MarkC From United States of America, joined Apr 2006, 259 posts, RR: 0
Reply 3, posted (4 years 6 months 3 weeks 16 hours ago) and read 2440 times:
OK, I have worked on more than my share of these things.
The 747 / MD11 / A300 / A310 / 767 PW4000's are the 94" fan version. The 777 is the 112" version.
There are three versions of the 112. The first is the original 74 / 77k thrust version. The second is the 90k version, which is similar, but slightly different. This is sometimes derated by operators to become an 84k, or even 77k version. These are then labeled 4084D and 4077D. The 98k version was much different from the others, but there were only 9 engines sold to 1 operator (Korean), and these were all taken back.
The core is remarkably roughly the same size in all fan diameter 4000 versions, with the same number of stages in both HPC (11) and HPT (2). It would fit into the same clearance envelope. The LPT in the 112 is 7 stages (huge) vs 4 in the 94's. LPC is 7 stages in the 112, and 5 in the 94's, although the 98k version had 8 stages. Suffice it to say the 98k's had an unbelievable airfoil count.
Gearbox is the same size, and is more based on the airframe manufacturer than the engine. (eg. MD11 has an extra pump).
This is some general background. Any specific questions?