XWB
in service - 11 years
Posts: 16,115
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Post by XWB on Nov 9, 2013 22:53:20 GMT 1
The Trent XWB however is significant heavier than the Trent 900 and will add a lot of weight to the airframe. And will EA upgrade its engine too?
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philidor
in service - 6 years
Posts: 8,950
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Post by philidor on Nov 10, 2013 0:07:00 GMT 1
To many customers, having the same engine family on A380s and A350s would probably be a plus.
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Taliesin
Final Assembly Line stage 1
In Thrust we trust
Posts: 228
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Post by Taliesin on Nov 10, 2013 0:43:08 GMT 1
The Trent XWB however is significant heavier than the Trent 900 and will add a lot of weight to the airframe. And will EA upgrade its engine too? The german Wikipedia lists the TrentXWB as 200kg or 3% heavier than the Trent 900. Even multiplied by 4, this adds up to under 1 ton and in my opinion is well offset by a lower fuel burn on pretty much every mission. The TrentXWB is not an upgrade as such, but a new engine, I don't think "upgrading" the GP7000 would do the trick but GE might offer the GE90X for the A380NG.
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mjoelnir
in service - 2 years
Posts: 4,089
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Post by mjoelnir on Nov 10, 2013 2:06:30 GMT 1
I do not believe in an engine upgrade in the near future. The biggest customer of the A 380 is not a RR customer so moving from the 900 to the XWB helps IMO little with EK. There are contracts regarding the Engine Alliance GP7000, it is a joint venture and has to be bought out. I think we will see more PIPs on both the Trent 900 and GP 7000. The Trent 900 EP2 next year will have quite a bit lower fuel burn than the Trent 900 started out with. We know that the XWB was supposed to be with a 6% better fuel burn at EIS than the T 900 at EIS. What is the real difference today regarding the EP2 version. The second point is that the XWB is in a higher thrust range than needed on the A380 and it is usually not good for the fuel burn using too big an engine.
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Taliesin
Final Assembly Line stage 1
In Thrust we trust
Posts: 228
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Post by Taliesin on Nov 10, 2013 2:28:25 GMT 1
I do not believe in an engine upgrade in the near future. The biggest customer of the A 380 is not a RR customer so moving from the 900 to the XWB helps IMO little with EK. It would help with competitiveness though. There are contracts regarding the Engine Alliance GP7000, it is a joint venture and has to be bought out. I admit that I'm largely ignorant when it comes to the details of the joint venture contracts. However, I really don't think Airbus backed themselves into a corner here and didn't foresee the eventuality of being forced into an engine upgrade. The second point is that the XWB is in a higher thrust range than needed on the A380 and it is usually not good for the fuel burn using too big an engine. Good point, but the difference isn't that big. The Trent 900 is in the thrust range of 70k-80k with the -900 probably clocking in at around 80k, the TrentXWB comes in 75k, 84k and 100k-ish, so not that far off. Additionally, the dimensions of the Trent 900 and TrentXWB are remarkably similar, the difference in fan diameter is a mere 2 inches. In cruise, the dominating part of thrust is produced by the inner circle and not the bypass circle, because velocity differences go down and the friction losses further reduce thrust. If the cores of the Trent 900 and TrentXWB are comparable, which I believe they are, cruise thrust will be comparable as well. In general, both aircraft and engines are designed with the concept of "broad maxima" in mind, which means that deviations from the design point should not incur dramatic drops in efficiency. During a regular A350 flight, the fuel load might well reduce by almost 150 tons and required thrust will reduce along with weight. The TrentXWB has to deal with that "off design" scenario as well. I don't think the thrust requirements for the A380 are going to be that dramatically different, but I admit I don't know for certain. Overall, the use of the TrentXWB is far from given and mjoelnir raises some good points, but I think these are pretty minor issues compared to the chance of using a next generation engine and keeping your plane competitive.
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philidor
in service - 6 years
Posts: 8,950
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Post by philidor on Nov 10, 2013 11:42:01 GMT 1
At Engine Alliance, any new project probably requires a joint GE/P&W decision. They may have conflicting interests at a given moment, so it may be difficult to introduce a design change ...
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Post by limoncello on Nov 19, 2013 20:27:01 GMT 1
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Post by FabienA380 on Nov 19, 2013 20:30:23 GMT 1
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philidor
in service - 6 years
Posts: 8,950
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Post by philidor on Nov 20, 2013 0:44:53 GMT 1
We now have every reason to believe that EK's latest order is not for the same aircraft they already have in their fleet. It is an order for an improved, more efficient A380.
From information provided in the above posts, and previous discussions, improvements are to be expected in three distinct fields :
- New winglets (within the allowed wing span limit ?) . - Improved engines (heralding a formidable upcoming competition). - New partly 11 abreast cabin setup (involving tricky engineering details).
This fascinating project can feed months of internet debate !
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Taliesin
Final Assembly Line stage 1
In Thrust we trust
Posts: 228
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Post by Taliesin on Nov 20, 2013 1:27:08 GMT 1
I still can't believe the numbers of the winglets.. That's a lot coming from a single source, even more so from winglets that are only some 15 years old at the time of their "EIS". Either the original winglets were treated like an unloved foster child, only so they would winglets that fit inside the 80m box, or those numbers are wildly exagerated. The worse the old winglets are, the more you can improve your new winglets, but I'm having trouble believing the current winglets are that bad.
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