In this YouTube video, discussing plans to use the 747 as an aircraft carrier, there is a brief sequence starting at 4 min 14 s, showing images of a B52:

B52 from underneath

B52 from side

What is the explanation for the very different inboard engine pod on the starboard wing? There is a current call for proposals to re-engine the B52 with eight modern engines. Was this an earlier test of moving to four larger engines instead?

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    $\begingroup$ Wikipedia mentions that retrofitting the engines was considered in the 1970s and again in the 1980s, but I can't find a quotation that indicates it was physically tested. $\endgroup$
    – ceejayoz
    Feb 6, 2020 at 21:41
  • $\begingroup$ You know, these days you could surely have a sort of "airborne drone aircraft carrier" - carrying a few dozen "big drones", say. Unreal! $\endgroup$
    – Fattie
    Feb 8, 2020 at 19:02

2 Answers 2


Testbed Aircraft Cameos

As a young engineer in the 1960s at Pratt & Whitney Aircraft (now UTC’s Pratt & Whitney) in East Hartford, Connecticut, I was involved (along with many others) in the development of their 44,000 pound thrust (lbt) JT9D turbojet, which powered the first Boeing 747 jumbo jet aircraft[ Display footnote number: 2 ]. Because of its then ground-breaking large fan diameter (new for the 1960s), P&WA had to use a U.S. Air Force Boeing B-52 as a testbed. The Stratofortress, with its high wing, allowed the JT9D to be mounted with adequate ground clearance for takeoff and landing. In Figure 1, the P&WA testbed aircraft is shown landing at the Windsor Locks, Bradley International Airport, after a test flight, with a JT9D engine replacing two TF-33 inboard engines on the right wing of the eight-engined B-52.

The B-52 continued as a P&WA testbed aircraft until 1981, even after being damaged in its hangar by a violent tornado that raced through Windsor Locks in 1979. Pratt & Whitney more recently used two Boeing 747SP aircraft for testbeds, to flight test their new geared fan jet engines.

enter image description here

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    $\begingroup$ Thanks for a definitive answer and image. The rest of that post is worth looking at too. Will leave this open for a further feedback but presumably this will be the answer I accept. $\endgroup$ Feb 6, 2020 at 21:56
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    $\begingroup$ Dammit, beaten by just minutes :) points to you good sir for quicker fingers. $\endgroup$
    – Jpe61
    Feb 6, 2020 at 22:01
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    $\begingroup$ Does anyone happen to know the ultimate fate of JB-52E? Since it's a -E and the only ones in service today are -H I would assume it was either scrapped or boneyarded, but would love to know for certain. $\endgroup$
    – Ian Kemp
    Feb 7, 2020 at 8:22
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    $\begingroup$ FTR, the JT9D is a turbofan, not turbojet. $\endgroup$ Feb 7, 2020 at 9:12

The plane in the pictures is Boeing JB-52E -test plane.

It used to test for instance the General Electric TF-39 engines for the C-5 Galaxy as it was under development

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    $\begingroup$ Nice - extends the other answer by showing that this was a testbed for several engine types. $\endgroup$ Feb 6, 2020 at 21:59

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