Sponsor Message:
Civil Aviation Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Doubts About The Engine Of The MAX  
User currently offlinerheinwaldner From Switzerland, joined Jan 2008, 2213 posts, RR: 5
Posted (2 years 3 months 2 weeks 6 days 15 hours ago) and read 24747 times:

The following article with the title "Even more doubts about B737MAX" has some detailed and recent information about the upcoming NB engines:
http://aeroturbopower.blogspot.com/2...en-more-doubts-about-b737max.html:

Quote:
"The end result is that you've got a really big gap between a P&W Neo and a CFMi Neo." To clarify: the gap is in favor of the P&W GTF and Airline Economics is quoting an senior industry expert here, who expects the LEAP to have a 4% disadvantage.

Comment: 4% might be at the upper end for the engine alone. But bundled with the disadvantage of the tricky engine installation on the MAX this gap could even become larger in total.

Other (almost weird) info from the article:

- CFM in an attempt to get market share in 2011 fought extreme price battles. They went so low that one customer is reported to have picked the GTF just by applying the principle "what is good, can't be cheap" (because the LEAP was offered at a suspiciously low price).

- The GTF on the MAX might become an option.

- There also seems to be much talk that the lack of MAX commitments might have to do with real deficits of the MAX.

- Even the scenario where Boeing would have to rethink the MAX strategy is discussed (and considered as likely).

- The GTF seems to beat all promises.

148 replies: All unread, showing first 25:
 
User currently offlineMD-90 From United States of America, joined Jan 2000, 8502 posts, RR: 12
Reply 1, posted (2 years 3 months 2 weeks 6 days 14 hours ago) and read 24531 times:

Quoting rheinwaldner (Thread starter):

- The GTF seems to beat all promises.

I hope it's true--I was born in Connecticut and I'm a P&W fan.


User currently offlinechuchoteur From France, joined Sep 2006, 762 posts, RR: 0
Reply 2, posted (2 years 3 months 2 weeks 6 days 14 hours ago) and read 24438 times:

Quoting MD-90 (Reply 1):
Quoting rheinwaldner (Thread starter):

- The GTF seems to beat all promises.

I hope it's true--I was born in Connecticut and I'm a P&W fan.

P&W are willing to offer performance guarantees.
That's all that matters really - if it doesn't deliver, they pay.

They've run that engine a lot of hours now, more than almost any other new engine design going into service, so their performance guarantees have substance I would say...


User currently offlineRoseflyer From United States of America, joined Feb 2004, 9509 posts, RR: 52
Reply 3, posted (2 years 3 months 2 weeks 6 days 14 hours ago) and read 24396 times:

First off aeroturbopower is probably one of the most pro-Airbus aviation blogs there is, so I do take the information with a little bit of apprehension as there typically is an obvious slant compared to Leeham, Scott Hamilton, Jon Ostrower, and Flight Global. Many of its posts sound more like an Airbus sales campaign than anything else. I'm not saying it is a bad blog, just one that shows bias.

I find it interesting that there are claims of 4% difference between the LeapX and PW GTF on the A320NEO. That is a big difference for a side by side comparison. If there was such a discrepency, I'd expect airlines to be very bias towards the GTF. The article's claim that CFMI slashing prices and making its engines virtually free is complete nonsense in my opinion. CFMI is a for profit company and is not selling engines virtually free to maintain market share. Anyone who thinks that is not a very knowledgeable because the overhaul and spares business on engines is not enough to slash prices to virtually free. CFM has about 40% of the A320 NEO market. To me that indicates that the GTF may be better. 4% is an interesting number.

One thing I find interesting is that it states "there is increasing evidence that the PW GTF is exceeding expectations in all aspects of testing". I'd be curious to learn more about that. It would be great for it to be exceeding expectations, although the line all aspects of testing makes no sense. If it exceeds all aspects of testing, then the expectations were not established correctly in the first place. One thing I learned early in my design engineering career is that if you find no failures in your testing, you overdesigned the product and there is more opportunity left. I'd like to learn more about that.

I find it interesting that the article comes up with the conclusion that Boeing is wrong with the 737MAX and they should go back to the drawing board.



If you have never designed an airplane part before, let the real designers do the work!
User currently offlinePhxA340 From United States of America, joined Mar 2012, 882 posts, RR: 1
Reply 4, posted (2 years 3 months 2 weeks 6 days 14 hours ago) and read 24357 times:

Quoting rheinwaldner (Thread starter):
There also seems to be much talk that the lack of MAX commitments might have to do with real deficits of the MAX.

My first issue with this post is that this is a blog .... not really an article. I can write whatever I want on a blog too ... until I see a customer cancel a MAX order because of a 4% short fall, it is all speculation.

Stitch can probably give you a more accurate number but doesn't that MAX have over 800 + commitments ?? That is a pretty solid number.

As far as the price battle - that almost made me laugh "whats good can't be cheap". Ask Ryanair how they feel about their rediculously cheap 737 order. I think they would use the word great.


User currently offlinegarpd From UK - Scotland, joined Aug 2005, 2629 posts, RR: 4
Reply 5, posted (2 years 3 months 2 weeks 6 days 14 hours ago) and read 24228 times:

Quoting rheinwaldner (Thread starter):
The following article with the title "Even more doubts about B737MAX" has some detailed and recent information about the upcoming NB engines:
http://aeroturbopower.blogspot.com/2...html:

I saw that post before you linked it here. That blog is glaringly Pro-Airbus and at times seems as if it is written someone after gulping down some Airbus brand 100% sugar Cool Aid.

People were dead certain Boeing was making a mistake launching the 737 NG with the same single engine manufacturer. Look how that turned out!

This blog post can be filed under "Irrelevant Fan-Boy post" IMO.

Quoting Roseflyer (Reply 3):

I find it interesting that the article comes up with the conclusion that Boeing is wrong with the 737MAX and they should go back to the drawing board.

What do Boeing know about making airplanes? Airbus are the pros and this blogger knows a lot. Boeing should listen to the both of them!
[/Scarcasm]



arpdesign.wordpress.com
User currently offlinenomadd22 From United States of America, joined Feb 2008, 1832 posts, RR: 0
Reply 6, posted (2 years 3 months 2 weeks 6 days 13 hours ago) and read 24080 times:

From the gearbox on the GTF being more efficient than Pratt had officially anticipated I had the feeling they were being conservative with their claims. Even with a 2% drop because of a smaller fan, I wondered about their exclusion from the Max.
The blog is a joke, but the fact remains that if Pratt can keep up with the other guys core wise, theyre going to have an advantage.



Andy Goetsch
User currently offlineneutronstar73 From United States of America, joined Mar 2011, 501 posts, RR: 0
Reply 7, posted (2 years 3 months 2 weeks 6 days 13 hours ago) and read 23974 times:

Quoting Roseflyer (Reply 3):

Absolutely. They are unabashed in their pro-Airbus, anti-CFM tirades. Only reason to read that site is for comedy. Aeroturbopower should not be taken seriously. If you do take it seriously, take it with a kilogram of salt, because I don't think I've ever read a "post" on that site that was in any way complementary to CFM or Boeing...ever.


User currently offlineRoseflyer From United States of America, joined Feb 2004, 9509 posts, RR: 52
Reply 8, posted (2 years 3 months 2 weeks 6 days 13 hours ago) and read 23801 times:

http://www.flightglobal.com/blogs/fl...reaking-boeing-reveals-new-73.html

I am not sure if these is just convenient timing, but flightglobal presented an article where Boeing reveals some real design parameters.

8'' nose extension
Fly by wire spoilers
Tail cone extension
Electronic Bleed Air control
Elevator strengthening

Flightglobal actually provides some facts unlike the blog which had a lot more speculation.



If you have never designed an airplane part before, let the real designers do the work!
User currently offlinePresRDC From United States of America, joined Jul 1999, 660 posts, RR: 1
Reply 9, posted (2 years 3 months 2 weeks 6 days 12 hours ago) and read 23667 times:

Quoting Roseflyer (Reply 3):
The article's claim that CFMI slashing prices and making its engines virtually free is complete nonsense in my opinion. CFMI is a for profit company and is not selling engines virtually free to maintain market share. Anyone who thinks that is not a very knowledgeable because the overhaul and spares business on engines is not enough to slash prices to virtually free.

Recall that, with the exception of spare engines, neither CFMI nor P&W sell engines directly to airlines. The engines are sold to the airframer at a price that is negotiated in a master contract for the specific engine model and does not change for different customers.

What engine manufacturers do, though, is offer credits for a percentage of the engine price that are issued directly to the airline and can, at the airline's option (an option that is usually taken), be converted to cash and wired directly to the airframer to help offset the cost of the aircraft. That percentage is highly negotiated and is typically well north of 65% of the price at which the engine is sold to the airframer.

Both P&W and CFMI offer performance guarantees. It is very much part of the business. Guarantees often include things like engine weight, fuel consumption, climb performance, maintenance cost, etc. The guarantees are typically expressed as rates on a fleet wide average (except for zero event guarantees, such as IFSD, remote site removal, uncontained failure, etc.) and are subject to the airline maintaining certain operating parameters (derate, stage length, etc.).


User currently offlineStitch From United States of America, joined Jul 2005, 30614 posts, RR: 84
Reply 10, posted (2 years 3 months 2 weeks 6 days 12 hours ago) and read 23586 times:
Support Airliners.net - become a First Class Member!

Pratt is said to be holding back a number of percent in SFC on the PW1100G to protect themselves as they cannot afford another engine program that does not meet contractual guarantees. So it's not inconceivable that the PW1100G will be better than Pratt is currently stating.

As to LEAP-X and the MAX, airlines forced Boeing to launch it so they must have faith otherwise they'd have waited for the NSA with GTFs.

I believe Pratt's VP of GTF development was overly optimistic in his opinion that the PW1100G could fit on the 737NG with little to no modification to the airframe. I would not be overly surprised if Boeing's decision to sole-source the LEAP-X was due to the amount of production and design changes necessary to accommodate the PW1100G.


User currently offlinefpetrutiu From United States of America, joined Aug 2007, 880 posts, RR: 0
Reply 11, posted (2 years 3 months 2 weeks 6 days 12 hours ago) and read 23553 times:

Quoting PhxA340 (Reply 4):
Stitch can probably give you a more accurate number but doesn't that MAX have over 800 + commitments ?? That is a pretty solid number.

Over 1000 now per Boeing: http://boeing.mediaroom.com/index.php?s=43&item=2212


User currently offlineHamlet69 From United States of America, joined Mar 2000, 2735 posts, RR: 58
Reply 12, posted (2 years 3 months 2 weeks 6 days 12 hours ago) and read 23356 times:

Quoting rheinwaldner (Thread starter):
- The GTF on the MAX might become an option.

Weirdly, this is the only part of the blog that actually has some meat behind it.

At last month's ISTAT conference, there was a lot of talk that Boeing is still considering the GTF as a second option on the MAX. While Boeing has dismissed this publically, there seems to be a lot of respectable sources indicating that the GTF is indeed, at least being looked, with a final "yea or nay" decision expected to come sometime this summer.

Aspire Aviation adds a bit more to this in their recent article here:

http://www.aspireaviation.com/2012/0...ing-continues-to-optimise-737-max/

They mention the potential of a 71" fan for a 737 GTF. I do wonder at that, as from my sources, Boeing can fit up to a 70" before they 'run into issues'.

Guess we'll just have to wait and see. . .

Regards,

Hamlet69



Honor the warriors, not the war.
User currently offline737tdi From United States of America, joined Sep 2007, 791 posts, RR: 1
Reply 13, posted (2 years 3 months 2 weeks 6 days 11 hours ago) and read 23229 times:
Support Airliners.net - become a First Class Member!

This has nothing to do with the engines but more with the last two posts.

Boeing best do something about the problems with the horizontal stabalizers on the NG v the Max, we are having a few problems with skin cracking on them. It's not a hard repair but takes the aircraft out of service for a couple of days. Maybe that is part of the "elevator strengthening"?


User currently offlinePlaneAdmirer From United States of America, joined Jul 2009, 561 posts, RR: 0
Reply 14, posted (2 years 3 months 2 weeks 6 days 11 hours ago) and read 23078 times:

Quoting Stitch (Reply 10):
Pratt is said to be holding back a number of percent in SFC on the PW1100G to protect themselves as they cannot afford another engine program that does not meet contractual guarantees. So it's not inconceivable that the PW1100G will be better than Pratt is currently stating.

While I know this is about the 737, the original post and yours made me think about the GTFon the 777NG. If the GTF is performing as well as rumored, then it may make the 777NG a very competitive offering for some time.


User currently offlineRoseflyer From United States of America, joined Feb 2004, 9509 posts, RR: 52
Reply 15, posted (2 years 3 months 2 weeks 6 days 10 hours ago) and read 23008 times:

Quoting 737tdi (Reply 13):

Boeing best do something about the problems with the horizontal stabalizers on the NG v the Max, we are having a few problems with skin cracking on them. It's not a hard repair but takes the aircraft out of service for a couple of days. Maybe that is part of the "elevator strengthening"?

If you are talking about the cracking and damage caused by the elevator tab system, there is an Airworthiness Directive published that you can read on the FAA website: 2010-17-19. That will all be fixed long before the MAX. AD's usually have a design change and Service Bulletin mandated in about 2 years time to fix the problems.



If you have never designed an airplane part before, let the real designers do the work!
User currently offline737tdi From United States of America, joined Sep 2007, 791 posts, RR: 1
Reply 16, posted (2 years 3 months 2 weeks 6 days 10 hours ago) and read 22811 times:
Support Airliners.net - become a First Class Member!

Quoting Roseflyer (Reply 15):
If you are talking about the cracking and damage caused by the elevator tab system, there is an Airworthiness Directive published that you can read on the FAA website: 2010-17-19. That will all be fixed long before the MAX. AD's usually have a design change and Service Bulletin mandated in about 2 years time to fix the problems.




Not that, I was involved in changing all of our elevators. We were doing them on RON every Friday night for what seemed like forever. We got quite good at it, ours have been completed for quite some time. This only addressed the vibration and flutter of the elevator.

What I'm referring to is the lower horiz. stab skin. We are finding small lateral cracks between the ribs. Like stated they are easy to repair with a simple doubler but still take awhile to perform and costly downtime. Don't know if you have ever taken a 737CL or NG to high power but there is a very noticeable difference between the two in relation to stab vibration. I suspect it is due to the hard mounted engines on the NG v the isolator mounted on the CL.


User currently offlinerheinwaldner From Switzerland, joined Jan 2008, 2213 posts, RR: 5
Reply 17, posted (2 years 3 months 2 weeks 6 days 10 hours ago) and read 22800 times:

Quoting Roseflyer (Reply 3):
blogs
Quoting PhxA340 (Reply 4):
blog
Quoting garpd (Reply 5):
blog

This is nor fair. Because they talk about an article in a publication. In fact it is almost zero opinion from aeroturbopower in the blog post. And the opinion that is expressed favours Boeing.

Quoting PhxA340 (Reply 4):
I can write whatever I want on a blog too

But not quoting a publication.

Quoting garpd (Reply 5):
That blog is glaringly Pro-Airbus and at times seems as if it is written someone after gulping down some Airbus brand 100% sugar Cool Aid.

Show some examples. I cant remember.

Quoting neutronstar73 (Reply 7):
If you do take it seriously, take it with a kilogram of salt, because I don't think I've ever read a "post" on that site that was in any way complementary to CFM or Boeing...ever.

So you probably didnt read a post from them at all?

IMO the bias of the readers might have affected a balanced judgment as much as any other bias...


User currently offlinePhxA340 From United States of America, joined Mar 2012, 882 posts, RR: 1
Reply 18, posted (2 years 3 months 2 weeks 6 days 9 hours ago) and read 22697 times:

Quoting rheinwaldner (Thread starter):
This is nor fair. Because they talk about an article in a publication

It is very fair ... the 'article' comes from the "Blogspot"... This is neither a balanced reveiw nor based on facts , just guesses.

I am all for a healthy debate on the merits of the NEO and MAX but this is clearly biased to the point where it stopped being fun to read after the first few sentences.


User currently offlineRoseflyer From United States of America, joined Feb 2004, 9509 posts, RR: 52
Reply 19, posted (2 years 3 months 2 weeks 6 days 9 hours ago) and read 22597 times:

Quoting rheinwaldner (Reply 17):

Quoting garpd (Reply 5):
That blog is glaringly Pro-Airbus and at times seems as if it is written someone after gulping down some Airbus brand 100% sugar Cool Aid.

Show some examples. I cant remember.

How about the analysis of Delta ordering the 739ER and only comparing it to the A320NEO and A321NEO? That was almost comical bias. When someone tried to point out that a realistic comparison would be versus the A320 or A321, the blogger ignored it and said that since the competition will eventually be operating A320NEOs and A321NEOs, then it is the only logical comparison and the blogger completely ignored the savings of replacing 30 year old 752s with brand new 739ERs and the fact that Virgin America and jetBlue have A320s on order that they will be taking delivery of side by side with A320NEOs.

How about the multiple posts, doubts on MAX, GTF exceeds expectations, Ryanair criticism of the MAX, American and Norweigian defecting from Boeing, etc? It's not that I am selecting a few anti-Boeing and pro Airbus articles, it is that every post on that blog is like this.

Then of course there was the technical analysis of block fuel burn comparison of the A320 vs 738. It was based on ACAPs and conveniently chose the highest MTOW of the A320 vs the lowest fuel capacity restricted 738 and conveniently chose a range and payload that was exactly where the A320 had it's peak performance. That's like saying that the A319 burns less fuel than the A320 when the A320 is artificially limited to the amount of payload that an A319 can. Of course when you ignore the 30 seat advantage and increased payload, the A319 burns less fuel than the A320. However airlines in actualy operating conditions prefer the A320 and its lower CASM.

That blogger searches for anything negative about a Boeing or CFM product and posts it. That blogger also finds everything positive about the GTF and posts it. There are some general posts, but unless they are pointing out straight facts like airline X ordered an airplane or a certain model was launched, most of them follow the pattern. Reading that blog is like watching Fox News and trying to get an understanding of the democratic party's political objectives. Sure there are some facts in there, but a lot more facts that are positive about one side are presented while facts promoting the other side are ignored.

[Edited 2012-04-11 14:20:44]

[Edited 2012-04-11 14:37:39]


If you have never designed an airplane part before, let the real designers do the work!
User currently offlinePresRDC From United States of America, joined Jul 1999, 660 posts, RR: 1
Reply 20, posted (2 years 3 months 2 weeks 6 days 9 hours ago) and read 22432 times:

Quoting Stitch (Reply 10):
I would not be overly surprised if Boeing's decision to sole-source the LEAP-X was due to the amount of production and design changes necessary to accommodate the PW1100G.

The CFMI 737 contract with Boeing gives CFMI exclusivity on a re-engined 737 platform. That is why CFMI is sole source on that aircraft.


User currently offlineracko From Germany, joined Nov 2001, 4856 posts, RR: 20
Reply 21, posted (2 years 3 months 2 weeks 6 days 8 hours ago) and read 22386 times:

Quoting Roseflyer (Reply 8):
8'' nose extension

Are we talking a wart like on the A330F or a more elegant solution, i.e. a lengthened gear?


User currently offlineMountainFlyer From United States of America, joined Jul 2005, 474 posts, RR: 0
Reply 22, posted (2 years 3 months 2 weeks 6 days 8 hours ago) and read 22242 times:

Quoting racko (Reply 21):
Are we talking a wart like on the A330F or a more elegant solution, i.e. a lengthened gear?
This blog says landing gear.

[Edited 2012-04-11 15:27:10]


SA-227; B1900; Q200; Q400; CRJ-2,7,9; 717; 727-2; 737-3,4,5,7,8,9; 747-2; 757-2,3; 767-3,4; MD-90; A319, 320; DC-9; DC-1
User currently offlineCM From , joined Dec 1969, posts, RR:
Reply 23, posted (2 years 3 months 2 weeks 6 days 8 hours ago) and read 22129 times:

Quoting 737tdi (Reply 13):
Boeing best do something about the problems with the horizontal stabalizers on the NG v the Max

The stab skin cracking issue is already solved and is either being delivered on new 737NGs today, or will begin delivery on new aircraft shortly. It is not something which will need to wait for the MAX.

Quoting racko (Reply 21):
Are we talking a wart like on the A330F

No. The nose gear doghouse is being enlarged (lengthened forward) so the longer gear does not have to extend below the current skin lines. There may be some small blisters incorporated into the NLG doors to accommodate the required space around the tires for a flailing tread, but there will be no A330F-style "box" hanging below the fuselage.


User currently offlineneutronstar73 From United States of America, joined Mar 2011, 501 posts, RR: 0
Reply 24, posted (2 years 3 months 2 weeks 6 days 3 hours ago) and read 19580 times:

Aeroturbopower is comical in its bias. I swear, I've never read a single article on that "website" that was NOT biased in favor of Airbus or didn't make jabs at GE or CFM. That blog has a ridiculously high Airbus and Rolls Royce bias.

At least from my perspective.


25 Post contains images PlanesNTrains : Well, that knife cuts both ways, now doesn't it? -Dave
26 Post contains images lightsaber : I find the blog's bias amusing. Pratt did hold 4% TSFC in reserve. However, they are not there yet. They shouldn't be expected to be there now either.
27 Post contains links sirtoby : At least, I found that one, saying a lot of positive things abut the 787 vs. the A330. http://aeroturbopower.blogspot.com/2...amliner-ready-to-fly-an
28 Post contains images faro : Read the article people. If they have displayed a certain bias in some of their prior articles, does that mean that every single article will be bias
29 Post contains images travelavnut : Haha!! Pot, meet Kettle I hope this actually comes to fruition. I really have a soft spot for P&W
30 rheinwaldner : I have noticed the articles about this. But the published information seems not to be new. IIRC these things have been mentioned beforeby Boeing . Th
31 Daysleeper : This being the first blog I’ve read from this author I’ve no idea to his bias, but it’s certainly not the first time I’ve read about Pratt ho
32 RickNRoll : Look how the 787 turned out. The GENx was late and under performing, but the RR was doing better. Putting all your money on one square might pay off
33 Stitch : Daniel Tseng's sources at Boeing have stated that SUH is wrong and the real weight gain is much smaller. If lightsaber is correct, that 4% likely won
34 RickNRoll : The article is in Aviation News, which is subscription only. We are relying on the blogger making fair quotes from the article, which he has read and
35 PhxA340 : The 737NGs being built today are ~ 10% more efficient that the ones built in the 90s. You can always make changes if there are shortfalls during prod
36 Stitch : Both engines were late and the Rolls-Royce Trent 1000's initial SFC miss was said to be almost double that of the GEnx-1B. GE did have significantly
37 neutronstar73 : Please be gone. You add nothing to the thread, except a targeted name calling. Meanwhile: I think CFM knows the constraints they are up against. I'm
38 rheinwaldner : Sorry, Daniel Tseng does not nearly qualify to be in the same league as SUH. SUH knows what he knows because Boeing has told him so as potential cust
39 Roseflyer : I am now really confused. The basis for the article was that the GTF is expected to have 4% advantage over the LeapX on the A320NEO according to an e
40 Daysleeper : Why would it be 2020? Final versions of the GTF are expected to be flying next year so in a best case scenario it’s would be reaching its potential
41 mham001 : That's right, SUH would never hype some numbers (real or imagined) to gain some sort of a benefit for himself. Not his style. Nope. No way..
42 Revelation : I think you are about half right. A lot of the reading I'm doing these days on the topic is more about how the fact that the fan spins at its slower
43 Daysleeper : The performance advantage isn’t guaranteed, I understand this to be “Pratt’s comeback” after over promising and under delivering on previous
44 Post contains images astuteman : Not sure I get this. The GTF will EIS in 2013. So IF (and I stress if) there is 4% up Pratt's sleeve, it should be pretty much manifest by the EIS of
45 Stitch : Why would Boeing only tell SUH, a potential customer, that the plane is 4 tons over weight and not tell the actual customers the same? None of them,
46 Daysleeper : As I said, I don’t doubt that they will indeed develop PIPs I just believe that they won’t materialise until at least 2 or 3 years after the GTF
47 PlanesNTrains : Sure, but again, it seems to go both ways. Of course, that's true everywhere. When you listen to political commentary, they will throw someone under
48 Roseflyer : That is a logical statement, but another factor is that the 737 is a higher production rate airplane and has more money to fund research and developm
49 Daysleeper : That’s not what I said, my point was that they have more to gain by improving the 1C as there is a competitor, where as they are going to sell the
50 Roseflyer : I think PW is in a very good spot with the GTF in that it will begin operation and production at a much slower rate than the LeapX will. The GTF will
51 Post contains images Stitch : Well CFM does have competition for the 1B in the form of the PW1100G. That being said, yes, Pratt could have all of the "reserve" SFC in production b
52 Post contains links and images Hamlet69 : Personally, I have not heard it either. And like you, I'd keep it at the 'rumor' stage until we hear something more substantial. However, as I said,
53 JoeCanuck : CFM is under a ton of pressure to make sure they at least meet specs right out of the box...and, like Pratt, I would be surprised if they aren't holdi
54 astuteman : I have no issue with that. Some of those dismissing this blog out of hand though would be all over it like a rash if the bias were in the other direc
55 Post contains images EPA001 : Well, that is the "normal pattern" we usually see here on A-net. The "usual suspects" have again not let us down. Which was to be expected and is als
56 rheinwaldner : Why? A better SFC pays back from the first meter of the taxi run. I think lightsaber mentioned 4% as the difference between the initial, conservative
57 Revelation : Right, but we can't have our cake and eat it too. If Pratt isn't willing to sign up to the margin, certain bloggers shouldn't act as if it's a certai
58 Daysleeper : Then ignore the blog and its conclusions and discuss the POTENTIAL 4% advantage the GTF may have . Why? As has been discussed the likely course of ev
59 rheinwaldner : If the fan would be as big as the turbine, the optimum speed of both would be the same. As the fan grows, a different speed becomes desireable. The G
60 Post contains images Stitch : One of the "a.net truths" is that airlines base their purchasing decisions on an airframe's fuel burn. Of course, "a.net truths" are anything but, wh
61 PlaneAdmirer : If it's going to be a hypothetical discussion, why not make it a POTENTIAL 10% advantage or even 15% or for that matter 1-2%?
62 Post contains images lightsaber : I believe I should discuss more on the 4% Pratt is holding in reserve. This amount is above an beyond the normal improvement in technologies that we s
63 Hmelawyer : If the improvements come around a 2020 timeframe, then that just may be the impetus for Boeing to really kick the planning for NSA into high gear. Th
64 Daysleeper : Because I believe 4% to be accurate, further up the thread Lightsaber suggested that 1%-2% would perhaps be the figure upon EIS and a PIP a couple of
65 PlaneAdmirer : Actually, I am very hopeful for the GTF. After reading Lightsabers post, I double checked to make sure that I show him as a RR and he is.
66 Post contains images EPA001 : Wow. What an interesting post from you again Lightsaber. Many thanks for that. . Regarding your last line I was thinking, wouldn't Boeing be better o
67 Post contains images Stitch : I don't see Boeing going with a CFRP wing on the MAX when they can go NSA unless by the mid-2020s the overall technological base for an NSA remains un
68 Roseflyer : Do we have indications of this or speculation by one article and blog? My personal opinion is that the statement of selling engines for virtually fre
69 nomadd22 : Didn't Pratt plan the design around a 98% efficient gearbox and come in at 99%, meaning only half the planned heat dissipation?
70 Daysleeper : You have essentially given the main reason as to why the GTF is expected to better its performance guarantees. As you point out this is a very signif
71 Revelation : I think it's worse than that, no? Meaning the 10% is including profits from sales, parts, services, etc. Thus your previous programs had better be pr
72 Roseflyer : I have very different logic than you do. Your logic makes good business sense, but I think about it from an engineering point of view. PW has taken o
73 Post contains links SeJoWa : Roseflyer, if I remember correctly, it is in this interview that Alan Epstein of P&W tells how they ran a test engine and took it apart after so-a
74 Roseflyer : Thanks for the article. One day it will be good to see GTFs in widespread use. It isn't that different from CVTs in cars. A few tried for decades unt
75 JoeCanuck : What I really don't get is why it's so easy to assume that Pratt is holding back 4% from published specs but CFM isn't. As of right now, GE/CFM is spa
76 Post contains links and images lightsaber : You are correct. As I think about what I would do with a re-wing... It keeps coming back to new taller landing gear and that breaks too much commonal
77 Roseflyer : I believe average flight for the 737NG is between 800 and 900 miles and right at 2 hours.
78 strfyr51 : Boeing will NOT abandon the CFM Leap engine on the 737 MAX. I worked with the CFM-56 -2,-3B abd 3C where more than a few were on wing 30,000+ Hours.Yo
79 lightsaber : I do not think anyone implies that. There has been a rumor that Pratt might be allowed onto the 737MAX. However, I've heard nothing substantial to ma
80 Post contains links and images rheinwaldner : Beside any personal opinion I remembered that this topic has been discussed earlier. Around the time of the last Paris air show (when CFM had a rush
81 Daysleeper : Regardless of the exact reason, I haven’t seen anything posted which would cast doubt on Pratt having a 4% performance reserve. In fact, after read
82 Post contains links and images Revelation : Emphasis is mine: Thanks for pointing these things out. I will add that according to http://airinsight.com/2011/11/09/com...nes-gtf-vs-leap-maintenanc
83 Roseflyer : You bring up many of the points on how CFM wins competitions. Commercially they have the strong support network, spares inventory, more overhaul shop
84 FRNT787 : Exactly. With the Frontier deal, they were negotiating with Republic, a major GE customer. (The E-Jets are all GE powered, and many GE financed). Add
85 JoeCanuck : The CFM56 is an old tech engine by now. It doesn't take much imagination to realise that there have been significant developments in engine tech, (be
86 Post contains links and images lightsaber : Two faults of mine: 1. One less LPT row for the same efficiency. So Pratt's is shy a pair of stages. 2. But the LPC will be far more efficient due to
87 Post contains links JoeCanuck : Some are saying the LeapX will also have a 45:1 to 50:1 pressure ratio range; http://www.flightglobal.com/news/art...core-2-initial-performance-35808
88 Post contains images lightsaber : Then that will help match up the TSFC. Those extra stages will have weight though... Lightsaber
89 JoeCanuck : It's a damned interesting time, isn't it? It's a geeks paradise.
90 kanban : How does a 6 inch longer nose gear break too much commonality other than the cost of spares?... seems to me the ass end redesign and the different en
91 Post contains images lightsaber : I was referring to a new 737 with a replaced CFRP wing. By the time that new re-winged 737 is considered, new engines will also have to be developed
92 kanban : now I'm with you.. thanks for the clarification.
93 Post contains images Revelation : Count me in!
94 rheinwaldner : Correct. Otherwise CFM could not build an engine about as good as GTF V1. My point is that GE has to rely on the edge of technology in a lot of other
95 par13del : The answer to your question, they did not invent the technology and will not demolish their billion dollar enterprizes to the benefit of Pratt. After
96 tdscanuck : It's *hard*. Developing a gearbox that can handle that amount of power with commercial turbofan reliability at an acceptable weight with not excessiv
97 Post contains links Roseflyer : Simply put gearboxes are notorious for being problematic, heavy and unreliable. Here's an article about some of the details of engine technology whic
98 Post contains images lightsaber : However some technology doesn't provide as much benefit at the more optimum mach numbers of a GTF. For example, a fan blade change that might help th
99 Revelation : If these technolgies are so inevitable, what is preventing Pratt from having them right now? After all, CFM has them, right? And if my uncle had boob
100 JoeCanuck : That's not completely true...especially where the engine cores differ...mostly in LPT. Not all technology that works on one is a direct transfer to t
101 sphealey : How does it compare to the gearbox in the Soviet NK-12 turboprop as found on the Tu-95? sPh [noting for the record that there are several different n
102 strfyr51 : I'd doubt that unless the A320 NEO outsells the 737 MAX 5:1 with the GTF on it. and as of yet? That's not the case.
103 JoeCanuck : That's something I've wondered as well. Those huge tu-95 tprops abuse the heck out of their gearboxes.
104 tdscanuck : Directly converting between shaft horsepower and thrust is fraught with physics and philosophy problems but, rule of thumb, one pound of thrust is ab
105 lightsaber : One nitpick: More stages=more surface area (of the blades as well as casing). Due to the high speed flow of the core, surface area=drag. Thus, one ad
106 Aesma : I don't know if it's any indication but SAFRAN was making a big campaign in the Paris subway and papers a few weeks ago, looking for engineers for the
107 moo : Is gearing and those "other technologies" mutually exclusive, or will we end up seeing RR et al having to put in the work anyway in the next generati
108 parapente : Another way of looking at this is through the actions of Rolls Royce. They were betting on "OR".That will not now come to fruition.One also notes that
109 tdscanuck : None of them are mutually exclusive that I can think of (except maybe the supersonic compressor but I don't think anyone even considers that anymore)
110 imiakhtar : Are you sure of this? Airbus A320 family deliveries in 2011 - 421 Boeing B737 family deliveries in 2011 - 372 I don't work in the manufacturing indus
111 Stitch : Daysleeper was of the opinion that CFM would develop PiPs for the C919 before they would the 737 MAX because the C919 has more competition and therefo
112 cmf : A320 is split between two engines whereas 737 only has one.
113 tdscanuck : It depends on what you use for the denominator in "rate". Airbus makes A320's at three sites with multiple final assembly lines per site (there are t
114 dfwrevolution : How does that balance with leakage per stage? Typically fewer stages = greater pressure drop per stage = greater leakage flow. For industrial turbine
115 JoeCanuck : I'm just using huge generalities...nothing is ever free...but definitely a good point to bring up...drag is as relevent as anything else when conside
116 Roseflyer : Sorry for the confusion, but I was referring to the quantity of CFM56s built for the 737NG versus the quantity of CFM56s built for the A320. More CFM
117 Post contains images lightsaber : Every stage has tip leakage as well as other inefficiencies (e.g., the rotor is drag too...). So there is a trade. The greater the *pressure drop* (u
118 Post contains links Revelation : And now: The Boeing 737 MAX and the GTF (Posted on April 16, 2012 by leehamnet) * GTF on the MAX is the story that won't die * Boeing's Mike Bair says
119 Post contains images Stitch : And order is restored to the world. Oh who am I kidding.
120 Post contains images rheinwaldner : So the scenario that the GTF could end up on the MAX requires a 3%-5% shortfall of the Leap vs the GTF. Boeing's considerations and the relating nois
121 Post contains links Revelation : That's not what I think a neutral party would get out of that statement. A reporter asked if Boeing had the rights to use an engine other than CFM, a
122 sirtoby : ...at list prices. But nobody pays list prices!
123 rheinwaldner : There are other statements in the article, that support overall what I have written. E.g. this one: "We continue to hear that Boeing is seriously eva
124 Post contains links and images lightsaber : That is a HUGE barrier for Pratt/UTC to overcome. The commercial terms would include GEAC's ability to finance the complete airframe. That is an adva
125 Roseflyer : So you believe that Leahy may be decieving his own customers to take an inferior product? He's selling just as many LeapX engines as PW GTFs. I think
126 PlanesNTrains : Wow - you must REALLY want the GTF on the MAX to become reality! I mean, he'd throw his own customers' best interests under the bus just to make Boei
127 PHXA340 : I take that consideration as a consideration and nothing more. Boeing also considered a sonic cruiser, and full double decker 747 ... but alas none o
128 neutronstar73 : This statement makes no sense. All that says is "Boeing has set a certain parameter by which, if GE/CFM fail to meet this benchmark, will trigger a c
129 Stitch : If Boeing really felt LEAP-X was going to flop, you'd think they could have made a stronger case to airlines to wait until NSA. Heck, the airlines the
130 Post contains links redrooster3 : On Flightglobal, there's an article on the MAX having a chance of getting raked wingtips like the P-8 and the 77W. They're testing it in the wind tunn
131 PHXA340 : I thought this was debunked because the raked wingtips wouldn't fit in most of the gate spaces of current operators.
132 Post contains links Revelation : Yes, it is understood that press releases cite list prices. The point I was making is that LEAP already has $billions of commitments on 737-MAX which
133 Post contains links and images redrooster3 : I never heard that? I know the 737NG's wingspan is wider than the A320 by 6 feet. After looking at previous posts from What About A 739ER With The Wi
134 Post contains images lightsaber : Boeing is being aggressive with several aerodynamic tweaks on the MAX. The new tail cone, I've heard discussion of other aerodynamic fairings too. Bo
135 Revelation : I'm a huge GTF fan too. Indeed. That was my point about putting up some of the sales numbers: it is already selling, and I'm sure it will continue to
136 Post contains images EPA001 : Big fans deserve big fans here. I am also very enthusiastic about the GTF-concept. I hope Pratt can really make it work. .
137 lightsaber : I agree with your other points. These two I'd like to discuss. The cost to integrate and qualify a second engine is hundreds of millions. That will b
138 Roseflyer : While it makes sense with narrowbody production rates to have multiple engine choices, if you look at history, the A320 was the first narrowbody to b
139 Post contains links redrooster3 : I was leaning more towards overall. I think the NG/A320 are very similar in overall costs for airlines. Its either 1000 MoU's/Firms, or 1000 MoU's +
140 Post contains links Hamlet69 : As Boeing "looks at their options" so-to-speak, I wonder how closely they'll look at APB's Next-Generation winglet: http://www.flightglobal.com/blogs
141 lightsaber : Winglets. They have several options. However, IIRC, the spiroid are more optimal at slightly lower Mach numbers than the 737s cruise speed. Since the
142 rheinwaldner : I agree. Sadly the GTF on the MAX in reality seems not to have much chances (despite all the talk). You know as well as I, that the terms under which
143 Post contains links Revelation : Sure, why not? Wiki writes the following: Ref: http://en.wikipedia.org/wiki/Rolls-Royce_Trent So RR had developed the T8104 to try to get on the 777-
144 Stitch : I've been hearing that Pratt has been holding back SFC for a good bit longer than mid-2011, when the 737 MAX was announced.
145 Roseflyer : So are you saying that because the customer picks the engines themselves, it is ok for Leahy to say misleading statements when comparing the two? If
146 Hamlet69 : Sorry, I should have been more specific. The spiroid's APB have been testing are not an option, IMO. They are a long way, if ever, of seeing commerci
147 Post contains images lightsaber : Mislead? Perhaps Leary (let's face it, this isn't Airbus as a who, we can pick a name) is extrapolating from good flight test data of the PW1500G? Af
148 Roseflyer : That is momentum to promote the GTF and not claim its efficiency is less than what they expect it to be which is what I think Rheinwaldner is claimin
Top Of Page
Forum Index

This topic is archived and can not be replied to any more.

Printer friendly format

Similar topics:More similar topics...
About The Guy Sucked Into The Engine. posted Wed Sep 5 2001 10:27:04 by Thom@s
Question About Thomson And The 787 posted Fri Jan 13 2012 14:18:27 by LGWflyer
Question About TAM And The Star Alliance posted Wed Apr 28 2010 16:27:45 by AirCanadaA330
What About A 739ER With The Wings Of The P-8? posted Tue Apr 6 2010 11:28:38 by EA772LR
Questions About DL And The 77L posted Wed Aug 5 2009 10:43:32 by EA772LR
Question About Iberia And The A-330 posted Sun Jun 21 2009 19:15:00 by Plairbus
So What Caused The Hole In The Engine? posted Wed Mar 25 2009 14:05:20 by Toering
Question About The Performance Of NYC Shuttles posted Wed Jul 16 2008 13:44:10 by B752OS
CRJ-200 Attrition Rate Is About 50% Among The U.S. posted Mon Oct 29 2007 11:28:48 by AirbusCanada
Question About The Future Of Avianca... posted Sun Sep 9 2007 15:21:46 by Adicool
Bring Back The Peter Max 777. posted Fri Nov 4 2011 22:21:11 by fxramper
Question About TAM And The Star Alliance posted Wed Apr 28 2010 16:27:45 by AirCanadaA330
What About A 739ER With The Wings Of The P-8? posted Tue Apr 6 2010 11:28:38 by EA772LR
Questions About DL And The 77L posted Wed Aug 5 2009 10:43:32 by EA772LR
Question About Iberia And The A-330 posted Sun Jun 21 2009 19:15:00 by Plairbus
So What Caused The Hole In The Engine? posted Wed Mar 25 2009 14:05:20 by Toering
Bring Back The Peter Max 777. posted Fri Nov 4 2011 22:21:11 by fxramper
Question About TAM And The Star Alliance posted Wed Apr 28 2010 16:27:45 by AirCanadaA330
What About A 739ER With The Wings Of The P-8? posted Tue Apr 6 2010 11:28:38 by EA772LR
Questions About DL And The 77L posted Wed Aug 5 2009 10:43:32 by EA772LR
Question About Iberia And The A-330 posted Sun Jun 21 2009 19:15:00 by Plairbus
So What Caused The Hole In The Engine? posted Wed Mar 25 2009 14:05:20 by Toering