Pratt & Whitney Les nouveaux GTF "Purepower"

Pratt's geared turbofan may be bright spot in difficult year

Pratt's geared turbofan may be bright spot in difficult year
Monday March 30, 2009 Pratt & Whitney executives said last week that interest in the PurePower PW1000G geared turbofan engine has increased since Lufthansa's recent commitment to Bombardier's CSeries and that additional orders may boost a company whose parent, United Technologies, has launched a major restructuring featuring up to 11,600 job cuts this year.

"Orders beget orders. We expect this to stimulate more order action for the CSeries," Pratt & Whitney President David Hess said last week at the company's Hartford headquarters. "There is a lot of discussion going on, a lot of orders out there that could potentially be announced this year. . .Getting a launch order from Lufthansa could really help get traction in the marketplace."

LH signed a letter of intent for 30 CSeries aircraft plus 30 options at last year's Farnborough Air Show but did not firm the order until this month (ATWOnline, March 12). The apparent delay produced speculation about the program's viability, although Pratt's GTF already had been selected by Mitsubishi for its new regional jet and launch customer ANA. Both aircraft are scheduled to enter service in 2013.

'We were highly confident because we felt we understood the process Lufthansa was going to go through to complete their selection," P&W President-Commercial Engines and Global Services Todd Kallman told ATWOnline. "I do feel very positive that there will be other orders. There are ongoing discussions and actually at [this month's ISTAT annual conference in Arizona] a couple people talked to us and said, 'Hey, this is good. We're going to continue to look at this thing'."

Kallman and VP-Next Generation Product Family Bob Saia also stressed that Pratt is on schedule with design and testing of the PW1000G's new core, which "will have 100% new parts." The fan drive gear system that anchors the engine has been tested on the core of a PW6000, which powers the A318 (ATWOnline, Feb. 4), although other new parts, such as the PW1000G's combustor, have been included. "We're doing pre-product demonstrations to a level we've never done before," Saia told this website.

The final design will include 60% fewer turbine airfoils thanks to efficiencies derived from decoupling the fan from the turbine. "Even though you add 200 lb. with the gear, you basically save over 300 lb. from a nongeared engine size," Saia said (ATW, February 2008).

Both Kallman and Hess said Pratt hopes to participate in any re-engineering or replacement of the A320 and 737 but that for the time being the focus is on bringing the CSeries and MRJ to market. The positive momentum generated by LH's commitment only can help a company hit hard by the global economic downturn. Hess said engine deliveries will be "flat to actually down" this year and possibly next. P&W Canada already had announced up to 1,000 layoffs, while Hess told Reuters that Pratt and Hamilton Sundstrand plan to cut some 1,500 additional jobs this year.

Pratt & Whitney's Geared Turbofan is taking off.
By Perry Flint
East Hartford, Conn.
Air Transport World, February 2008, p.71

WITH A DEMONSTRATOR ENGINE IN ground tests and its recent selection on two new aircraft programs, Pratt & Whitney's Geared Turbofan is flying high. Last October, Mitsubishi Heavy Industries announced that the engine would be the sole powerplant on the proposed 70/90-seat Mitsubishi Regional Jet. That was followed a month later by the news that Bombardier likewise had selected it as the exclusive engine for its CSeries family of aircraft in the 110/130-seat class, pending final approvals from both boards. Although neither aircraft has been launched formally, MHI has authority to offer with a go decision expected in the first half. A decision on the CSeries also could come this year. Both airframe manufacturers are targeting a 2013 entry into service.

Commenting on the selections, Senior VP-Sales and Marketing-Large Commercial Engines Robert Keady says, "I've been with Pratt & Whitney for 29 years. I think this is the most exciting year I've seen in terms of upside potential." The wins appear to validate Pratt's strategy of investing heavily in its GTF demonstrator technology program ahead of a product selection and potentially 3-4 years before either Airbus or Boeing is ready to move forward on a next-generation narrowbody.

VP-Next Generation Product Family Robert Saia characterizes selections on the CSeries and MRJ as "very important: That was my number one assignment."

In December, Pratt announced that the GTF demonstrator successfully completed its first series of engine runs, reaching full power 30,000 lb. thrust at its test facility in West Palm Beach, Fla. As of early January the demonstrator, which is using a PW6000 core, had achieved more than 50 hr. of tests, primarily focused on "understanding the structural characteristics of the engine, looking at things like thermal systems oil systems, fuel, air temperatures [and] structural integrity," Saia tells ATW. The second series of tests, which began last month, focused on performance and noise. Perhaps as early as the end of February, the engine will be placed in its Goodrich-developed nacelle "and then what we'll do is a series of testing with that flight architecture to validate the total propulsion system for our readiness for the [flight] tests," which should begin in mid-year on Pratt's 747 flying testbed, Saia says.

Originally, Pratt focused its attention on the 20-30,000 lb. thrust class for the 737/A320 successor. Strong interest from the regional sector, however, caused it to expand downward and it now describes a family of engines in the 15-30,000 lb. thrust range. This in turn has caused it to decide on a two-core approach. The engine for the MRJ is built around a core in the 15-17,000 lb. thrust class. The second core, which was marketed to Bombardier, "has the ability to get to 27-28,000 lb. thrust class." Saia believes this core also will be well suited for the new aircraft from Boeing and Airbus. He says, "We can go above 30,000 lb. [thrust]. But where we see the requirements today, with all the focus on lightweight materials . . . to save fuel, we think the high end of this market will be about 30,000."


Big Gains

The company has set aggressive performance targets for the baseline GTF, including a 12% improvement in fuel burn (and equivalent cut in carbon dioxide emissions) and a 40% reduction in maintenance costs compared to the V2500 and CFM56-5B/7B engines in service today, with a 55% reduction in NOx emissions relative to CAEP6 and a cumulative 20 dB decrease in noise levels from Stage 4. The dramatic cut in NOx emissions comes from the rich-quench-lean TALON (Technology for Advanced Low NOx) combustor. The newest version, TALON X, is being developed in partnership with NASA for the GTF.

Central to most of the other improvements is the gear system that enables the fan to operate independently of and at a slower, more optimum speed than the low-pressure compressor and turbine. "The fan will turn at about one-third the speed of the LPT, whereas in a conventional engine the fan turns at the same speed," Saia notes. In the case of the GTF, the LPT will operate at 8,500-9,000 RPM with the fan running at approximately 2,800-3,000 RPM. This results in substantially greater efficiency and less noise at the front, while the LPC and LPT can be run at much higher speeds, likewise maximizing their efficiency. Because it is running slower, the fan and the bypass ratio can be significantly larger and the characteristic flow disruption at the tip of the blade is minimized. "The slower you can make the blade, the less loss of the actual airfoil," he explains.

Noise reduction is "a key element." Saia suggests the quietness of the GTF could result in noteworthy operational savings arising from the ability to use preferred runways and more optimum flightpaths. On a 500-nm. mission, 3 min. saved avoiding a noise abatement track results in a 3.5% fuel burn saving, he says, while the ability to use a more preferential runway can reduce fuel burn 0.4% for every minute saved.

Historically, the drawbacks to using a gearbox in a jet engine have been reliability and added weight. Pratt says neither is an issue today. Saia claims that the company's gear system adds less than 1% in weight while permitting the powerplant to be 10% lighter than today's engines. The availability of lighter materials certainly plays a role, but the savings is largely because the core can be run at its optimum speed, resulting in far more efficiency. This means fewer stages and airfoils, driving down maintenance costs as well. Today's narrowbody engines have around 3,500 LPT and LPC airfoils while the GTF will have 2,000.

Lowering the fan speed also saves weight. Saia explains: "When you slow the blade down, the impact damage of a bird or of a fan blade release is a lot less because you don't have all that velocity impact on the airfoil or on the containment case . . . We can get a lot of weight out of the fan structure just because of the lower velocity of the blade."

As for reliability, officials note that Pratt has spent more than a decade developing geared technology. "We flew our geared PropFan in 1988-89 [in cooperation with Allison] and we did a PW2000 demonstrator in 1992-93 and then we did a Pratt Canada ATFI [Advanced Turbofan Engine] in 2001-02," Saia recalls. The GTF demonstrator project got underway in 2004, which means the engine-maker will have nine years of experience before it enters service.


Fewer Fan Blades

The engine will have 18 wide-chord swept blades compared to 22 on Pratt's PW4084 for the 777 and 38 on its earlier 747-400 engine. The blades in the demonstrator are solid titanium but the company is looking at three options for production engines: Hollow titanium, a lighter hollow metallic material and a composite similar to that used in large propellers. It is working with sister company Hamilton Sundstrand on the last.

"They've been doing a lot of research and development on very large wide-chord [composite] propellers. They are responsible for the propeller on the A400M [military transport]. They've also been doing work with high-speed architecture," Saia points out. Pratt's plan is to use the lightweight metallic material for the MRJ and CSeries applications. He speculates that "it might be that we would use a lightweight metal in some thrust classes and the composite lay-up for a different thrust class," while cautioning that the company is still very much in the development stage.


Positive Response

Keady says that "very broadly and very uniformly, customer response to the GTF has been really positive . . . Since we launched first on the MRJ and subsequently with Bombardier, we have visited 50 customers. What we find is that once we've had a chance to go through technical briefings with airlines, any discussion of a barrier on the fan drive gear system quickly moves away, [with] broad acceptance that the value proposition that the engine brings is so compelling and positive." He also notes that "we've got 340 million hours of gearbox time at Pratt & Whitney."

Tests on the GTF are going well. Saia says: "We're really pleased with the rig testing we've done on the fan, the fan drive gear, the low compressor, high compressor and now at the engine level. We are well within our prediction range with results coming in within 1%-2% of what we had hoped to see. In most cases, we're actually better than what we predicted."

This engine for the CSeries will have a bypass ratio of 12 compared to 5-6 for today's narrowbody engines and 9-10 for those that power the 777 and A380. For the lower-thrust MRJ application, the BPR will be around 8, versus 5 to 5.5 or current RJ engines.

By the time a 737/A320 replacement enters service, Pratt expects to have gotten the BPR up above 20. "That's our focus," Saia states. "We laid a technology plan that goes all the way out to 2020. We are going to continue to invest in and develop capability, and this higher bypass ratio architecture will be available to Airbus and Boeing." The goal is to achieve a 1% improvement in fuel burn each year from 2013. "If we go from a [bypass ratio of] 5 to a 10 we get a 4%-5% increase; you go from a 12 to a 16 to a 20 you get another 5%-6% in reduced fuel consumption."

The company is not going it alone on the demonstrator program. In addition to Goodrich on the nacelle, MTU is the partner on the HPC and LPT, Volvo Aero is participating on the engine structure and large cases and Avio is working on the fan drive gear system. MTU recently agreed to be a 15% partner on the engines for the MRJ and CSeries, providing a combination of HPC and LPT content. Pratt is working to develop partnership agreements on these engines with the other companies as well.

Although it has placed the GTF on two smaller models, the company continues to believe that the International Aero Engines consortium in which it holds 32.5% is, in Keady's words, "the preferred route to market for the narrowbody replacement." Officials here will not speculate on what would happen if IAE's other leading shareholder, Rolls-Royce, declines to support the engine for the successor to the 737/A320 families.

For now, however, Pratt is focused on the near-term applications that could leave the blackboard this year. Saia says, "From my personal perspective, the best way to get an engineer focused on optimizing a configuration is to have a product commitment. Having secured the MRJ and the CSeries, it allows us to take all this technology we've been developing, apply it to a product, optimize that product for value for those initial applications and then build that plan for whatever the following application will be." Keady sums up: "We've been selected by MHI and we've been selected by Bombardier. Now we need to go sell them."

Admin a écrit: Bonjour à tous

Le champion du monde de l'intellectualisation profite de ce moment de calme sur le forum pour sévir

Quelle est la différence entre :

1) un réducteur sur un TP400 ou un NK12 qui passent tous les deux 100% de la puissance à l'hélise soit 10-15000 cv
2) un réducteur (MTB) d'hélico, qui passe 3*4380 cv dans un Super Stallion ou 2*11000 cv dans un mil-26
3) un réducteur de GTF qui passe une fraction (>75 %) de la puissance du moteur ? Soit quelle puissance en cv?

Admin a écrit: En quoi finalement est-ce si difficile à fiabiliser et à alléger un réducteur ?

Admin a écrit: Comment peut-on relier besoin de circulation de fuel en refroidissement à une surconsommation ? Cela revient t'il à dire qu'il est nécessaire pour ne pas surchauffer le fioul d'en consommer en excès ?

On arrête là, pour le moment ! Le post ci-dessus est déjà trop lourd !

Admin a écrit:
Les RB282 et 285 sont ils commercialisés ?

Admin a écrit: Quid du LeapX ?

Admin a écrit: Maintenant, il est fort possible que le GTF arrive trop tôt est qu'il ne réalise que 50% de l'amélioration attendue par les moteurs saut de génération...

Une partie du succès du GTF ne reste t'il pas lié aux prix du pétrole... s'il reste bas... et si c'est effectivement un moteur 1/2 génération d'avance... il risque de souffrir...

-- cela se traduit par la fracture très tôt, et sans préavis, ......et en général, il y aurait des pièces qui se "fracassent" ;

Admin a écrit: Merci cher Sevrien...

Quelques éléments au passage péchés lors de mes lectures pour me renseigner sur le MD-11

flight Int'l 20-26 juin 1990 : "ADP Planetary gear goes to prototype"

Advances Ducted Pro : gamme de poussée 53 000 lbsf, puissance transmise au réducteur : 40 000 cv...*

Admin a écrit:Autre référence : http://findarticles.com/p/articles/mi_6712/is_n34_v177/ai_n28618295

PW1000G -> classe 15-30 000 lbf ...une règle de trois donne une gamme de puissance à transmettre par le réducteur de 11 000 à 22 000 cv...
Et je dis donc que c'est une gamme connue au moins pour quelques hélicoptères ... et explorée depuis longtemps avec le NK12...

Voilà donc pour les fun facts et la réverie...

Admin a écrit: Tout à fait d'accord pour dire que ce n'est pas forcément simple de réaliser un réducteur, mais le réducteur est né avec la turbine... le jour où on a remplacé les "reciprocating engines"...
Il me semble donc qu'à ce stade, intellectualiser permet aussi de remettre en perspective les enjeux et jauger les sauts technologiques prévoir....

Admin a écrit: Et pour moi c'est simple, mais c'est ,

Admin a écrit: le GTF explore une gamme de puissance dans les réducteur qui est connnue... et donc avec un risque limité ... ce qui permet de se focaliser sur l'optimisation de la pièce.
Me dire si je me trompe !

Admin a écrit: Pour le reste, la limitation aux courts et moyens courrier découle certainement de ce que déroule ci-avant... à moins que derrière cette question il y ait des sources bien cachées

-- cela se traduit par la fracture très tôt, et sans préavis, ......et en général, il y aurait des pièces qui se "fracassent" ;

Admin a écrit: Cela traduit bien, me semble t'il, les rupture sur les TGB des GE90-115...

art_way a écrit:Article très intéressant...et/ou effet Bourget ?

P&W sees GTF architecture as viable for nextgen widebodies.

P&W, dans une décision de bon sens, pragmatique et réaliste.
The manufacturer's PW1000G has already been selected by Bombardier to power the 110/130-seat CSeries and by Mitsubishi to power the Mitsubishi Regional Jet (MRJ). The
CSeries will be powered with the 20,000lb-24,000lb thrust class
PW1000G, designated the PW1500G, while the MRJ will be powered with the
PW1200G, which offers thrust between 13,000lb and 17,000lb.P&W's
initial product definition for its geared engine architecture
represents a technology level that is targeted to a 2013
entry-into-service for both the CSeries and MRJ.

Cessna suspend le développement du Columbus !
Le moment du lancement n’est pas venu. Cessna a suspendu le programme Citation Columbus le 29 avril, en raison des difficultés que rencontre le constructeur américain avec la crise économique. Il souhaite ainsi se focaliser sur les produits déjà existants et qui ont fait leurs preuves.

Le Columbus n’est cependant pas complètement abandonné. Il est en effet prévu que son développement reprenne dès que les conditions du marché s’améliorent.

A suivre, dans un post ci-dessous !

Pratt & Whitney (P&W) has not found any thrust limitations
to its geared turbofan engine architecture, and believes its design is
capable of powering the next generation of widebody aircraft, including
Boeing's replacement for the 777 if such an aircraft is pursued.

However, late last year the company launched its second phase of technology
development, which is really targeted for aircraft that will enterservice in the 2015-2020 time period. "Our objective, our goalis to improve fuel consumption in the order of 1% to 1.5% per year foreach year of time. So if we were to go from 2013 to 2018, we have set atarget to have fuel reduction in 8%-10% step change or improvementregime," P&W vice-president next generation product family Bob Saiatold consultancy Innovation Analysis Group (IAG) in an exclusive interview that aired on 6 May.

With regard to power, there are "some basic fundamental elements associated with higher thrust that we're developing for a 30,000lb thrust class or even a 35,000lb thrust class so as Boeing and Airbus look at their next generation products and as they define requirements, which we know will drive higher thrust, we will be able to add
incremental benefit for our geared architecture at that higher thrust".

However, P&W has "tested up to 40,000lb of thrust, and we've run the test up
to that level to ensure that we cleared any thrust requirement for this next generation of aircraft that will operate up to about 250 passengers", says Saia.

A 40,000lb thrust engine is capable of powering an aircraft like the Boeing 757, which requires 37,000lb to 38,000lb of thrust, notes Saia. "So we have covered that type of thrust requirement."

To date, however, P&W has not found any thrust limitations "that would
prevent us from using this geared architecture to even a twin-engined,
long-range aircraft like a Boeing 777 or an Airbus A350".

P&W is not targeting the A350. And the reason for that, says Saia, is that
"if you wanted to really optimize the gear, you'd really like to start
with a brand new paper airplane at the same time so then you have the
ability to optimize both the aircraft, the structure, the positioning
of the engine, and the engine design all in that design phase".

If, for example, a replacement aircraft was being designed for today's Boeing 777 "then certainly we believe a geared architecture would be a very viable offering for that kind of airplane", says Saia.

P&W does not rule out installing a geared engine on existing aircraft if the aircraft is expected to be in production for another five to ten years. But Saia points out that the business economics don't fully support re-engining aged aircraft versus a re-fresh of a production variant because re-engining involves adding a new nacelle and a new
pylon, in addition to a new engine.

He adds: "We believe that as we evolve and get more testing under these early programmes that we've launched that we will have the ability of installing a geared
architecture in a next generation widebody aircraft that would happen post-2018, 2020 so it would not be any of the aircraft certainly either being designed or in service today."
http://www.flightglobal.com/articles/2009/05/20/326754/pw-sees-gtf-architecture-as-viable-for-nextgen-widebodies.html

Jeannot a écrit: Mais sur ce sujet je me pose deux questions :
.. a-t-on les résultats des essais faits sur le 340. Je me demande si cette absence de données ne cache pas quelque chose que'aucuns veuillent effacer derrière de la communication.

--P&W does not rule out installing a geared engine on existing aircraft if the aircraft is expected to be in production for another five to ten years. But Saia points out that the business economics don't fully support re-engining aged aircraft versus a re-fresh of a production variant because re-engining involves adding a new nacelle and a new pylon, in addition to a new engine.

Jeannot a écrit: .. est-il facile de monter en puissance par une simple homotéte des solutions? PW va rencontrer des contraintes de charge. Non ?