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Developing Leap Engine Technology for 737MAX  
User currently offlinefrmrcapcadet From United States of America, joined May 2008, 1731 posts, RR: 1
Posted (1 year 10 months 3 weeks 4 days 14 hours ago) and read 15021 times:

http://seattletimes.com/html/busines...gy/2019849748_sundaybuzz09xml.html

The story features a bit of commentary on the A versus B dustup with two new narrow body updates. But the interesting part is a brief discussion of the very advanced technology and some of the problems which had to be solved to get ever more efficient engines. To a 'non-techie' is all sounds pretty amazing, and a response is almost, 'you mean you can make all of that work?!'


Buffet: the airline business...has eaten up capital...like..no other (business)
51 replies: All unread, showing first 25:
 
User currently offlinegoosebayguy From United Kingdom, joined Sep 2009, 406 posts, RR: 0
Reply 1, posted (1 year 10 months 3 weeks 4 days 12 hours ago) and read 14845 times:

From what I know Rolls Royce is also working on very similar technology for its large engines. Technology is changing and quickly here.

User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 2, posted (1 year 10 months 3 weeks 4 days 12 hours ago) and read 14772 times:

Quoting frmrcapcadet (Thread starter):
To a 'non-techie' is all sounds pretty amazing, and a response is almost, 'you mean you can make all of that work?!'

That's the appropriate response, even for techies. A modern commercial jet engine is the most advanced product ever produced by the human race. With the possible exception of the semiconductor guys at Intel, it's probably also the world forefront of materials research.

Tom.


User currently offlineAA737-823 From United States of America, joined Mar 2000, 5875 posts, RR: 11
Reply 3, posted (1 year 10 months 3 weeks 4 days 11 hours ago) and read 14573 times:

Quoting tdscanuck (Reply 2):
A modern commercial jet engine is the most advanced product ever produced by the human race. With the possible exception of the semiconductor guys at Intel, it's probably also the world forefront of materials research.

It really and truly is; it's amazing how we can take such a simple concept as the jet engine (one main moving part, all cycles happening at the same time, in different places), and complicate things further and further (variable bleed valves, variable stator vanes... and that's just twenty years ago!!) in the name of efficiency. I HOPE that reliability doesn't suffer, but with increased complexity, a corresponding decrease in dependability is to be expected, particularly once you bring software into the equation.


User currently offlineDocLightning From United States of America, joined Nov 2005, 20007 posts, RR: 59
Reply 4, posted (1 year 10 months 3 weeks 4 days 10 hours ago) and read 14406 times:

Quoting AA737-823 (Reply 3):
It really and truly is; it's amazing how we can take such a simple concept as the jet engine (one main moving part, all cycles happening at the same time, in different places), and complicate things further and further (variable bleed valves, variable stator vanes... and that's just twenty years ago!!) in the name of efficiency. I HOPE that reliability doesn't suffer, but with increased complexity, a corresponding decrease in dependability is to be expected, particularly once you bring software into the equation.

If that's the case, then why have engines become more and more reliable over time? FADEC isn't exactly new technology. It's been around at least since the A300. Engines have continually gotten more and more reliable...and they have gotten simpler. Many of the new designs manage to be so efficient by using fewer stages to accomplish the same job.

Early jet engines were horribly finicky. Modern jet engines are among some of the most reliable machines made. They have to be.


User currently offlineRevelation From United States of America, joined Feb 2005, 12757 posts, RR: 25
Reply 5, posted (1 year 10 months 3 weeks 4 days 9 hours ago) and read 14263 times:

Quoting tdscanuck (Reply 2):
A modern commercial jet engine is the most advanced product ever produced by the human race. With the possible exception of the semiconductor guys at Intel, it's probably also the world forefront of materials research.

FWIW, the world's fastest production microprocessor, by a fair margin, comes from IBM... Granted to get there they've had to master water cooling as opposed to air cooling, but as you imply, the power density of a high end microprocessor is greater than that of a rocket nozzle, and all this heat can't impact the nanometer features or else it's all over...



Inspiration, move me brightly!
User currently offlinelightsaber From United States of America, joined Jan 2005, 13302 posts, RR: 100
Reply 6, posted (1 year 10 months 3 weeks 4 days 8 hours ago) and read 14085 times:
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Even I found the article interesting as it helped me understand why the LEAP is as light as it is. (I'm an aero guy, so I focus on those aspects first.) In particular the extra stages of the LPT have had their extra weight compensated by the improvements in the fan region.

But the article didn't go into the aspects of the LEAP that let it compete with the GTF. In particular the scaloped low compressor and the 7 stage low compressor.    It also didn't go into how GE is having to push the aerodynamics of the fan to attain efficiency at tip speeds not previously attempted while reducing noise. For the low turbine efficiency is compromised by the low mach number of the blade tips (that is the main advantage of the GTF, improving the LPT efficiency).

But what I find startling in this article is that it skips over that GE is pushing high turbine inlet temperatures to new records for commercial narrow-bodies. While each generation must increase that temperature, GE is going to be the leader in the next generation as the PW2000 was in a past life. That is how 2 stages are powering 10 modern high pressure compressor stages.

I'm personally excited on how two very different approaches to engine technology are competing. Pratt has their risk in the gears. GE in the high turbine with a little more risk in the fan and LPC.

I do wonder with GE noting both are improving the same (I disagree). But then again, they have a financial incentive to downplay competition. Am I being cynical? I think we'll know within 7 years.   But not much sooner.  
Quoting goosebayguy (Reply 1):

From what I know Rolls Royce is also working on very similar technology for its large engines. Technology is changing and quickly here.

And so is Pratt. It is about who is ready for the right risk level at EIS at a given time. No one should dismiss any of the big 3 engine makers. Pratt right now has the most to prove (due to its very low market share).

Quoting Revelation (Reply 5):
the power density of a high end microprocessor is greater than that of a rocket nozzle

   microprocessors do not require cryogenic evaporative cooling to survive.

Quoting DocLightning (Reply 4):
FADEC isn't exactly new technology.

Understatement. FADECs are now a given. Sensor reliability has improved dramatically.

This is a battle where Pratt only pushed the gearbox technology and not much else. This put them at risk of being matched or even beaten by a non-GTF. GE has taken on the risk of implimenting some leading edge technology. Most of which is little more risk than just designing a new engine. The one I think will be an issue is the high turbine temperature. Then again, I'm biased. I used to design combustor airflow into the turbine and the flow was critical for turbine life. If GE's materials are as good as promise, then they will have pulled off as big a feat as the GTF.

So we could then speculate on combining the technologies for the next engine.   

Lightsaber



Societies that achieve a critical mass of ideas achieve self sustaining growth; others stagnate.
User currently offlineJAAlbert From United States of America, joined Jan 2006, 1615 posts, RR: 1
Reply 7, posted (1 year 10 months 3 weeks 4 days 6 hours ago) and read 13526 times:

Quoting DocLightning (Reply 4):
Modern jet engines are among some of the most reliable machines made.

Each time I fly I marvel at how reliable the engines are. They fly literally thousands of miles in a day - some aircraft fly half way around the world and then fly right back a few hours later, day in day out. That airlines have so few engine problems given the amount of use is astonishing (and of course very reassuring!)

It's part of the magic of flight that draws me to flight again and again.


User currently offlinenomadd22 From United States of America, joined Feb 2008, 1881 posts, RR: 0
Reply 8, posted (1 year 10 months 3 weeks 4 days 5 hours ago) and read 12878 times:

Quoting lightsaber (Reply 6):
Quoting Revelation (Reply 5):
the power density of a high end microprocessor is greater than that of a rocket nozzle

microprocessors do not require cryogenic evaporative cooling to survive.

Those two statements aren't exactly contradictory. Processors can be cooled through conduction to a much larger radiative area. Some rocket nozzles are only cooled by radiation, some by ablation and some by circulating cryogenic fluid. I know of processors that generate about 60 watts per cm2, which might be close to what a large purely radiative nozzle like the Merlin vacuum one does.

The point being, liquid cooling for processors isn't because a heat sink couldn't handle the job, It's generally because you can't just put a big heat sink at the chip location, but need to move the heat somewhere else to be disposed of.

[Edited 2012-12-09 19:48:25]


Andy Goetsch
User currently offlineprebennorholm From Denmark, joined Mar 2000, 6494 posts, RR: 54
Reply 9, posted (1 year 10 months 3 weeks 4 days 4 hours ago) and read 12827 times:

Quoting AA737-823 (Reply 3):
and complicate things further and further (variable bleed valves, variable stator vanes... and that's just twenty years ago!!)

For airliners variable stator vanes were first time used on the GE CJ805 engine on the Convair CV-880.

The CJ805 was the civil version of the GE J79 engine (sans aft flame thrower) which first ran on a test bench on June 8, 1954. That's not 20 years ago, but 58 and a half years ago.

The first US produced engine with variable stator vanes was the slightly earlier GE J73 used on F-86H Sabre fighters.

There could be earlier applications of variable stator vanes in other countries, France, Britain, Russia, I haven't investigated that. I would gladly take a bet on that not being the case, but not more than I can afford to lose.



Always keep your number of landings equal to your number of take-offs, Preben Norholm
User currently offlineRickNRoll From Afghanistan, joined Jan 2012, 862 posts, RR: 0
Reply 10, posted (1 year 10 months 3 weeks 4 days 4 hours ago) and read 12623 times:

Quoting tdscanuck (Reply 2):
That's the appropriate response, even for techies. A modern commercial jet engine is the most advanced product ever produced by the human race. With the possible exception of the semiconductor guys at Intel, it's probably also the world forefront of materials research.

That's a big statement to make. The modern microprocessor is quite an achievement. They have the circuit lines on commercially available processors down to 22 nanometers, using 1.4Billion transistors on a die that is only 160mm2. The CPU is fetching, and executing, instructions in parallel. It will execute instructions speculatively in parallel, ahead of knowing which path is the correct one. They have been following "Moore's Law" for 50 years now, doubling the number of transistors on a chip every two years. (It's not really a law, it was just a guess that most would have assumed could only hold for perhaps ten years or so).

I'm not putting down the amazing achievements of the modern jet engine, they are mind boggling, just saying there are very smart people out there in more fields who are also doing work that is just as impressive, IMHO.


User currently offlineContnlEliteCMH From United States of America, joined Mar 2005, 1464 posts, RR: 44
Reply 11, posted (1 year 10 months 3 weeks 4 days 3 hours ago) and read 12283 times:

Quoting AA737-823 (Reply 3):
I HOPE that reliability doesn't suffer, but with increased complexity, a corresponding decrease in dependability is to be expected, particularly once you bring software into the equation.

(1) Since software is already heavily used on today's modern turbofan, how is it now being brought into the equation?

(2) Since the engines equipped with this software are the most efficient and reliable to-date, upon what experience do you single out software as a critical element contributing to a lack of reliability? Are you suggesting that today's engines would be even more reliable without software?

Quoting DocLightning (Reply 4):
If that's the case, then why have engines become more and more reliable over time?

They get more reliable *because* of software, not despite it. Software yields (at least) two benefits for commercial jet engines:

(1) During design, software enables designs to be refined much more than was ever possible with paper designs. During testing, software permits data to be collected on a larger scale, and analyzed much more quickly (and with far more detail) than was previously possible.

(2) In operation, software permits more precise, more repeatable, and more complex control of engine components and their interaction than any flight engineer could provide. It also provides for substantial data collection and ever-increasing real-time and post-failure analysis, which permits OEM's and airlines to zoom in on problems quickly and identify their root causes. Software can even be used to detect problems before they become serious incidents. It seems counterintuive, but there are scenarios in which an IFSD is vastly preferable to the failure that could occur if a problem went undetected.

If engines get more reliable (or maintain their current stellar track record), I expect it will be "particularly" once *more* sotware is introduced.

[Edited 2012-12-09 21:12:30]


Christianity. Islam. Hinduism. Anthropogenic Global Warming. All are matters of faith!
User currently offlineautothrust From Switzerland, joined Jun 2006, 1596 posts, RR: 9
Reply 12, posted (1 year 10 months 3 weeks 3 days 22 hours ago) and read 10831 times:

Quoting tdscanuck (Reply 2):
A modern commercial jet engine is the most advanced product ever produced by the human race.

Offtopic but i would dare to say the SSME are the most advanced product ever produced.



“Faliure is not an option.”
User currently offlineAA737-823 From United States of America, joined Mar 2000, 5875 posts, RR: 11
Reply 13, posted (1 year 10 months 3 weeks 3 days 20 hours ago) and read 10415 times:

Well, in a way that only a.net can do, we've turned this into an argument.
 
Quoting ContnlEliteCMH (Reply 11):
(1) Since software is already heavily used on today's modern turbofan, how is it now being brought into the equation?

I didn't say that the Leap will be the "first ever engine to use software," did I? I'm simply saying that engines are becoming more and more reliant on electronic controls. And the earliest versions of FADEC most assuredly pale in comparison to what's being done today; it's amazing.

Quoting ContnlEliteCMH (Reply 11):
(2) Since the engines equipped with this software are the most efficient and reliable to-date, upon what experience do you single out software as a critical element contributing to a lack of reliability? Are you suggesting that today's engines would be even more reliable without software?

Reliability can be defined in a couple of different ways. One way (which you seem to refer to) might be explosions inflight, failures inflight, catastrophic uncontained fireballs of parts, etc. ANOTHER way to measure reliability is in the number of times that I myself am at the gate changing stupid electronic components, compared to the number of times I've performed similar tasks on, say, the venerable (if noisy) JT-8D. Which is, for the record, zero.
Now- does a CFM56 stay on wing for a lot longer than a JT-8? Absolutely. But rest assured, they have their quirks, and many of them are related to the onboard monitoring hardware and software, which in the end, causes a lot of gate delays that the JT-8D simply doesn't produce.

Quoting DocLightning (Reply 4):
If that's the case, then why have engines become more and more reliable over time? FADEC isn't exactly new technology. It's been around at least since the A300. Engines have continually gotten more and more reliable...and they have gotten simpler. Many of the new designs manage to be so efficient by using fewer stages to accomplish the same job.

To say that engines have gotten simpler is mostly eroneous; sure, stages are eliminated as possible, but that's about the end of it. We've gone from can combustors to TAPS (Twin-annular, pre swirlers!! Whoa baby!). We've gone from relatively low pressure ratios to insanely high ones. Active Turbine Clearance Controls.
Heck, the engines now have their own built-in alternators to power the EEC in the event that the generators fail; ya won't see/need that on a JT-8.
And sure, the reliability of FADEC.... it's dual channel on the CFM56 (and I assume everything else, but my area of expertise is limited to the topic at hand), but go ahead and ask me if we're able to dispatch on a single-channel failed EEC. The answer is no.

Lest you think I'm singing the praises of a JT-8, I'm not; it was a fantastic engine in its day. I'd rather have CFM56's on the wings of the airplane as I look out the window at 41,000 feet. But- to say that the CFM56 is a simple engine is a slap in the face to countless engineers and assembly workers. It's not simple, it's a remarkably complex feat of engineering.


User currently offlinespink From United States of America, joined Aug 2005, 318 posts, RR: 1
Reply 14, posted (1 year 10 months 3 weeks 3 days 20 hours ago) and read 10277 times:

Quoting Revelation (Reply 5):
FWIW, the world's fastest production microprocessor, by a fair margin, comes from IBM... Granted to get there they've had to master water cooling as opposed to air cooling, but as you imply, the power density of a high end microprocessor is greater than that of a rocket nozzle, and all this heat can't impact the nanometer features or else it's all over...

FWIW, Intel could release much faster production microprocessors than they currently do, but it doesn't make economic sense to do so.

The IBM Power series gets a large portion of its performance from a greatly expanded power budget and the ability of a quite different economic model to allow them to increase the average cost per chip over an order of magnitude more than intel (IBM doesn't sell microprocessors, they sell systems, and sell in much much less volume, volume has some interesting impacts).

For process technology, Intel is well over a year ahead of anyone else in the industry currently and the gap has been increasing. Unless others step up they rate of new process introduction, Intel will likely get beyond a 2 year lead in process technology.

Regardless, I would say that the modern microprocessor is probably the most advanced manufactured good in the world at the moment. While the new Jet engines will be pushing HPT inlet temperatures beyond what most people considered economically viable, modern semi-conductor fabs are pushing feature sized below what many people considered physically possible given the light sources they are using. Modern feature geometry is roughly 1/18th of the width of the light sources being used which is pretty incredible.

As far as heat flux, there are modern semiconductors that are well over 100W/cm2.


User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 15, posted (1 year 10 months 3 weeks 3 days 17 hours ago) and read 9027 times:

Quoting RickNRoll (Reply 10):
That's a big statement to make. The modern microprocessor is quite an achievement.

No disagreement, but a modern microprocessor is just one of the parts of a modern jet engine...one kinds of subsumes the other, in my mind.

Quoting autothrust (Reply 12):
Offtopic but i would dare to say the SSME are the most advanced product ever produced.

At their time, I'd agree. But a lot has happened to jet engines since then and the SSME has remained pretty static.

Tom.


User currently offlineNeutronStar73 From United States of America, joined Mar 2011, 511 posts, RR: 0
Reply 16, posted (1 year 10 months 3 weeks 3 days 17 hours ago) and read 8913 times:

I'm gonna say, as much as I adore jet engine technology, it is NOT the most advanced technology produced by man. I think modern rocket technology / space technology takes that cake.

User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 17, posted (1 year 10 months 3 weeks 3 days 16 hours ago) and read 8257 times:

Quoting NeutronStar73 (Reply 16):
I think modern rocket technology / space technology takes that cake.

Who's doing what in space that compares to what the commercial jet engine makers are doing? You show me a rocket engine that goes 50,000 hours without major overhaul.

Tom.


User currently offlineyowviewer From Canada, joined Jun 2010, 59 posts, RR: 0
Reply 18, posted (1 year 10 months 3 weeks 3 days 14 hours ago) and read 7758 times:

Quoting NeutronStar73 (Reply 16):

If we're talking 1960's then I agree with the rocket/space technology and the race for space. Voyager 1 and 2 are also great examples. But with research cutbacks, etc. I think advances have slowed in the last 30 years or so.
Because of the continued demand for improvements in commercial jet engines due to both competition and oil prices, I have to agree with the jet engine. The reliability factor just absolutely amazes me !


User currently offlineferpe From France, joined Nov 2010, 2804 posts, RR: 59
Reply 19, posted (1 year 10 months 3 weeks 3 days 14 hours ago) and read 7672 times:

Quoting lightsaber (Reply 6):
But what I find startling in this article is that it skips over that GE is pushing high turbine inlet temperatures to new records for commercial narrow-bodies. While each generation must increase that temperature, GE is going to be the leader in the next generation as the PW2000 was in a past life. That is how 2 stages are powering 10 modern high pressure compressor stages.

Where is the component efficiency on an engine like the Leap? I understand they should be above 90% on the compressor and perhaps 92-93% on the turbine, any info? I understand the pressure ratio is 40, with about 22 in the high compressor.



Non French in France
User currently offlinenomadd22 From United States of America, joined Feb 2008, 1881 posts, RR: 0
Reply 20, posted (1 year 10 months 3 weeks 3 days 14 hours ago) and read 7656 times:

Quoting tdscanuck (Reply 17):
Quoting NeutronStar73 (Reply 16):
I think modern rocket technology / space technology takes that cake.

Who's doing what in space that compares to what the commercial jet engine makers are doing? You show me a rocket engine that goes 50,000 hours without major overhaul.

Tom.

And, rocket engines are mainly one stage turbines sending fuel and oxidizer into a combustion chamber. maybe with some diversion for regen cooling of the nozzle. Much less complicated than the modern jet engine.



Andy Goetsch
User currently onlineSEPilot From United States of America, joined Dec 2006, 6971 posts, RR: 46
Reply 21, posted (1 year 10 months 3 weeks 3 days 14 hours ago) and read 7420 times:

Quoting AA737-823 (Reply 3):
I HOPE that reliability doesn't suffer, but with increased complexity, a corresponding decrease in dependability is to be expected, particularly once you bring software into the equation.

In fact a lot of the increase in reliability is due to more and more functions being electronically controlled instead of mechanically (this is true for automobiles and trucks as well.) I encountered this in my own career designing grinding machines; when we transitioned to full computer control from mechanical and electro-mechanical control reliability took a quantam leap forward. The electronics and software are probably the most reliable parts of the whole engine.

Quoting lightsaber (Reply 6):
But the article didn't go into the aspects of the LEAP that let it compete with the GTF. In particular the scaloped low compressor and the 7 stage low compressor. It also didn't go into how GE is having to push the aerodynamics of the fan to attain efficiency at tip speeds not previously attempted while reducing noise. For the low turbine efficiency is compromised by the low mach number of the blade tips (that is the main advantage of the GTF, improving the LPT efficiency).
Quoting lightsaber (Reply 6):
So we could then speculate on combining the technologies for the next engine.

The problem for GE is that if Pratt takes the technology that GE is applying to the LEAP and applies it to the GTF then they will leave the LEAP in the dust. For this reason I was surprised and disappointed that Boeing did not include the GTF as an option on the MAX. I do believe that the gamble on the gears is a good one (my grandfather developed the basis of modern gear design-he popularized the involute form, and his manuals printed in the 30's are still in use today, so I am biased toward gears). Also, since the gear ratio can be changed to match the fan diameter the smaller fan diameter of the MAX should have a smaller efficiency penalty for the GTF than for the LEAP.



The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
User currently offlineArrow From Canada, joined Jun 2002, 2676 posts, RR: 2
Reply 22, posted (1 year 10 months 3 weeks 3 days 13 hours ago) and read 7386 times:

Quoting prebennorholm (Reply 9):
There could be earlier applications of variable stator vanes in other countries, France, Britain, Russia, I haven't investigated that. I would gladly take a bet on that not being the case, but not more than I can afford to lose.

I may be way off base on this -- but take a look at the Orenda Iroquois engine developed in Canada in the 50s for the ill-fated Avro Arrow. It was a world-beater at the time (until the government got its mitts on it). Apparently NASA's Propulsions Systems Laboratory had a look at it:


"In 1957 PSL also had a chance to test a rare Canadian jet engine, the Iroquois PS.13. The Avro Canada Company began designing its CF-105 Arrow jet fighter in the mid-1950s. Although not originally in the design, the decision was made to use two PS.13 engines developed by another branch of the company. These engines were more powerful than any contemporary U.S. jet engine, lightweight, and fuel efficient. The engines were tested in PSL during the extensive ground testing phase. The Arrow made its flight debut in March 1958, but was cancelled the following year when its perceived mission disappeared."

I have no idea if this engine incorporated variable stator vanes -- but I guess it's possible. (my father worked as an engineer on the Arrow).



Never let the facts get in the way of a good story.
User currently offlineJoeCanuck From Canada, joined Dec 2005, 5476 posts, RR: 30
Reply 23, posted (1 year 10 months 3 weeks 3 days 13 hours ago) and read 7257 times:

Quoting SEPilot (Reply 21):

The problem for GE is that if Pratt takes the technology that GE is applying to the LEAP and applies it to the GTF then they will leave the LEAP in the dust.

On the flip side, there is no reason GE can't make a GTF of their own, (and I'd be shocked if they weren't working on it already). As far as I understand it, the advantage of the GTF is that the low pressure turbine can have fewer stages, (making the engine as a whole lighter and shorter), since it will be turning at its optimal speeds. GE is using more stages and cutting edge materials and shapes, to achieve similar levels of efficiency with a slower turning LPT. The fans are probably turning at similar speeds, the Leap probably a bit faster.

I'm guessing Pratt won't copy the GE LPT design since they don't have to. More stages probably means more losses as well as more weight...certainly more complexity.

The GTF seems the simpler way to go, (not to take away from Pratt's decades of research into the gearbox), but that doesn't mean the LEAP method doesn't have merit. GE, Boeing and Airbus are all betting on it.

I realise I'm leaving out huge swaths of technicality and accuracy, but it's probably a decent thumb nail sketch of thing.



What the...?
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 24, posted (1 year 10 months 3 weeks 3 days 12 hours ago) and read 7206 times:

Quoting JoeCanuck (Reply 23):
On the flip side, there is no reason GE can't make a GTF of their own, (and I'd be shocked if they weren't working on it already).

If GTF is as good as promised, they will. But, like Pratt, it will take them decades to figure it out and they're starting from waaaayyyy behind.

Tom.


25 DocLightning : Not only that, but they have to duck and dodge patent infringements.
26 SEPilot : Most of the real technology has long passed the patentable stage. Planetary gears are so ubiquitous that it would be very difficult coming up with a
27 lightsaber : It will cost GE less than the Billion Pratt put into researching the concept. Cooling and failure mode prediction are key. The low compressor and low
28 JoeCanuck : GE won't be starting completely from scratch. They do have extensive experience with gearboxes on their turboprop and helicopter engines. While not i
29 mffoda : Hey lightsaber, I have question regarding turbine temperature. Do higher turbine temperatures assist in fuel burn efficiency or is this mostly a pena
30 RickNRoll : Those Mars rovers are pretty impressive, especially the new one, with 70,000 hours by my calculation for Opportunity. No chance of any overhaul up th
31 Post contains images tdscanuck : Good point. On the reliability score, I have to hand it to the Spirit/Opportunityh team. However, I'd argue that those rovers are working in a far mo
32 Post contains images lightsaber : Higher turbine inlet temperatures help fuel burn efficiency as there is more energy to extract for the turbine. However, every 50 degrees F higher th
33 packsonflight : to attain 100% thermal efficiency of the engine you need two things: Engine inlet temprature at 0 deg Kelvin (-273 Celcius) and turbine inlet temprat
34 nomadd22 : I take it cooling isn't too big an issue on the finished gearbox. Pratt indicated they designed a 98% efficient gearbox and it came in at 99%, so it'
35 lightsaber : How its done is a big deal. The total heat isn't. Part of what keeps a gearbox efficient over the hours is cooling where the heat is. And where tells
36 brindabella : Thanks guys. There is an elephant in the room, of course, Let's say it is the morning of Nov. 1, 2016, and the boys in Chicago get a definitve report
37 SEPilot : This is the exact point I was alluding to earlier. If PW can get the GTF reliable enough it is a game changer. They can more easily incorporate the t
38 frmrcapcadet : Suppose Boeing (actually the airlines - airlines ordering the neo will have the same concern) have an escape clause allowing an engine switch. Does an
39 Post contains images autothrust : True but the SSME have got upgrades as well and the reliability were enhanced too. Disagree, the SSME was almost ridiculously complicated compare to
40 Post contains links dynkrisolo : 7 stage low compressor? I don't think I have ever heard any engines with 7 stages of low compressor. Do you mean low turbine? Based on this picture:
41 tdscanuck : I think it's absolutely hilarious that they're including "Direct Drive" as a "technology for performance and durability". Sure, it's technically true
42 RickNRoll : They all do it. To quote Madmen "It's toasted".
43 ContnlEliteCMH : Why can P&W more easily incorporate GE's technology for higher temps than GE can add a gearbox? One of the major changes GE is working on involve
44 ferpe : I don't think it is what technology is the more difficult to develop, it is about what technology has more long-term potential. There are several sig
45 Post contains images mffoda : That, and the fact RR would be out of the NB business anyway...
46 Post contains links JoeCanuck : I think both will be end up being developed concurrently in both camps. As the quest for even more efficiency goes on, the GTF's will go with higher
47 astuteman : Intuitively? Because aero engine makers are ALWAYS pushing the limits of materials and core temperatures across the range of their engines. The GTF i
48 Post contains images SEPilot : Just look at how long PW has been working on the gearbox. If it were easy it would have been flying on the A340 25 years ago. Materials, once develop
49 JoeCanuck : Still, the Leap can make a good starting point. Other than the gearbox, the biggest difference between the two is the LPT stages. I imagine most, if
50 Post contains links planemaker : For those interested, here is a link to a 6 page Boeing article about the NG's PIP outlining engine and aero tweaks. While not directly related to the
51 lightsaber : Or GE could pull it off with the turbine materials and Pratt makes a mistake. Yes. Thank you for catching my typo. GE is ahead on turbine materials a
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P&W Completes First A320neo Engine posted Fri Oct 26 2012 12:55:24 by KarelXWB
A380 Trent Engine Inspections Ordered posted Fri Oct 26 2012 07:45:09 by LAXintl
AB A332 Parked At SFO 5 Days Now Awaiting Engine? posted Mon Oct 22 2012 15:59:20 by mikeology
EK A332 Uncontained Engine Failure posted Mon Oct 22 2012 15:42:15 by Gonzalo
Guess What Color BA's 787 Engine Nacelles will be? posted Sat Oct 13 2012 06:31:58 by by738
Faulty 787 Engine In CHS Part posted Thu Sep 27 2012 14:42:57 by rotating14