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.
Photo © Frank C. Duarte Jr.
Whereas this one below possibly is a JT4A engine with 10 noise compression pipes in the outer ring.
However, on "the other site" I came across pics of a JT3C equipped B720 with 10 noise compressor tubes.
My research revealed that earlier noise compressor design has 10, later has only 8 noise compressor tubes.
Is anybody out there able to heklp my with these questions? is there a doc or further info on the noise compression pipes??
Any help is highly appreciated!
Thanks a million!