Pratt & Whitney Les nouveaux GTF "Purepower"

Pratt & Whitney’s (P&W’s) first production geared turbofan engine, the PW1500G for Bombardier’s CSeries aircraft, has passed a crucial blade-out test, keeping the program on track for certification in the fourth quarter.

The milestone test comes as P&W nears completion of the first shipset of engines for Bombardier’s initial CS100 flight test aircraft at Mirabel, near Montreal. “They will be delivered to Bombardier shortly,” says P&W VP-Development Programs President Bob Saia, adding that the engine program is 90% through the certification process. First flight is expected late this year or early 2013.

The blade-out evaluation, which took place in late August, was one of the two “nail-biter” tests on the road to regulatory approval, says Saia. Two more full engines will undergo endurance runs, “and one of those at the end of 150 hours will do the triple ‘red-line’ test, which is the other nail-biter.”

In the test, one of the PW1500G’s 18 blades was deliberately detached at full power by detonating an explosive charge at its root. The test is designed to show the engine is capable of containing damage without catching fire and without failure of its mounting attachments when operated for at least 15 sec., unless the resulting damage induces a self-shutdown. “It has the highest risk because it has the highest level of unknowns, but the following blade [to the detached blade] was fully intact,” says Saia.

Although “we suffered minor damage to some of the other blades,” the remainder of the engine is in “such good condition we will use it for lightning tests.” Saia also was P&W’s VP for the Engine Alliance and oversaw certification of the GP7200 for the Airbus A380. He says that after the same test on the GP7200, which it passed, the fan rotor seized after 15 sec. and the high-pressure rotor after 3 sec. “After the PW1500G blade-off, in contrast, the engine could still be turned or ‘motored.’ I’ve never seen that done before,” he notes.

The triple red-line evaluation, which is expected to run through early October, will see another engine run for about 60 hr. at maximum fan speed, core speed and exhaust gas temperature to demonstrate its capability beyond the most extreme operating conditions. Another endurance engine, running at about the same time, will be used to verify the initial maintenance interval.

A PW1500G also is in the third and final flight-test phase on one of P&W’s Boeing 747SP flying testbeds. The program, which P&W admits began about a month later than scheduled, incorporated the latest software changes from Bombardier. It is the first to validate a fully compliant variable area nozzle and thrust reverser. Tests will “confirm the software logic and validate that for Bombardier’s flight readiness,” says Saia, who expects the flights to conclude by the end of September.

Although acknowledging “there are some sleepless nights here,” Saia says problems encountered have been “the normal optimization you’d hope to do in a situation like this.” Despite some early issues with inadequate tip clearances and endurance of some parts, all of which he says are now corrected, Saia eplains “. . . we are tickled pink with the performance. We will hit our contractual obligations on fuel burn, weight, noise and emissions on the first Bombardier engine to enter service.”

Saia says that while fuel burn on the first flight-test engine shipsets “will be under [guarantees] by 1%,” he adds planned improvements for the PW1500Gs on the fourth aircraft will bring it up to specification. The company, which base-lined a 15% fuel burn improvement for the larger CS300 variant over the CFM56- and V2500-powered Airbus A319, expects to regain some performance through efficiency improvements now under test on the sixth development engine. In addition, the engine is “better than spec” for weight after the fan blade-out tests showed the planned structural margin was not required.

THE FIRST TRULY SCALABLE CORE

Perhaps the most interesting innovation for this new core is scalability. Scalability of the new core enables Pratt & Whitney to offer a variety of thrust ranges for various applications, which currently include the 70-90 seat Mitsubishi Regional Jet, the 110-130 seat Bombardier CSeries, the 130-180 seat Airbus A320 neo family and the 150-212 seat Irkut MS-21 family, without a redesign, by simply rescaling of specifications using today’s computer generated design tools. Pratt & Whitney could easily scale the PW1000G series to more than 100,000 lbs of thrust for narrow and wide body applications with minor modifications to the existing designs. An aircraft manufacturer can specify a thrust level, and PW can quickly develop an engine optimized to that performance for each application, scaled from the basic design, and mated to an appropriate fan size.

Cooling Technology: The PW1000G will run at higher temperatures than today’s engines and will require advanced cooling technologies. There will be an increase in the use of specialized coatings in this engine, much of which has already been proven in the V2500 Select engine. In addition, PWs proprietary cooling technology is such that it requires less cooling air, and therefore no penalty in terms of cycle efficiency, without the need for exotic materials such as ceramics. While the PW1000G is expected to run hotter than today’s engines, it should be lower in temperature than a comparable performing direct-drive engine, enabling it to utilize existing coated metal rather than more exotic, and more expensive, ceramic materials.

Pratt began its march back into the single-aisle mainstream at 11
p.m. on Nov. 28, when the first PW1100G NEO engine fired into life on
the company's West Palm Beach, Fla., test stand. “The first time we put
power to the igniter it lit,” says the engine maker's Next-Generation
product family Vice President Bob Saia. Since then, the engine has been
taken through a 'break-in' cycle from idle to full thrust, ensuring the
mechanical integrity at various power levels before clearing the PW1100G
for the remainder of the forthcoming test effort.
Although it is
too soon to know whether the engine is on track to meet critical
fuel-burn targets, the overall performance from a temperature and speed
perspective “is right on pre-test predictions,” says Saia. “We haven't
yet got a true calibration in terms of fuel efficiency,” he adds.
Mechanically, the engine has completed the break-in cycle testing with
“no anomalies. We're really pleased with what we got.”
The
initial work allows Pratt to make some design tweaks to optimize the
engine at the early stages if needed. It also incorporates lessons
learned from the two forerunner geared turbofan (GTF) developments, the
PW1500G for Bombardier's CSeries airliner and the PW1200G for the
Mitsubishi Regional Jet (MRJ). “On the PW1500G, for example, we had an
unexpected rub in the last stage of the low-pressure compressor. This
wasn't due to the way we broke in the engine, but because of the way it
was designed,” says Saia, who adds that a quick change corrected this
“subtlety.” Similarly, the initial runs also indicated that designers
had allowed too much clearance in the PW1500G high-pressure compressor,
which had to be tightened.
Testing now is focused on measuring
the effectiveness of the engine's secondary flow system to adequately
cool and seal the turbine, and other hotter running stages, as well as
the various cavities. “So this first engine is involved in a lot of
first-of-model testing, and evaluations of the fundamental architecture.
So if we uncover anything, we will have time to adapt the design,” Saia
says.
The second and third engines are in assembly with the
second expected to start tests around mid-February. This will be used
for operability and performance trials, as well as fan work that will
include crosswind testing to check the ability of the inlet and
compressor to handle various simulated angles of attack. For
“fan-mapping” tests, the engine will be fitted with flapper valves to
form a rudimentary variable area fan nozzle to alter the pressure ratio.
“We also want to characterize the structural element of the fan for
operability as well as for stress or flutter,” Saia adds. The same
engine will be flown in the second quarter of 2013 on Pratt's Boeing
747SP flying testbed with a production-representative variable nozzle.
The
third and fourth test engines will be heavily instrumented
“stress-test” units aimed at gathering strain-gauge measurements of the
high- and low-pressure spools, respectively. The sheer amount of
internal wiring required for these measurements means the stress-test
engines enter the build cycle much earlier, says Saia. Here again, Pratt
hopes to take advantage of work already performed on the PW1500G. “We
have completed all of the certification testing on things like aerofoil
stress (on PW1500G), so before the PW1100G starts testing we've already
got the fundamentals of it characterized. There may be differences in
the lengths of the blades and such, but it takes a lot of risk out of
the early engines. That is not to say we still may not break a motor now
and then.”

Beochien a écrit:
Les Nacelles seront sous traitées à Short , c'est intéressant, mais depuis UTC a racheté Goodrich ... on peut penser que c'était prévu comme une faveur à Bombardier !

With its landmark selection by Embraer to power the second-generation E-Jet, Pratt & Whitney has nearly eliminated General Electric's once dominant position as a propulsion supplier in the large regional jet segment.
P&W will supply the PW1700G geared turbofan
for the 76-seat E-175 and the PW1900G for the 90-120 seat E-190/E-195
family, with deliveries starting in late 2015, says Bob Saia, P&W
vice president for the next-generation production family.
"We're very pleased - ecstatic," Saia says.
P&W's
emotional response is not surprising. Prior to Embraer's selection, the
geared turbofan had been selected by three new platforms and the Airbus A320neo, which is based on a platform that also uses a partially P&W-sourced engine.
But the geared turbofan had never before won a contract facing GE or its CFM International joint venture with Snecma as an incumbent supplier. Most notably, Boeing rejected P&W's attempts to even compete with the CFM Leap-1B for the 737 Max.
Now,
the geared turbofan unseats GE as the incumbent supplier for the
second-generation E-Jet, defeating a bid by GE for the eCore-derived
NG34 powerplant.
Until Embraer's decision, GE had achieved a
near-monopoly in the 70-120-seat engine market, having supplied the
military-derived CF34 turbofan for the first-generation E-Jet, Bombardier CRJ700/900/1000 and the Comac ARJ21.
The only platforms to escape GE's grasp in the sector was the PowerJet SaM146-equipped Superjet by Sukhoi and the developmental Mitsubishi Regional Jet, which is powered by a geared turbofan variant called the PW1200G.
"Pratt's
PurePower looks extremely promising, and has generated a very positive
market response," says Richard Aboulafia, an aerospace consultant with
the Teal Group. "As the MRJ powerplant, PurePower has clearly created a
threat to Embraer, in much the same way that the PurePower/CSeries
combination created a threat to Airbus. Airbus, of course, reacted by co-opting new engines. Embraer must do the same."
P&W will adapt the PW1700G from the MRJ's PW1200G and the PW1900G from the Bombardier CSeries' PW1500G, Saia says.
The
PW1700G will feature the same 142cm (56in)-diameter fan of the MRJ
engine, and the PW1900G will share the 185cm-diameter fan with the
CSeries engine.

"We have completed all the certification testing—endurance and ice
testing. We are moving forward with the paperwork for CSeries
technology," Chief Executive Louis Chenevert
said in an interview. He said testing was completed over the weekend
and that the company expects certification of the engine by regulators
in about two weeks.

Bombardier Aéronautique et Pratt & Whitney ont annoncé
aujourd’hui que Pratt & Whitney avait obtenu avec succès
l’homologation de Transport Canada pour son premier moteur PurePower
Geared Turbofan^mc – le moteur PW1500G qui propulsera les avions CSeries
de Bombardier. Pratt & Whitney a mené plus de 4 000 heures d’essais
de moteur rigoureux depuis le début des essais du moteur initial, en
septembre 2010. Le programme d’essais du moteur PW1500G comprenait
340 heures d’essais en vol à bord du banc d’essai volant 747 de Pratt
& Whitney. Pratt & Whitney est une division de United
Technologies Corp. (NYSE: UTX).
« L’homologation du moteur
PW1500G est une étape importante et cruciale dans le soutien de la
transition graduelle du premier véhicule d’essais en vol CSeries au programme d’essais en vol », a déclaré Rob Dewar, vice-président et directeur général, CSeries,
Bombardier Avions commerciaux. « Nous sommes très heureux des
performances du moteur et de la progression générale constante du
programme d’avions CSeries. Nous avons franchi plusieurs étapes
clés depuis quelques mois, nous avons reçu deux premiers groupes
motopropulseurs PW1500G et nous nous apprêtons à effectuer l’assemblage
final du premier avion d’essais en vol CSeries. »
« Nous
avons réussi à démontrer la durabilité et les performances
révolutionnaires de notre architecture moteur des turbosoufflantes à
réducteur Geared Turbofan », a affirmé Bob Saia, vice-président, Famille
de produits de nouvelle génération, Pratt & Whitney. « Jusqu’à
maintenant, nous avons effectué plus de 9 000 heures d’essais de notre
système d’entraînement de soufflante à réducteur, faisant la
démonstration de son état de préparation. Nous avons également validé
l’amélioration d’efficacité carburant et de réduction du bruit que nous
nous étions fixée comme objectif en 2007, au lancement du programme
PurePower PW1500G. »
Les moteurs PW1500G ont reçu leur
certificat d’homologation de type de Transport Canada par Pratt &
Whitney Canada et sont assemblés au Centre aéronautique de Mirabel de
Pratt & Whitney Canada, au Québec. UTC Aerospace Systems, formée
après l’acquisition de Goodrich par UTC, fournit le système de fuseau
moteur.
Chaque avion CSeries est propulsé par deux
moteurs PurePower de la série PW1500G. Les moteurs PurePower de la série
PW1500G font appel à un système d’entraînement évolué, permettant à la
soufflante du moteur de tourner à une vitesse différente de celle du
compresseur et de la turbine basse pression. La combinaison du système
d’entraînement et un noyau évolué entièrement nouveau assure des
améliorations de 10 pour cent et plus en efficacité carburant, et dans
la réduction des émissions et du bruit