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Real A300, 310, 757, 767 replacement aircraft idea

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Real A300, 310, 757, 767 replacement aircraft idea

Old 6th Dec 2007, 08:29
  #21 (permalink)  
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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?
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Old 6th Dec 2007, 11:28
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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.
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Old 6th Dec 2007, 11:58
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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
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Old 6th Dec 2007, 16:08
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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.
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Old 6th Dec 2007, 17:18
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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..


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.
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Old 6th Dec 2007, 20:41
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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?
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Old 6th Dec 2007, 23:19
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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.



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.



EOS has nice aircraft but these seats arenīt exactly wide & probably wouldnīt qualify as First in the next decade. Look at JAL, EK, BA, AA, ANA and SQ First for reference. BTW I think EOS donīt 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 donīt come up with the fact that Breguet Deux-Ponts seats are wider
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Old 7th Dec 2007, 18:08
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Interesting concept, but how are you going to achieve the OEW?

Mutt
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Old 7th Dec 2007, 20:10
  #29 (permalink)  
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Mutt good question, I did an iteration with comparable aircraft and technology involved.



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 itīs longer, has bigger wings and larger payload and range.

As can be seen the Greenliner isnīt 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..
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Old 8th Dec 2007, 04:04
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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
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Old 8th Dec 2007, 04:38
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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.
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Old 8th Dec 2007, 13:18
  #32 (permalink)  
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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 donīt 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 donīt 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 doesnīt get the tanker contract)



Real long haul capability (>6000nm, including a good load of side by side LD3īs) 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

Last edited by keesje; 8th Dec 2007 at 19:24. Reason: 1 small adjustments, 2 engine thrust
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Old 8th Dec 2007, 16:25
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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
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Old 8th Dec 2007, 17:00
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Keesje, you have a misprint in this table
The B767 engines are not 161000 lbs/thrust, more like 120000 for 2 engines!
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Old 8th Dec 2007, 17:00
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90,000 lbs for the engines
Isn't that the engine thrust he's stating?
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Old 8th Dec 2007, 20:06
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Swedish Steve you are absolutely right, a typo. I saw it, but a picture isnīt that easy to correct and relink.. Imagine the climb performance on short trips

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.



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 isnīt 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.

Itīs 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 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. Thing is I have a partner in crime (Henry Lam, kaktusdigital.com) that can make fantasies look pretty convincing..
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Old 8th Dec 2007, 20:36
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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?
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Old 15th Jan 2008, 12:35
  #38 (permalink)  
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Open rotor short / medium haul 230-290 seater design greenliner II

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 . Live is full of compromises..

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

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Old 15th Jan 2008, 13:40
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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?
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Old 15th Jan 2008, 14:13
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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.



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.../3513052/1/#40
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