Longer B-47 Service Life?

[isayyo2]

Greatly inspired by the "Longer B-58 Hustler service?" thread by @Rule of cool

How could the B-47 have had a more impactful service life?

Improved engines and aerodynamics?

Exports to friendly nations?

As a total What-if thought, I would consider a four-engine B-47 evolution as seen with the B-47C/B-56 designs. I propose GE's J73 as they provided a 50% increase in thrust over the J47, I would also be curious if a thrust-reverser could be developed for the J73/B-47 upgrade to reduce its landing roll. Would the increase in thrust decrease the B-47's "Coffin Corner" susceptibility?

 

[Rule of cool]

There was some idle talk of the RAAF getting some at one point, but they were obsolete when they were offered so the offer was rejected.

 

[riggerrob]

Greatly inspired by the "Longer B-58 Hustler service?" thread by @Rule of cool

How could the B-47 have had a more impactful service life?

Improved engines and aerodynamics?

Exports to friendly nations?

As a total What-if thought, I would consider a four-engine B-47 evolution as seen with the B-47C/B-56 designs. I propose GE's J73 as they provided a 50% increase in thrust over the J47, I would also be curious if a thrust-reverser could be developed for the J73/B-47 upgrade to reduce its landing roll. Would the increase in thrust decrease the B-47's "Coffin Corner" susceptibility?

B-47 was most valuable to nations that also had nuclear weapons.
How well would B-47 have worked dropping iron bombs?

 

[isayyo2]

How well would B-47 have worked dropping iron bombs?

About 25,000 pounds worth...

The B-47B and E had differing bomb-bay lengths as "long" and "short" lengths, as conventional weapon carriage was a distant secondary concern. Per a Beyond the Sprues post we can see their conventional load out:

Loadouts were for B-47B:
Long bay, low density kit:
2 x 4000lb or 9 x 2000lb or 16 x 1000lb or 16 x 500lb WW2 box fin bombs
6 x 2000lb or 8 x 1000lb or 8 x 500lb "interim design" bombs (WW2 fitted with new conical fin)
1 x 25000 lb
8 x 750lb (M117)
Long bay, high density kit:
6 x 2000lb or 18 x 1000lb or 28 x 500lb "interim design" bombs (WW2 fitted with new conical fin)
1 x 25000 lb or 1 x 12000lb or 1 x 10000 lb (I assume these are nukes though, or did the US have Grand Slams and Tallboys?)
4 x 3000lb (M118) or 21 x 750lb (M117)
Short bay, high density kit:
3 x 2000lb or 6 x 1000lb or 13 x 500lb "interim design" bombs (WW2 fitted with new conical fin)
7 x 750lb (M117)

For B-47E:
Long bay, high density kit (only on Block III and prior, strangely low density kit is not given as an option here):
6 x 2000lb or 18 x 1000lb or 28 x 500lb "interim design" bombs (WW2 fitted with new conical fin)
1 x 12000lb or 1 x 10000 lb
4 x 3000lb (M118) or 21 x 750lb (M117)
Short bay, high density kit:
3 x 2000lb or 6 x 1000lb or 13 x 500lb "interim design" bombs (WW2 fitted with new conical fin)
7 x 750lb (M117) or 6 x 750lb (MC-1 chemical cluster)
Short bay, low density kit:
3 x 2000lb or 4 x 1000lb or 8 x 500lb "interim design" bombs (WW2 fitted with new conical fin)
4 x 750lb (M117) or 4 x 750lb (MC-1 chemical cluster)

 

[Dilandu]

Exports to friendly nations?

This seems to be most likely. The export market for long-range bomber was pretty much occupied by USSR with Tu-16 and Britain with Canberra. It's plausible that some pro-American but neutral nations may ask for compatible plane (especially if USA would bother to develope some missile-carrying version)

 

[isayyo2]

It's plausible that some pro-American but neutral nations may ask for compatible plane (especially if USA would bother to develope some missile-carrying version)

Australia is the natural choice as they were the closest to adopting 24 Stratojet's as interim before their F-111s were delivered.

I think Iran is another possibility as they were keen on the F-111s, B-47s would serve as a regional deterrent against its Arab neighbors and RB/EB-47s would serve along their Soviet border.

Another possibility for the J73/B-47 is being transferred from SAC to TAC much like the FB-111As "transforming" into F-111Gs. TAC could use B-47s in a conventional role alongside B-57s, or be converted into KB-47 fast tankers to replace the KB-29/50s.

 

[BlackBat242]

As a total What-if thought, I would consider a four-engine B-47 evolution as seen with the B-47C/B-56 designs. I propose GE's J73 as they provided a 50% increase in thrust over the J47, I would also be curious if a thrust-reverser could be developed for the J73/B-47 upgrade to reduce its landing roll. Would the increase in thrust decrease the B-47's "Coffin Corner" susceptibility?

J71s were proposed for the YB-47C (YB-56).

The J73 produced 9,200 lb thrust without an afterburner.

Boeing YB-56/B-47C Stratojet
The early versions of the Stratojet were all severely underpowered, and in pursuit of a more powerful Stratojet the Air Force proposed a version of the B-47 powered by four 10,090 lb.s.t. Allison J71-A-5 turbojets. The designation YB-56 was assigned to this project, since the different engine configuration was thought to justify a change in designation. A reconnaissance version known as RB-56A was also planned. According to the original planning, the 88th B-47B (50-092) was scheduled be converted to YB-56 configuration as a testbed for the concept.
For a time, the YB-56 was intended to be the "definitive" Stratojet. However, since the airframe was basically that of a "stock" B-47B, the designation of the YB-56 was changed to YB-47C. The J71 engine was later found to be unsuitable for the Stratojet, and a decision was made to switch to the new Pratt & Whitney YJ57 turbojet. However, these engines were not yet available, and in any case they were already earmarked for the B-52. Consequently, the YB-47C program was cancelled in December of 1952, and no four-jet Stratojet was ever built.

The cockpit seems to have been not finalized before cancellation.

 

[Apophenia]

... How could the B-47 have had a more impactful service life?

Improved engines and aerodynamics? ...

Re-wing to deal with spar cracks and related fatigue problems?

 

[Archibald]

B-47 retirement was in 1965-66 : Operation FAST FLY

Development of Strategic Air Command, 1946-1976

books.google.fr

By 1966 Davis Monthan boneyeard had a thousand B-47s in storage ! They were quickly melted.

Compared to a B-52 the B-47 had vicious flight characteristics and all kind of maintenance issues. Plus the B-52 was a quantum leap in performance.

Outside export I can't see a bright future for B-47s past 1965. Unless they are deployed to Vietnam to bolster Rolling Thunder tonnage of explosives dropped: somewhat like the B-29s in Korea (near the end of their careers they were sent in Korea rather than B-50s or B-36s or any jet bomber).

 

[isayyo2]

J71s were proposed for the YB-47C (YB-56).

I've read the J71 was a bit of a POS and the contributing factor on why the YB-56/B-47C got shelved. Now the J73 ain't all sunshine either, with major parts shortage grounding the F-86Hs routinely. But J73 has the performance which could be further improved with an afterburner or water injection, and more importantly a production line with little demand hence why I suggested the J73 as a "what-if" option.

 

[Yellow Palace]

B-47 was most valuable to nations that also had nuclear weapons.
How well would B-47 have worked dropping iron bombs?

Badly. They were set up as dedicated nuclear delivery vehicles. You could convert them for conventional weapons, but

especially if USA would bother to develope some missile-carrying version

They did: the DB-47E carrying the GAM-63 RASCAL.

It was viewed as too limited to be a useful weapons system and cancelled. That may be as indicative of the USAF's attitude as the usefulness of weapons, though.

The GAM-67 Crossbow was probably more promising, and the B-47 was planned to carry four, though it didn't get as close to deployment.

Australia is the natural choice as they were the closest to adopting 24 Stratojet's as interim before their F-111s were delivered.

This, or the earlier iteration of the Canberra replacement requirement for which Vulcans were considered, are probably the most plausible.

I think Iran is another possibility as they were keen on the F-111s, B-47s would serve as a regional deterrent against its Arab neighbors and RB/EB-47s would serve along their Soviet border.

Not a chance. The sale of F-111s to Iran in the late 1960s was blocked as being too much aircraft for their needs. By that time, B-47s were being turned into beer cans. That probably applies to most potential exports - those that could justify it, wanted to operate their own aircraft.

The Soviet Union seemed to be happier exporting the comparable Tu-16. Whether this was because of the economic situation of their allied states, or because of political considerations, I'm not sure.

A tanker conversion, the KB-47G was actually tested, but thought to have too little fuel and to be uneconomic to operate. Transfer to TAC for theatre strike is a possibility, there were early plans for the USAF that had TAC operating as many as seven wings of medium bombers.

One option might be a USN land-based 'high speed minelayer' in the vein of the early concept for the P4M Mercator. Which logically leads to USN ELINT versions. And maybe missile-carrying maritime strike versions if the USN decides it wants to go that route for some reason. Not sure why, but it's there.

The existence of the Tu-16S lifeboat carrier makes me think of an HB-47 in USCG service, but that's silly in the extreme.