Why B-52 was not re-engined as a more efficient (also for maintenance) 4-engine but is still an 8-engine aircraft?

In history, almost all others models were re-engined with new engines also quite different from original, some examples could be C5 Galaxy or also B737 that in latest geneations requires also to extend undercarriage or make bottom "flat" area of engines, to accomodate new bigger ones.

So why B-52 remains the original projects despite its long history? Did development cost be affordable in this very long period?


There were several proposals to do just that, none of them ever went beyond the proposal phase.

Part of the reason is almost certainly the large stockpile of spare engines the USAF had (and maybe still has), taken in part from re-engined KC-135s.

Part of the reason no doubt is also that there have been near constant plans to retire the B-52 "soon" and a major project like this was never deemed economical.

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  • $\begingroup$ B-52's are going to remain flying through 2050, so "soon" isn't very soon. $\endgroup$ – Ron Beyer Feb 8 '19 at 15:36
  • $\begingroup$ +1. Another way to describe the aspect of being retired “soon”, is that the B-52s don’t do a lot of flying hours per year, especially when compared to passenger aircraft. So, the cost/benefit analysis isn’t very favourable, because you have the same cost to replace no matter how much you fly, but the benefit only occurs if you fly a lot before the aircraft is retired. $\endgroup$ – Penguin Feb 9 '19 at 8:24
  • $\begingroup$ @RonBeyer that's the latest plan. Back when reengening was considered it was thought the B-1 was going to replace the B-52 within the decade. Later it was thought the B-2 was going to replace the B-52 within the decade. Neither happened of course, the B-1 is gone and the B-2 looks to be the next to be replaced while the B-52 keeps soldiering on. $\endgroup$ – jwenting Feb 11 '19 at 4:32

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