Rotary bomb bay

AeroFranz

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The Martin XB-51 pioneered a curious weapons bay right after WWII. The weapons were mounted on the inside of this rectangular "slab" that would also form the door of the bay. The whole assembly would rotate 180 degrees around the longitudinal axis to expose the weapons to the airstream. This was done because of acoustic/structures problems associated with opening large cavities while flying fast on the deck (the XB-51 mission).

The same design was subsequently applied to the P6M Seamaster, and the Martin-built B-57 Canberra. The Buccaneer also has a rotary bomb bay, i wonder if it's the same design.

Does anyone have good pictures/diagrams of these systems? I have been looking like crazy but don't have much to show for... :(
 
The F-101 VooDoo had something similar but with missiles on BOTH sides of the door.
 
These are from the best XB-51 reference ever, Scott Libis' Air Force Legends #201 Martin XB-51 by Ginter Books. I highly recommend obtaining a copy and looking their other titles, I've collected almost all of them - that's how these books must be made by standard.
 

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From Tim Laming "Buccaneer" a drawing of the bomb door :
 

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F-101B Weapons bay door (from Detail&Scale #21)
 

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Interesting, I wonder why it fell out of favor. Of course rotary bomb bays are in vogue for large bombers, but they're still tucked very much away inside.
 
The Blackburn Buccaneer had such a weapons bay. I wonder, did any other aircraft apart from the Buc, the US Canberra and the aforementioned XB-51?
 
F-101B, P6M Seamaster as well - if you are reading carefully :)
 
Just call me Ray said:
Interesting, I wonder why it fell out of favor. Of course rotary bomb bays are in vogue for large bombers, but they're still tucked very much away inside.

I think the rotary door arrangement tends to occupy more volume for a given weapons load than a conventional arrangement. Structures-wise, the door leaves a gaping hole in the bottom of the vehicle, which requires overall strengthening. I guess with a conventional bay, you can still run a keel/stringer through the middle and split it in two. I am not sure on the last point since I failed most of my structures classes in college :)

By the way, thanks for the awesome pics. I spent a couple of hours on the flight archive and came up empty handed. Now I have plenty to work with :)
 
...and again CodeOne Magazine rocks

A Martin technician inspects the six 750-pound bombs loaded on the innovative rotary launcher used on the XB-51 medium bomber prototype, circa 1949. The bombs, rockets, or other weapons would be loaded on to the door itself. Once hoisted up into the aircraft, the wheels would be removed and the weapon/door combination would be attached to a spindle at each end of the bomb bay. Near the target, the door and weapons would be rotated 180 degrees. The weapons would be released or fired and the now-empty door would rotate back into place. The system allowed for accurate bombing at relatively high speeds. Two XB-51s were built, but the Air Force's medium bomber competition went to the English Electra Canberra design, which Martin later built under license.
 

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The F-108 used (well, it would've used) a bay with a rotary pallet. One side was the bay door, the other side had a T-shaped assembly mounting the three GAR-9 AAMs.

The F-101B initially used a rotary pallet with six Falcon AAMs. Three on the "outer" side had retractable launch rails for low-drag carriage, three on the "inner" side had launch rails that did not retract. Anyone know when they stopped using that one?
 
AeroFranz said:
The Martin XB-51 pioneered a curious weapons bay right after WWII. The weapons were mounted on the inside of this rectangular "slab" that would also form the door of the bay. The whole assembly would rotate 180 degrees around the longitudinal axis to expose the weapons to the airstream. This was done because of acoustic/structures problems associated with opening large cavities while flying fast on the deck (the XB-51 mission).

The same design was subsequently applied to the P6M Seamaster, and the Martin-built B-57 Canberra. The Buccaneer also has a rotary bomb bay, i wonder if it's the same design.

Does anyone have good pictures/diagrams of these systems? I have been looking like crazy but don't have much to show for... :(

Hi'
There was a British proposal circa 1937 for a British bomber with such a system, Possibly Airspeed? Looked a bit like an early Boeing but with a rotary bomb bay. Will try to find the original article but it was published many years ago.
 
No, they had true weapons bays.
 
flateric said:
...and again CodeOne Magazine rocks

A Martin technician inspects the six 750-pound bombs loaded on the innovative rotary launcher used on the XB-51 medium bomber prototype, circa 1949. The bombs, rockets, or other weapons would be loaded on to the door itself. Once hoisted up into the aircraft, the wheels would be removed and the weapon/door combination would be attached to a spindle at each end of the bomb bay. Near the target, the door and weapons would be rotated 180 degrees. The weapons would be released or fired and the now-empty door would rotate back into place. The system allowed for accurate bombing at relatively high speeds. Two XB-51s were built, but the Air Force's medium bomber competition went to the English Electra Canberra design, which Martin later built under license.

Airtime Publishing's Classic Wings issue on the XB-51 has a shot of the rotary bay door used with the 4000lb bomb. Bulges out quite a bit.
 
Spark said:
Hi'
There was a British proposal circa 1937 for a British bomber with such a system, Possibly Airspeed? Looked a bit like an early Boeing but with a rotary bomb bay. Will try to find the original article but it was published many years ago.

I believe you may be thinking of the Boulton-Paul P.79 to B.1/35 featured in 21st Profile Vol.2, No. 16.

The design featured rotary bomb dispensers, similar to the B-1B, rather than a rotary bomb bay.

Attached are the GA and bomb dispenser drawings from the article.

Jon
 

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wow, not what i was expecting but just as interesting. I wonder if the wing racks can be considered an early example of 'semi-conformal' carriage. I was also happy to find an explanation for the raked back windshield, which had always baffled me.
Thanks for posting that! :)
 
verner said:
Didn't the F-111 and B-1B have these also?

Verner my friend I think they had conventional bomb bays (with the B-1B and the proposed 'FB-111H' utilizing a rotary launcher system within them.

Regards
Pioneer
 
G'day gents

I have found this Youtube footage, which shows the SeaMaster's weapons bay deploying air-to-sea mines!

http://youtu.be/mqhhs5xrGek

Enjoy!

Regards
Pioneer
 
One plane that we seem to be overlooking is the Thud, the F-105. I believe (I know someone will correct me if I'm wrong) it had a rotary bomb bay mostly intended for nukes, but theoretically conventional gravity bombs could be loaded. In practice, though, the bay was not used for ordnance but to carry a large internal fuel tank, as illustrated here.
 

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Now THAT'S a rotary launcher!!! ;D
 

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F-14D said:
One plane that we seem to be overlooking is the Thud, the F-105. I believe (I know someone will correct me if I'm wrong) it had a rotary bomb bay mostly intended for nukes, but theoretically conventional gravity bombs could be loaded. In practice, though, the bay was not used for ordnance but to carry a large internal fuel tank, as illustrated here.

The Thud's bay door didn't carry the load, but it did slide out of the way rather than being hinged.
 
Madurai said:
F-14D said:
One plane that we seem to be overlooking is the Thud, the F-105. I believe (I know someone will correct me if I'm wrong) it had a rotary bomb bay mostly intended for nukes, but theoretically conventional gravity bombs could be loaded. In practice, though, the bay was not used for ordnance but to carry a large internal fuel tank, as illustrated here.

The Thud's bay door didn't carry the load, but it did slide out of the way rather than being hinged.

Thanks for the correction. They were pretty strong doors, as they mounted full bombed-up pylons on them during the Vietnam War.
 
This is a naïve question, but when the Buccaneer had the bomb bay door fuel tank fitted, did the rotary bomb bay still work? Or did the tank fill the bay? I ask because the tank always appears 'bulged,' and it's hard to imagine how the door could rotate and release ordnance.
 
Yes, the internal bay still worked even with the bomb door tank installed. The tank rotated into the space normally occupied by the bombs.
 
Here's a video uploaded the other day on the Periscope Films channel and it's an instruction-video concerning the pitch-up characteristics of the F-101 and how to handle them:


"The Word on Pitch-Up", circa early 1960s, is a McDonnell Aircraft Corporation presentation looking at the pitch problems of the McDonnell F-101 Voodoo supersonic jet fighter. The film is adapted from a story by D.H. Stuck, a famous Test Pilot most well known for a November 16, 1959 accident involving a McDonnell JF-101B Voodoo aircraft where he ejected successfully, though the plane crashed near Edwards Air Force Base in California. Designed by McDonnell in the 1950’s , the F-101 had a 20+ year career, first as a fighter-bomber, then as a reconnaissance / interceptor and eventually as a training aircraft. Despite some of its advanced capabilities and its speed, it had a terrible aerodynamic issue which caused the aircraft to “pitch-up” . The pitch-up was caused by downwash on the stabilizer during high angle-of-attack flight, which caused both a pitch up from the downward force and a reduction in the effectiveness of the stabilizer itself. The jet would then become highly unstable. This problem was never fully fixed; the film attempts to guide pilots through a typical scenario.​
00:30 Squadrons of Delta Darts and Voodoos cross the sky in formation.
01:04 An F-101 Voodoo spirals out of control, diving towards the ground.
01:22 An F-101B in flight. Its rotary bomb bay opens and fires an AIR-2 Genie rocket.
01:46 The Voodoo scorches the sky just above the ground and pitches up and climbs high.
02:06 An F-101B in flight and performs a slow, descending barrel roll.
02:29 Animation of an F-101 demonstrating why pitch-up occurs. The nose of the aircraft pitches up increasing its angle of attack. Motion lines representing wind push against the plane, over the wing, and push down on the tail demonstrating action called “tucking,” “stick lightening,” “dig in,” “stick reversal,” or “pitching moment.”
03:21 Animation of the Voodoo. The plane pitches up and the vortex from the wing tip rises and falls, pushing down on the tail.
03:46 An F-101B begins pitch-up.
03:56 Barrels down a desert runway and takes off.
04:06 Comes in for a landing.
04:12 Begins pitch-up.
04:17 Animation of an F-101 showing a dramatic angle of attack.
04:38 Animation showing how angle of attack is affected by gross weight, indicated air speed, and ‘G’ loading. The animation demonstrates varying weight in stabilized flight. The airplane lifting and then dropping as its weight decreases from fuel consumption.
05:53 Animation of airplane instruments showing change in air speed, the nose high attitude increasing and decreasing as the aircraft slows or speeds.
06:37 Animation demonstrating ‘G’ loading, showing a 40,000 lbs aircraft needing 40,000 lbs of lift at 1G flight. The plane goes into a 3G turn requiring 3 times the lift.
07:15 Ground crew work on a Voodoo.
07:27 A Voodoo taxis on the tarmac.
07:41 Voodoo in flight.
07:55 A team operates a ground-based tracking camera.
08:06 Voodoo demonstrates recovery from pitch-up. It deploys a chute to recover. The same action is shown from inside the cockpit.
09:35 A sequence of tests in which the chute is not deployed, showing prolonged out-of-control time, spinning, and recovery.
10:48 The pilot pushes the stick forward and recovers the aircraft.
11:19 Voodoo pitches up; the pilot deploys the drag chute.
11:34 Voodoo pitches up; the pilot maintains neutral ailerons and ruder to aid the craft in recovery. Intercut between pilot at the controls and the plane as seen from the ground showing how the pilot returns control and stick to neutral as the aircraft rolls and falls into a recovery dive.
12:41 Voodoo uses the drag chute in a full scale pitch-up.
13:04 Voodoo uses immediate full forward stick, and neutral ailerons and rudder.
13:55 Voodoo yaws and rolls while diving.
14:30 Voodoo in extended recovery time.
14:49 Voodoo in flight with external tanks.
15:42 Graphics showing various factors involved with altitude loss, and fundamentals and facts about altitude loss.
16:52 Voodoo in flight and graphics comparing pitch-up altitude to altitude lost in recovery.
17:13 Illustration of a Voodoo demonstrating the ways to avoid a pitch-up.
17:46 Voodoo in flight and a graph of a knee pad card showing the number of Gs a pilot can pull for a given indicated airspeed.
18:13 Animation of a Voodoo in flight and a pilot harshly, then smoothly pulling back on the stick.
18:38 Voodoo in flight demonstrating airspeed bleed off.
19:33 END.​
 

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