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FARNBOROUGH - Pratt & Whitney has been approached by an unspecified manufacturer to conduct an initial study for a Geared Turbofan engine for a widebody application.

Vice President for P&W's Next Generation Product Family, Bob Saia tells FlightBlogger that the engine would be a PW4000 replacement in the 60,000 to 100,000 lb thrust range for a 250 passengers and above aircraft. Saia declined to specify which manufacturer, Airbus or Boeing, had commissioned the study.

Saia added that the request was for the 2020 or 2025 time frame, though Steve Finger, President of Pratt & Whitney, said in a separate interview that a PW4000 replacement could be ready as early as 2017 or 2018 if required.

"We think it will be about the end of the next decade - 2017 or 2018 - before we are ready to offer a geared turbofan in that thrust size," said Finger.

Saia emphasized the growth potential for the newly launched PW1000G family of engines. The gearbox permits for the optimization of the large diameter fan and engine core to maximize fuel burn and reduce noise.

Pratt & Whitney added that the application was not a second engine option on the Airbus A350 XWB.

Potential applications include a refresh or full replacement for Boeing's 777 family or a Airbus' A330. The PW4000 engine is offered currently on both 777 and A330 aircraft. Placing a geared turbofan engine on an A330 replacement or refresh would fill a gap in Airbus's product line between the A321 and A350-800, 185 to 270 seats for the next decade.

THIS STORY IS DEVELOPING AND WILL BE UPDATED

FARNBOROUGH -- On the heels of the launch of Bombardier's CSeries aircraft, engine maker Pratt & Whitney announced Monday it has commenced flight testing for its new Geared Turbofan engine that will power the new narrow body.

Flying under the wing of a Boeing 747SP, the GTF took to the sky for the first time Friday in Plattsburg, New York.

The GTF employs a gearbox to allow the engine fan to spin 3 times slower than the engine core allowing for increased airflow through the engine and reduced fuel burn and noise.

The GTF has been selected to power both the CSeries and the Mitsubishi Regional Jet which are both scheduled to enter service in 2013.

In dramatic fashion, Pratt & Whitney has produced a video previewing its upcoming flight test program for the new Geared Turbofan engine. The company graciously given FlightBlogger the trailer for its world premier here on the blog.

Some more background:

Geared Turbofan™ Engine Completes Phase II Ground Testing, Cleared for First Flight

BERLIN AIR SHOW 2008 - May 28, 2008 - Pratt & Whitney's Geared Turbofan demonstrator engine has completed Phase II ground tests and has been cleared for flight testing on Pratt & Whitney's 747SP flying test bed mid-year.  Phase II, which began in April at Pratt & Whitney's advanced test facility in West Palm Beach, Fla., focused on engine performance and ground acoustics with the Geared Turbofan engine's flight capable nacelle system.  The engine completed 120 hours of testing during Phase II and has logged a total 250 hours since ground testing began in November 2007.  Pratt & Whitney is a division of United Technologies Corp.

Now, without further delay...

Every once in a while, I like to go wading in the "Radical New Aircraft Design" bin that is the United States Patent and Trademark Office. Occasionally I come out with something written in patent speak that only a rocket scientist can decipher and I just stare blankly at, however, this time I came out with a real gem.

I give you Patent Number 20080099633, which was published yesterday, called Aircraft airframe architectures, a wholly innocuous title. An engineer at Pratt & Whitney came up with a radical new design to improve the fuel efficiency of a shorthaul aircraft. Rather than have two engines, the design calls for a "single gas generator core including a forward compressor driven by a rearward turbine about a core axis and configured to remotely drive multiple bladed propulsion elements."

Now in English. What the designer describes here is one main gas core mounted in the tail of the aircraft that drives two fans or turboprops which are mounted to the sides of the aft fuselage.

The benefits :
-Improves fuel efficiency by adding a gearbox to the core which optimizes the speed of the core and fans.
-Improves fuel efficiency further by providing a significantly higher bypass ratio. That is to say the ratio of air that passes through the fans is significantly greater than the air that goes through the engine's core. Having two fans and a single core the thrust generated from the fans improves fuel burn.
-Reduces noise by evening the gases exiting the rear nozzle.
-There is also additional fuel and weight savings by only having a "single gas generator core" that drives the fans.

I put together a rendering of how the engines are mounted on the rear fuselage of an aircraft, based off of the diagrams enclosed in the patent application.