Warreng24 From United States of America, joined Nov 2005, 716 posts, RR: 0 Posted (9 years 2 days 15 hours ago) and read 13481 times:
I know the B-52's are powered by the TF33 engines. Those are a derivative of the JT3C engines.
I believe that Pratt & Whitney developed the JT8D as a "replacement" for the JT3C series. They both have similar thrust ratings. I also have read that the JT8D has been used by FedEx to replace the two outboard JT3C's on the 727's.
Would it be more cost-effective to replace the 8x TF33's with 8x JT8D's rather than the current Boeing proposal of 4x RB211's?
I mean to go from 8 to 4 wouldn't there be a lot of expensive re-design work for the spars and the such? I assume that the JT8D's could be almost as simple as a drop-in replacement?
Granted the JT8D's aren't as fuel efficient as the RB211's would be, but they'd have a lower re-engine cost, I think. Quicker return on investment?
StealthZ From Australia, joined Feb 2005, 5821 posts, RR: 42
Reply 1, posted (9 years 2 days 13 hours ago) and read 13457 times:
Not sure of the numbers flying or intended to be flying after this "re engine" program.
For discusion sake let's say 60 aircraft to be refitted that is 480 engines without any spares. Where in today's world will you find 500 or so JT8D's in a suitable condition for this project.
OK a 2nd question the JT8 is generationally quite close to the JT3 what would be the big benefit?
Having said that I am fairly sure the RB211 program is long "off the table" anyway.. where would you get RB211 is as valid a question as JT8
[Edited 2006-06-30 04:13:32]
If your camera sends text messages, that could explain why your photos are rubbish!
Warreng24 From United States of America, joined Nov 2005, 716 posts, RR: 0
Reply 4, posted (9 years 2 days ago) and read 13328 times:
You may be right about the availability.
I remember reading through the P&W website and there was a page outlining the 727 re-engine program. I assumed that the tooling was still there and that they's just have to start up the line again.
Some of the older 727's came with JT3C's. The rest came with an early version of the JT8D. According to this webpage, P&W has a new -200 version of the JT8D which they are marketing as a replacement. The page also talks about only replacing the two outboards... only. http://www.pratt-whitney.com/prod_comm_jt8d.asp
I think the RB211 operators that are having difficulty finding spares are the operators of the really early version. TZ is dumping their L1011-1's b/c of that reason. Apparantly the engine on the L1011-5 (newer version) is not as bad to find spares for.
The reason I bring this up is that most of the other other aircraft flying the TF33 have been replaced with JT8D's.... so why not also on the BUFF? I just thought it might be easier than updating all the spars and stuff to go from 8 engines to 4. http://www.pratt-whitney.com/prod_mil_jt8d-219.asp
747400sp From United States of America, joined Aug 2003, 3992 posts, RR: 2
Reply 5, posted (9 years 1 day 22 hours ago) and read 13299 times:
The first 727 was powered by JT8D-1, then they went from JT8D-15,16 and 17. Some 727 was re engined with JT8D-217. UPS 727 are now powered by RR Tay engines. The JT3C was a turbo jet, so it would have hurt the 727 in the market it was aiming for. That is why I believe Pratt & Whittney made a turbo fan version of the J-52 turbo jet which the JT8D is, because the 727 had to be quieter and have shorter take off time than the 707. If it had turbo jets it could not land at small airports due to noise and time it would take it to get off the ground. If you have prof of a JT3C powered 727 please post it in your reply to my post, because am a 727 fan and it would be nice to see JT3C on them.
As for re engining the B-52 they are going to retire them with 8 TF-33, anyway I want them to keep using TF-33 the sound of them are hard to beet.
KC135TopBoom From United States of America, joined Jan 2005, 12276 posts, RR: 51
Reply 6, posted (9 years 1 day 4 hours ago) and read 13198 times:
Quoting 747400sp (Reply 5): As for re engining the B-52 they are going to retire them with 8 TF-33, anyway I want them to keep using TF-33 the sound of them are hard to beet.
I'm pretty sure that is what is going to happen. The 6 engine CFM-56 (F-108) proposal, form the late 1980s and early 1990s, is long gone, and the 4 engine RB-211 is not going to happen. The only logical engine available, now, for a POSSIBLE B-52H re-engine is the PW2040 used on the C-17s. But, I doubt that will ever happen, either.