Reggaebird From Jamaica, joined Nov 1999, 1154 posts, RR: 0 Posted (4 months 6 days 19 hours ago) and read 3129 times:
Looking at this video ( http://www.youtube.com/watch?v=k32EhddYxK4 ), I started to wonder when Pratt & Whitney made the transition from these old style JT9Ds to the successor PW4000s. This plane was built in 1988 so it was sometime after that. I did a search but could not find the date when Pratt actually ceased JT9D production. That said, these were sweet sounding engines.
KELPkid From United States of America, joined Nov 2005, 5610 posts, RR: 4 Reply 1, posted (4 months 6 days 19 hours ago) and read 3040 times:
IIRC, the 767 introduced the P&W4000, with the intent that the upcoming 747-400 would share the engine (right down to the same variant, so an airline having '67s and 744s in the fleet could swap engines between the fleets). However, some 767 operators actually wanted to use JT9D's on 767s (for crossfleeting with their older 747s). Boeing caved, and you had a few 767's built with JT9Ds
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
imiakhtar From United Kingdom, joined Apr 2006, 543 posts, RR: 3 Reply 2, posted (4 months 6 days 18 hours ago) and read 2976 times:
Quoting Reggaebird (Thread starter): This plane was built in 1988 so it was sometime after that. I did a search but could not find the date when Pratt actually ceased JT9D production. That said, these were sweet sounding engines.
The PW4000x were introduced into the 747 line-up with the development of the 747-400. I'm not sure of the exact date, but Northwest Airlines received their first 747-400 in 1989 (N661US) and it was powered by the PW4056.
The earliest iterations of the PW4000 received their type certificate in 1986 so it could very well have appeared on the 767 before the 747.
MarkC From United States of America, joined Apr 2006, 255 posts, RR: 0 Reply 3, posted (4 months 6 days 16 hours ago) and read 2933 times:
You can't swap a JT9 from a 767 to a 747, but you can do it with a 4000. But, the maintenance tools and such are almost the same on a JT9 from 767's to (later) 747's.
I would have to look it up, but the first 4000 could have been on a 767, 747, A300, A310. Actually, now you have me curious. I will look this up on Monday.
ha763 From United States of America, joined Jan 2003, 3374 posts, RR: 7 Reply 6, posted (4 months 6 days 12 hours ago) and read 2829 times:
Quoting Reggaebird (Thread starter): I did a search but could not find the date when Pratt actually ceased JT9D production.
According to this fact sheet from the P&W website, the JT9D ended production in 1990. Seeing that the last classic 747 was delivered in 1991 it makes sense that production ended in 1990.
Viscount724 From Switzerland, joined Oct 2006, 18467 posts, RR: 17 Reply 7, posted (4 months 6 days 10 hours ago) and read 2794 times:
Quoting imiakhtar (Reply 2): Northwest Airlines received their first 747-400 in 1989 (N661US)
Actually, the first 744 delivered to NW was N663US in January 1989. N661US (the first 744 built) was the 6th delivered almost a year later after Boeing was finished with it. N663US was followed by 662, 664, 666, 665...and then 661.
MD11Engineer From Germany, joined Oct 2003, 12568 posts, RR: 68 Reply 8, posted (4 months 6 days 2 hours ago) and read 2650 times:
Quoting MarkC (Reply 3): but you can do it with a 4000.
Been there, done it. But it is not a straightforeward swap. E.g. the engine rear mount is different and has to be changed, as the PRV controller of the bleed system. Also many 747-400s have the autostart option incorporated, which requires an additional box on the engine, the SCU, which is not installed (or needed) on the 767.
Thrust From United States of America, joined Sep 2003, 2668 posts, RR: 16 Reply 9, posted (4 months 23 hours ago) and read 2018 times:
I'm assuming that the PW 4000 was quieter, more powerful, and more fuel efficient than the JT9D. Could the JT9D have produced 60,000 pounds of thrust had the engine been kept on? I'm actually slightly curious what kind of changes the PW 4000 featured that were more advantageous than the JT9D, such as the fan design, etc.
MarkC From United States of America, joined Apr 2006, 255 posts, RR: 0 Reply 10, posted (4 months 19 hours ago) and read 1977 times:
JT9's and 4000's are very similar in design. That is, if I showed you a part from one, you would recognise it the other. 4000 used more composites, but I doubt this had a difference on thrust. Weight, yes. Big differences was materials in the combustor and high turbine allowing higher pressure ratios. Single crystal HPT blades, and powder metal disks. Also, the 4000 has drum rotors for the LPC and HPC.
imiakhtar From United Kingdom, joined Apr 2006, 543 posts, RR: 3 Reply 11, posted (4 months 19 hours ago) and read 1968 times:
Quoting Thrust (Reply 9): I'm assuming that the PW 4000 was quieter, more powerful, and more fuel efficient than the JT9D.
The PW4000 had a 7% fuel burn advantage over the JT9 according to LaxIntl's link above. Quiter without a doubt. Some of the B747-200s operated by PK had special "Q" nacelles fitted on the JT9D aircraft to keep noise within limits.
Quoting Thrust (Reply 9): I'm actually slightly curious what kind of changes the PW 4000 featured that were more advantageous than the JT9D, such as the fan design, etc.
A new fan and the use of PW1480 nickel-based super alloys in the turbine section. Hopefully, someone who knows more about the mechanics will chime in soon.
That a few 767s were built with JT9Ds is news to me. Who ordered those, and were those aircraft subsequently reengined with 4000s (or even CF6s) once 747 classics started disappearing?
Further, are/were the JT9D powerplants different-looking on the 767? Case in point: the visible exhaust cone on 747 JT9Ds; I don't recall ever seeing exhaust cones on a PW-powered 767.
plane507 From Panama, joined Sep 2011, 4 posts, RR: 0 Reply 14, posted (4 months 2 hours ago) and read 1841 times:
Quoting imiakhtar (Reply 11): Quoting Thrust (Reply 9):
I'm assuming that the PW 4000 was quieter, more powerful, and more fuel efficient than the JT9D.
The PW4000 had a 7% fuel burn advantage over the JT9 according to LaxIntl's link above. Quiter without a doubt. Some of the B747-200s operated by PK had special "Q" nacelles fitted on the JT9D aircraft to keep noise within limits.
Quoting Thrust (Reply 9):
I'm actually slightly curious what kind of changes the PW 4000 featured that were more advantageous than the JT9D, such as the fan design, etc.
A new fan and the use of PW1480 nickel-based super alloys in the turbine section. Hopefully, someone who knows more about the mechanics will chime in soon
...also PW4000 has greater MTBR and much greater number of operators. 767 that operate with JT9's are not converted to PW4000. I dont know if there is even a SB that covers such a conversion and it would be economically unfeisable.
KELPkid From United States of America, joined Nov 2005, 5610 posts, RR: 4 Reply 15, posted (3 months 4 weeks 1 day 22 hours ago) and read 1791 times:
Quoting plane507 (Reply 14): I dont know if there is even a SB that covers such a conversion and it would be economically unfeisable.
Probably now. It might have made economic sense when the birds were younger, especially if the operators in question went on to order newer 767 models (like the -300)
Just curious (again): did the JT9D used in the 767 have a FADEC controller? Seems that most of the 767 engine choices were FADEC...
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
MarkC From United States of America, joined Apr 2006, 255 posts, RR: 0 Reply 16, posted (3 months 4 weeks 1 day 18 hours ago) and read 1727 times:
Quoting western727 (Reply 12): Further, are/were the JT9D powerplants different-looking on the 767? Case in point: the visible exhaust cone on 747 JT9Ds; I don't recall ever seeing exhaust cones on a PW-powered 767.
That is very difficult to do. If you are standing right in front of the engine, the 4000's have black composite fan exit guide vanes, 9's have aluminium ones anodized in different colours. The fan rubstrip on 4000's have circumferential grooves. 9's have discrete rectangular holes. I cannot think of a way to tell from the side or back off of the top of my head.
Quoting imiakhtar (Reply 11): A new fan and the use of PW1480 nickel-based super alloys in the turbine section. Hopefully, someone who knows more about the mechanics will chime in soon.
I thought i did in the post above you. I normally do not get very specific (even in tech ops) as people are more into planes than engines. Its very much a niche subject. Maybe this seems as if I do not work on these engines every day. Any specific differences you want to know? No problem. I'll post it as long as its not intellectual property or export controlled. Example: I cannot post the specific alloy of parts.
Quoting plane507 (Reply 14): ...also PW4000 has greater MTBR and much greater number of operators. 767 that operate with JT9's are not converted to PW4000. I dont know if there is even a SB that covers such a conversion and it would be economically unfeisable
Possibly, but its an airframe issue that I would not know of. You can switch a 747-200 from older JT9-7's to the JT9D-7R4G2. This temporarily jumped up the price of the G2's. This is probably a bigger difference in operating economics than going from a G2 to a 4000.
FYI, 4000's are manufacturer specific, not model specific. That is, a boeing 4000 can be switched to a different model boeing, but not an MD11 or an airbus. Airbus 4000's can go from a 300 to a 310 (but I do not think any one has done this), but not boeing or MD11.
Quoting MarkC (Reply 16): The fan rubstrip on 4000's have circumferential grooves. 9's have discrete rectangular holes.
Most of the JT9's I have worked with have the skewed groove type you mentioned. I have seen however a few with circumferential groove and with honeycomb type. (On -7A & -7F engines IIRC)
They had as well a different fan blade configuration to match the case assembly.
Quoting MarkC (Reply 16): I normally do not get very specific (even in tech ops) as people are more into planes than engines. Its very much a niche subject.
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