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Does Rolls Royce produce any engine that matches the capabilities of the GE9x?

If not, does Rolls Royce have any public plans for such an engine in the future?

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    $\begingroup$ Interesting question. Do you mean a specific competitor in terms of installment on a specific plane, such as the 787 or just one in general that was made as a response? Different applications would consider different engines/variants of an engine. $\endgroup$ – Jihyun Jun 17 '18 at 3:24
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    $\begingroup$ Which "capabilities" are you talking about specifically? Thrust output? Size? Fuel Efficiency? Cost? Weight? $\endgroup$ – Ron Beyer Jun 17 '18 at 3:54
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    $\begingroup$ But the Trent 1000 or 7000 are designed for 787 or a350 or a330 Neo. Not for 777x which is bigger. It is totally incomparable. $\endgroup$ – Chris Lau Jun 17 '18 at 9:16
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    $\begingroup$ @TayWeeWen I don’t think they design engines without an application in mind, so without access to the 777X, why would they need one? $\endgroup$ – Cpt Reynolds Jun 17 '18 at 9:54
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    $\begingroup$ @Therac what these companies actually compete in technologically is the thrust per/drag and thus fuel economy. With more thrust per square unit of surface area companies can reduce fuel consumption by reducing drag, and with enough advancement, be able to reduce the number of engines necessary to move the aircraft, further improving efficiency. What I'm trying to say is that the name of the game is efficiency, and thrust increase without increasing other negative factors (drag, size, weight) is a viable and much pursued area of technological development. $\endgroup$ – Jihyun Jun 17 '18 at 20:58
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First let's talk about thrust. Jet engines are designed for very specific thrusts for every specific applications. For example, look at the GEnx-1B versus the GEnx-2B. The Boeing 787-8 has GEnx-1B engines rated for ~70k lbf takeoff thrust. At about the same time as Boeing was developing 787-8, it was also developing the 747-8. That plane needed slightly less thrust per engine, about 5% less. Boeing could have just put the GEnx-1B on that plane. But they didn't. Instead they had GE develop the GEnx-2B, rated for 66.5k lbf thrust. They did that because an engine that had five percent too much thrust was a completely unfeasible option. The GEnx-2B is smaller and several hundred pounds lighter. So my point here is that RR is never going to develop an engine the size of the GE9X unless they have a very specific contract for a plane that needs exactly that much thrust. Every engine RR makes is going to be sized exactly as big as it needs to be and no bigger.

RR certainly could make an engine that big if they had a contract to do so. If you know how to make an engine that produces 70klbf of thrust, you know how to make an engine that produces 100 klbf of thrust. Just make everything a little bit bigger. Turbomachinery is not perfectly scaleable, so just because you know how to make an engine with 100 lbf of thrust does not mean you know how to make an engine with 100,000 lbf of thrust. But from 70k to 100k is not a big leap. Definitely within their capability.

As for everything else, I'd say just look at the market share. There's some interesting statistics here. http://www.alafco-kw.com/upload/Media_Library__March_2016____Aircraft_Market_Report__March_2016__921.pdf

For example: RR has 59% of the A330 market, a plane on which there are 3 different engine options available (GE, RR, P&W). RR is certainly behind GE on the 787, but not by a lot. And RR has an exclusive contract on the A350. Overall RR is competitive in the market versus the other manufacturers. If RR was "losing out in the technological advancement", you would see this reflected in their market share, but this is not what is happening.

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  • $\begingroup$ Regarding the GEnx-2B. I always assumed, that the usage of bleed air for air conditioning - and not only anti-icing - is the major reason for the differences? And the other changes are minor optimizations for 747-8 and side-effects. $\endgroup$ – Peter Jun 18 '18 at 14:12
  • $\begingroup$ Certainly the bleed air versus electrical generators is a difference, but really the generators extract about the same amount of power as the bleed air. So if you took at GEnx-1B and put a bleed system on it, you'd still basically have 70k thrust. Maybe a little different, but not 5%. The 5% thrust difference is mostly from scaling the fan diameter down. $\endgroup$ – Daniel Kiracofe Jun 18 '18 at 20:29
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After some research, I believe RR Ultrafan is the answer to GE9x. At this point of time, there is too little information for comparison.

GE9x is one generation ahead of Trent XWB. As per now, the development (bug fixed) is still on going.

That partly explains that despite 777x being overwhelmingly heavier than A350, it is still competitive at the 400 passengers segment on the 777-9 platform.

Nevertheless the A350 frame could have more potential. By 2025 upon the release of RR Ultrafan (or if it is possible to design with a GE9x based derivative), Airbus could easily do a A350Neo, which could easily be the most efficient plane in the market.

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    $\begingroup$ You still seem to be making a false assumption that RR need “an answer” to the GE 9x, which means an engine with the same thrust output. They don’t. They don’t need to make a good engine for an aircraft they have not won a contract to supply with an engine. They need to make good engines for the aircraft they have won a contract on. These are not the 777x, so, their engines are optimised for those aircraft instead. $\endgroup$ – Penguin Jun 18 '18 at 9:32
  • $\begingroup$ It is understood that the top 3 engine maker could meet the thrust specification of Boeing and Airbus as long as they scale the diameter. But engine of generational difference can provide a higher thrust vs weight ratio on top of higher fuel efficiency. Then these engine makers will scale up or down the thrust base on the requirement of commercial aircraft maker. I dont think I have to explicitly explain that. Without competition why would RR invest money on Ultrafan and PW on GTF. GE9x will eat their lunch if they just sit by. $\endgroup$ – Tay Wee Wen Jun 18 '18 at 10:02

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