OyKIE From Norway, joined Jan 2006, 2789 posts, RR: 4
Reply 4, posted (9 years 5 months 1 week 1 day 20 hours ago) and read 9752 times:
Quoting Gigneil (Reply 3): Weight is the main advantage. The engine has also been optimized for high-cycle operations.
Hopefully PW got the fuel burn down.
Shouldn't a weight reduction help get down the fuel consumption? I know that Volvo reduced the weight of the moving parts inside their 5 cylinder engines which made the inner friction lower, and so reduced fuel consumption and increased the torque.
Dream no small dream; it lacks magic. Dream large, then go make that dream real - Donald Douglas
It's a lighter, smaller engine than the CFM (which I think is really optimised for planes larger than the A318), so is somewhat heavy and thirsty (note that Airbus doesn't even offer the V2500 on the A318 because it's heavier than the CFM).
In theory, the PW6000 should have been an optimal engine for the A318. However, it has largely been another nail in the coffin of PW's civil engine future. It will be interesting to see if PW features at all in the next generation of engines for the A320/737 replacements.
Time flies like an arrow. Fruit flies like a banana!
It was bound to happen sooner or later, to give operators a choice of engines. I wonder how the PW6000 would fare on long-range routes.
Quoting Scbriml (Reply 7): In theory, the PW6000 should have been an optimal engine for the A318. However, it has largely been another nail in the coffin of PW's civil engine future. It will be interesting to see if PW features at all in the next generation of engines for the A320/737 replacements.
Remember the early teething problems when the PW6000s were first flight tested?
Quoting Scbriml (Reply 7):
I think compared with what PW said it would.
The pw6000 missed initial target fuel burn by 7%. That's huge! Alas, I left Pratt before the pw6000A went to the test stands... and my sources while very positive on the engine won't tell me squat that isn't in the public domain.
Quoting Boeing7E7 (Reply 12): They did. It's also cheaper so the engine lowers the price tag by $3 million for 318 PW variants over the CFM. And as projected, a few hundred pounds lighter.
On a 500 mile stage it supposedly burns 650 GPH vs. 688 on the CFM all factors considered in the hourly consumption rate. Equal to the burn of the RR the 717.
I can attest that the pw6000 is amazingly cheap to build and maintain. You won't believe the cycle life the engine is designed for. (It will really put the CFM-56 to shame in that regard.) The $3million cheaper sounds about right.
However, the PW6000A is the engine that the pw6000 should have been. I've posted here before how the HPC compressor engineers knew they were going to miss target and management didn't listen. If Pratt had been able to hold onto the initail A318 orders (with a PW6000A performance engine), they would have a little more life left in them.
Personally, after the pw6000 has proven itself, Pratt needs to buy its way onto the A319 (largest airframe/thrust allowed by the IAE contract). Only then will the PW6000 get enough volume to pay off the engineering. Its a great engine. Bummer that even though its derived from the F119 that we didn't keep it contra-rotating. (That would have cut the fuel burn another 3%.)
Lightsaber From United States of America, joined Jan 2005, 14169 posts, RR: 100
Reply 18, posted (9 years 5 months 1 week 15 hours ago) and read 9036 times:
Quoting A342 (Reply 15): Derived from the F119 ?? Are you sure about that ? Do you work for P&W (WE didn´t keep it...) ? And why wasn´t it kept contra-rotating ? Higher manufacturing/maintenance costs ?
Am I sure its derived from the F119? Yes. Directly? No
Did I work at P&W during the time the PW6000 was developed? Yes. In a department called "combustors, Augmentors, and Nozzles." There I worked with the compressor guys/gals to take their rather "stired up" air flow and move it through the combustor where I then work with the turbine guys/gals as the combustor doesn't exactly deliver a constant velocity or temperature to the turbine. So I feel qualified to talk about the PW6000. As I do not currently work for P&W, there are some details of the PW6000A I feel qualified to discuss, some I do not (e.g., exact fuel burn).
Why wasn't the pw6000 kept contra rotating? When the commitment to the PW6000 was made the contra-rotation was considered high risk. The decision was made to go with standard commercial bearings to make the engine more "sellable". I disagree with that decision, but I don't have all the facts. (Just as anyone who works for a company won't know every reason a decision was made unless they make the decision.)
Contra rotation is basically free ONCE THE TECHNOLOGY IS DEVELOPED. It cost big bucks to develop bearings that could take the differential velocities. There is a reason *all* future engines will have the technology but none in service currently have it... its when the technology matures. The same was true of single crystal turbine blades, curved fan blades, impingement cooling, annular combustors, airblast fuel injectors (which are being replaced), tubine case cooling with optical sensors, etc.
Quoting WAH64D (Reply 17): I really hope this gets P&W at least some way out of the sh*t they're in. P&W have made outstanding engines for many years and I hope they continue for more years still.
FlyDreamliner From United States of America, joined Jan 2006, 2759 posts, RR: 14
Reply 22, posted (9 years 5 months 1 week 14 hours ago) and read 8974 times:
The RR on the 717 is a nice engine, in a lot of aspects, noise especially. The IAE V2500 is a good engine. Unquestionably however, GE/Snecma's CFM56 is the most widely proven engine in the segment, finding widespread use under the wings of both 737 and A320 aircraft. That's hard to deal with. My understanding is that Pratt and Whitney went for a greatly simplified design in PW6000, believing they could make it as efficient as more complex and sophisticated rivals, while maintaining a lower cost and weight. It seems like it took them a long time to get it right, and as a result missed making it to market on time. Moreover, Pratt and Whitney isn't offering a next generation long-haul engine for the A350/787, leaving it exclusively to RR - and to a larger extent - GE, who has been making power play after powerplay lately it seems. Too bad to see PW stumbling like this, there was a time they were the number one gold standard in aircraft engines. The era of JT8D, JT9D, and even later on with the PW4000 and PW2000 series, they had strong contenders. What's happened?
"Let the world change you, and you can change the world"
EnginesRUs From United States of America, joined Aug 2000, 82 posts, RR: 0
Reply 24, posted (9 years 5 months 6 days 23 hours ago) and read 8802 times:
Quoting FlyDreamliner (Reply 22): Too bad to see PW stumbling like this, there was a time they were the number one gold standard in aircraft engines. The era of JT8D, JT9D, and even later on with the PW4000 and PW2000 series, they had strong contenders. What's happened?
Quoting OyKIE (Reply 23): Maybe the problems with the PW6000 influenced Boeings decision?
Let's be very clear - P&W made a conscious decision in the end not to offer an engine on the 787 and by extension A350. The large jet engine business, while glamorous, is a lousy business proposition, sometimes requiring decades to recoup an investment thanks to intense (and some say out of control) discounting. P&W, for better or for worse, is part of a large conglomerate that includes such famous names as Otis, Carrier, and Sikorsky. In evaluating where to invest its money, its parent company can get much higher returns much more quickly in ventures other than a billion-dollar high thrust jet engine program. P&W does not have a parent company with deep pockets and a cash cow in the form of a 737 exclusive (like GE) or patient shareholders operating under a slightly different set of rules (like RR). As such, it decided to concentrate on its strengths in military, regional, and space propulsion engines and save its energy for the next-generation 737 and A320 (ostensibly via IAE). You can debate the relative merits of that decision, but it has been made and there's a good reason why UTC continues to outperform the S&P 500 year after year. Oh - and despite conventional wisdom, P&W delivered more than 2,500 jet and turboprop engines last year (including a large number of V2500s) - the rumors of their demise are just a little premature. Its a funny thing about the engine business, though - all it takes is one small change (like, oh say getting on the 737 and/or its successor) and suddenly it's a whole new ball game.