LH526 From Germany, joined Aug 2000, 2414 posts, RR: 14 Posted (5 years 11 months 4 weeks 1 day 8 hours ago) and read 14841 times:
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Guys, another in depth B707/B720 question:
I'm in bit of a trouble here: Below is a Boeing doc about the cowl dimensions of the Boeing 707/720 JT3C & JT4A
Apperently both cowls are different in size and length (the dimension differences are nearly unnoticeable on photos) However my question is more exhaust oriented as I would need some information on the exhaus pipes / noise compressor pipes:
The photo below shows the JT3C engine on a B720. The noise compressors clearly consists of 8 pipes in 2 rings each.
Aaron747 From Japan, joined Aug 2003, 8843 posts, RR: 27
Reply 4, posted (5 years 11 months 4 weeks 12 hours ago) and read 14727 times:
Quoting Lh526 (Reply 3):
The point is that there are 8-pipe and 10-pipe exhausts and (from photos) i can't figure out wich engine had what noise compressor configuration.
I recall seeing pictures in the 1962 World Book encyclopedia (my grandparents kept them for ages) of a typical airline flight featuring Pan Am. The aircraft pictured was one of the early build 707-123s with JT3Cs. In one of the pictures, the Captain was doing an underwing walkaround and there were clearly 10 nozzles. However, in another picture, probably taken later (who knows?) there were only 8. I am now thoroughly confused.
This website may be FS-related, but a lot of the posters are old 707 hands with mountains of knowledge - I highly suggest inquiring there:
Lh526 From Germany, joined Aug 2000, 2414 posts, RR: 14
Reply 8, posted (5 years 11 months 3 weeks 6 days 22 hours ago) and read 14628 times:
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Quoting 474218 (Reply 7): I am a little confused about this entire thread: I think what you are calling "Noise Compressors" are really "Noise Suppressors". They were the first attempt to quite jet engines on civilian airliner.
Correct, some documents call them noise compressor, guess that's where I got the wrong term from.
Off course I'm inquiring about the noise suppressors ... hard to find any information about them whatsoever .... hence I'm moreso highly appreciating your input!
[Edited 2009-10-16 20:39:13 by LH526]
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Timz From United States of America, joined Sep 1999, 7059 posts, RR: 7
Reply 9, posted (5 years 11 months 3 weeks 6 days 7 hours ago) and read 14568 times:
My notes from Airlift/American Aviation (the magazine) say the JT3C on the 707-120 used 21 tubes, but the 720 and 707-320 both used 9 total. That must mean one centered with eight around it? Seems like we ought to be able to find a pic.
Viscount724 From Switzerland, joined Oct 2006, 27782 posts, RR: 22
Reply 10, posted (5 years 11 months 3 weeks 6 days 1 hour ago) and read 14544 times:
Quoting Timz (Reply 9): My notes from Airlift/American Aviation (the magazine) say the JT3C on the 707-120 used 21 tubes, but the 720 and 707-320 both used 9 total. That must mean one centered with eight around it? Seems like we ought to be able to find a pic.
These photos not very clear but it does look like the -120 (left) has more tubes than the the -320 (right).
Ex52tech From United States of America, joined Dec 2006, 559 posts, RR: 1
Reply 11, posted (5 years 11 months 1 week 5 days 23 hours ago) and read 14242 times:
On another note.
Those suppressors could not have held up well. We had some cracking trouble with the tail pipes on the J-57-P-43WB on the B-52G, which had some wedges added to help suppress the noise.
These things must have had cracks everywhere, especially with water injection being used. I know that there was some thrust loss associated with them. Which made a bad situation worse I'm sure.
"Saddest thing I ever witnessed....an airplane being scrapped"