Boeing B-47 Ideas and Inspiration

[GTX_Admin]

Somehow it seems that we do not have a thread dedicated to Indeas and Inspiration for the Boeing B-47 family.  Well we do now!

[GTX_Admin]

And to kick off, what about an "almost happened" regarding RAAF B-47s:

[Rickshaw]

My understanding was that the B-47s on offer were all equipped only to carry nuclear weapons, not conventional ones, which would have rendered their use questionable by the RAAF.   That was the main reason why they were refused AIUI.   Didn't stop Washington doing a "tour" of all our capital cities with two IIRC B-47s during the election campaign in 1964,  which of course was designed to influence Australian voters to vote for the Liberal-Country Party Coalition Government. 

[Kelmola]

Actually, B-47's could carry conventional bombs and were wired for that, but as this was the period when the USAF wanted to get rid of all conventional ordnance, so training was lacking and they were rarely carried. Also, the conventional load was nothing to write home about in the later versions (B-47E-IV and onwards) with the short bomb bay (though the short bay and long bay were interchangeable in maintenance, but only on "certain aircraft" and only up to B-47E-III).

The "high density" conventional kit (long or short bay) could be fitted to airframes from #617 onwards (only 500 kits were ever produced), "low density" conventional kit (short bay) only to airframes #617 through #730. High Noon and Ebb Tide progarms modified B-47B's up to E standard so presumably they could fit the "high density" kit only after those modifications.

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)

Source: Detail & Scale #18

[GTX_Admin]

B-47 in Australia in 1964 with RAAF roundel:

[kitnut617]

Actually, B-47's could carry conventional bombs and were wired for that,

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):

So how long was the 'long bay'

[Kelmola]

Actually, B-47's could carry conventional bombs and were wired for that,

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):

So how long was the 'long bay'

Sorry, none of my source books seem to state how long the two variants were Even Google-fu fails me, actually the best estimate is the one given by you a few years back at whatifmodelers: short bay 15 feet, long bay 25 feet

You're thinking of the same thing as me, aren't you - could you fit a SRAM launcher inside, and if not the full 8-round rotary launcher, then at least individual missiles? That would make it at least semi-viable for a while longer.

Failing that, there's always the possibility to make it a long-range Wild Weasel bird, since it was employed in the ECM role already in the EB-47E version.

[kitnut617]

actually the best estimate is the one given by you a few years back at whatifmodelers: short bay 15 feet, long bay 25 feet

   OK in my defense that was seven years ago, I can't remember what happened last week     I was actually thinking either a conventional load or a Tallboy.  According to a website called Heavy Conventional Ordinance (I think) and can't find again because the link I saved has gone dead, the USAF got examples of both Barnes Wallis bombs and they manufactured their own afterwards.

[elmayerle]

Just a thought, a Canadian version with the J-47s replaced by Orendas for a bit more "poke" and more capability for conventional weapons and then exported to Australia, too.  I rather imagine the RAAF could also use a version equivalent to the ERB-47H and would likely keep it updated for a fair while longer than the USAF did.

[Jeffry Fontaine]

I have one Hasegawa B-47 kit in the stash that I wish to modify by replacing the kit engine pods with four engine pods from an Italeri B-58.  One obstacle in this project is to determine where the outrigger wheels should be located and what can be used for this purpose.  Currently looking at the outrigger wheels from the Harrier in 1:48th scale as a suitable substitute for the original parts. 

[elmayerle]

I have one Hasegawa B-47 kit in the stash that I wish to modify by replacing the kit engine pods with four engine pods from an Italeri B-58.  One obstacle in this project is to determine where the outrigger wheels should be located and what can be used for this purpose.  Currently looking at the outrigger wheels from the Harrier in 1:48th scale as a suitable substitute for this purpose.

Consider how the outrigger wheels were placed on the XB-47D for inspiration.

[kitnut617]

I have one Hasegawa B-47 kit in the stash that I wish to modify by replacing the kit engine pods with four engine pods from an Italeri B-58.  One obstacle in this project is to determine where the outrigger wheels should be located and what can be used for this purpose.  Currently looking at the outrigger wheels from the Harrier in 1:48th scale as a suitable substitute for this purpose.

Consider how the outrigger wheels were placed on the XB-47D for inspiration.

The proposed B-47C was to be a 4-engined variant but the development of the engines didn't go as planned. Even one with four of the B-52 engines got considered.

[Kelmola]

You're thinking of the same thing as me, aren't you - could you fit a SRAM launcher inside, and if not the full 8-round rotary launcher, then at least individual missiles? That would make it at least semi-viable for a while longer.

To answer myself, CSRL rotary launcher is supposedly about 15 feet in length (unloaded) and has a diameter of 7 feet (when loaded with ALCM's). SRAM without tailcone is 14 feet long, and the diameter of the SRAM is half a feet less than ALCM, so a CSRL with eight SRAM's could just about fit the short bay if we assume it's 7x6x15 feet (might require with small modifications to bomb bay doors and/or the fuel tank in the aft part). Of course, with the full-length bay you could then have an eight-pack of ALCM's (might require slightly bulged bomb bay doors though).

[The Big Gimper]

I'm going to re-engine one of my kits with TF33s.

Aircraft   Original Engines   New Engines   Old Thrust   New Thrust
B-47      6 x J47                  4 x TF33         43,200        84,000

[elmayerle]

I'm going to re-engine one of my kits with TF33s.

Aircraft   Original Engines   New Engines   Old Thrust   New Thrust
B-47      6 x J47                  4 x TF33         43,200        84,000

Might something a bit more mid-range be appropriate, say 4 x JT8D-1's which would give you a total of 56,000 lbf thrust for takeoff and a maximum of 49,000 lbf thrust at full military power in cruise.  If aircraft weight increased over time, you could always go to later model JT8D engines, especially after the -200 series became available (you could then match the TR33 performance with better fuel burn).  JT8D-1 engines would be available in the earyl sixties, just about the time re-engining would start to matter.

[The Big Gimper]

I'm going to re-engine one of my kits with TF33s.

Aircraft   Original Engines   New Engines   Old Thrust   New Thrust
B-47      6 x J47                  4 x TF33         43,200        84,000

Might something a bit more mid-range be appropriate, say 4 x JT8D-1's which would give you a total of 56,000 lbf thrust for takeoff and a maximum of 49,000 lbf thrust at full military power in cruise.  If aircraft weight increased over time, you could always go to later model JT8D engines, especially after the -200 series became available (you could then match the TR33 performance with better fuel burn).  JT8D-1 engines would be available in the earyl sixties, just about the time re-engining would start to matter.

Thanks Evan. I don't have any spare JT8Ds but I will review my stashed C-135/B707 kits and see what engines they come with.

[elmayerle]

Probably be easier to do in 1/144 where you can raid 727, DC-9, or early 737 kits for JT8D nacelles.  I'd be tempted to suggest using some 727 kit nacelles simply because it was Boeing's sudden need for a US-produced and serviced engine for the 727 that brought about the JT8D from the JT8B/J52.

[Rickshaw]

Actually, B-47's could carry conventional bombs and were wired for that, but as this was the period when the USAF wanted to get rid of all conventional ordnance, so training was lacking and they were rarely carried. Also, the conventional load was nothing to write home about in the later versions (B-47E-IV and onwards) with the short bomb bay (though the short bay and long bay were interchangeable in maintenance, but only on "certain aircraft" and only up to B-47E-III).

The "high density" conventional kit (long or short bay) could be fitted to airframes from #617 onwards (only 500 kits were ever produced), "low density" conventional kit (short bay) only to airframes #617 through #730. High Noon and Ebb Tide progarms modified B-47B's up to E standard so presumably they could fit the "high density" kit only after those modifications.

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)

Source: Detail & Scale #18

Thats interesting, thanks.   I've never seen pictures of the B-47 dropping bombs - either conventional or nuclear.   I wonder how often the USAF actually fitted their B-47s to carry conventional bombs?

[M.A.D]

Like Volkodav has alluded to in the Valiant ideas and inspirations

Maritime strike version developed by the RAF to counter the Sverdlov threat?

But instead make it a USN and or USAF counter to Sverdlov threat - say armed initially with two to four GAM-67 ASM's each....

M.A,D

[Jeffry Fontaine]

Consider how the outrigger wheels were placed on the XB-47D for inspiration.

From the one image I found of the XB-47D, it appears that the outrigger wheels are still located on the inboard engine pod.  Definitely not an option, the Harrier outrigger wheel can fit in the area outboard on the wing where the original outboard engines were mounted.  The wing has a chunk of plastic molded to the wing that was intended to be part of the outboard engine pods so that has me focused on getting rid of the molded on material and mounting the Harrier outrigger wheels in that location.  Since the wheels fold up front to back it should be simple enough to mount the wheels at that location and leave the engine pods clean and free of anything other than the engine contained within.  The other two engine pods will be mounted at the position last occupied by the auxiliary fuel tanks. 

Thats interesting, thanks.   I've never seen pictures of the B-47 dropping bombs - either conventional or nuclear.   I wonder how often the USAF actually fitted their B-47s to carry conventional bombs?

Pretty much the same way the B-52 carried conventional bombs on bomb clips containing individual bomb release units that were attached to several racks hanging from the clip which was in turn attached to the roof of the bomb bay. 

I have only seen one image of a B-47 at low level dropping a train of general purpose bombs.  There is a YouTube video showing the B-47 performing the LABS maneuver with what appears to be a GP bomb shape but the quality of the video leaves much to be desired. 

This link to an open box on the tabletop review of the kit shows you the two bomb racks that fit inside the bomb bay for this kit: International Scale Modeler > Board index > Forum Group Builds & SiGs GB & SiG Archive > Shiny Things SiG 2016 > Builds > 1 72 Hasegawa B-47E Stratojet by Scot2go .  The kit contains 24 X  general purpose bomb shapes fitted with box fins.  I disposed of the bomb shapes from my kit but from memory they look to be about 500 pounder sized which is well within the carrying capacity of the B-47. 

[M.A.D]

Or what about a radar-equipped nuclear or conventional armed GAM-63 Rascal armed anti-ship B-47?

Imagine Bell Aircraft Company deriving a conventionally-armed derivative of the supersonic air-to-surface GAM-63 Rascal missile! Or perhaps even more effective, a derivative of its RTV-A-4 (later X-9) Shrike!

I like the notion of a specialised anti-ship variant of the X-9 Shrike, because I’m thinking of a B-47 being able to carry two Shrike's on pylons between the inner twin engine pylons and fuselage!
The Shrike could reach a range of about 80 km (50 miles) at a speed of more than Mach 1.5 – well outside of the Sverdlov anti-aircraft guns!

M.A.D

[jcf]

Actually, B-47's could carry conventional bombs and were wired for that,

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):

So how long was the 'long bay'

Long bay added 300 inches, primarily by removing a fuel tank.

[GTX_Admin]

Or what about a radar-equipped nuclear or conventional armed GAM-63 Rascal armed anti-ship B-47?

Or a slight twist on this:  A RAF B-47 armed with Blue Steel?

[elmayerle]

Just a thought, the RAF needing something between the Canberra and the V-bombers and going for a B-47 derivative powered by either four Avon or four Sapphire engines installed similarly to various studies of four J57 installations.

[GTX_Admin]

I think a B-47 would be equal to one of the V-bombers