Post by LOU on Sep 3rd, 2011 at 7:36pm
The JT8D-xx was pretty much state-of-the-art in the sixties.
It was a fan by-pass with very good reliability. The engine, when all the
surge bleed valves were set properly was not too bad when it came to
spin-up time. The JT9 which came a bit later was a high by-pass fan.
The early models had some problems with high EGT spikes when
coming out of reverse. That was solved by not reversing the rear
part of the engine and only reversing the fan section. The larger
problem with the JT9's was some surging and a thing called fan rub.
All the problems were solved in time and the engine became pretty steady.
Here is a photo of a former TWA 767-200 with the P&W JT-9D 7R4D engine.
Here is a look at the 7R4D in section.
The Diffuser is the area of the engine with the highest pressure. The burner cans are just aft of this area.
Lou
Uploaded with ImageShack.us
It was a fan by-pass with very good reliability. The engine, when all the
surge bleed valves were set properly was not too bad when it came to
spin-up time. The JT9 which came a bit later was a high by-pass fan.
The early models had some problems with high EGT spikes when
coming out of reverse. That was solved by not reversing the rear
part of the engine and only reversing the fan section. The larger
problem with the JT9's was some surging and a thing called fan rub.
All the problems were solved in time and the engine became pretty steady.
Here is a photo of a former TWA 767-200 with the P&W JT-9D 7R4D engine.
Here is a look at the 7R4D in section.
The Diffuser is the area of the engine with the highest pressure. The burner cans are just aft of this area.
Lou
Uploaded with ImageShack.us