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Will The PW1000G Trump The CFM Leap-X?  
User currently offlinekeesje From , joined Dec 1969, posts, RR:
Posted (4 years 12 hours ago) and read 21705 times:

The GLGroup has become a bit less predictable recently, apparently some new experts joined the group. There is a new article on the Pratt & Whitney PW1000G versus GE LEAP-X competition. http://www.glgroup.com/News/Why-the-...CFM-Leap-X---Innovation-50296.html

Those two new engines (and their customers) have been causing some uproar in until recently peaceful NB segment. The author is (very) convinced the PW1000G series is on the winning hand and he explains why;

   revolutionairy technology instead of evolutionairy
   larger thrust range (up to 40k lbs)
   potential to further lower fuel burn



Myself I tend to give the LEAP-X the benefit of the doubt based on the CFM Safran+GE) track record, GE's GENX technology and a natural skepticism about a hot running gearboxes in compressor inlets.

Last week Airbus John Leahy said he is "comfortable" with Pratt & Whitney's P1000G maintenance projections of 20% lower maintenance costs compared with today's engines and that Airbus tests of a P1000G on an A340-600 testbed support Pratt's claims. http://www.flightglobal.com/articles...ave-7-8-million-price-premium.html



Now I'm not so sure anymore..

17 replies: All unread, jump to last
 
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 1, posted (4 years 2 hours ago) and read 21516 times:

Quoting keesje (Thread starter):
potential to further lower fuel burn

I think this applies to the Leap-X as well, so I'm not sure why they're giving that to the GTF.

It's an interesting fight, since the two companies are tacking the same problem (fuel burn) via two different paths. One is going after propulsive efficiency, one after thermodynamic efficiency. Both are viable paths and it's a question of which company can push farther down their respective roads.

One advantage I think Leap-X has is that that technology would scale to a new large engine a lot more easily than GTF would.

Tom.


User currently offlineStitch From United States of America, joined Jul 2005, 30909 posts, RR: 87
Reply 2, posted (4 years 2 hours ago) and read 21510 times:
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Quoting tdscanuck (Reply 1):
One advantage I think Leap-X has is that that technology would scale to a new large engine a lot more easily than GTF would.

Pratt believes that the GTF can scale to over 100,000 pounds for use on the 777 and they note the bigger the fan, the shorter the engine (relative to a conventional engine) because they reduce engines stages along with their attendant discs and airfoils. So the bigger the engine, the lighter it gets and the less maintenance it needs compared to a conventional engine.


User currently offlinerheinwaldner From Switzerland, joined Jan 2008, 2223 posts, RR: 5
Reply 3, posted (3 years 12 months 4 days 20 hours ago) and read 21441 times:

Quoting tdscanuck (Reply 1):
One is going after propulsive efficiency, one after thermodynamic efficiency

How good would be a combination of both?


User currently offlinekeesje From , joined Dec 1969, posts, RR:
Reply 4, posted (3 years 12 months 4 days 19 hours ago) and read 21429 times:

Quoting rheinwaldner (Reply 3):
How good would be a combination of both?

That's what I wonder about too, it seems much of the technology used by CFM and PW , doesn't exclude each other.

A Leap-X with a geared turbofan and a slower more efficienct and silent airstream / more optimized hot section RPM's, why not..


User currently offlinesirtoby From Germany, joined Nov 2007, 370 posts, RR: 22
Reply 5, posted (3 years 12 months 4 days 18 hours ago) and read 21402 times:

Quoting tdscanuck (Reply 1):
One advantage I think Leap-X has is that that technology would scale to a new large engine a lot more easily than GTF would.

The LEAP-X is more or less a downscaled version of the GEnx...

Quoting tdscanuck (Reply 1):
Quoting keesje (Thread starter):
potential to further lower fuel burn

I think this applies to the Leap-X as well, so I'm not sure why they're giving that to the GTF.

If you are already running hot that is harder to achieve as you cannot get very much hotter as you then would hurt maintenance costs and your NOx emissions go up.


User currently offlineaerotech777 From United States of America, joined Aug 2009, 67 posts, RR: 0
Reply 6, posted (3 years 12 months 4 days 13 hours ago) and read 21332 times:

Hi,

It was mentioned in the first link that the core of the Leap X will use the concepts from lower cycle wide body engines and apply them higher cycle narrow body environment. It will be nice if some engine gurus can post some details about these concepts.

In the same link it was also mentioned that the Leap X will use 2 stages high pressure turbine instead of single stage. What%u2019s the benefit of the use 2 stages HP turbine versus single stage and is this related to lower cycle versus higher cycle?

Feedback appreciated.
Regards


User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 7, posted (3 years 12 months 4 days 12 hours ago) and read 21317 times:

Quoting rheinwaldner (Reply 3):
Quoting tdscanuck (Reply 1):
One is going after propulsive efficiency, one after thermodynamic efficiency

How good would be a combination of both?

The benefits should be cumulative...they're basically independent technologies.

Quoting keesje (Reply 4):
it seems much of the technology used by CFM and PW , doesn't exclude each other.

Agreed.

Quoting aerotech777 (Reply 6):
It was mentioned in the first link that the core of the Leap X will use the concepts from lower cycle wide body engines and apply them higher cycle narrow body environment. It will be nice if some engine gurus can post some details about these concepts.

The major drive on Leap-X is to carry all the latest aerodynamic improvements (most of which have come on large engines recently) back into the smaller engines, like 3D airfoils and improved combustors, plus a higher pressure core (greater thermodynamic efficiency).

Quoting aerotech777 (Reply 6):
In the same link it was also mentioned that the Leap X will use 2 stages high pressure turbine instead of single stage. What%u2019s the benefit of the use 2 stages HP turbine versus single stage and is this related to lower cycle versus higher cycle?

I don't think it's a benefit so much as a necessity. Higher thermodynamic efficiency requires a higher pressure ratio, which requires a more powerful compressor, which requires more turbine to drive the more powerful compressor. If you can't get enough power extraction from a single stage, you go to two.

I don't think these particular design features are particularly cycle related.

Tom.


User currently offlinekeesje From , joined Dec 1969, posts, RR:
Reply 8, posted (3 years 12 months 4 days 11 hours ago) and read 21297 times:

UTC seems to all but confirm Airbus has approved their GTF as a 3rd engine option.

http://www.automatedtrader.net/real-...nfident-airbus-will-re_engine-a320


User currently offlineLumberton From United States of America, joined Jul 2005, 4708 posts, RR: 20
Reply 9, posted (3 years 12 months 4 days 6 hours ago) and read 21227 times:

Quoting keesje (Thread starter):
The GLGroup has become a bit less predictable recently, apparently some new experts joined the group.

They're not new; they've been with GLG for some time. Anyway, here's the other side of the GLG debate on which of these engines looks more promising.
http://www.glgroup.com/News/CFM-Inte...ything-But-A-Derivative-50258.html

Quote:
There is nothing worse than misinformation, so let’s clear up a few issues. For those of us who bothered to go to the Farnborough Air Show, then like me, you’ll have known that the CFM International LEAP-X engine is not a derivative engine. It is a brand new engine from the ground up.

In contrast, the Pratt & Whitney GTF engine is a derivative engine – the geared engine concept is a 1960s based design, compromised, risky and airlines have witnessed issues with reliability with such designs before. The LEAP-X engine is a new product launched in 2008 – hardly the definition of derivative when even CFM doesn’t even have a related engine to it.

If any engine is going to reach limitations first, it’s the GTF. Don’t be duped by claims that the LEAP-X engine cannot be expanded. When speaking extensively the LEAP-X program director, at the show, he informed me that the demonstrator testing had exceeded expectations, was ahead of the planned development timeline and has scope to grow in both thrust and further fuel burn reduction.



"When all is said and done, more will be said than done".
User currently offlineNicoEDDF From Germany, joined Jan 2008, 1099 posts, RR: 1
Reply 10, posted (3 years 12 months 4 days 5 hours ago) and read 21216 times:

Quoting aerotech777 (Reply 6):
In the same link it was also mentioned that the Leap X will use 2 stages high pressure turbine instead of single stage. What%u2019s the benefit of the use 2 stages HP turbine versus single stage and is this related to lower cycle versus higher cycle?

Not to mention that CFMI is at the absolute limit of material technology regarding their HPT Blades on the CFM56-5A/B.
The one stage has to drive the complete HPC with the result that there is apparently so much load on the one stage, that CFMI up to now is not capable of producing a reliable blade (not even the latest and greatest P/N).
That leads to a soft time limit on the blades (12.000 cyc?!) and a lot of HPT blade separations in the past beginning from cracks at the platform.

Not to nice and airlines are not happy...

Interestingly enough, the V2500 engine has two stages, as do all bigger engines apart from Rolls Royce with their triple spool design and their single stage HPT + single stage IPT, resulting effectively in load distribution of the compressor system to two stages also.


User currently offlinekeesje From , joined Dec 1969, posts, RR:
Reply 11, posted (3 years 12 months 3 days 17 hours ago) and read 21098 times:

Quoting Lumberton (Reply 9):
Anyway, here's the other side of the GLG debate on which of these engines looks more promising.

Doesn't sound like a very proffesional editorial. He/she attack someone;

Quoting Lumberton (Reply 9):
There is nothing worse than misinformation, so let’s clear up a few issues. For those of us who bothered to go to the Farnborough Air Show, then like me, you’ll have known that the CFM International LEAP-X engine is not a derivative engine. It is a brand new engine from the ground up.

Who claimed the Leap-X is a derivative ?! Haven't seen it anywhere! Talking about misinformation, what a Don Quixote.

Then to claim the PW1000G is a derivative because gearboxes were tested in the sixties, I won't even go into that..

+ I have spoken to a saleman at an airshow so I know, too funny.


User currently offlineaerotech777 From United States of America, joined Aug 2009, 67 posts, RR: 0
Reply 12, posted (3 years 12 months 11 hours ago) and read 20862 times:

Hi,

I am wondering why the aft part of PW 1000G engine cowl is moving according to this link:
http://www.youtube.com/watch?v=vgQgEftEd8c


User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 13, posted (3 years 12 months 9 hours ago) and read 20842 times:

Quoting aerotech777 (Reply 12):

I am wondering why the aft part of PW 1000G engine cowl is moving according to this link:

I don't know for sure, but I can think of two possible reasons offhand:
1) They're trying to define the optimum fan duct profile and, by putting different "rings" on the aft end of the nacelle and then sweeping them fore/aft they can track TSFC and find the optimum.
2) They're actually implemented a very simple variable area nozzle for production, which would allow them to tweak the fan stream exit velocity in flight and squeak out a small propulsive efficiency gain.

Tom.


User currently offlineBogi From , joined Dec 1969, posts, RR:
Reply 14, posted (11 months 1 week 14 hours ago) and read 4236 times:

MTU: PW 1000G engine is an unexpectedly huge success.
http://www.youtube.com/watch?v=BwfagWEabi4


User currently offlinefrancoflier From France, joined Oct 2001, 3747 posts, RR: 11
Reply 15, posted (11 months 1 week 9 hours ago) and read 4109 times:

Quoting Bogi (Reply 14):

Nice thread digging.  

Any highlights of the interview for us non-teutons?


I am a big fan of the geared fan...
Even though CFM has managed to keep up orders-wise thanks to the NEO and being the only supplier on the MAX, I believe the geared technology will eventually mature and benefit from the thermodynamic advances of the LEAP, giving it the best of both worlds.

Whereas it feels like the LEAP is squeezing conventional engine technology, the PW 1000G, on the other hand, still has a lot of room for improvement.

Go PW.



Looks like I picked the wrong week to quit posting...
User currently offlineBogi From , joined Dec 1969, posts, RR:
Reply 16, posted (11 months 1 week 8 hours ago) and read 4076 times:

Quoting francoflier (Reply 15):
Any highlights of the interview for us non-teutons?

Only a written summary in German.

http://www.aero.de/news-18251/MTU-Pu...wer-PW1000G-ein-voller-Erfolg.html

You can translate it with goggle.


User currently offlineLH707330 From United States of America, joined Jun 2012, 754 posts, RR: 0
Reply 17, posted (11 months 1 week 7 hours ago) and read 4045 times:

Quoting francoflier (Reply 15):
Any highlights of the interview for us non-teutons?

I thought there were enough Anglicisms in there like "fan" and "open rotor" that it was half English anyway  Give it another 10 years and all the complicated descriptive words (Mantelstromtriebwerk) will be replaced by their English equivalents (Turbofan).

Joking aside, Dr. Henne discusses the overall market for the GTF (platforms, basic structure, etc.) and moves on to talk about the future of the GTF. What I found most interesting were four main points he made near the end:
1. GTFs will become much more efficient when the fan and nacelle weight can be reduced, thus allowing larger fan diameters to become more feasible
2. GTFs are only in the beginning of their development cycle, and will benefit greatly from further optimizations, especially for widebodies
3. Open rotors are a riveting/exciting (German "spannend") development, but likely won't be around for at least 12-15 years. Obstacles to adoption include noise, mounting issues (the need to co-optimize plane and engine), and #1 eroding the advantages of OR vs. GTF
4. Thermodynamic improvements in the form of heat exchangers will enable further increases in efficiency in the future

The first three of these points seem relatively straightforward to understand, what I'd like to understand more about is the heat exchanger technology, especially given the recent comments round about the water injection in the GE9X. Would it make sense to have a fuel-cooled intercooler somewhere in the HPC to take heat energy out of the incoming air to lower pressure and thus reduce work load (=fewer HPC stages) while maintaining core mass flow, and then re-introduce this heat energy in the form of heated fuel in the combustor?


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