North American XB-70

[Forest Green]

I am trying to get my head around the dimensions of the bomb bays on the proposed production version of the B-70. I know what weapons load it was specified to carry as we discussed it here. Peter E. Davies states in his Valkyrie book that the weapons bay was in two 14ft sections (including 1ft of unusable space between them- so effectively 13.5ft each) with a total volume of 1,200cu ft. For comparison:

B-52: 1,003ft, total length 27ft, sometimes divided in two by a moveable bulkhead
B-1A: 3 x 14ft bays with a total volume of 1,643cu ft

The near exact two-thirds of a B-1 bomb bay configuration and the similarly sized individual bomb bays suggests that the B-70 and B-1 may have had similar design drivers (e.g. specific bomb types) for bomb bay length and volume. Does anybody know if this was the case? what was the original bomb load specification for the AMSA program?

What were the width and depth measurements for the B-70 bomb bays?

B-1 weapons bays were sized for SRAM (14ft length) I believe.

The AGM-86A was originally designed to be interchangeable with the AGM-69 but it didn't have the required range so it had to be stretched, such that it no longer fit in the internally bays of the B-1B or B-52G. The B-52H was made with longer bays.

 

[TomS]

B-1 weapons bays were sized for SRAM (14ft length) I believe.

13-14 feet was a versatile dimension for lots of weapons. B28, B41, B43, and B48 were all around 12-13 feet long, depending on how they were configured. Conventional Mk84s are around 12.5 feet as well (the B-70 was supposed to carry conventional bombs too).

 

[sferrin]

I am trying to get my head around the dimensions of the bomb bays on the proposed production version of the B-70. I know what weapons load it was specified to carry as we discussed it here. Peter E. Davies states in his Valkyrie book that the weapons bay was in two 14ft sections (including 1ft of unusable space between them- so effectively 13.5ft each) with a total volume of 1,200cu ft. For comparison:

B-52: 1,003ft, total length 27ft, sometimes divided in two by a moveable bulkhead
B-1A: 3 x 14ft bays with a total volume of 1,643cu ft

The near exact two-thirds of a B-1 bomb bay configuration and the similarly sized individual bomb bays suggests that the B-70 and B-1 may have had similar design drivers (e.g. specific bomb types) for bomb bay length and volume. Does anybody know if this was the case? what was the original bomb load specification for the AMSA program?

What were the width and depth measurements for the B-70 bomb bays?

B-1 weapons bays were sized for SRAM (14ft length) I believe.

The AGM-86A was originally designed to be interchangeable with the AGM-69 but it didn't have the required range so it had to be stretched, such that it no longer fit in the internally bays of the B-1B or B-52G. The B-52H was made with longer bays.

AGM-86B would have fit in the B-1B when the removable bulkhead between the forward two bays was removed.

 

[JFC Fuller]

Without knowing the width and height of the B-70 weapons bays this is just conjecture: As built (168 inches) the SRAM probably would not have fitted in the B-70 weapons bays, however, I have seen one source state that when it was conceived SRAM was originally intended to be 150 inches (diameter and length apparently changes several times during development) which absolutely would have fitted (up to about 162 should have done).

The B-61 probably would have fitted and its plausible (again conjecture without knowing the height and width of the B-70 weapons bays) that a shorter version of the eight round rotary launcher from the B-1 could have been installed for a total load out of 16 weapons.

Of course, weapons would likely have been built to its dimensions.

 

[Johnbr]

 

[Orionblamblam]

I am trying to get my head around the dimensions of the bomb bays on the proposed production version of the B-70.

Gentlemen, BEHOLD:

 

[Orionblamblam]

The REAL question, of course, is just what the "rocket packages" were that the B-70 was to carry in dedicated side-bays.

 

[overscan]

I am trying to get my head around the dimensions of the bomb bays on the proposed production version of the B-70.

Gentlemen, BEHOLD:
View attachment 615775

1704 - 1357 = 347 inches = 28ft 11 in = 8.8m

 

[JFC Fuller]

Thanks everybody, wonderful images. I think that all but confirms two 14ft weapons bays which would in turn make them viable for SRAM as built (which would have an impressive range from 70,000ft). It would be fascinating to know if the guided missiles in the weapons bay drawing were based on actual concepts or were just generic shapes sized to the B-70 weapons bays.

With regard to the "rocket package" bays, would they be the two doors directly behind the main undercarriage doors in this image (and circled in the attachment)? As they are directly behind the under-carriage, and given the "rocket package" label I wonder if they were for RATO packs, or alternatively for an emergency performance boost as a defensive measure?

 

[sferrin]

Thanks everybody, wonderful images. I think that all but confirms two 14ft weapons bays which would in turn make them viable for SRAM as built (which would have an impressive range from 70,000ft).

There's a slide around here somewhere showing the range of SRAM launched from an SR-71 at speed and altitude, Something like 500 miles.

 

[JFC Fuller]

NA366-600?

I just realised that the missiles in the weapons bay drawings look similar to the one in this painting, may I ask where you found it? I note also that NAA-366 was a project number for a missile.

 

[GeorgeA]

Could it be a bay for a BDM?

 

[TomS]

With regard to the "rocket package" bays, would they be the two doors directly behind the main undercarriage doors in this image (and circled in the attachment)? As they are directly behind the under-carriage, and given the "rocket package" label I wonder if they were for RATO packs, or alternatively for an emergency performance boost as a defensive measure?

Could it be a bay for a BDM?

I think RATO is the most likely option here. Just a gut feeling, but a BDM (Bomber Defense Missile) bay woudn't need to be that tall, given the likely proportions of the missiles.

 

[JFC Fuller]

Could it be a bay for a BDM?

Definitely a candidate: "WS-132A (Air Force) Bomber defense missile for the B-70. Under development by G.E./McDonnell and Republic/Westinghouse teams when work was ordered suspended in November 1956."

Source: Missile and Space Projects Guide 1962.

 

[GeorgeA]

. . .
work was ordered suspended in November 1956."

Ah, that would well predate the definitive XB-70 design, so it's probably not a BDM bay. I guess RATO is the more likely option.

 

[aim9xray]

FWIW, note the 'rocket' nomenclature.

B-52G/H were later fitted with wing pylons between the inner and outer engine nacelles - for penaids (penetration aids), which were forward firing chaff rockets. The current B-52H's now use one of the pylons for Litening pod carriage. Just a stray thoughtlet.

OTOH, forward-firing rockets would need some sort of flip-out launcher. Likely, this was a "provisions & space reserved" features.

 

[DermotODyna]

Where were the Pye Wacket LDM's supposed to be carried? They were 70" in diameter and 9" tall.

 

[sferrin]

FWIW, note the 'rocket' nomenclature.

B-52G/H were later fitted with wing pylons between the inner and outer engine nacelles - for penaids (penetration aids), which were forward firing chaff rockets. The current B-52H's now use one of the pylons for Litening pod carriage. Just a stray thoughtlet.

OTOH, forward-firing rockets would need some sort of flip-out launcher. Likely, this was a "provisions & space reserved" features.

On that note, a poster by the name of BUFFDRVR, on F-16.net, mentioned they'd considered putting a couple AIM-120s on those pylons for self-defense at one point.

 

[aim9xray]

Uh huh. Pointing which direction?

 

[sferrin]

Uh huh. Pointing which direction?

Forward.

Thought it was F-16.net. Turns out that's just where a discussion came up. The actual quote was from a bit earlier. Like exactly 19 years.

"

BUFDRVR​

6/26/00​

Other recipients:

They've actually fit checked and flight checked both AIM-120's and AGM-88's on the B-52 ACMI hardpoints. I'll take the HARM's, leave the A-A to stuff to the guys that are professionals in that realm. I'd be scared out of my mind with BUFF's and
>No,today we would use Amraams! Maybe a few HARM's,too.
>Dale Brown's EB-1,EB-52 ??? You could fit a lot of stuff on a EB-52!
They've actually fit checked and flight checked both AIM-120's and AGM-88's on
the B-52 ACMI hardpoints. I'll take the HARM's, leave the A-A to stuff to the
guys that are professionals in that realm. I'd be scared out of my mind with
BUFF's and BONE's flying around an AOR with A-A missiles on them !

BUFDRVR
"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
everyone on Bear Creek"

 

[Johnbr]

Although often described as a single 29-foot long weapons bay, there were in reality two separate 14-foot-long bays covered by a shared set of doors. The combined bay extended from FS1356 to FS1704. Using a pair of sliding doors on a single set of tracks instead of the usual outward-opening snap-action doors solved the problem of opening the weapons bay doors at very high speeds. The length of the track permitted only one door to be opened at a time. Moving both doors aft opened the forward 14 feet of the bay; moving only the aft door opened the rear 14 feet of the bay; the center 1 foot was unusable since the doors never cleared the area. This also meant that weapons longer than about 13 feet could not be carried by the B-70. In the closed position, the leading edge of the forward door was held tight against the step fairing of the fuselage by two interconnected hooks that engaged the fuselage structure. The aft door was locked to the forward door in a similar manner. It should be noted that the weapons bay doors on A/V-1 and A/V-2 were not powered and could not be opened in flight. The forward weapons bay contained the flight test instrumentation package while the aft weapons bay contained the air inlet control system equipment. A/V-3 would have had powered doors, as well as suspension and release equipment in the rear portion of the weapons bay for a single type of weapon for demonstration purposes.1

The weapons bay was sized to house a variety of bombs, including thermonuclear devices up to 10,000 pounds each, 20,000-pound conventional bombs, various smaller conventional bombs, chemical and biologial weapons, or up to two new air-to-ground missiles. The missiles were to have a range of 300 to 700 nautical miles and an accuracy of less than a mile; conceptually these missiles were much like the later AGM-69A SRAM. Other missiles (probably Douglas GAM-87 Skybolts) were to be carried on external hard points under the wings, along with additional fuel in external drop tanks.

 

[TomS]

Uh huh. Pointing which direction?

Forward.

Thought it was F-16.net. Turns out that's just where a discussion came up. The actual quote was from a bit earlier. Like exactly 19 years.

"

BUFDRVR​

View attachment 615832 6/26/00​

Other recipients:

They've actually fit checked and flight checked both AIM-120's and AGM-88's on the B-52 ACMI hardpoints. I'll take the HARM's, leave the A-A to stuff to the guys that are professionals in that realm. I'd be scared out of my mind with BUFF's and
>No,today we would use Amraams! Maybe a few HARM's,too.
>Dale Brown's EB-1,EB-52 ??? You could fit a lot of stuff on a EB-52!
They've actually fit checked and flight checked both AIM-120's and AGM-88's on
the B-52 ACMI hardpoints. I'll take the HARM's, leave the A-A to stuff to the
guys that are professionals in that realm. I'd be scared out of my mind with
BUFF's and BONE's flying around an AOR with A-A missiles on them !

BUFDRVR
"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
everyone on Bear Creek"

Wow, there's a blast from the past (USENET)! And I remember BUFDRVR. He certainly seemed a credible source at the time.

 

[sferrin]

Uh huh. Pointing which direction?

Forward.

Thought it was F-16.net. Turns out that's just where a discussion came up. The actual quote was from a bit earlier. Like exactly 19 years.

"

BUFDRVR​

View attachment 615832 6/26/00​

Other recipients:

They've actually fit checked and flight checked both AIM-120's and AGM-88's on the B-52 ACMI hardpoints. I'll take the HARM's, leave the A-A to stuff to the guys that are professionals in that realm. I'd be scared out of my mind with BUFF's and
>No,today we would use Amraams! Maybe a few HARM's,too.
>Dale Brown's EB-1,EB-52 ??? You could fit a lot of stuff on a EB-52!
They've actually fit checked and flight checked both AIM-120's and AGM-88's on
the B-52 ACMI hardpoints. I'll take the HARM's, leave the A-A to stuff to the
guys that are professionals in that realm. I'd be scared out of my mind with
BUFF's and BONE's flying around an AOR with A-A missiles on them !

BUFDRVR
"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
everyone on Bear Creek"

Wow, there's a blast from the past (USENET)! And I remember BUFDRVR. He certainly seemed a credible source at the time.

Yep. I always looked forward to his posts. Searching through those old threads sure brought back memories. Wonder where some of them are these days.

 

[JFC Fuller]

FWIW, note the 'rocket' nomenclature.

B-52G/H were later fitted with wing pylons between the inner and outer engine nacelles - for penaids (penetration aids), which were forward firing chaff rockets. The current B-52H's now use one of the pylons for Litening pod carriage. Just a stray thoughtlet.

OTOH, forward-firing rockets would need some sort of flip-out launcher. Likely, this was a "provisions & space reserved" features.

When I went looking for the Phrase "rocket package" in the context of the US aerospace in the 1950s I found two consistent examples:

1) A rocket propulsion package, e.g. the "X-15 rocket package"
2) Multi-cell rocket launchers of the type installed instead of guns on some fighters in the 1950s

Both would work for the bays in question.