Warbird Information Exchange

Two B-52Es were modified for use as engine test beds. One aircraft (B-52E-55-BW, S/N 57-0119) was used to test the General Electric TF-39 for the Lockheed C-5A Galaxy program. The TF-39 was mounted on the right inboard engine pylon in place of the two J57s normally installed. The single TF-39 turbofan, rated at about 40,000 pounds, had as much thrust as four J57 turbojets on a standard production B-52E.

Despite being a military aircraft, two copies of the B-52 were specially modified to be used as a test platform for aeronautical engines. One of these aircraft, serial number 56-0636 in 1968, was rented by Pratt & Whitney for testing the JT9D engines that would be used in the then brand-new Boeing 747-100 , which was in the final stages of its development, and flew by first time on February 9, 1969.

The information gathered during these tests also led to a series of feasibility studies for the B-52's redevelopment, where the 8 Pratt & Whitney TF33-P-3 engines, which propelled the aircraft, would be replaced by 4 higher power engines. The subject routinely returned to the ranks of US military commanders for further consideration.

Two engines had never been an option. The same issue arose with the KC-135 upgrade. It would cost too much to re-engineer the wings, pylons, flight controls, and systems. Hence the KC-135 retained 4 motors on 4 pylons. The B-52 upgrade studies of the past did the same; kept 4 motors on the 4 available pylons.



Boeing JB-52E (serial number 57-0119) used in tests of the General Electric TF-39 engines, which would be employed on the Lockheed C-5A Galaxy military freighter (Photo: USAF)








Boeing JB-52E (serial number 56-0636) used in testing the Pratt & Whitney JT9D engines, which would be used in the then brand-new Boeing 747-100 (Photo: USAF)




Boeing JB-52E (serial number 57-0119) used in tests of the General Electric TF-39 engines, which would be employed on the Lockheed C-5A Galaxy military freighter (Photo: USAF)

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Zero Surprise!!...

I wonder if they saved that plane?

Nice photos: thanks for posting. Talking to a BUFF driver last year, he said that the rudder is the issue with a 4-engined version. Apparently the existing one lacks the moment to counter an outside engine failure on take-off, when you'd lose 50% of thrust on that side. It's obviously OK when you only lose 25% of thrust on one side with it in eight-motor config.

Or so I was told...

Here is a good review of the past re-engining effort (with RB211s...the 757 engine which was seriously considered in the 80s), and the current thoughts on the issue.

In short, it looks like it might finally happen, baring huge political changes.

https://www.ainonline.com/aviation-news ... nes-radars

And using bailed bombers for engine test beds is nothing new.
B-47s were used as test beds for J57s and later, for TF34s. The turboprop B-47D doesn't count as it was a prototype for a projected model, not a testbed.
Unusually, a B-47 was loaned to Canada for testing the powerplant for the CF-105.
Overseas, plenty of Lancasters were used for a variety of power plants and a Vulcan tested the Concorde engine.

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Remember the vets, the wonderful planes they flew and their sacrifices for a future many of them did not live to see.
Note political free signature.
I figure if you wanted my opinion on items unrelated to this forum, you'd ask for it.

Another benefit of an 8 engined plane is the ability for each engine to run 2 Generators for electrical generating capability. The requirements of next gen radar, sensors and countermeasures gear both active and passive require prodigious amounts of power. As things Evolve, the offensive use of electronic power will be a huge component of survivability for such an aircraft...

Wouldn't it be just as easy to run larger generators off of larger engines?

The first and second images appear to be of a CF-6 engine and cowling on 0119. Was it used for additional tests after the TF39? I say this because the cowling is clearly too long for the TF39 or JT-9 and the fan is a more conventional fan-forward design instead of the odd T-fan forward design of the TF39.

Correct, 57-0119 tested the CF6-6 and CF6-50 after TF-39 testing was completed.

Meanwhile, 56-0636 tested JT9D-59/70 and JT8D-200 after the initial JT9D testing completed. So if you look at enough photos of these two jets, you’ll see a variety of test engine installations.

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Greg Spahr
USAF veteran 1990-1994

The remains of B-52E, serial number 57-0119, At Edwards AFB abandoned in the desert which was used by General Electric during the 1960s to test their new TF-39 engine, designed for the Lockheed C-5 Galaxy. It was blown up to comply with the Start treaty I was told, but most likely they just wanted to have some fun with explosives.
The other B-52 in the Google image is RB-52B, which was transferred to the Air Force Flight Test Center at Edwards in 1965 for use in barrier testing. The bomber, serial number 53-0379A, was struck off charge in 1970.

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Six minute animated cartoon (August 2017) from Boeing describing the rational for re-engining the B-52:

http://www.thedrive.com/the-war-zone/13148/boeing-made-a-six-minute-long-cartoon-about-re-engining-the-b-52

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Keep your PDI centered!