the ability to carry cargo containers and pallets, while the 737 and 757 can not.
Its cargo capability, much lower weight and operating costs was one of the factors that pushed the 757 out of the market.

The containers in question... 114 cm high, 156 cm bottom width, 241 cm top width... they cannot fit B737 or B757 solely because they are built specially for A320. Mind yo, they cannot easily be packed into A330 or A380 either - plenty of space wasted.

Which means that unless your Greenliner uses the exact belly hold cross-section of A320, there will be space left over and wasted in Greenliner belly hold. And if you do build Greenliner belly hold to fit the cross-section of A320 belly hold while making the cabin wider, you are getting farther from double bubble, which means your floor loading and weight increases.

[Desert Diner]

Desert Liner, the number aisles is related to safety. So 5-5 would probably never get approved. The 2-2-2 I specified has narrow seats and minimum width aisles. Also the double seats are placed at minimum pitch that wouldn't go well on 4-5 seaters.

You missed my point. 2+2+2 makes no economic sense for the real industry.

[chornedsnorkack]

However IMO it wouldn't really offer the payload range operational flexibility to be a 757 / 767 / A310 successor.
Because you forgot to expand the wing and MTOW?

You can certainly match as well as exceed the payload and range of 757!

[keesje]

Hi thanks for all the responses !

It makes me review doubt the choices i made, but I'm not giving up yet!

"2-2-2 makes no economic sense"

what if it was 3-3 with a 50% wider aisle and A380 width economy class seats, would it then be a good fuselage? It would be exactly the same fusealge width. I guess this is about options.

Technicallly: taking a just wide enough 3-3 fuselage and putting up to 300 people in it is probably structurally over the limit. You have to add lots of material the make the narrow long pipe stiff & strong enough adding a lot weight. Apart from that a single aisle with more then 300 people starts to serious prevent efficient moving around of crew and passengers.

The additional 20 inch also pays of in the front of the aircraft making possible an additional fifth seat in domestic first and most importantly giving room for new generation 4 abreast long haul Business Class cabins. Business class is the money maker in many markets..

About the containers pallets used on A320s, there would not be much room lost. Remember a greenliner wouldn't be that much wider then a A320 (about 20 inch) and the cargo deck isn't higher.

The additional width is also height in the cabin providing center bins that puts of the pressure of restrained stowage. As can be seen they are higher then the side bins enabling people to easily cross the cabin where the folding seats are located.

What do you think about giving the middle seats long haul a few inches extra width?

[chornedsnorkack]

what if it was 3-3 with a 50% wider aisle and A380 width economy class seats, would it then be a good fuselage? It would be exactly the same fusealge width. I guess this is about options.
A380 width economy class seats?
3 seat block on 3-4-3 abreast A380 main deck is 157 cm.
2 such seat blocks are 314 cm. A320 cabin is 369 cm wide. This leaves 55 cm for aisle plus gaps between wall and armrest. 50 cm aisle is sensible.
50% wider aisle means 25 cm extra width over A320. Which happens to be the width of Tu-114 (420 cm outside, 392 cm inside).
Technicallly: taking a just wide enough 3-3 fuselage and putting up to 300 people in it is probably structurally over the limit. You have to add lots of material the make the narrow long pipe stiff & strong enough adding a lot weight.
Boeing 757-300 has 289 seats inside. And there are longer narrowbodies - Concorde is longer than either 757-300 or DC-8-61, and a narrower tube at that.
Making a Tu-314 which is comfortably wider than A320 and longer than DC-8-61 should not be prohibitively hard.
Apart from that a single aisle with more then 300 people starts to serious prevent efficient moving around of crew and passengers.

Even with an extra wide aisle?
L-2000, by the way, is close to 300 seats at 5 abreast, and it is actually narrower than DC-9/MD-90. So no extra wide aisle there.
The additional 20 inch also pays of in the front of the aircraft making possible an additional fifth seat in domestic first
5 abreast premium seating is already in use on quite some 737 operators. It is presumably possible on A320.
and most importantly giving room for new generation 4 abreast long haul Business Class cabins. Business class is the money maker in many markets..

Eos is doing a lot with 4 abreast on 757.
The additional width is also height in the cabin providing center bins that puts of the pressure of restrained stowage. As can be seen they are higher then the side bins enabling people to easily cross the cabin where the folding seats are located.

Still a bad idea.
The height of A320 is 213 cm at ceiling of aisle, 160 cm below the bins. A330 is 240 cm at the top of aisle, 165 cm below the side bins, 178 cm below the centre bins.
Add 25 cm to the width of A320 cabin, and to height because you are not adding any height to underbelly, and you wind up with 238 cm ceiling. Plenty of space to make the side bins slightly higher than on A320, and far more spacious. No need to stick in centre bins.
Oh, and as for wider middle seats, it is certainly offered as an option on Boeing 737 documentation.

[Anti-ice]

Wow,some hard work in there! and not unappreciated either!

Whether your idea would work or not, it certainly proves there is a gap in the market - and certainly that there is a gap that will not be filled until the 787 is in the skies...

Probably the one biggest hurdle would be the concept of a 'mid-width' twin aisle airliner - no airline will pay for an aisle where they can put loads of extra seats.

The A300 and 757/767 families were technological marvels of their time, but are fast being superceded by new technology and fuel saving airframe/engine mixes...

You have to look at what the airlines are doing differently too ie BA were operating a huge 757/767 mix on shorthaul 10 years ago, completely (almost) replaced by much smaller airbuses now - instead of 3 767's to ARN/FRA/MAD a day, they now operate 5-7 airbuses instead offering greater flexibility for the business traveller/increased transfer options for it's own longhaul and codeshare partners..not one concept will appeal to every business model.

Your thought and effort is superb though :ok:

[Swedish Steve]

Well done Keesje, I really appreciate your graphs and diagrams.
BA operates a fleet of 7 B763 in Europe. Their big advantage is that they can carry B747 sized pallets in the fwd hold. The BA B763 have a large fwd freight door and the pallets are loaded sideways into the hold. This means that when they arrive at LHR they can be transshipped directly to the next flight without being repacked in the cargocentre. The 6 B767 every week from ARN are always full of cargo pallets, up to 12tons a day. The route could not support a larger aircraft for pax, so whats going to replace it? I was disappointed BA did not buy interim A330s for long haul which could have gone to Europe afterwards.

[keesje]

Anti-ice, Swedish Steve thnx! I tried to put a LD3 (which is the most commonly used long haul container onto the design). Problem is that it is so high (1,63m) you have to fit two to fill a round lower fuselage and then you end up with a widebody..

Maybe right seized 0.8 m high pallets / containers that can be piled could be developed that are more transferable..

A strongpoint of the 767 vs the A330 is that it fits ICAO cat D gates that are present all over the world. Not conincidently I gave the Greenliner about the same wingspan as the 767.

The 787 and A330 have big lean wings to carry high loads & fuel over long distances efficiently but won't fit many gates and this might require many 767 oriented gates / airports to be adjusted..
http://www.pilotcareercentre.com/images/APL/Monarch-A330LDG-APL.JPG

As an operator you probably have to choose between the superior cargo capabilities of widebodies and low weight / operating costs / airport compatibility of narrowbody aircraft. No wonder the 757 & A321 are so popular with Leisure operators.

I think cargo on long / medium haul is less important then on medium / long haul. The enormous growth in air traffic also makes dedicated cheaper cargo flights possible on routes where it wasn't feasible before.

On the 2 aisles: you'll notcie it is still a narrowbody. The two aisles allow for pitches / seatwidth's in economy that would probably not be acceptable on 3-3 configurations. It also provides options for more seat on the front of the aircraft (e.g. 5 abreast domestic F (you cant have middle seats there) and some realistic long haul premium options (I can't imagine efficient long haul First on a 757 sized aircraft).

Looking at the empty weight (about ten tons more then the a 757-300 without full carbon wings / fuselage) and new generation engines, I think a significant step in operating costs could be archived compared to the 757, A310 and 767. If the 787 can do 20% better, this aircraft that is more then 25% lighter then the 787 could offer something that would make airlines happely accept shortcomings in e.g. cargo capability.

IMO for the passenger there is a win too, in terms of seatcomfort, handluggage allowance and more direct connections.

[chornedsnorkack]

A strongpoint of the 767 vs the A330 is that it fits ICAO cat D gates that are present all over the world. Not conincidently I gave the Greenliner about the same wingspan as the 767.

The 787 and A330 have big lean wings to carry high loads & fuel over long distances efficiently but won't fit many gates and this might require many 767 oriented gates / airports to be adjusted..

B707-320, DC-8-62 and VC-10 have wingspans of 44...45 m. DC-10-10 and Tristar have 47,3 m, DC-10-30 and Tristar 500 have 50 m, A300 has under 45 m, Il-86 has 48 m, B767-200 has 47,6 m, A310 has 43,8 m, MD11 has 51,7 m and B767-400 has 51,8 m.

On the 2 aisles: you'll notcie it is still a narrowbody. The two aisles allow for pitches / seatwidth's in economy that would probably not be acceptable on 3-3 configurations.

As for what seat widths are acceptable on 3-3, have a look at Bring Another Engine 146 in 6 abreast.

and some realistic long haul premium options (I can't imagine efficient long haul First on a 757 sized aircraft).

What do you call what Eos has?

IMO for the passenger there is a win too, in terms of seatcomfort, handluggage allowance and more direct connections.


Compared to what?

[keesje]

chornedsnorkack I think the wingspans of the aircraft you mention are interresting but not really relevant. I meant that the "smaller" wide bodies like the A330 and 787 that can fly medium ranges and are 757/767 options have wings spans around 60 meters.

http://i191.photobucket.com/albums/z160/keesje_pics/greenlinerdimensions.jpg?t=1196981558

That makes many gates at many airports useless in their current layouts.

E.g. Atlanta is a 757/767 hub that would require dramatic rebuilding when 767/757 would be replaced by aircraft not fitting cat D.

http://capecodfd.com/Pics%20ARFF/ARFF%20ATL%20041506%200903.jpg

EOS has nice aircraft but these seats aren´t exactly wide & probably wouldn´t qualify as First in the next decade. Look at JAL, EK, BA, AA, ANA and SQ First for reference. BTW I think EOS don´t have to either, because of the unique niche they operate and sub-business class prices they charge..

I think the economy class seats as dimensioned for medium / long haul in the drawing (21 & 23 inch incl. armrest 19, 21 inch without) are wider then almost any widebody economy class seat. e.g. on 747 they are 17.3 inches without armrest, in the 787 9 abreast a bit more. Nearly 4 inches extra is noticeable..

and pls don´t come up with the fact that Breguet Deux-Ponts seats are wider ;)

[mutt]

Interesting concept, but how are you going to achieve the OEW?

Mutt

[keesje]

Mutt good question, I did an iteration with comparable aircraft and technology involved.

http://i191.photobucket.com/albums/z160/keesje_pics/greenlinerOEWcomparison.jpg?t=1197056844

It think what can make the Greenliner lighter then the similar sized widebody B767-200 and A310-300 are:

- full composite CFRP fuselage (757 fuselage= 727: sixties), wings and tail
- the absense of a serious cargo deck & required loading system/door and overall fuselage / LDG strenght for lower MTOW.
- new technology engines incorporating carbon reinforced fanblades & cowlings
- new technology like FBW, less pneumatics, cabling
- new lighter materials in cabins, galleys and seats

Still 10 tons heavier then the 757-300 because it´s longer, has bigger wings and larger payload and range.

As can be seen the Greenliner isn´t extremely light but the 787-3 seems relatively heavy & has low payload for the range it offers. I doubt the 787-3 will be a succes, the 787-8 offers so much more flexibility for an additional 10 % OEW..

[mutt]

Something doesnt add up... or its just to early for my brain to work:):)

Anyway, 70,000 kgs plus 40,800 kgs (90,000 lbs engine weight) = 110,800 kgs OEW. Plus 30,000 Kgs passenger weight = 140,800 kgs.

MTOW 146,000 kgs - 140,800 kgs = 5,200 kgs for fuel?

Where did i go wrong? Or maybe you should express the engine weight in KGS as included in the OEW?

Mutt

[Desert Diner]

Something doesnt add up

Yes, the 787 is real while the "Greenliner" is fictional.

keesje, as much as your posts and ideas are very interesting as well as thought provoking about airline design, bashing an airliner that has gone through millions of man hours of desing and review and testing with something you have drawn up on a computer is a bit over the top.

If your idea was such a winner, don't you think that A or B would not have it in their lineup? Perhaps it may be due to the fact that there is not a market out there big enough for them to recoup the development costs.

I doubt that any startup manufacturer would be able to compete against the "relatively low cost" 330 range which your greenliner seems to mimic range/capacity wise. Plus don't assume the 764 is "discontinued", only that there are no orders for it as airlines prefer the beter capacity/range of the 777. Your greenliner will find the same sales hurdles if it were to be build.

Again, great post, but please don't belittle a real design with something that will never pass the conceptual phase.

[keesje]

I think the 787-8 and 787-9 are excellent long haul designs offering a lot of payload range are very low fuel and operating costs. The 787-3 IMO falls out. It has not been ordered since ANA & JAl ordered them yrs ago for domestic services. Recently Boeing decided to not go after certification of this version in Europe.

Personaly I would not be surprices if Boeing & JAL/ANA come to an agreement on the 787-3 or Boeing redoes the specification adding say 1500-2000 nm to its range.

Mutt I think a Trent 500 weighs about 10.000 lbs, and a GENX a few thousand pounds more, so I don´t really understand your 90,000 lbs engine weight calculation.

MTOW = OEW + nominal payload + fuel mass. Engines are included in Operating Empty Weight.

I think 15.500 gallons or 48 tons of fuel is realistic for the max range with passenger load.

72 OEW + 48t Fuel= 110 tons, leaving 36 tons for payload. If we take 90-100 kg for passenger + luggage, it confirms it would not be a great cargo aircraft.

230 passenger (long haul) * 95 kg = ~22 ton include catering crew etc : 25 tons, leaves about 10 tons for cargo at maximum range / fuel (which would occur seldom of course).

I don´t claim the greenliner would be an exceptional aircraft / better then others (its based on existing technology), however it seems the big OEMS have left a real passenger range gab after the A300/310/757 and 767 got (nearly) out of production. (I know the 767 is still available, however stopped selling yrs ago & I wonder what will happen to the 76 if Boeing doesn´t get the tanker contract)

http://i191.photobucket.com/albums/z160/keesje_pics/greenlinerseatranges.jpg?t=1197119330

Real long haul capability (>6000nm, including a good load of side by side LD3´s) at low CASM is were the A330/787 (will) excel..

P.S Mutt now I see what you mean, excuse the lbs in the small table are lbs thrust, not weight :)

[mutt]

http://i191.photobucket.com/albums/z160/keesje_pics/greenlinerOEWcomparison.jpg?t=1197056844

Look at your table, you have the figure 72 metric tonne and then 90,000 lbs for the engines, its confusing!

For your information, we are analyzing the 787-3 as a short range high density aircraft, we need the cargo capacity, so we wouldnt consider your greenliner. Its also worth noting that you are basing everything on the false impression that you can achieve maximum takeoff weight, if not, then your whole equation fails.

Nice effort, but its a fantasy!

Mutt

[Swedish Steve]

Keesje, you have a misprint in this table
The B767 engines are not 161000 lbs/thrust, more like 120000 for 2 engines!

[Fargoo]

90,000 lbs for the engines

Isn't that the engine thrust he's stating?

[keesje]

Swedish Steve you are absolutely right, a typo.:O I saw it, but a picture isn´t that easy to correct and relink.. Imagine the climb performance on short trips :D

Matt, the greenliner would suck compared to the 330/787 as a cargo aircraft indeed, just like the 757. I was considering a payload range diagram but became lazy.. max range would be with a "typical" optimistic full passenger load of about 250 passengers. Range with cargo would decline.

http://www.wingsoverkansas.com/photos/boeing/787/750px-787_range.jpg

On the short high density with cargo market (I think you aim LD3 & pallets) : in other discussions looking at the numbers it became clear the good old A300 isn´t so bad.. Ask AA and LH, they are looking to replace it & will likely have to give in at the cargo department.. and for now opt to accept the rising maintenance / availability /upgrade costs of the old A306s ..

What I understand is the 787-3 was a special Japanese requirement that Boeing filled in return for big launch orders and state support (via MHI etc). I can not imagine what the ROI for the 787-3 stand alone would be. None were sold during the economic boom of the last three years.

It´s twin brother the 787-8 can fly nearly three times as far & has superior payload range. Do you have an idea how / why Boeing killed the range so dramatically? What did it gain by doing so?

I think preserving an additional 1500nm would have made it a serious option for e.g. the big DL, AA, UA etc fleets and its resale value alone would get more acceptable.. Iyt could also do South America, Western Europe etc.. Maybe a 787-5 will emerge one day.. Maybe AA or LH would be stronge enough to convince Boeing.

On the Greenliner being a fantasy : you are damn right :ok: Interstingly I did a similar pp on a 747 successor "ecoliner" (do a google) and got nice / inquiring feedback from not so amature / unknown folks. :cool: Thing is I have a partner in crime (Henry Lam, kaktusdigital.com) that can make fantasies look pretty convincing..

[chornedsnorkack]

I think the wingspans of the aircraft you mention are interresting but not really relevant. I meant that the "smaller" wide bodies like the A330 and 787 that can fly medium ranges and are 757/767 options have wings spans around 60 meters.

Indeed. In fact, they all have wingspans exceeding the 59,6 m wingspan of Boeing 747.

My point is that there are large numbers of airplanes with wingspan in the range of 43 to 52 m. Calling the list again, the classical longhaul narrowbodies B-707, DC-8, VC-10 and small widebodies DC-10, Tristar, A300, A310, B767, MD11 and Il-86. All of those are meant for category D gates. Boeing 747 was the only aircraft bigger than category D till A340 came out.

Would 3 abreast, 2-1 seating on a narrowbody make a nice first class?

[keesje]

Would 3 abreast, 2-1 seating on a narrowbody make a nice first class?

I don't think so. Direct access to the aisle is a First Class benefit.

The wider fuselage of the Greenliner might provide this benefit for Business, facilitating 1-2-1 seating in business.

Few aircraft with less then 250-300 seats have intercontinental First anyway.. Even airlines like CX, SQ and LH seldom include it. Big aircraft fly big city pair, big city's have First business.

Another thing I tried to include open rotors. That not easy in terms of noise, fibration, wing-engine interference, maintenance access, ground clearance, down wash and blade containment / safety.

In the end I "ducted" the open rotor, adding drag, weight :bored: . Live is full of compromises..

The canard seems is nearly inevitable when moving on to very high BPR's / big rotors / pushers ..

http://i191.photobucket.com/albums/z160/keesje_pics/greenlinerIIcg.jpg?t=1200400263

[chornedsnorkack]

Another thing I tried to include open rotors. That not easy in terms of noise, fibration, wing-engine interference, maintenance access, ground clearance, down wash and blade containment / safety.

In the end I "ducted" the open rotor, adding drag, weight . Live is full of compromises..

The canard seems is nearly inevitable when moving on to very high BPR's / big rotors / pushers ..

Cannot see why. Most big turboprops do without canards.

But high bypass rotors would still do well if they are not blanked by the wing. The conventional props do interact with wing airflow, but this is at rather slow speeds...

I observe that Pratt and Whitney want to make a geared turbofan with 203 cm fan diametre. Producing 30 000 pounds thrust.

What plane is it meant for? A320 engines are smaller.

An existing plane which does have about 200 cm fan diametre is B757. But those engines give well over 40 000 pounds of thrust each.

Now imagine a plane which has 3 geared turbofans, 30 000 pounds thrust each. 2 underwing, the third in the tail. The MTOW is restricted by 1 engine out climbout case, 2 engines out of 3 gives more total thrust than 1 of 757... so you could support a greater MTOW than 757. And more fuel efficient, because of GTF.

What would the range be like?

[keesje]

I can't estimate the range of a trijet without a good look. Thing is open rotors are heavy too, as is the structure keeping them in place. Then noise is a problem, fibrations, hot gears, lubrication. They didn't stop for no reason in the late eighties..

Still : a fuel consumption reduction of >20% make OEMS look again (Snecma, RR).


I observe that Pratt and Whitney want to make a geared turbofan with 203 cm fan diametre. Producing 30 000 pounds thrust.

No doubt they are aiming for a 20-30 klbs familiy for the next generation NB. The 757 with it srelatively big fans is very high on its wheels. I think most studies from Boeing and Europe move the engines up the aft fuselage for that reason.

http://seattletimes.nwsource.com/ABPub/2006/05/09/2002983476.gif

Last year I did a study on this with Henry lam, assuming GTF on a five abreast 110-165 seater.

http://www.airliners.net/discussions/general_aviation/read.main/3513052/1/#40

[chornedsnorkack]

Thing is open rotors are heavy too, as is the structure keeping them in place.

Agreed.

Still : a fuel consumption reduction of >20% make OEMS look again (Snecma, RR).

And might outweigh the advantages of twins.

No doubt they are aiming for a 20-30 klbs familiy for the next generation NB.
The biggest next generation NB, C-series, has 23 300 pounds of thrust per engine (the thrust is shared by all variants from C110 to 130). Mitsubishi Regional Jet engines are smaller. MRJ70 has just 15 500 pounds and MRJ90 has 17 700.

I think most studies from Boeing and Europe move the engines up the aft fuselage for that reason.

But this brings back the CoG problems of aft engines, which the weight of extreme bypass engine only makes worse.

Going to 3 engines, 2 wingmounted and 1 in tail like Tristar and DC10, would keep the CoG under control - only 1/3 of engines in tail - and it would keep the underwing engine size within reasonable limits.

[keesje]

But this brings back the CoG problems of aft engines, which the weight of extreme bypass engine only makes worse.


I´m not sure if I see the center of gravity issue in relation to high BPR engines. The position of the wing is adjusted to make it right. An issue I see on the concept I drew is stability at low speeds with 1 engine out past V1.

The moment the rudder / vertical stabalizer has to create for longitudal stability / control would be high requiring a large control surface. On the other hand a B2 can do it too. There are smart multi control solutions.

[chornedsnorkack]

I´m not sure if I see the center of gravity issue in relation to high BPR engines. The position of the wing is adjusted to make it right.

Well, if you have not thought of it before:

For a plane which rotates on takeoff, the CoG and wing have to be in a narrow range, slightly ahead of the main gear. If the CoG is too far back, the plane tips on tail. If the CoG is too far forward, the plane will not rotate despite elevator downforce.

If the engines are mounted on the wing, they are near the CoG. The fuel is in the wing as well. The tail and nose are balanced between each other. The big variable is the payload, but since there is a significant amount of fuselage volume both ahead and behind the wing, those tend to balance as well.

Now if you place the engines in the tail, you have to counterbalance them by bringing the wing and main gear backwards. You have long front fuselage trying to counterbalance short rear fuselage and engines.

Except that now, most of your payload volume is ahead of the wing. Which means that yout plane is liable to fall on the tail when the payload is small or absent. Il-62, VC-10, B-727... there are incidents falling on the tail on ground, needing tail supports to avoid this, asking passengers to disembark tail first...

[oceancrosser]

Keesje,

We have done a study on the A321-200 vs. the B757-200W. The payload range capabilities of the 75W far exceeds the A321. It is basically useless beyond 5-5.5 hrs whereas the 757 will take a 20 ton payload and full tanks of fuel, giving it a range of about 8 hours.

[keesje]

True, the A321 is useless (& not designed / used) for longer ranges like transatlantic. It is however 13 tons lighterthen the 757 & much more fuel efficient for anything shorter then 5 hours.

It is also more comfortable (wider cabin), 100% competible with widely used A320 and A319, can carry cargo containers & pallets but most importantly : it is for sale.:)

http://aviation.fh-joanneum.at/Resources/5Projekte/airbus_boeing_large.jpg

Coincidently I found this oldish picture today, it shows the situation. Marking the places for the Greenliner, LRJ and Ecoliner like new aircraft designs.

The A300/A310/767-200/757-200/757-300 leave a big replacement market in the B737-900ER/A321 - B787-8/A330-200 gab.

[chornedsnorkack]

True, the A321 is useless (& not designed / used) for longer ranges like transatlantic. It is however 13 tons lighterthen the 757 & much more fuel efficient for anything shorter then 5 hours.

It is also more comfortable (wider cabin), 100% competible with widely used A320 and A319, can carry cargo containers & pallets but most importantly : it is for sale.

One problem with 757 was that apart from fuselage cross-section, it shared little with 737.

What about Airbus 322/323? With new, bigger wing and engines, but keeping otherwise a heavy commonality with 321? The plane would get heavier and less efficient on short range, but it would gain range.

Consider the big narrowbodies:
Boeing 737-900: maximum 189 seats, MTOW 79 tons
Airbus 321: maximum 220 seats, MTOW 93 tons, OEW 48 tons.
Boeing 757-200: maximum 239 seats, MTOW 115 tons, OEW 58 tons.
Tu-204-200/Tu-214: maximum 212 seats, MTOW 110 tons, OEW 59 tons. An advantage over B757 is that Tu-204 is for sale!

DC-8-63: maximum 259 seats, MTOW 158 tons, OEW 70 tons.

[keesje]

What about Airbus 322/323? With new, bigger wing and engines, but keeping otherwise a heavy commonality with 321? The plane would get heavier and less efficient on short range, but it would gain range.

Nearly 2 years ago I did a study on that named it "A320 enhanced performance" with a lenght inbetween the A320 and A321.

http://www.ilfc.com/images/3airbus.jpg

The A321 is significantly longer then the A320. Something inbetween would offer growth for A320 customers. An A320.5 ..

As you suggested it had improved wings, engines, cabin etc. Funny thing is a few months later Airbus announced the A320 Enhanced. So it probably was a logical evolution.

http://www.cardatabase.net/modifiedairlinerphotos/photos/big/00007055.jpg

Henry Lam created a nice artist impression. It also had rooftop windows offering a nice natural light in the cabin, enabling every passenger to see the blue sky..:)

http://www.airliners.net/discussions/general_aviation/read.main/2724857

[chornedsnorkack]

It also had rooftop windows offering a nice natural light in the cabin, enabling every passenger to see the blue sky..

Those rooftop windows are huge!

Start with bringing back DC-8 windows. 36X46 cm. Biggest ever on pressurized jetliner - all the bigger windows have been on wholly unpressurized planes or slightly pressurized low-flying propeller planes like Vickers Viscount. Even 787, if it ever flies, has windows that are mere 28 cm wide.

[halas]

With IFE being a big part of long-haul these days the roof top windows would seem surpurfolous.

On Emirates they shut all the window blinds in the cabin so the punters can sleep or see their 1000 channels clearly on the LCD screen.

Like your ideas though - very well thought out.

halas

[Kiwiguy]

Keesje I am certain your post here has set off some ideas at the Boeing and Airbus marketing departments. You may not be bang on with all your thinking but it is a good effort and you should welcome the constructive debate here.


But... an aircraft designed for long range, is so efficient in short hops?


On this note I honestly wonder if a carbonfibre fuselage can withstand the repetitive stress of short haul cycles and so many landings ?

Long haul airliners get high hours but low cycles. The Dreamliner wouldn't fill that gap so you've definitely identified a future gap in the market... cheers.:ok: