Pratt & Whitney has completed the first phase of flight testing for its Geared Turbofan demonstrator as it prepares to fly the engine with Airbus in September.
The GTF demonstrator amassed 43.5 hours over 12 flights that demonstrated the handling characteristics and overall performance of the engine up to 40,000 feet and .85 mach, exploring the full flight regime up to redline at 30,000 lbs of thrust.
The test programme, which began 11 July, included a robust package of accelerations and decelerations, high angle of attack takeoffs and other maneuvers, including wind up turns, as well as the starter assist and windmill relight capability of the engine.
Phase one focused on short range aircraft performance in preparation for applying the lessons learned to the Mitusbishi Regional Jet and Bombardier CSeries, both expected to enter service in 2013.
The engine "met our prediction of what the ground to altitude relationship would be" and P&W has an improved understanding of the "geared components in terms of optimizing the engine for fuel [burn]," says Bob Saia vice-president of next generation product family.
P&W achieved "near double-digit" improvements in fuel burn on the demonstrator and validates the 12-15% improvement P&W hopes to deliver in service. In addition, Saia adds that P&W is "on the path to hit the maintenance cost values we've committed to for ANA and Lufthansa," launch customers for the MRJ and CSeries.
P&W identifies three objectives for the two-month, 75-hour flight test programme with Airbus, which is set to kick-off in the second half of September on a A340-600 test bed. First, validate the data from the 747 test bed by repeating phase one conditions. Second, explore the acoustic characteristics, not a done on phase one because of the older and significantly louder P&W JT9Ds on the 747. Finally, "work closely with Airbus" to determine the ideal design for mounting engine components on the pylon to improve the aerodynamic characteristics.
The engine is scheduled for handover to Airbus during the 3rd week of August.
Airbus has distanced itself from any suggestion that its role in GTF flight testing implies future usage on a commercial platform, though Airbus Executive Vice President for Programmes Tom Williams said recently it would take 24 to 30-months to develop a GTF-powered A320 if the airframer decides to do so.
P&W says it is "on track" for the new PurePower engine family and expects detailed design work to begin when the demonstrator flight testing is complete. The non-geared PW810 engine core will begin ground testing in mid-2009, followed in December by testing for the MRJ's PW1217G and 1st quarter 2010 for the CSeries PW1524G. For the PW1000Gs, twin 40-50 hour flight test programmes are planned for the mid 3rd quarter of 2010 and "a few months later" on the PW1217G and PW1524G respectively.
Posted as written for Flight International
The GTF demonstrator amassed 43.5 hours over 12 flights that demonstrated the handling characteristics and overall performance of the engine up to 40,000 feet and .85 mach, exploring the full flight regime up to redline at 30,000 lbs of thrust.
The test programme, which began 11 July, included a robust package of accelerations and decelerations, high angle of attack takeoffs and other maneuvers, including wind up turns, as well as the starter assist and windmill relight capability of the engine.
Phase one focused on short range aircraft performance in preparation for applying the lessons learned to the Mitusbishi Regional Jet and Bombardier CSeries, both expected to enter service in 2013.
The engine "met our prediction of what the ground to altitude relationship would be" and P&W has an improved understanding of the "geared components in terms of optimizing the engine for fuel [burn]," says Bob Saia vice-president of next generation product family.
P&W achieved "near double-digit" improvements in fuel burn on the demonstrator and validates the 12-15% improvement P&W hopes to deliver in service. In addition, Saia adds that P&W is "on the path to hit the maintenance cost values we've committed to for ANA and Lufthansa," launch customers for the MRJ and CSeries.
P&W identifies three objectives for the two-month, 75-hour flight test programme with Airbus, which is set to kick-off in the second half of September on a A340-600 test bed. First, validate the data from the 747 test bed by repeating phase one conditions. Second, explore the acoustic characteristics, not a done on phase one because of the older and significantly louder P&W JT9Ds on the 747. Finally, "work closely with Airbus" to determine the ideal design for mounting engine components on the pylon to improve the aerodynamic characteristics.
The engine is scheduled for handover to Airbus during the 3rd week of August.
Airbus has distanced itself from any suggestion that its role in GTF flight testing implies future usage on a commercial platform, though Airbus Executive Vice President for Programmes Tom Williams said recently it would take 24 to 30-months to develop a GTF-powered A320 if the airframer decides to do so.
P&W says it is "on track" for the new PurePower engine family and expects detailed design work to begin when the demonstrator flight testing is complete. The non-geared PW810 engine core will begin ground testing in mid-2009, followed in December by testing for the MRJ's PW1217G and 1st quarter 2010 for the CSeries PW1524G. For the PW1000Gs, twin 40-50 hour flight test programmes are planned for the mid 3rd quarter of 2010 and "a few months later" on the PW1217G and PW1524G respectively.
Posted as written for Flight International
Pretty amazing engine, the ability to get around 10% fuel burn (but...as compared to what?) is a real positive thing.
As I have been saying lately: GTF or GTFO
(time for me to lurk moar)
Do these geared turbofans only make sense for smallish engines, or would they make sense for something on the scale of a 787 or A350? As I understand it, the GTF allows a slower-turning bigger fan, with a higher bypass ratio, than would be possible with conventional turbofan -- but is it possible that the fans for the bigger planes are already as large as is practical?
Thad,
In general just think of the gearing as a generic way to allow mismatch between turbine and compression rotor speeds. It allows some decoupling between the compression and turbine sections so that they can be independently optimized rather than being constrained by having to run at the same rotor speed. Aside from the weight and geartrain cooling penalties, this should allow a more efficient overall cycle to be attained.
In general it is vastly, vastly easier to increase the loading on turbines than on compression sections. This means you can decrease the number of stages and/or reduce turbine diameter, and as that can lead to higher turbine RPMs, you can still couple that turbine with your efficient compressor that wants to turn slower.
And yes, we may in fact be near the point where enclosed fan diameters are about as big as we'd want. From ~1988 to about ~1998, there was a lot of interest in "Ultra-High Bypass" engines, both ducted and unducted. See the vast quantities of (mostly printed) literature on the GE36, or the Pratt-Allison 578DX. MTU also did a lot of studies on ducted UHB designs. Nacelle/installation drag, and other huge-diameter issues definitely make it unlikely that we will see monstrous ducted UHBs, IMO. For bigger efficency gains, we'll need to go unducted/unshrouded/"open rotor".
Can't help but wonder if upgrade is the viable long term option for 737 and A320. Most of these planes are going to LCC's. Are the benefits of a clean sheet design outweighed by the lower initial costs of evolving the old designs--even with higher maintenance costs, more drag etc.? Does it make more sense financially to go to GTF, weight reduction, perhaps a better wing; improved but not radically reinvented? It's not what you can do, but what you can do at a pricepoint.