FWD: "Pratt making progress with Geared Turbofan, LLP certification"

Sorry to interrupt the other fascinating threads dominating the group
lately I received the following in e-mail and though it might be of
interest to some. Hope it's somewhat on-topic

Regards,
Jon

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Pratt making progress with Geared Turbofan, LLP certification
ATW Daily News - March 21
Pratt & Whitney said this week that it has installed the flight inlet
and nacelle system on its Geared Turbofan demonstrator engine and is
ready to begin the second phase of ground testing next month.
GTF demonstrator program partner Goodrich provided the system and
installation took place during a fit check that precedes connection of
final test sensors.
P&W President Steve Finger, briefing reporters at the company's East
Hartford headquarters, said, "The Geared Turbofan brings a new step
change in technology and lets us go to a steeper improvement path as
we capitalize on the bigger trade space with the new components" (ATW,
February 2008).
The next phase of testing features analyses of engine performance,
acoustic characteristics and the nacelle system to be conducted at
Pratt's West Palm Beach facility.
"The results surpassed our pre-test predictions in every major area,
demonstrating the fuel burn, noise and emissions characteristics of
this new architecture," VP-Next Generation
3
Product Family Bob Saia said. "As we enter Phase II testing, we will
validate the full performance and noise characteristics of this game-
changing technology." The first phase validated the design and
efficiency of the fan, low pressure compressor, fan drive gear system
and thermal management system (ATWOnline, Dec. 5, 2007).
"The Geared Turbofan will be available by 2013 and airlines don't have
to trade," Finger claimed. "They can get better fuel burn, better
greenhouse gas emissions, significantly lower noise and significantly
better economics." Last year the GTF was selected to power the new
Mitsubishi RJ and Bombardier CSeries. Pratt is in the process of
evaluating GTF components on 15 test rigs worldwide.
Separately, Pratt won US FAA STC authority for its CFM56-3 engine fan
and booster alternative life limited parts including the fan disk,
booster spool and fan shaft. "We are very excited about this
certification because it validates the Pratt & Whitney OEM-quality of
our CFM56-3 engine parts," VP and GM-Global Material Solutions Matthew
Bromberg said.
The STC grants each part FAA Chapter 5 life limits equal to the
original type certificate holder. Pratt is pursuing three additional
STCs covering the high-pressure compressor, high-pressure turbine and
low-pressure turbine.
http://www.atwonline.com/news/story.html?storyID=12136
Editor's Note: Pratt & Whitney's geared turbofan presentation at the
ATA's "Aviation and the Environment" Forum March 19-20 was a
fascinating view of engine fuel efficiency.
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On Mon, 7 Apr 2008 17:43:27 -0700 (PDT), Jon
wrote:

"The Geared Turbofan will be available by 2013 and airlines don't have
to trade," Finger claimed. "They can get better fuel burn, better
greenhouse gas emissions, significantly lower noise and significantly
better economics."


Here's some more information:


http://www.flightglobal.com/articles...he-geared.html
Pratt & Whitney’s long-standing passion, some might say obsession, for
the geared turbofan (GTF) concept is well known. Equally familiar,
however, is the frequency over the past 20 years with which this
apparently promising technology has either failed to live up to its
promise, or been ruled out on the grounds of high cost, or risk, or
both.



http://www.prnewswire.com/cgi-bin/st...4398944&EDATE=
The expected benefits will include up to a 12 percent improvement in
fuel efficiency and a 30-decibel noise reduction over Stage III
requirements. A ground demonstration test is planned in the third
quarter 2007 and a flight demonstration test in 2008.



http://www.freerepublic.com/focus/f-news/1908833/posts
“We believe the [GTF] offers a technological breakthrough that will
provide the best economy and performance for the Mitsubishi Regional
Jet," said Kazuo Tsukuda, President, Mitsubishi Heavy Industries,
Ltd., in a statement. The MRJ is a 70-seat to 90-seat airliner.

Photo



http://en.wikipedia.org/wiki/Pratt_&_Whitney_GTF
Geared fan
As bypass ratio increases, the mean radius ratio of the fan and low
pressure turbine (LPT) increases. Consequently, if the fan is to
rotate at its optimum blade speed the LPT blades will run slow
(because they are on the same shaft), so additional LPT stages will be
required to extract sufficient energy to drive the fan. Introducing an
epicyclic reduction gearbox, with a suitable gear ratio, between the
LP shaft and the fan, enables both the fan and LP turbine to operate
at their optimum speeds. This increases the engine's complexity,
however, which is why it is not a common solution. Only the Honeywell
TFE731 has seen widespread use.

Pratt & Whitney claims the GTF will be 10% to 15% more fuel efficient
than current engines used on regional jets and single-aisle jets, as
well as being substantially quieter.