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Let's Build The Y3  
User currently offlineDocLightning From United States of America, joined Nov 2005, 20334 posts, RR: 59
Posted (5 years 9 months 4 weeks 1 day 16 hours ago) and read 14472 times:

Since we know that Boeing always takes the input of A.net members very seriously  Wink let's build their Y3 for them.

My predictions: it will neither be a flying wing nor an SST. Sorry for smashing your dreams.

It will be a large tube, probably similar to the 747 in size, but it will likely be a single deck. It will be made out of CFRP. It will be all-electric and use many other 787 technologies.

The 787-10 will replace the 772, so the smallest variant will be similar in size to a 773. A larger variant might be made into a quad a-la A330/A340.

It will have a curvy, sterile, white interior with cute LED effects and a low cabin altitude. Marketing pics will only show the roomy, high-tech J and F class seats and not the sardine-class seats in the back where the flight will be just as long and painful and boring is it was back in the days of the DC-10 and3 741. It might make use of overhead space for some cute things like crew rest, galleys, and passenger lounges. But airlines hate passenger lounges; some might figure out how to put extra seats up there. But I don't think it will be a double-decker, per se. I bet the largest variant will look something like a 747 without the upper deck.

But if it's by Boeing, it will probably be quite pretty. Unlike A, I have to grant B that they do try to make their planes pretty.

105 replies: All unread, showing first 25:
 
User currently offlineHloutweg From United States of America, joined Aug 2007, 242 posts, RR: 0
Reply 1, posted (5 years 9 months 4 weeks 1 day 15 hours ago) and read 14394 times:

This sounds like a fun assignment. I was just thinking about the same subject as I read the thread on the A380's possible cancellation of orders.

Quoting DocLightning (Thread starter):
My predictions: it will neither be a flying wing nor an SST. Sorry for smashing your dreams.

 checkmark 

Tome Y3 will indeed not be a flying wing nor an SST. I don't think they'll make the flying wing, theater-like interior appeal to airlines and customers enough to develop it, specially in this seat capacity size. If built, it should be an aircraft that spans from the 773 capacity range and above, but that's only if they decide that the 787-10 will replace the smallest 777. If they decide instead that the 777 is to be replaced by a new aircraft, then they could develop an A350XWB like aircraft made of composites that really wont focus on reaching the capacity of the A380. I ponder that if the 787-10 becomes a reality, Y3 will have capacities similar to 777-300, 747-8, and A380-800 but not larger.



In Varietate Concordia
User currently offlineAdam42185 From United States of America, joined Dec 2005, 416 posts, RR: 0
Reply 2, posted (5 years 9 months 4 weeks 1 day 14 hours ago) and read 14317 times:

I am speaking not from my voice of reason but my love of the DC-10 and MD-11 (and basically any other tri-jet)

With better engine efficiency is there any way it could be justified to have a three engined plane that was say similar in size to a 748/A388? Are there any distinct aerodynamic disadvantages to having a center line engine? Basically, looking to the future, would it be possible to have an engine and aircraft combination where the plane was too big for two engines but not big enough to warrant four engines?  cloudnine 


User currently offlineN7190JR From United States of America, joined Jul 2008, 110 posts, RR: 0
Reply 3, posted (5 years 9 months 4 weeks 1 day 14 hours ago) and read 14277 times:



Quoting Adam42185 (Reply 2):
With better engine efficiency is there any way it could be justified to have a three engined plane that was say similar in size to a 748/A388? Are there any distinct aerodynamic disadvantages to having a center line engine?

I Have always wondered the samething! wouldn't it be great to see a new tri-jet!

BTW welcome to my Respected Users list.  Cool

N7190JR  airplane 



The Only Way Up is Up: KEEP CLIMBING
User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 4, posted (5 years 9 months 4 weeks 1 day 10 hours ago) and read 14089 times:



Quoting Adam42185 (Reply 2):
With better engine efficiency is there any way it could be justified to have a three engined plane that was say similar in size to a 748/A388?

It's not really a matter of efficiency, since any time there's an efficiency gain it can be applied equally to quad/tris/twins. The problem is that the maintenance and integration penalty of the center engine is tough to overcome on a typical configuration. A BWB is the one obvious case where a third engine is a winner.

Quoting Adam42185 (Reply 2):
Are there any distinct aerodynamic disadvantages to having a center line engine?

You need to be more careful about the inlet on a center-line engine than a strut mounted one, but that can obviously be overcome. It's the structural and maintenance issues that are a bigger problem.

Quoting Adam42185 (Reply 2):
Basically, looking to the future, would it be possible to have an engine and aircraft combination where the plane was too big for two engines but not big enough to warrant four engines?

If you fix the engine, you can always find a weight range where you need more than two but not four. But it's very rare to design the aircraft for the engine...you either design the engine for the aircraft, or do it as a partnership in parallel. So, for any particular weight, you can find a solution with three really big engines or four slightly smaller ones (the A380 could have comfortably been a trijet).

Tom.


User currently offlineFlyingClrs727 From United States of America, joined Apr 2007, 733 posts, RR: 0
Reply 5, posted (5 years 9 months 4 weeks 1 day 10 hours ago) and read 14072 times:



Quoting Adam42185 (Reply 2):
say similar in size to a 748/A388? Are there any distinct aerodynamic disadvantages to having a center line engine? Basically, looking to the future, would it be possible to have an engine and aircraft combination where the plane was too big for two engines but not big enough to warrant four engines?  

Due to weight, a trijet like the DC-10 is less structurally efficient than a quad engined plane with four smaller engines. A trijet flying wing might be feasible.


User currently offlineWingedMigrator From United States of America, joined Oct 2005, 2259 posts, RR: 56
Reply 6, posted (5 years 9 months 4 weeks 1 day 10 hours ago) and read 14043 times:

It will have no hydraulics.  cool 

User currently offlineFlyingClrs727 From United States of America, joined Apr 2007, 733 posts, RR: 0
Reply 7, posted (5 years 9 months 4 weeks 1 day 10 hours ago) and read 14049 times:



Quoting Tdscanuck (Reply 4):
If you fix the engine, you can always find a weight range where you need more than two but not four. But it's very rare to design the aircraft for the engine...you either design the engine for the aircraft, or do it as a partnership in parallel. So, for any particular weight, you can find a solution with three really big engines or four slightly smaller ones (the A380 could have comfortably been a trijet).

Originally Boeing wanted the 747SP to be a trijet with a rear engine mounted simlarly to the Tristar. Boeing dropped the idea, because Pan Am wanted the 747SP sooner than would be possible if the trijet version were developed. If Boeing had developed the trijet, I wonder if it would have been feasible to build the 747-8 with three GE90 engines rather than four GEnX engines?



User currently offlineBrons2 From United States of America, joined Sep 2001, 3017 posts, RR: 4
Reply 8, posted (5 years 9 months 4 weeks 1 day 10 hours ago) and read 13973 times:



Quoting Hloutweg (Reply 1):
Tome Y3 will indeed not be a flying wing nor an SST

Or built at all. There's no profits to be made in it. Ask Airbus.



Firings, if well done, are good for employee morale.
User currently offlineSiromega From United States of America, joined Sep 2005, 735 posts, RR: 0
Reply 9, posted (5 years 9 months 4 weeks 1 day 9 hours ago) and read 13904 times:

IIRC, the third engine is a lot of weight (structural) for not a lot of thrust during T/O and ascent (where you need it) because of the AoA of the aircraft and the reduction of airflow into the inlet.

The Y3 will be an exercise in how big you can make a circular fuse with two engines. Making it out of CRFP barrels would be very difficult to transport, they make take the panel approach like Airbus.

How much weight savings does CRFP deliver for a 12Y cross-section, and how much bigger do you have to make the engines over the 115Bs now available. 125k might be doable, but I dont think you'll see 150k or some crazy figure.


User currently offlineJoeCanuck From Canada, joined exactly 9 years ago today! , 5478 posts, RR: 31
Reply 10, posted (5 years 9 months 4 weeks 1 day 9 hours ago) and read 13840 times:

With CFRP and other fiber composites, they need not be married to the circular tube.

I'm thinking it could be a flat oval cross section, 1 deck, at least 12 seats across and 3 containers wide, 2 engines, all electric.



What the...?
User currently offlineDynamicsguy From Australia, joined Jul 2008, 887 posts, RR: 9
Reply 11, posted (5 years 9 months 4 weeks 1 day 8 hours ago) and read 13798 times:



Quoting JoeCanuck (Reply 10):
With CFRP and other fiber composites, they need not be married to the circular tube.

It doesn't matter whether your material is an aluminium alloy or some form of composite, for a pressure vessel the circular-ish tube will be more structurally efficient. Material choice doesn't change that.


User currently offlineJoeCanuck From Canada, joined exactly 9 years ago today! , 5478 posts, RR: 31
Reply 12, posted (5 years 9 months 4 weeks 1 day 8 hours ago) and read 13783 times:



Quoting Dynamicsguy (Reply 11):

Composites do make complex curves easier to deal with. There are plenty of pressurized aircraft that don't have circular cross sections.



What the...?
User currently offlineTSS From United States of America, joined Dec 2006, 3070 posts, RR: 5
Reply 13, posted (5 years 9 months 4 weeks 1 day 7 hours ago) and read 13701 times:



Quoting Dynamicsguy (Reply 11):
It doesn't matter whether your material is an aluminium alloy or some form of composite, for a pressure vessel the circular-ish tube will be more structurally efficient. Material choice doesn't change that.



Quoting JoeCanuck (Reply 12):
Composites do make complex curves easier to deal with. There are plenty of pressurized aircraft that don't have circular cross sections.

How about splitting the difference? Have the actual pressure vessel itself remain more-or-less circular in cross section, but use much more complex/compound curves for fairings and non-pressurized areas of the aircraft such as the wing root.



Able to kill active threads stone dead with a single post!
User currently offlineDEVILFISH From Philippines, joined Jan 2006, 4952 posts, RR: 1
Reply 14, posted (5 years 9 months 4 weeks 1 day 7 hours ago) and read 13684 times:



Quoting Siromega (Reply 9):
125k might be doable, but I dont think you'll see 150k or some crazy figure.

There's a post in Tech Ops which says it is possible.....

http://www.airliners.net/aviation-forums/tech_ops/read.main/249390/

Quoting Lightsaber (Reply 15):
The engine manufacturers could make a 150k engine today. There have been quite a few advancements since the GE-90-115.



Quoting Hloutweg (Reply 1):
If built, it should be an aircraft that spans from the 773 capacity range and above, but that's only if they decide that the 787-10 will replace the smallest 777. If they decide instead that the 777 is to be replaced by a new aircraft, then they could develop an A350XWB like aircraft made of composites that really wont focus on reaching the capacity of the A380. I ponder that if the 787-10 becomes a reality, Y3 will have capacities similar to 777-300, 747-8, and A380-800 but not larger.

From the same post.....

Quoting Lightsaber (Reply 15):
The A350XWB will compete with the 77W with far less thrust. The same would be true of a 450 passenger twin (the largest I current conceive). Its possible to make a 400 seat replacement for the 77W that requires less thrust than the 77W with 8,000nm range!

Please pardon my use of another person's ideas for my replies, as I've no deep knowledge of the matter. However, I regard his opinions very highly.



"Everyone is entitled to my opinion." - Garfield
User currently offlineZvezda From Lithuania, joined Aug 2004, 10511 posts, RR: 64
Reply 15, posted (5 years 9 months 4 weeks 1 day 6 hours ago) and read 13615 times:

If I were Boeing, I would save about 60% of the development costs and use the cross-section, cockpit, empennage, and systems from the 787 and the engines from the A350. That would allow use of most of the production and logistics infrastructure already in place for the 787 including the DreamLifters. I would develop new wings with an area of 450-500 sq meters and a span of about 75 meters, plus new maingear with six-wheel bogeys and enough clearance for the slightly larger engines and to avoid tailstrikes. I would offer it in the same length as the 787-9, and 24 and 48 feet longer. That would give the middle version a cabin floor area of 297.7 sq meters, compared to 279.0 for the 777-200ER, 279.3 for the A350-900, and 314.2 for the A340-600, and would give the longest version a cabin floor area of 338.0 sq meters, compared to 318.6 for the A350-1000, 330.4 for the 777-300ER, and 372.0 for the 747-400. Overall length of the longest variant would be 77.14 meters. Obviously, the design goal would be matching the CASM of a hypothetical 80-meter A380-900.

User currently offlineKeesje From , joined Dec 1969, posts, RR:
Reply 16, posted (5 years 9 months 4 weeks 1 day 2 hours ago) and read 13455 times:

What about 2.5 engined ?

http://www.youtube.com/watch?v=CVWQ5h5UOfk


User currently offlineTexL1649 From United States of America, joined Aug 2007, 299 posts, RR: 0
Reply 17, posted (5 years 9 months 4 weeks 1 day 1 hour ago) and read 13360 times:

It certainly won't be a quad. They're simply not going to build it until the engine technology is near-term achievable. Flying wings don't scale up and down very well, but otherwise that type of design with a few GE-90 style large turbofans on the roof would be quiet and efficient. The real trick is figuring out how to reliably just put the fuel/cargo toward the wing-tips so your pax don't get motion sick on approach/takeoff.

And it would be nice if a composite airframe was on time, on budget, somewhere in the world, prior to going full bore in a new layout with one.

Ecoliner is interesting, but I truly believe that airlines (and regulators) will be skeptical about 1-engine out takeoffs relying on an APU for the necessary supplemental thrust for 800 pax and fuel and cargo heading out on a 4000+ mile trip. Plus, I just feel Boeing will break the tube-and-wings, tail at the back mold on this one.


User currently offlineBOACVC10 From United States of America, joined Jul 2006, 623 posts, RR: 0
Reply 18, posted (5 years 9 months 4 weeks 1 day ago) and read 13050 times:



Quoting DocLightning (Thread starter):
My predictions: it will neither be a flying wing nor an SST. Sorry for smashing your dreams.

I would support if Boeing would launch Y3 project, and employee hundreds of college graduates to develop the next next next generation of aircraft before the world catches up to the US aerospace industry.

Reasoning: the current "tube with wings concept and rubber wheels" leads to less economical uses of propulsion energy and the modern concept of travel-now in more-quantity needs a paradigm shift, and

the "USA" is a high density, small area to cover in flight times

Of course, we need to consider:

larger aircraft to overcome all-weather ops restrictions and danger with smaller aircraft
* capable of flying through wintry mix and thunderstorms

speed
* supersonic in cruise with no after burners

cargo-cum-pax operation
* variants of palletized cargo, or palletized seat payload

maintenance improvement
* quick deployment engine pods

short take off landing
* thrust vectoring
* V/STOL

navigation aids
* satellite

telecom aids
* broadband satellite telecom for all pax

pilot and crew safety improvement
* hijack proof command and control systems

cabin improvement
* cabins with space for movement by pax and handrails
* higher pressure cabin (sea level!)
* reclining / flat beds everywhere

Other a.netters and would be aerospace engineering students should have some serious fun with this, and try to shoot for a concept proposal creation to Boeing (or other private aerospace mfr if any)



Up, up and Away!
User currently offlineSpudsmac From United States of America, joined Feb 2008, 307 posts, RR: 0
Reply 19, posted (5 years 9 months 4 weeks 1 day ago) and read 12883 times:



Quoting DocLightning (Thread starter):
Since we know that Boeing always takes the input of A.net members very seriously

wat?


User currently offlineFlyBoy84 From United States of America, joined May 2005, 384 posts, RR: 4
Reply 20, posted (5 years 9 months 4 weeks 1 day ago) and read 12883 times:

Okay, since this is a FUN exercise, I'll add my  twocents !

Y3 = 4 Engines 4 The Long Haul!

And a HUMP...Y3 needs A HUMP!

Seriously, though, I thought one of the most functional features of the current 747 was the ability to swing the nose open for cargo loading! The HUMP with the flight deck up there facilitated the swinging nose cone! I realize though that one of the drawbacks of the 747 was the forward passenger seating ahead of the first doors meaning that those passengers doubling up against pax behind them trying to exit the plane through the same door, which could be a safety problem.

THEREFORE, I imagine that Boeing will try to fix that resulting in a different  airplane  from the 747 in the future!


User currently offlineAstuteman From United Kingdom, joined Jan 2005, 10230 posts, RR: 97
Reply 21, posted (5 years 9 months 4 weeks 1 day ago) and read 12873 times:
Support Airliners.net - become a First Class Member!



Quoting Zvezda (Reply 15):
If I were Boeing, I would save about 60% of the development costs and use the cross-section, cockpit, empennage, and systems from the 787 and the engines from the A350

With (completely) new wings, new engines, new landing gear and new lengths of fuselage, I struggle to see how this approach will save 60% of the development cost....

Quoting Zvezda (Reply 15):
I would develop new wings with an area of 450-500 sq meters and a span of about 75 meters, plus new maingear with six-wheel bogeys and enough clearance for the slightly larger engines and to avoid tailstrikes. I would offer it in the same length as the 787-9, and 24 and 48 feet longer.

Completely new wings, new engines, new landing gear, new lengths/weights aerodynamics etc = new plane IMO.
Boeing may as well make this plane Y3, with a cross section that merits a plane of this size - just my  twocents 

Quoting Zvezda (Reply 15):
and would give the longest version a cabin floor area of 338.0 sq meters, compared to 318.6 for the A350-1000, 330.4 for the 777-300ER, and 372.0 for the 747-400. Overall length of the longest variant would be 77.14 meters. Obviously, the design goal would be matching the CASM of a hypothetical 80-meter A380-900.

The longest version described here is a plane with near enough the footprint of a 6m stretch A380-900, with all of the attendant logistical issues at airports extensively discussed with respect to the A380, for a plane with little more than 50% of the cabin area (338m2 vs 630m2)

On gut feel, that doesn't sound sensible.
I would have thought that planes of this size would be as well kept in ICAO Cat E (65m span)

And as the similarly sized A350-1000XWB with "the engines from the A350" fails to match the CASM of the current A380-800, I think the stated "design goal" looks optimistic.
Again, just my  twocents 

Rgds


User currently offlineAdam42185 From United States of America, joined Dec 2005, 416 posts, RR: 0
Reply 22, posted (5 years 9 months 4 weeks 23 hours ago) and read 12431 times:



Quoting BOACVC10 (Reply 18):
speed
* supersonic in cruise with no after burners

if youre talking about intra-US travel there wont be supersonic travel until they can suppress the shockwave. I have read in magazines like "popular mechanics" or some other science related magazine that there are people working on, and close to achieving that for smaller jets.


User currently offlineZvezda From Lithuania, joined Aug 2004, 10511 posts, RR: 64
Reply 23, posted (5 years 9 months 4 weeks 22 hours ago) and read 11958 times:



Quoting Astuteman (Reply 21):
With (completely) new wings, new engines, new landing gear and new lengths of fuselage, I struggle to see how this approach will save 60% of the development cost....

It worked for the A340-500/600. Also, I didn't suggest new engines. I suggesting using XWB engines.

Quoting Astuteman (Reply 21):
Boeing may as well make this plane Y3, with a cross section that merits a plane of this size

The 787/A350 cross section has great volumetric efficiency. Going larger sacrifices that.

Quoting Astuteman (Reply 21):
The longest version described here is a plane with near enough the footprint of a 6m stretch A380-900, with all of the attendant logistical issues at airports extensively discussed with respect to the A380

77.14 meters is much nearer to the 76.3 meters of the 747-8 than to the 79.4 meters of the hypothetical A380-900.


User currently offlineYULWinterSkies From United States of America, joined Jun 2005, 2185 posts, RR: 5
Reply 24, posted (5 years 9 months 4 weeks 22 hours ago) and read 11861 times:

If Boeing is listening to us, one advice: build the 787 first! There are dozens of customers anxiously waiting for it.


When I doubt... go running!
25 SEPilot : You forget the floor. Since you need a floor in any case, making the floor beams strong enough to withstand the force tending to make the fuselage ci
26 Astuteman : Which would be new to the airframe.... Although that could be countered by "laying the oval on its side", As Joe mentioned earlier Which is fine if i
27 JoeCanuck : A ceiling brace can be significantly lighter than the floor since it doesn't have to support nearly as much weight, though it could be used to suppor
28 Zvezda : A wide oval cross section would sacrifice structural efficiency by putting the floor beams into compression rather than tension. It would also requir
29 SEPilot : True; this is what I was referring to by "added structure". It is still weight that would not be required with a cylindrical cross section. The diffe
30 Astuteman : Ah, but an A380-900 would be 79m x 79m, a box of 6241m2, which is only 466m2 different A passion for accuracy is admirable in the right circumstances
31 Zvezda : The WhaleJet's wingspan is 79.8 meters. I'm quite surprised you jumped on me for rounding 79.8 up to 80 and then insisted on rounding 79.8 down to 79
32 Flipdewaf : I think it's silly to measure the footprint as the actual area is a bit silly. using this method a 150m long plane with a 35m wingspan would be bette
33 Zvezda : I'm not the one who introduced this concept in this thread. I just corrected the numbers.
34 DocLightning : See, that's where I disagree with you. Airbus had the right idea with the A330/A340. The A330 is a shorter, but otherwise identical fuselage to the A
35 SEPilot : I have to disagree with you here. From what I have read 150K is feasible now, which is a considerable jump over the 115K that the GE-90's now produce
36 SeaBosDca : They are actually just a bit bigger around than an E-Jet. Still huge, but hardly 767-size. I remember these sorts of arguments being made about 777 e
37 SEPilot : I used "when" deliberately; I have no doubt that at some point there will be demand for it, and it will be built. I did not specify when that will be
38 DocLightning : There was a wink at the end of that.
39 DocLightning : See, I think there will be a market for some truly enormous aircraft, like the A380. Especially as the population and traveling population grow and c
40 Tdscanuck : Unfortunately, there's no way to suppress the shockwave. It's physically impossible to fly supersonic and not generate shockwaves. What you can suppr
41 BOACVC10 : I think it is not a big issue anymore... as long as the project employs US persons (a legal term) and US resources .. and contribute to the economy (
42 SeaBosDca : You'll be breaking the 80m box by more than a little with an A380-size aircraft built using a 777-size (or slightly bigger) tube. That's not a deal-b
43 Zvezda : Actually, the original 777 engines' nacelles were about the same diameter as the 737's fuselage. Two were a bit smaller and one was a bit larger. Of
44 Astuteman : In which case you didn't take the point offered. To be honest SEP, I don't think that a big jump in engine power is necessary. A 450 seat 748i matchi
45 DocLightning : There's also a trick to get them to destructively interfere with each-other that makes them all but inaudible. The QSST has that feature. That's my p
46 Platinumfoota : Would it be too much to ask for a higher service ceiling than most commercial jets?
47 DocLightning : Especially with big planes, wing size gets to be an issue. You really need a lot of wing to get way up there, and that's a lot of drag and mass to ha
48 Zvezda : Huh? Yes. No. It would be more like 747-200 sized. That assumes you can sell very roughly 1000 airliners with the width of a 747 and the length of a
49 DocLightning : Boeing lists 368 pax in a 773 and3 366 in a 742. So a 747-width plane the length of a 773 would be like a 748. Just a touch smaller.
50 Zvezda : Passenger counts are not an accurate reflection of airliner sizes. I hope we can agree that, since you've stipulated 747 width for your hypothetical
51 JoeCanuck : The width of the 777 is only a foot smaller than the 747. Volumetric efficiency wouldn't really be that much different. I doubt that would be the dea
52 Post contains links and images Keesje : During innitial concept development the A380 was smaller, it became "18 abreast' in the later stages. http://www.youtube.com/watch?v=SmigvHkBQIc Leave
53 Zvezda : The 777 already suffers a bit in volumetric efficiency relative to the A330/787/A350 cross sections. I would need to see several times the demand we'
54 Rheinwaldner : I am not convinced that a big "unused" crown is so bad. Beside the additional front area I see no disadvantage. Structurral efficiency surely is bett
55 Zvezda : It's not just the crown. There is also more wasted space around the cargo deck. No, structural efficiency is better for smaller airliners (because we
56 Flipdewaf : Huh? you think airbus forgot to take into account present value factors when they came up wih the 400 frame break even number? Frame
57 SEPilot : This is true; however, by using intelligent design (such as trusses, tubes, etc.) this can be done without excessive weight penalties, especially whe
58 Astuteman : I suspect service ceiling has far more to do with aerodynamics, lift, and wing stalling, than anything to do with the fuselage itself. Perhaps one of
59 Post contains images Rheinwaldner : Yes, but that does not mean that a present or future VLA program can only generate losses as you first claimed. I agree with that. Then, why do we sa
60 Keesje : Boeing stretched the 737 into the -900, 747 into the -8, 757 into the -300, 767 into the 767-400ER, 777 into the -300Er and will stretch the 787. Air
61 SEPilot : Actually, the fuselage has a lot to do with it, because of the differential pressure on it. I don't believe that the aerodynamic issues (which do exi
62 Rheinwaldner : Both remarks seem reasonable. IIRC once there were ideas for hydrogen-driven aircrafts presented. The tanks for those would have been located in the
63 Keesje : Cron areas are used for overhead crewrests, IFE headend equipment, trolleys stowage (maybe), airco and aircraft systems. But generally very empty. Bo
64 Astuteman : Is it? I would have thought the (CFRP) A350-1000 would (of necessity) have a substantially lower CASM than the 773ER (else why build it?), and yet th
65 Zvezda : No, but Airbus said a few years ago that the number had risen beyond 420, and declined to disclose the new number. That projection was also based on
66 Keesje : I really hoped the 747 was a profitable program. Maybe it wasn't because the market was much smaller and fuel cheaper during its life time?
67 Post contains images PW100 : The Royal Navy will certainly operate some interesting subs . . .      [Edited 2009-02-24 07:35:16]
68 Flipdewaf : The value was at 450 or so in may last year but with the change between the dollar and the euro means that it could easily be below 400 now. I was to
69 Astuteman : No. Should it? Or is this just trolling? Rgds
70 SEPilot : I was going by the charts that somebody (I believe it was Widebodyphotog) posted on another thread a while ago. My memory is that the 77W was the onl
71 Zvezda : The 747 had a monopoly on range for most of its life. The same principles are in play. One who understands either, understands both.
72 Keesje : Lets face some emerging realities : the A380 has a capasity-range monoploy in the 400-600 seat segment for a (very) long time to come. The 747-8i sof
73 Astuteman : The position in the water of a submarine is dictated by buoyancy, which it has whether it is moving, or not. It's maximum depth is dictated by the hu
74 SEPilot : That is not the issue. The 747 did so well because it was for a long time the ONLY airliner offering the range it had. The A380 does not enjoy that a
75 Zvezda : For commercial airliners, the limit results from the limits of acceptable stresses on the fuselage. Some bizjets are certified to FL510. They can do
76 Platinumfoota : So would a higher service ceiling be plausible? If both wing and fuselage were engineered to do so? What else would have an affect? Off the top of my
77 Zvezda : Yes, it's possible. CFRP construction reduces the weight penalty for increasing the strength needed to maintain cabin pressure. The fuel temperature
78 Post contains links Jambrain : If Widebodyphoto is correct (I don't know better but some of his numbers look plain wrong to me) L/seat km assume 1 m2 per pass 388 0.0297 77W 0.0321
79 GAIsweetGAI : How so? Does this mean CFRP is not subject to aging, or the pressurization/depressurization cycles, or other phenomena? (asks the not-very-knowledgea
80 DocLightning : I love how they trotted out a 747 copy briefly. I was like "Really? That didn't get laughed out of the board room instantly?" The question is whether
81 Post contains links JoeCanuck : Subsonic aircraft are also limited by the speed of sound, which decreases with altitude. At the same time, stall speed rises with altitude. At some p
82 Zvezda : Yes, but the coffin corner is way beyond current service ceilings which are based on the limits of the fuselage coping with pressure differentials. I
83 Astuteman : Be careful. That is only fuel burn, which accounts for about 1/3 of CASM (and if the aviation specialist engine SFC assumptions are anything to go by
84 Post contains links JoeCanuck : Not really...different planes, or even the same plane at different weight, have a different coffin corner. The U2 could fly at 80,000 feet...with a m
85 SEPilot : This is true. However, the penalties of raising the altitude of the "coffin corner" are not that severe; essentially it means lowering the stall spee
86 DocLightning : Doesn't wing area figure in, though?
87 DocLightning : So if you wanted to make a plane that weighed 1.5 as much as a 773, I worked out in another thread that you'd only need 85kN engines, or two 170 kN en
88 Rheinwaldner : It can't be ruled out also on this planet. There is no prove or even a trend. It is far too early to say the A380 will not return its investments. Do
89 SEPilot : To some degree; but the best way to decrease stall speed without increasing drag is to lengthen the wing. Just look at the U-2's wing. It is that lon
90 Post contains links and images Keesje : Hopefully it will be a huge success but probably have capasity under 5000 seats. Some overlap but not more then that. Remember the -800 is the 767-20
91 Part147 : Sorry to interrupt the flow ... but what exactly do you mean when you refer to Y1, Y2 and Y3 - I know it's a future concept for an aircraft design, bu
92 Rheinwaldner : I agree with what you meant! The area at let's say > 6000 seats belongs to the A389!
93 Zvezda : There is a very clear trend. That's like saying it's too early to say there will be life on earth a year from now. Life might get wiped out by a come
94 Astuteman : Depends what Y3 is - it is most unlikely to do so if its a 350 seat 787 derivative..... if the A350-1000 is anything to go by... Rgds
95 Keesje : You just triggered me to take a look at an "Airbus Y3"
96 Astuteman : If you ever get a job, you'll be in big trouble... Rgds
97 DocLightning : At least it's prettier than the A380... It carries 1,000 cu ft. more cargo than the 744, but 50 fewer passengers. MTOW is 100,000 pounds less, too (a
98 Glacote : Why take squares? My (limited) understanding of airport planning is that area (square meters) is irrelevant - only the longest dimension (meters) is.
99 Post contains images Rheinwaldner : There is no trend. The size of the market is about the same as ever in absolute numbers. You know absolute numbers are the important figure to justif
100 DocLightning : Although it somewhat depends on the stress involved. IIRC, a hollow tube is just as strong as a solid tube for longitudinal loads, but less strong fo
101 747400sp : I would love it to be an ultra larger twin, with a up stairs hump like on the 747, or a giant size four engine sonic cruiser.
102 NZ2 : Apologies if I have missed this being posted earlier, but if the airplane needed 150kn after an engine out situation, it would mean a twin required 15
103 DocLightning : This has been proposed. But you do run into the commonality issue. First of all, the engines on the Y3 will be more advanced than those on the 787, m
104 Cloudy : One other penalty a trijet faces is that of length. The rear engine and the stuff associated with it occupy a portion of the plane's length. You need
105 2707200X : The 747-8i is not really selling, only two airline customers so far, unfortunately, this looks like the end of the 747 as a passenger carrying aircraf
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