Quoting tortugamon (Reply 26): Interesting. Was not aware. I would think that was relatively uncommon. It would change the dynamic slightly if that was the case.

Not that uncommon, where I work A330/A340/A350/777/747 pilots are paid the same, same with the cabin crew.

Quoting Chaostheory (Reply 33): Suffice it to say, the benefit of taking me over to the 777 fleet greatly outweighs the cost.

They always manage to get their pound of flesh. Normally you can only change fleets when there are vacencies.

Quoting LH707330 (Reply 41): My point is that the 350 has both the thrust and the wing advantage, at a very small weight disadvantage. The mission is 8-10 hours pax+cargo out of DXB. There was a thread here or an article laying out the takeoff limitations. TL;DR version was the 359 burns a few % more fuel but takes a bunch more payload, thus comes out ahead.

In reality the majority of EKs flights are not flying around at 100% load factors, they average around 80% so any small payload advantages are not that relevant IMHO.

Quoting tortugamon (Reply 46): Or they really were not considering the A350 for this regional order once the 78X was launched and they only bring up the A350 to get a better price on the 78X... but now that they want the A380neo the A350 order is truly back on the table so they can incentivize Airbus to launch that program.

  

The longest Europe route is probably DXB-LIS at 3800mi.

I think if the 781 can't make this at MZFW, even on a somewhat warm day, there is a problem.

Quoting BobMUC (Reply 5): Or Randy is playing this down because they have a good chance of winning this bid.

Randy is playing this down due to Boeing having lost that playoff.

It's all about giving reasons why something didn't happen.

Quoting seabosdca (Reply 32): I think Emirates' hot/high concerns are likely a bit overstated in any case. The thing should have no issue flying 8 hours from DXB after a hot afternoon takeoff. That ought to be more than enough. But if there's one thing we know about Tim Clark, it's that he wants as much flexibility as he can possibly get, so he'll keep banging the drum for what he wants. I doubt, though, that in the end the 359 will actually be more attractive for the missions he wants these frames for. If he wanted a smaller plane to fly to Boston or Melbourne, it would be a different story.

   Sure Clark wants the perfect plane and there's nothing wrong with him asking for it. He'd be remiss in his duties if he didn't. When all is said and done, IMHO the 781 is the better choice for the missions the aircraft in the RFP are to be used for. I think they'll go that way, but the wild card is the 380NEO and how that may play into a possible 359 order.
Will be looking forward to the decision being announced next year.

Quoting LH707330 (Reply 34): $20 says this goes A359.

Quoting Stitch (Reply 47): If I had to put $20 down, I'd put it down on the 787-10

Well, we seem to have a wager here......  

Ek is surely pressuring Airbus for a 38X neo and sweetening the deal with a huge A359 order… but heck after seeing the cancelation or the a350 and the huge 779 order..who knows…

TRB

So I read a climate change article:

http://www.cnn.com/2015/10/27/world/persian-gulf-heat-climate-change/

That indicates the gulf region could be unbearable by 2100. Now, if people don't believe in climate change, this can just be ignored. However, if the region does get increasingly hot over the decades, I imagine the performance of an asset that depends on weather conditions is increasingly important. An aircraft that 'mostly' achieves what EK wants now may not do so well in as little as a decade from now.

I also wonder how robust the air conditioning for aircraft in the region must be on those very hot days must be.

Quoting ER757 (Reply 54): Sure Clark wants the perfect plane and there's nothing wrong with him asking for it.

Why don't EK design, develop and build their own aircraft? They could make it perfect for themselves, and potentially even offer it to other airlines.

Quoting tortugamon (Reply 10): They don't have any A350s on order so splitting the order would mean training a whole new set of pilots. 777 pilots can be trained on the 78X in less than a week and they share a common operating cert.

A380 pilots can transition to the A350 in the same time frame, I beleave it was noted as 12 days, as 777/787 so what point are you making with this comment? Not mush difference & they have lots of A380 & 777 plots to chose from.

Quoting KarelXWB (Reply 13): Changing of the spec won't come from Boeing. Its the engine that would need changes, not the frame. Though a heavier engine may require additional airframe strengthening.

Change of spec on an engine does not always mean increased weight. The RB211-524 when to G/H-T improving hot/high performance while lowering weight with the trent 700 core by around 500 lb. I do believe.

The RB211started out at 42000 lb. st. with the -22B and ended with 60600 lb. st 524G/H-T.
Both with the same 84.8" fan size & 119.4" original & some 524 models, the rest at 122.3"
18600 lb. difference in thrust with improvements.
Main differences were improved cores with same number of stages & redesigned fans.

Trent 1000 started out at 64100 lb. st. has been derated to 53200 & 58000 lb. st and increased to 78000 lb. st.
Based on initial (64100) and largest (78000) models what makes you think they cannot get the 82700 out of it.
Thats close to the 84k EK wants and could seal the deal.

[Edited 2015-11-06 18:51:42]

Quoting MrHMSH (Reply 49): Quoting roseflyer (Reply 35): Emirates already has the 777x on order. The 777-8x is only 30-50 seats larger than the 787-10. I think the 787-9, 787-10, 777-8, 777-9 and A380 would be a good line up. The 787-9, 777-8 and A380 work well for flights over 10 hours whereas the 787-10 and 777-9 can focus on some of the shorter routes. I don't know if the A350 is really needed. It does fit in between the 787 and 777x, but the capacity gap isn't that big. The 789 won't make an appearance, it's a little too small for EK. This competition is purely for the short/medium haul fleet, and that's what the A359 is being considered as. While they could use the A359 as a long hauler, I don't expect to see it happen.

The 787 is a lot more efficient at short ranges than the A350. The 787-9 and 787-10 would work well for flights within the Middle East, Africa, India and Eastern or Central Europe. The 787-9 is only 30 seats smaller than the A359. The A350 does better at the long haul flying but Emirates dropped the A359 order for 777s, so I am not sure he A350 really fits. If emirates wants to fly the 787-10 to Western Europe or China then they may have problems.

Quoting roseflyer (Reply 62): The 787 is a lot more efficient at short ranges than the A350. The 787-9 and 787-10 would work well for flights within the Middle East, Africa, India and Eastern or Central Europe. The 787-9 is only 30 seats smaller than the A359. The A350 does better at the long haul flying but Emirates dropped the A359 order for 777s, so I am not sure he A350 really fits. If emirates wants to fly the 787-10 to Western Europe or China then they may have problems.

But EK aren't interested in the 789, there has never been an indication of this. No, the A350 is not as good at long haul flying, but it offers extra performance that EK wants, it's now down to them deciding whether they want the more efficient frame that stuggles at longer ranges in extreme temperatures, or the heavier and less suited plane that has performance to spare.

Quoting MrHMSH (Reply 63):

I don't see why they would not be interested in the 787-9/10 combo. They have a lot of different seating capacities to replace on the smaller Airbus and Boeings type currently in service.

We also need to draw lessons from the A320/737 space when aircraft have similar performance, the financing terms can be the deal maker.

Quoting zeke (Reply 64): I don't see why they would not be interested in the 787-9/10 combo. They have a lot of different seating capacities to replace on the smaller Airbus and Boeings type currently in service.

Maybe, but this competition is between the A359 and 78X, and while it's not as if the 789 is unsuitable for EK, I don't think really necessary. I would be very surprised if it wasn't a simple 70 A359s or 70 78Xs with no 789s. Given that the 78X's unit costs are lower than the 789's, you'd have to ask what routes EK fly that justify a 789 instead of a 78X, and the answer is not many. Probably not worth a 789 order.

Quoting zeke (Reply 64): We also need to draw lessons from the A320/737 space when aircraft have similar performance, the financing terms can be the deal maker.

The deal tipper could be EK using an A350 order as leverage for an A380neo. I don't think financing terms will favour either OEM.

Quoting rbavfan (Reply 59): A380 pilots can transition to the A350 in the same time frame, I beleave it was noted as 12 days, as 777/787 so what point are you making with this comment? Not mush difference & they have lots of A380 & 777 plots to chose from.

I could be wrong but I doubt pilot training is the largest expense with a mixed fleet. It seems to me that parts, service and support for radically different airframes would be more of an issue.

Quoting JoeCanuck (Reply 66):

Pilot training for a large airline is more of a fixed cost. They tend to have the instructors on salary, pilots on salary, and own the simulators. The actual running cost of a simulator is negligible.

Quoting rbavfan (Reply 61): Trent 1000 started out at 64100 lb. st. has been derated to 53200 & 58000 lb. st and increased to 78000 lb. st. Based on initial (64100) and largest (78000) models what makes you think they cannot get the 82700 out of it. Thats close to the 84k EK wants and could seal the deal.

Maybe they can get the thrust but I guess one engine out on a hot day would get tricky at max TOW... my .02

TRB

Quoting Pellegrine (Reply 57): It's a somewhat crippled airplane.

It flies nearly as far as a 747 which did the majority of Long haul flying before 1998. Crippled is an interesting word for a 14 hour airplane.

Quoting Pellegrine (Reply 57): Boeing was supposed to right-size the wing for the 789, and they didn't even care to do that

They found that the extra span did not compensate for the extra weight. The wing was most efficient as is.

Quoting Pellegrine (Reply 57): You could keep the gear, and boost the MTOW just enough to cover OEW increase from a little more wing

Supposedly the gear is the limiting item. No immediate MTOW lift available.

Quoting rbavfan (Reply 59): A380 pilots can transition to the A350 in the same time frame, I beleave it was noted as 12 days, as 777/787 so what point are you making with this comment?

5 days for each. Fewer A380 pilots than 777 pilots, therefore the latter is cheaper.

tortugamon

Quoting zeke (Reply 67): Pilot training for a large airline is more of a fixed cost. They tend to have the instructors on salary, pilots on salary, and own the simulators. The actual running cost of a simulator is negligible.

Thanks, zeke, for that very interesting bit of insight. So, I guess the main cost arises from having to pay pilots to attend training rather than flying planes and generating revenue? Regards. -ir

Quoting JerseyFlyer (Thread starter): No "emiratisation" it seems: http://news.airwise.com/story/boeing...-not-make-787-changes-for-emirates Do they think they will win the order without changing the spec for better hot and high performance, or have they given up on it?

Airbus didn't "Emiratise" the A350 either.

Quoting tortugamon (Reply 69): It flies nearly as far as a 747 which did the majority of Long haul flying before 1998. Crippled is an interesting word for a 14 hour airplane.

If Tim Clark calls the A350-1000 a 10 hour aircraft I don't see how ones with less range can be classed as 14 hour aircraft...      

I went back to a Leeham article about the limitations of the 787-10 in hot conditions. Bjørn/Ferpe ran a simulation between DXB and MAD. Grat circle distance is 3055nm. Due to wind and diversion he need a 3800nm still air equivalent distance. He plans with 45C air temperature at takeoff.

His result was that due to runway limit at 12.000 feet and brake energy absorption limits the max take off weight would be around 230 tonne. Subtracting empty weight and fuel for a 3800nm still air mission he was left with a payload of about 43 tonne. At ca 330 passengers each ca 110 kg? with bags that leaves about 7 tonnes for cargo if the plane is full booked. I Dont know if catering etc also should be subtracted. If that is the case then even less cargo.

Edit: For comparison, acording to Wikipedia the max take off weight of the 787-10 is 251 tonne.
Flying DXB-MAD at some modest headwind takes aproximately a little bit less than 7 hours if there is no delay for landing etc.

[Edited 2015-11-07 04:08:33]

[Edited 2015-11-07 04:11:25]

[Edited 2015-11-07 04:13:43]

What is a '7810' supposed to be? Is it just me that is irked by made up abbreviations? Surely it is not difficult to type B787-10 or 787-10 in the title of a thread.

Quoting enzo011 (Reply 72): If Tim Clark calls the A350-1000 a 10 hour aircraft I don't see how ones with less range can be classed as 14 hour aircraft

Quoting UK_Dispatcher (Reply 74): Is it just me that is irked by made up abbreviations?

It does get a bit hard to follow, doesn't it?

For reference, the official ICAO type designator codes are A35K for the A350-1000 and B78X for the 787-10.

Quoting XAM2175 (Reply 75):

OEJ is a 744ER

Quoting XAM2175 (Reply 75):

Erm...yeah we are discussing the 789 (I believe that is what tortugamon was talking about when discussing the 14 hour missions) being a "crippled" design. My take on it, Tim Clark has said the A350-1000 is good for 10-12 hours and yet it has more advertised range than the 789, so what does this make the 789? Where does the 78X fit in with those standards?

Quoting zeke (Reply 67): Pilot training for a large airline is more of a fixed cost. They tend to have the instructors on salary, pilots on salary, and own the simulators. The actual running cost of a simulator is negligible.

Thanks...that's good information.

Quoting enzo011 (Reply 77): Erm...yeah we are discussing the 789 (I believe that is what tortugamon was talking about when discussing the 14 hour missions) being a "crippled" design. My take on it, Tim Clark has said the A350-1000 is good for 10-12 hours and yet it has more advertised range than the 789, so what does this make the 789? Where does the 78X fit in with those standards?

Actually the discussion here according to the title is about the 787-10. Therefore the range of the 787-9 would have no connection to this thread.

An airplane that could face payload restrictions on a hot day out of DXB for a 7 hour flight is perhaps not up to what Tim Clark calls regional, that could perhaps include all of Europe.

One big point here is, the A350-900 is in use. Real numbers are available from Qatar and Emirates could have received them. Perhaps the expected advantage of the 787-10 on shorter routes is less than first expected and the more versatile A350-900 has some advantages for Emirates. Beside a regional role, it could fill the "route opener" role for more distant destinations.

Quoting SteinarN (Reply 73): His result was that due to runway limit at 12.000 feet and brake energy absorption limits the max take off weight would be around 230 tonne.

The runways at DXB and JXB are both over 14,000 feet. So unless the 787-10 is hitting tire/wheel speed limits at 12,000 feet, they should be able to support a longer take-off roll (unless 12,000 is the actual runway length used prior to rotation and the rear wheels losing contact).

Quoting enzo011 (Reply 77): Erm...yeah we are discussing the 789 (I believe that is what tortugamon was talking about when discussing the 14 hour missions) being a "crippled" design.

I believe he is referring to the 787-10 having a 60m wing instead of a 63m wing (as the 787-9 and 787-10 were originally designed around). For the 787-9, the shorter span seems to be a wash as the lighter weight cancels out the poorer aero in terms off fuel burn on long flights. But for the 787-10, the extra aero likely would have been more helpful in hot and high conditions.

Quoting enzo011 (Reply 77): My take on it, Tim Clark has said the A350-1000 is good for 10-12 hours and yet it has more advertised range than the 789, so what does this make the 789?

Tim Clark wanted the A350-1000 as a 777-300A replacement and a high-capacity regional bird. So it's good for 10-12 hours for him, but for everyone else, it's good for 14-16.

Quoting enzo011 (Reply 77): Where does the 78X fit in with those standards?

I expect it to be used on the same missions the 777-300A and two-class 777-300ER are.

[Edited 2015-11-07 09:04:40]

Quoting Stitch (Reply 80): The runways at DXB and JXB are both over 14,000 feet. So unless the 787-10 is hitting tire/wheel speed limits at 12,000 feet, they should be able to support a longer take-off roll (unless 12,000 is the actual runway length used prior to rotation and the rear wheels losing contact).

I didn't quite understand the 12.000 feet runway limit. But anyway, Bjørn/Ferpe came to the conclusion that on a 45C day at DXB the 787-10 was limited to a max take off weight of only about 230 tonnes compared to the structurally max take off weight of 251 tonnes.

Quoting enzo011 (Reply 77): Erm...yeah we are discussing the 789 (I believe that is what tortugamon was talking about when discussing the 14 hour missions) being a "crippled" design.

No, I was referring to the 78X. 14hrs is a touch high but it should be able to do 13 hour flights with a full load of passengers, the 789 should be pushing 17 hour flights for your reference and its already flying 16 hour flights - hard to call either of them a crippled design. Its when you add cargo and 45 deg C temperatures that the 78X becomes a 8.5-10 hour plane.

Quoting mjoelnir (Reply 79): An airplane that could face payload restrictions on a hot day out of DXB for a 7 hour flight is perhaps not up to what Tim Clark calls regional, that could perhaps include all of Europe.

Shall we take STC on his word: "
[/quote]"We wouldn't put it on New York or Sydney, but as a workhorse up to 8.5h without a kink in the payload, it looks like a good aeroplane," he says."[/quote]

Its not a 7 hour plane.

tortugamon

Quoting tortugamon (Reply 82): Its not a 7 hour plane.

According to Björn at Leeham, it is on a 45° C day with a full load out DXB a 7 hour plane, and full load does mean in that case passengers and cargo.

Quoting mjoelnir (Reply 83): According to Björn at Leeham, it is on a 45° C day with a full load out DXB a 7 hour plane, and full load does mean in that case passengers and cargo.

I'm not buying the Leeham report given some of its assumptions. Lets leave aside the fact that a 45C day with full load will be a RARE occurrence, it also assumes 12,000 roll which shouldn't apply.

EK knows their loads and weights, there's no way they are assuming this scenario for deciding on their order.

Quoting mjoelnir (Reply 83): According to Björn at Leeham, it is on a 45° C day with a full load out DXB a 7 hour plane, and full load does mean in that case passengers and cargo.

Yes, but 45° days are going to be the exception (possibly the rare exception) and not the rule. So for the vast majority of the time, a 787-10 will be able to take a "full load" out of DXB and fly it 8-9 hours.

So do you buy a plane that is most-efficient 90% (or more) of the time, or do you buy one that is capable of pulling it's full weight for that 10% (or less) of outlier cases, but the rest of the time is not as efficient as the other plane?

Quoting Stitch (Reply 85): Quoting mjoelnir (Reply 83): According to Björn at Leeham, it is on a 45° C day with a full load out DXB a 7 hour plane, and full load does mean in that case passengers and cargo. Yes, but 45° days are going to be the exception (possibly the rare exception) and not the rule. So for the vast majority of the time, a 787-10 will be able to take a "full load" out of DXB and fly it 8-9 hours. So do you buy a plane that is most-efficient 90% (or more) of the time, or do you buy one that is capable of pulling it's full weight for that 10% (or less) of outlier cases, but the rest of the time is not as efficient as the other plane?

But than it depends on how much the difference in efficiency is and perhaps it is not as significant as some believe.

Quoting mjoelnir (Reply 86): But than it depends on how much the difference in efficiency is and perhaps it is not as significant as some believe.

OEM empty weight differences could be in the neighborhood of 10,000kg or more, which is also in the neighborhood of what the OEM empty weight difference is between an A330-300 and 777-200. If Aspire's numbers are to be believed (which they will not by many), the difference could be twice that in two-classes.

On missions up to 4000nm, the A330-300 is up to 15% more fuel efficient than the 777-200. So the 787-10 could very well have a double-digit lower fuel burn (as a percentage) per hour on such missions compared to the A350-900.

Which could explain why EK is asking for more from the 787-10 - trade some of that lower fuel burn for better performance because overall the 787-10 is still not-insignificantly more fuel efficient than the A350-900 in missions up to 4000nm.

Quoting Stitch (Reply 87): OEM empty weight differences could be in the neighborhood of 10,000kg or more, which is also in the neighborhood of what the OEM empty weight difference is between an A330-300 and 777-200. If Aspire's numbers are to be believed (which they will not by many), the difference could be twice that in two-classes.

That's quite a big difference, it's much more than I would expect. Is there any evidence (yet) that the 78X will be that much lighter? And also, the A350's trip fuel burn is not dissimilar to the 789's, would it be similar to the 78X?

Quoting Stitch (Reply 87): On missions up to 4000nm, the A330-300 is up to 15% more fuel efficient than the 777-200. So the 787-10 could very well have a double-digit lower fuel burn (as a percentage) per hour on such missions compared to the A350-900.

I find that hard to believe, 10% difference on unit cost or trip cost seems very high to me, and if that were the case surely it would never be a contest if it's the 78X against the A359?

Quoting Stitch (Reply 87): Which could explain why EK is asking for more from the 787-10 - trade some of that lower fuel burn for better performance because overall the 787-10 is still not-insignificantly more fuel efficient than the A350-900 in missions up to 4000nm.

I can believe it's better, it is slightly larger in terms of capacity, but if the advantage is by as much as the 772/A330 then this is not going to be a contest...

Quoting mjoelnir (Reply 83): According to Björn at Leeham, it is on a 45° C day with a full load out DXB a 7 hour plane, and full load does mean in that case passengers and cargo.

I looked up temperatures in the DXB for the last year and this is the grand total of days in which the temperature ever reached 45 degrees C: 1 day in June, 6 days in July, 4 days in August. That's it, 11 days.

http://www.wunderground.com/history/...reqdb.zip=&reqdb.magic=&reqdb.wmo=

Quoting Stitch (Reply 85): Yes, but 45° days are going to be the exception (possibly the rare exception) and not the rule. So for the vast majority of the time, a 787-10 will be able to take a "full load" out of DXB and fly it 8-9 hours. So do you buy a plane that is most-efficient 90% (or more) of the time, or do you buy one that is capable of pulling it's full weight for that 10% (or less) of outlier cases, but the rest of the time is not as efficient as the other plane?

Based on what I can tell its ~3% of the days and if you think that the hottest temperature is only around for ~20% of the day then even less. And again, even then, that assumes full seats and fully dense cargo before there is a payload hit in reality.

Quoting mjoelnir (Reply 86): But than it depends on how much the difference in efficiency is and perhaps it is not as significant as some believe.

It certainly will be not-an-insignificant-amount lighter but even then, it will offer more revenue (seats) and cargo (volume and payload) on routes that EK is proposing. Its not just cost efficiency.

Quoting MrHMSH (Reply 88): That's quite a big difference, it's much more than I would expect. Is there any evidence (yet) that the 78X will be that much lighter? And also, the A350's trip fuel burn is not dissimilar to the 789's, would it be similar to the 78X?

My conservative estimate was 5t difference so Stitch may have better numbers than I do but the weight really should be significantly different, essentially every part of the airplane should be lighter. Lighter wings, engines, empenage, fuselage....etc. We are being told that the A359LR is an 18 hour machine with minimal changes to the standard A359...it can't be everything to everyone.

tortugamon

Quoting tortugamon (Reply 89): My conservative estimate was 5t difference so Stitch may have better numbers than I do but the weight really should be significantly different, essentially every part of the airplane should be lighter. Lighter wings, engines, empenage, fuselage....etc. We are being told that the A359LR is an 18 hour machine with minimal changes to the standard A359...it can't be everything to everyone.

I don't think it's a shock that the A359 isn't the best regional aircraft, nor that it's less efficient than the 78X. But by a similar amount to the A330 and 772/E difference? The 772 has slowed to a trickle by 2007, where the A333 has soldiered on. And that was down to the A333 being capable enough, it was not a long ranger. The 78X even allowing for a possible shallower payload/range curve is more capable than the A333 by a fair amount, but I just think that if it was that much of a difference there would simply be no contest for EK, even allowing for the 3% of days you estimate the 78X may struggle a little. It is a little weird that EK would rather take an aircraft more suited to the 3% than the 97%, I mean it could just be politics with the A380neo, but from a technical perspective if the difference was as much as Stitch suggests then I see no reason why this competition would be so close.

Out of interest, though the A359 is heavier, would its larger wing make the difference in fuel burn less proportionally when considering weight? Or are the routes a little too short for that to make a difference?

Quoting MrHMSH (Reply 90): The 772 has slowed to a trickle by 2007, where the A333 has soldiered on. And that was down to the A333 being capable enough, it was not a long ranger.

I think on here we chalk up the decline of sales of the 77E to the A333 when I think the 77W also played a significant role. Just like the 788 not selling well when the 789 is available the 77E doesn't sell well when the 77W is available. Anyway, certainly the A333 played a significant role and I don't want to take away from that, its just not the entire story.

The MTOW of the A359 is 17t more than the 78X yet its Max Fuel Weight is only 9t higher, that implies a not-insignificant OEW difference.

tortugamon

Quoting rbavfan (Reply 60): Change of spec on an engine does not always mean increased weight. The RB211-524 when to G/H-T improving hot/high performance while lowering weight with the trent 700 core by around 500 lb. I do believe.

The RB211-524G2-T-19, -524G3-T-19, -524H2-T-19 and -524H-T-36 are the variants of the RB211-524G2-19, -524G3-19, -524H2-19 and -524H-36 engines and feature the RB211-Trent 700´s 04 high pressure Module - technology developed on the Trent 700 engine family in 1997, but also comprising some other modifications to provide improved engine performance and reliability. On the RB211-524G/H-T engines, the HP turbine system is designed to operate at Trent 700´s temperatures that are significantly higher than at the previous models of engines. Engine models with a suffix ´-T´ in their name have 87 kg (192 lbs) lower masses than the previous models of the engines…

Quoting rbavfan (Reply 61): The RB211started out at 42000 lb. st. with the -22B and ended with 60600 lb. st 524G/H-T. Both with the same 84.8" fan size & 119.4" original & some 524 models, the rest at 122.3" 18600 lb. difference in thrust with improvements.

Not exactly. Those engines do not have the same fan´s diameter…

RB211-22B, RB211-524B2 and RB211-524C2 ….......... 84,8 in. - 215,4 cm fan diameter
RB211-524B4, RB211-524D4 and RB211-524D4-B …… 85,8 in. - 217,9 cm fan diameter
RB211-524G, RB211-524H ………………………………. 86,3 in. - 219,2 cm fan diameter
RB211-524G-T, RB211-524H-T…………...................... 86,3 in. - 219,2 cm fan diameter

Regardless of the fact that all Rolls-Royce RB211-524 engines share the same architecture, F-7IPC-6HPC ^ 1HPT-1IPT-3LPT, it is obvious that the higher required thrusts - T[N] and the propulsive efficiency - ŋ[P] of the engines were obtained through the increased fan´s mass flow - m[f] .

I believe that most people do not understand to what were those figures, and in a vague context mentioned: ´& 119.4" original & some 524 models, the rest at 122.3"´, related to. Those are the incorrect data that Wikipedia states as the length of the mentioned engines. The certificated length of those 524X-T engines, measured from the front case flange to the rear of INA, is 187,35 in. - 475,9 cm.
For the RB211-524B2 and -524C2 engines, it is 180,4 “ - 458,2 cm, for the RB211-524B4 it is 189,2 “ - 480,5 cm, and for RB211-524D4 and -524D4-B engines, this value is 189,8 in. - 482,1 cm, measured from the front of the nose to the end of the jet pipe nozzle.

Quoting rbavfan (Reply 61): Trent 1000 started out at 64100 lb. st. has been derated to 53200 & 58000 lb. st and increased to 78000 lb. st. Based on initial (64100) and largest (78000) models what makes you think they cannot get the 82700 out of it.

To my knowledge, there are no . Trent 1000 engines rated or derated at ˙53200 & 58000 lb. st´. Trent 1000 engine with the lowest rated thrust is Trent 1000-E, rated at 265,3 kN - 59.631 lb s.t. Also there is no ´(64100 lb. st.)´ engine. The closest to this value is Trent 1000-H engine, rated at 284,2 kN - 63.900 lb s.t. The engines rated at the highest thrusts are Trent 1000-J2 and Trent 1000-K2, both at 347,5 kN - 78.129 lb s.t.

With the respect to the required efficiency and competitiveness of the now-day engines, they are, from the beginning, designed with a small power reserve and work with the very high operating parameters (temperatures, pressures, speeds of rotations, flow speeds...) at their upper calculated limits of the Brayton thermodynamic cycle (thermodynamic cycle that describes the workings of a constant pressure heat engine). It means that the recently constructed engines have smaller, thermally and mechanically more loaded engine´s core and larger fan´s diameter than the engines with the comparable thrust in the (recent) history, including those . RB211-524 engine models...

The development of the material technology, to a large degree, condition the efficiency of the construction of the modern turbofan engine, and searching for more power and thrust out of the existing or completely new engine´s constructions, implies the existence of the higher thermal and mechanical stresses of the engine´s construction, and all because of the increasing of their operating parameters (FPR, CPR, OPR, TIT, flow speeds, rotational speeds…). In the same way as the increased mechanical stresses may affect the fractures and tearing-offs of the materials, the increased long-term temperature stresses could easily cause a change in the structure of the materials leading to their disintegration. Besides, to have a thermally efficient engine does not mean that it is, in the same time, a propulsive efficient engine, just for every purpose.

The fact is that the Emirates are looking for the increased thrusts for their eventual Boeing 787-10 aircrafts, and all because of the specific climatic conditions at their largest airport. Although it was said that EK´s Boeing 787-10s are going to be powered by the . Trent 1000 -TEN engines, I would not be surprised at all if the EK would, once again, change their mind(s) and try to find the solution on the other side, with the General Electric. The indisputable fact is that the both engines, . GEnx-1B and . Trent 1000, certified for the Boeing 787-9 aircraft, are already at their upper limit, but still in the anticipated working area where you can expect them to be highly reliable and safe in their exploitation. It is difficult to speculate how much more thrust could be extracted out of those GEnx-1B and Trent 1000 engines, but the value of 84x10e3 lb, and that was mentioned, seems to be pretty high for both of those engines, especially if the same expected time of the reliable service and maintenance intervals would be required.

Those recently certified and more powerful General Electric´s engines: . GEnx-1B75/P2, rated at 345,2 kN - 77.604 lb s.t. and . GEnx-1B78/P2, rated at 357,6 kN - 80.392 lb s.t., have not been installed yet, not to my knowledge, on any of the Boeing 787-9 aircrafts delivered to the customers. There are several possible reasons for that, and one of them is that the higher thrust ratings and increased engine´s structural load capabilities would require a somewhat redesigned engine´s nacelles…

On the other side, some of the Boeing 787-9 Dreamliners are already powered by the Trent 1000-J2 and Trent 1000-K2 engines (Package C), rated at 347,5 kN - 78.129 lb s.t., while those Boeing 787-9s, powered by the GEnx-1B engines, use -1B74/75 version, certified at 340,7 kN - 76.592 lb s.t. It will be very interesting to see on which thrust ratings the new Trent 1000-TEN engine will be certified…

There is no doubt that the development of those two engines will remain very strong. Trent 1000-TEN engine is, in a much greater extent, a derivative of a great Trent XWB engine than the evolution of the existing Trent 1000, and that speaks enough how much dedicated Rolls-Royce remains to the Boeing 787 Dreamliner aircraft and how well prepared they will meet the new Boeing 787-10. On the other side, General Electric, in the order to achieve even higher engine´s thrusts, is ready to increase the mass-flow through its GEnx-1B engine, searching for, not only the higher thrusts, but the increased propulsive efficiency of the engine. Will it be enough to implement in the design all the modern technology aimed for the future GE9X engine and the technology applied on the already existing LEAP engine, especially the utilization of the new CMC material in the engine´s hot section (already widely tested on the GEnx-1B engine), making that way the engine thermally more efficient or the increased fan diameter, redesigned core´s geometry and the architecture will be unavoidable, remains to be seen. Given what have been said in the recent days, I can´t see . going so far with the development of its GEnx-1B engine...

Since the Boeing has recently expressed its unreadiness and unwillingness to adjusts Boeing 787-10 to the Emirates´s needs excessively, and aircraft itself was not designed for the MTOW (557.000 lb - 252.657 kg, according to Boeing´s ´Airport Compatibility Brochure - 787-10 Dreamliner´) higher than the one of the Boeing 787-9, I wonder how realistic, at all, is it to expect Boeing 787-10 with the engines rated at the thrusts higher than the 80 klb s.t. - 356 kN, if and so much...

As I have already said, a few days ago, in the 787 Production/Delivery thread: no matter what, one thing is certain; at the time of the increasing market polarization and all the more pronounced joining of the aircraft manufacturers with the certain engine factory, especially in the field of the wide-body aircrafts, one battle remains very present and interesting, and that is the one around the Boeing 787 Dreamliner…


Nice regards

Mario

Quoting Stitch (Reply 47): If I had to put $20 down, I'd put it down on the 787-10. Emirates loses nothing asking for a more-capable 787-10 and if they get it, so much the better. But I believe they decided two years ago that for the missions they plan to employ the planes on, the 787-10 pencils out the best.

Deal. We'll have to do a HH sometime once the answer's in.

Quoting tortugamon (Reply 69): Quoting Pellegrine (Reply 57): Boeing was supposed to right-size the wing for the 789, and they didn't even care to do that They found that the extra span did not compensate for the extra weight. The wing was most efficient as is.

They also got better aero on the wing, so there was less reason to go for the weight sacrifice.

Quoting mjoelnir (Reply 79): Actually the discussion here according to the title is about the 787-10. Therefore the range of the 787-9 would have no connection to this thread.

Yeah, just realized the discussion was about the 78X being a 14 hour plane and not the 789. I am not sure how we are discussing the 78X as a 14 hour plane though, do we really think airlines are looking at it that way. And if it was a 14 hour capable plane the A350 would be obsolete as it is lighter than any A350. People fall for marketing numbers from one OEM way to quickly on this site.

Quoting Stitch (Reply 80): I believe he is referring to the 787-10 having a 60m wing instead of a 63m wing (as the 787-9 and 787-10 were originally designed around). For the 787-9, the shorter span seems to be a wash as the lighter weight cancels out the poorer aero in terms off fuel burn on long flights. But for the 787-10, the extra aero likely would have been more helpful in hot and high conditions.

I believe the discussion was about the 789 being slightly crippled as it was supposed to have the larger wing. The fact that the even larger and heavier 78X shares this same wing would suggest that it is also crippled. Or are we thinking that having less range and payload due to restrictions from the design (wing) does not mean crippled in performance?

Quoting Stitch (Reply 80): Tim Clark wanted the A350-1000 as a 777-300A replacement and a high-capacity regional bird. So it's good for 10-12 hours for him, but for everyone else, it's good for 14-16.

That is what he wanted, yet other airlines wanted more. Airbus seem to have listened to the majority and not just one airline. Do you believe the current A35K is only a 10-12 hour aircraft?

Quoting Stitch (Reply 80): I expect it to be used on the same missions the 777-300A and two-class 777-300ER are.

Wasn't really talking about the 78X and its role in the EK route planning, more along the lines of, if the current A35K is a 10-12 hour plane (7800nm range) what does that make the 78X (6430nm range)? I think we can put to bed the Tim Clark quote about the performance of the A35K. He wanted a lesser performing design which would have been a 10-12 hour mission aircraft. The current A35K isn't this.

Quoting tortugamon (Reply 82): No, I was referring to the 78X. 14hrs is a touch high but it should be able to do 13 hour flights with a full load of passengers, the 789 should be pushing 17 hour flights for your reference and its already flying 16 hour flights - hard to call either of them a crippled design. Its when you add cargo and 45 deg C temperatures that the 78X becomes a 8.5-10 hour plane.

We don't know what restrictions are placed on those flights. Are they going out at 100% capacity or are there weight restrictions? We know the range calculations for both Airbus and Boeing are the best case scenarios with as light as possible catering and furnishings.

Quoting tortugamon (Reply 91): I think on here we chalk up the decline of sales of the 77E to the A333 when I think the 77W also played a significant role. Just like the 788 not selling well when the 789 is available the 77E doesn't sell well when the 77W is available. Anyway, certainly the A333 played a significant role and I don't want to take away from that, its just not the entire story.

No, it's not as one-sided as I made out, but the point still stands, the A333 certainly ruled the roost on medium haul routes, and the 77W on long haul routes where both used to be more the preserve of the 772/77E.

Quoting tortugamon (Reply 91): The MTOW of the A359 is 17t more than the 78X yet its Max Fuel Weight is only 9t higher, that implies a not-insignificant OEW difference.

If we take that to mean an empty weight difference of 8t, it is a fair amount, not insignificant as you say, and even more so when you consider the 78X has a higher seat count.

BUT

My confusion is over Stitch's claim that the difference in weight between the 78X and the A359 could be similar to the 77E and A333. A quick look at Wikipedia (sorry) says the difference between the A333 and 772 is 13.6t.

So I'm just wondering how the A359 and 78X could have a similar difference in efficiency between them if there is an extra 5.6t difference on the older aircraft, combined with the fact that the A359 should theoretically have the advantage on aerodynamics (larger wings).

The reason I'd be skeptical of my figures is that the same source (sorry) says the 789 is 126t empty and the A350 115t empty. I wouldn't expect that to be the case. What is the difference

I apologise if I've read into the figures wrong or interpreted them wrong, but that's just the way I see it.

Edit:
I see the distinction between MEW and OEW, which would explain why the A359 is lighter. What's the difference?

[Edited 2015-11-07 13:52:45]

Quoting mfranjic (Reply 92):

Amazing post as always. It is pure joy to read your very detailed and accurate writing  

Quoting MrHMSH (Reply 90): Out of interest, though the A359 is heavier, would its larger wing make the difference in fuel burn less proportionally when considering weight? Or are the routes a little too short for that to make a difference?

Of interest:

" He (Hazy) declined to give details beyond saying that the 787-10’s advantage was smaller than Boeing’s estimate of a 10 percent gain over the Airbus plane. Air Lease has ordered 25 A350-900s."

"“If it’s identically configured, the -10 has a little bit of an edge on the -900,” Udvar-Hazy, 67, chief executive officer of Air Lease Corp., told reporters today at the Paris Air Show after the company agreed to buy 30 of the planes. “The -900 has a little more range, but this has lower fuel burn.”"

http://www.bloomberg.com/news/articl...boeing-787-10-beats-airbus-on-fuel

Now that's if "identically configured" however. The B787-10 is about 1.5 meters longer so I'm not so how that would mean in terms of actual seating between the two.

I guess there would be a trade-off between the two planes.

Quoting Stitch (Reply 87): Quoting mjoelnir (Reply 86): But than it depends on how much the difference in efficiency is and perhaps it is not as significant as some believe. OEM empty weight differences could be in the neighborhood of 10,000kg or more, which is also in the neighborhood of what the OEM empty weight difference is between an A330-300 and 777-200. If Aspire's numbers are to be believed (which they will not by many), the difference could be twice that in two-classes. On missions up to 4000nm, the A330-300 is up to 15% more fuel efficient than the 777-200. So the 787-10 could very well have a double-digit lower fuel burn (as a percentage) per hour on such missions compared to the A350-900. Which could explain why EK is asking for more from the 787-10 - trade some of that lower fuel burn for better performance because overall the 787-10 is still not-insignificantly more fuel efficient than the A350-900 in missions up to 4000nm.

It is difficult to find numbers that are comparable between the A350-900 and the 787-10. On one I find an MEW, on the other a OEW.
Here is one, MZFW, that is supposed to be for the A359 192 metric ton and for the 78X 193. If I should believe your 10 t difference in MEW or OEW, that would mean a difference in payload of 11 t. The maximum landing weights are also not far apart.
I would find a MEW difference of less than 5 t rather more credible. Against the weight difference, the A350 would offer more span and slightly more efficient engines and I could believe in a not yet identified range, where the A359 gets more efficient.

In the end we will know the real numbers when both are flying.

[Edited 2015-11-07 14:01:40]

is LIS really EKs longest European route?