Bomb and Bomb-Bay Sizes

[33k in the air]

For B-17 internal loads, see page 410 of Erection and Maintenance Instructions for Army Model B-17G / British Model Fortress II Airplanes (AN 01-20EG-2 dated 25 August 1944). That page shows for various bomb types the maximum number of stations on the bomb racks which could simultaneously carry that bomb type. The main loads of interest:

24 x 100-lb AN-M30 GP
24 x 100-lb AN-M47 incendiary
24 x 120-lb AN-M1A1/M2A1 fragmentation clusters
16 x 250-lb AN-M57 GP
16 x 300-lb M31 Demolition
12 x 500-lb AN-M43/AN-M64 GP
16 x 500-lb AN-M58 SAP
10 x 1,000-lb AN-Mk 33 AP
06 x 1,000-lb AN-M44/AN-M65 GP
08 x 1,000-lb AN-M59 SAP
06 x 1,600-lb AN-Mk 1 AP
02 x 2,000-lb AN-M34/AN-M66 GP

Operationally, the maximum load for some bombs was increased through the use of cluster adapters which allowed more than one bomb to be carried by a bomb rack station. (These same cluster adapters were used in the B-24 and B-29 to greatly increase their small bomb capacities.) The new B-17 maximums:

38 x 100-lb AN-M30 GP
42 x 100-lb AN-M47 incendiary
38 x 120-lb AN-M1A1/M2A1 fragmentation clusters
20 x 250-lb AN-M57 GP
18 x 300-lb M31 Demolition
16 x 500-lb AN-M43/AN-M64 GP

The aircraft could also carry a maximum of 30 x 260-lb AN-M81 fragmentation bombs internally..

I'm uncertain of the number of 150-lb T1 GP that could be carried internally. (The T1 is a little-known bomb that was developed as a more powerful substitute for the 100-lb AN-M30 GP. The bombers of the 8th Air Force dropped 74,920 of these bombs during the last two months of the war.) Given that the T1 had the same diameter as the AN-M30, presumably similar numbers could be carried,, since a bomb's diameter was a key limiting factor in how many could be carried.

 

[33k in the air]

These mission reports confuse me.

View attachment 794411

View attachment 794412

12 x 1,000lb bomb load seems unlikely, especially with additional incendiary bombs.

12 x 1,000lb + 38 x M47A1 (nominally 100lb) seems impossible.

Are these the load across the group?

The most likely explanation is a typo plus poor phrasing. If the load said, "12 x 500 lb GP or 38 x M47A1 incendiaries" then the loads would be entirely in keeping with what I posted earlier.

 

[Thumpalumpacus]

Great work, J Jugman .

 

[33k in the air]

Is the 4,000lb M2, a 4,000lb HC Mk.2? Or is it an MC?

I'm fairly certain M2 refers to 4,000 lb HC bombs filled with Minol-2, an explosive with a significantly greater blast effect than the previous fillings of Amatol 60/40 or 50/50. British records sometimes list separately bombs with such more powerful fillings -- the same thing happened with 1,000 lb MC bombs filled with RDX/TNT 60/40 instead of the usual Amatol 60/40 or 50/50.

The strength of these fillings relative to TNT (peak blast pressure):

095 = Amatol 60/40
097 = Amatol 50/50
100 = TNT
110 = RDX/TNT 60/40
115 = Minol-2

From Harris' Despatch on War Operations 1942-1945:

In the middle of 1943, improved fillings became available for HE bombs, the first of these being RDX/TNT,
which was filled into 500-lb and 1,000-lb MC bombs from July onwards. At approximately the same time,
small quantities of Torpex became available, and this was used in 12,000-lb HC bombs. Towards the end of
the year, Minol was filled into 4,000-lb HC bombs, becoming standard for these bombs and also, subsequently, for the smaller MC types. No troubles were encountered with any of these fillings and their increased power over Amatol fillings proved of great value.

 

[33k in the air]

Back to the main target.
A comparison of bomb loads between AAF bombers . . .

The maximum loads for the B-32, late model, AAFPGC test findings:

40 x 100-lb AN-M30 GP
40 x 500-lb AN-M64 GP
12 x 1,000-lb AN-M65 GP
08 x 1,600-lb AN-Mk 1 AP
08 x 2,000-lb AN-M66 GP
04 x 4,000-lb AN-M56 LC
40 x 500-lb T4E4 frag clusters
36 x 500-lb E46 or E48 incendiary clusters
40 x E28 or E36 incendiary clusters

With the use of cluster adapters:

112 x 100-lb AN-M30 GP
112 x 100-lb M12 incendiary clusters
136 x 100-lb AN-M47 incendiary
080 x 260-lb AN-M81 fragmentation

 

[Jugman]

The E28 is an E6R2 cluster adapter and 38 6lb M69 incendiaries. The E38 is probably an E6R2 filled with something else. The E46 may be the M-19 (M23 cluster adapter and 38 M69s).
The E48 is an M23 filled with 38 10lb M74 incendiaries.
The dimensions of these cluster adapters and the M6 (used in the M1/M7 and M9) and M7 (M2/M13) cluster adapters and the M43/M64 500lb GP bomb:

​	M6​	M7​	E6R2​	M23​	M43/M64​
Overall Length​	42.78in​	58.88in​	59.06in​	59.5in​	56.8in​
Body Diameter/Width​	14.3in​	17in​	14.69in​	14.75in​	14.2in​
Tail Width​	​	​	16-18in​	19in​	18.9in​
Height​	12.63in​	12.8in​	​	​	​

 

[Reluctant Poster]

Greg's Planes and Automobiles weighed in on the Mosquito vs the B-17 debate.


View: https://youtu.be/7Wdq0bkRdzE?si=8Hatj475yXgU7ONF

It is mostly fair.

To me it does seem like he suggests that the "cookie" was only used against cities, and the "cookie" was the only 4,000lb bomb that the Mosquito could carry.

And he seemed to suggest that it was only used against cities.

Also suggests that RAF accuracy was measured against the area of an entire city, compared to USAAF using a 1,000ft circle around the aiming point.

The RAF aiming for cities is BS. To get a firestorm you need concentration. As I have pointed out in the Past according to the USSBS report on oil the RAF achieved better overall accuracy than the USAAF. The USSAF did well on clear days but those days were few.

 

[wuzak]

The method the Eighth Air Force used of bombing in formation meant that many of the bombs would miss the target, no matter how good the aim.

IIRC in that video Greg argues that it was OK if US bombs missed, because they would hit workers' housing and kill them.

But surely that is thr same as targetting an area within a city?

 

[Reluctant Poster]

The method the Eighth Air Force used of bombing in formation meant that many of the bombs would miss the target, no matter how good the aim.

IIRC in that video Greg argues that it was OK if US bombs missed, because they would hit workers' housing and kill them.

But surely that is thr same as targetting an area within a city?

The 8th AF dropped a large portion of its bombs by radar which can only be area bombing. Read the papers I have posted previously.

 

[Paul Crowe]

Clearance requirements vary based on what the weapons are, launch or drop requirements and whether they are dumb or guided munitions. Folding fins could get you a denser loading configuration, keeping within the weight and location limits.

For a bit more current loading, one can have 3 Mk82's on a TER rack and there is only two or three inches clearance between tail fin sets. In something like a B-17, depending on the planned load, the load order and the particular release shackles, you might have as little as 6" clearance. With there being dozens and dozens of load configurations, it's hard to be very specific on what you would have.


BTW....BB stacking (aka bomb loading) is probably the most dangerous part of flight ops.....Doesn't matter if it's inert or live, it's way too easy to get dead in an instant.

Agreed. There were many occasion when a bomb 'fell' off. A lot of ground crew could be killed as well as the destruction of the plane concerned plus other planes in the vicinity. One of the Barnes Wallace designed " bouncing" bombs fell off when being loaded fortunately it did not explode!

 

[Zipper730]

I'm fairly certain M2 refers to 4,000 lb HC bombs filled with Minol-2, an explosive with a significantly greater blast effect than the previous fillings of Amatol 60/40 or 50/50. British records sometimes list separately bombs with such more powerful fillings -- the same thing happened with 1,000 lb MC bombs filled with RDX/TNT 60/40 instead of the usual Amatol 60/40 or 50/50.

The strength of these fillings relative to TNT (peak blast pressure):

095 = Amatol 60/40
097 = Amatol 50/50
100 = TNT
110 = RDX/TNT 60/40
115 = Minol-2

How did Torpex compare in terms of blast-pressure?

 

[33k in the air]

How did Torpex compare in terms of blast-pressure?

Torpex came in at 122, making it the most powerful chemical explosive used in bombs during the war as far as as I'm aware. (Torpex was composed of 42% RDX, 40% TNT, and 18% powdered aluminum. Minol-2 consisted of 40% TNT, 40% ammonium nitrate, and 20% powdered aluminum.)

 

[Jugman]

I'm uncertain of the number of 150-lb T1 GP that could be carried internally. (The T1 is a little-known bomb that was developed as a more powerful substitute for the 100-lb AN-M30 GP. The bombers of the 8th Air Force dropped 74,920 of these bombs during the last two months of the war.) Given that the T1 had the same diameter as the AN-M30, presumably similar numbers could be carried,, since a bomb's diameter was a key limiting factor in how many could be carried.

The T1 was a 115lb M70 chemical bomb with the tail replace with that of the 260lb M81 frag bomb and the Mean Mr Mustard gas replaced with TNT. The M70 was basically a 100lb M47 chemical bomb made out of a seamless steel tube in stead of welded sheet steel like the M47.

 

[33k in the air]

The E28 is an E6R2 cluster adapter and 38 6lb M69 incendiaries. The E38 is probably an E6R2 filled with something else. The E46 may be the M-19 (M23 cluster adapter and 38 M69s).
The E48 is an M23 filled with 38 10lb M74 incendiaries.
The dimensions of these cluster adapters and the M6 (used in the M1/M7 and M9) and M7 (M2/M13) cluster adapters and the M43/M64 500lb GP bomb:

​	M6​	M7​	E6R2​	M23​	M43/M64​
Overall Length​	42.78in​	58.88in​	59.06in​	59.5in​	56.8in​
Body Diameter/Width​	14.3in​	17in​	14.69in​	14.75in​	14.2in​
Tail Width​	​	​	16-18in​	19in​	18.9in​
Height​	12.63in​	12.8in​	​	​	​

U.S. incendiary clusters, according to my reading of multiple period ordnance manuals.

100-lb class
AN-M6 = quick-opening, 34 x 4-lb AN-M50
AN-M8 = quick-opening, 34 x 4-lb AN-M54
M10 = quick-opening, 51 x 2-lb AN-M52
AN-M12 = quick-opening, 14 x 6-lb AN-M69

500-lb class
AN-M7 = quick-opening, 128 x 4-lb AN-M50
M9 = quick-opening, 128 x 4-lb AN-M54
M11 = quick-opening, 192 x 2-lb AN-M52
AN-M13 = quick-opening, 60 x 6-lb AN-M69
E57 = quick-opening, 60 x 10-lb M74
AN-M14 = aimable, 110 x 4-lb AN-M50
AN-M17 = aimable, 110 x 4-lb AN-M50
M19 = aimable, 38 x 6-lb AN-M69
M21 = aimable, 38 x 6-lb AN-M69
E28/M18/E6R2 (designations used interchangeably) = aimable, 38 x 6-lb AN-M69
E29 = aimable, 38 x 10-lb M74
E36 = aimable, 38 x 6-lb AN-M69
E46 = aimable, 38 x 6-lb AN-M69
E48 = aimable, 38 x 10-lb M74
E61 = aimable, 38 x 10-lb M74

The clusters carrying the 10-lb M74 were developed late in the war, and I don't think any saw combat use.


According to the AAF statistical summary, the top three most used incendiary weapons against Germany were: (1) the 100-lb AN-M47 bomb with 806,394 dropped; (2) the AN-M17 aimable cluster with 267,023 dropped; and (3) the 500-lb AN-M76 bomb with 33,905 dropped. Against Japan: (1) the 100-lb AN-M47 bomb with 862,650 dropped; (2) the various aimable clusters containing 38 x 6-lb AN-M69, a total of 255,703 dropped; and (3) the AN-M17 aimable cluster with 93,417 dropped.

 

[33k in the air]

The T1 was a 115lb M70 chemical bomb with the tail replace with that of the 260lb M81 frag bomb and the Mean Mr Mustard gas replaced with TNT. The M70 was basically a 100lb M47 chemical bomb made out of a seamless steel tube in stead of welded sheet steel like the M47.

Ah, so that's the origin. The most I found was a mention of it being developed in response to a shortage of the 100-lb GP bomb. Out of eleven ordnance publications from 1943 to 1947, only one listed the 150-lb GP and gave its specifications (47.4" o/a length, 8.1" body diameter, 11.0" tail width, 141.6 lbs total weight, 82.0 lbs TNT filling).

 

[Thumpalumpacus]

The 8th AF dropped a large portion of its bombs by radar which can only be area bombing. Read the papers I have posted previously.

The difference between American bombing and British bombing was one of announced policy, not operational facts. We Americans bombed through clouds, put aiming-points in town centers, and had secondary targets assigned as "city of XXX".

Put shortly, we paid lip-service to precision, but if it wasn't precise, we didn't sweat it.

 

[Jugman]

Ah, so that's the origin. The most I found was a mention of it being developed in response to a shortage of the 100-lb GP bomb. Out of eleven ordnance publications from 1943 to 1947, only one listed the 150-lb GP and gave its specifications (47.4" o/a length, 8.1" body diameter, 11.0" tail width, 141.6 lbs total weight, 82.0 lbs TNT filling).

It's from "UNITED STATES BOMBS AND FUZES PYROTECHNICS" USNBD 1 September, 1945 page 47

 

[33k in the air]

It's from "UNITED STATES BOMBS AND FUZES PYROTECHNICS" USNBD 1 September, 1945 page 47

That's the one publication which covered the bomb. I completely forgot about the descriptive text; I only remembered the bomb specs from the document. I thought I had read about the bomb's background somewhere else.

 

[wuzak]

Greg's source for the RAF's bombing accuracy is the Butt report!


View: https://youtu.be/zIBgUya_b_8?si=wHuZIwFCTuIsfzFX

 

[HP52]

Clearance requirements vary based on what the weapons are, launch or drop requirements and whether they are dumb or guided munitions. Folding fins could get you a denser loading configuration, keeping within the weight and location limits.

For a bit more current loading, one can have 3 Mk82's on a TER rack and there is only two or three inches clearance between tail fin sets. In something like a B-17, depending on the planned load, the load order and the particular release shackles, you might have as little as 6" clearance. With there being dozens and dozens of load configurations, it's hard to be very specific on what you would have.


BTW....BB stacking (aka bomb loading) is probably the most dangerous part of flight ops.....Doesn't matter if it's inert or live, it's way too easy to get dead in an instant.

The Old Man, talked of the British J bomb. He set one up on a rifle range and put a bullet through it. He said it was spectacular, not sure whether it was phosphorous or sodium; the aircrews hated carrying them.