Originally Posted by
tdracer
Perhaps hearsay, but I was told that Pratt wanted to go with a larger fan on the JT8D-200 series, but was limited by the center inlet capabilities (apparently Boeing was willing to re-engineer the engine mount for the larger fan, but not the S-duct). Going with a larger diameter fan would have given the JT8D-200 better fuel burn and perhaps a bit more thrust capability.
If true, Boeing actually managed to hurt the performance of the MD-80
Yes, I was wondering that after I wrote it.
I'm not that familiar with the engineering of the 727, but from what I remember of the similar Trident, there was room to hold a party in the centre engine bay. So I'm quite prepared to accept that it was intake flow constraints rather than physical space in the bay that prevented the replacement of the 727 centre engine.