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Pratt & Whitney Geared Turbofan Engine Cleared for First Flight
4 July 2008
Pratt & Whitney’s Geared Turbofan (GTF) demonstrator engine has completed Phase II ground tests and has been cleared for flight testing. The GTF engine targets a more than 12% improvement in fuel burn with significant reductions in engine noise, environmental emissions and operating costs. (Earlier post.)
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| The GTF gear system. Click to enlarge. |
In a GTF engine, an advanced gear system allows the engine’s fan to operate at a different speed than the low-pressure compressor and turbine, resulting in greater fuel efficiency and a slower fan speed for reduced noise. In 2007, the GTF was selected as the exclusive power for the new Mitsubishi Regional Jet and the proposed Bombardier CSeries.
In addition to the more than 12% improvement in fuel consumption and corresponding reduction in CO2 emissions, the GTF is targeting a 50% reduction in NOx emissions; a 50% reduction in engine noise (20 dB quieter than the strictest noise standards introduced this year); and double-digit reductions in overall operating costs equal to more than $1.5 million in cost savings per aircraft, per year.
Pratt & Whitney held its first Asia-Pacific Next Generation Technology Symposiums in Singapore and Beijing, China recently, reviewing the GTF development for more than 180 representatives from airlines, leasing companies and aviation authorities from throughout the Asia-Pacific region.
The conferences were co-hosted by Mitsubishi Aircraft Corporation and Bombardier Aerospace.
July 4, 2008 in Brief | Permalink | Comments (5) | TrackBack (0)
Comments
Posted by: gary | July 04, 2008 at 09:13 AM
The planes the GTF are slated for are smaller than anything Boeing builds. They're probably not even interested yet.
Posted by: Jason | July 05, 2008 at 01:32 AM
@ gary-
Please don't spread misinformation. Before you start Boeing bashing- get your facts straight.
Boeing did not shut any engine manufacturer out of the 777 program.
The current Boeing 777 family is powered by the following turbofan families:
Pratt & Whitney 4077-4098: 77,000-98,000lb thrust
Rolls Royce Trent 877-895: 76,000-93,400lb
GE 90-77B-115B: 77,000-115,300lb*
*On the longer range 200LR and 300ER 777 variants (where +110,000lb thrust ratings are required by design), there is only one engine manufacturer who has met the certified thrust requirement: GE.
Pratt & Whitney have intelligently targeted their GTFs at lower thrust ratings- where cost and stresses are lower. Remember, when it costs several BILLION dollars to develop an entirely new family of turbofans, it is a wise practice to first crawl, then walk, then run.
The Boeing 777 family's lowest thrust rating requirement is 77,000lbs. P&W's GTF, while scalable, still has quite a ways to go before reliably reaching that thrust range.
Posted by: DieselHybrid | July 08, 2008 at 06:25 AM
The tradoffs between pure jet, propfans, turboprops and everyhing in between ebb and flow, based on turbine aerodynamic science (how few stages can efficiently directly drive the "slow" fan) and gearbox technology.
Garrett has been making geared turbofan engines since the TFE731 "engine was introduced in 1972 - [over 30 years ago]. Over 11,000 engines have been built, flying over 100 million flight-hours." http://en.wikipedia.org/wiki/Honeywell_TFE731
Posted by: Vernall | July 08, 2008 at 11:15 PM
vernall-
Thanks for the input. However, the TFE 371 family of "geared" turbofans are tiny as they were derived from the original DC-10 APU core. As such, their max thrust ratings of ~3,500lb are hardly suitable for anything larger than small corporate jets.
What P&W's is trying to offer with their PW8000 GTFs is a potentially game-changing technology in the realm of regional, single-aisle jets. To put things into perspective in order to produce 25,000-35,000lb thrust the PW8000's gearbox needs to be light enough while reliable enough (six sigma) to withstand over 40,000shp! No small feat in aviation!
Now scale that up to 777 thrust requirements and you'll find that you'll need gearboxes that can handle in excess of 150,000shp. Currently only massive shipboard gearboxes can handle that level of power reliably.
I sincerely hope P&W succeeds and scales-up to apply the promising GTF benefits to larger aircraft.
Posted by: DieselHybrid | July 09, 2008 at 07:47 AM
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I'm sure Mitsubishi,the Chinese and Airbus will be using this type of jet engine long before boeing. Since boeing froze P&W out bidding on the 777 engines several years ago.