Out of the Big Three WW2 bombers (B-17, B-24, Lancaster), was the Flying Fortress the most redundant?

[GrauGeist]

Yeah, in my linked posts, I mentioned that the B-17, B-24 and B-29 were equipped to have external bomb racks.

I just felt it was easier to link to the previous posts than to copy the text and images over and over again...

 

[ThomasP]

Hey GrauGeist,

Sorry, but those are not 4000 lb bombs on the external racks. The 4000 lb bomb was as ~long as the external rack, the ones in the phots you posted are only ~1/2-2/3 the length of the rack. Also the sway braces are in the wrong position for the 4000 lb bomb. By the position and spacing of the sway braces it looks like the bomb in the photos with the words "You To Joseph . . " on the side is the 1000 lb. The 2000 lb and 4000 lb used wider spacing for the sway braces with the forward one farther forward. The lower diagram in the link to your post#62 in the Fake B-26 photo? thread shows the required sway brace spacing and positions, as well as the relative size of the bombs to the bomb rack.

Here is another diagram of the rack and sway brace position and spacing, with the relative size of the 1000 lb and 4000 lb bomb in comparison to the length of the rack. Note the spacing of the sway braces.

 

[33k in the air]

Click the link on post #334 and #335 above.
You'll see 4,000 pounders in action.

From summer 1943 onward, they bombed French targets and further inland as the war progressed.

Those aren't 4,000-lb bombs in the photos, however.

Roger Freeman's Mighty Eighth War Manual on page 223 has the same photo of the aircraft on the ground with the bombs on the underwing racks; note the image on your linked post is cropped tighter. The caption for the photo reads:

"M-44 1000 lb GP slung on a 303rd BG B-17F's wing racks, 18 Sept. 1943, ready for a mission to France. Single yellow band round rear and front of bomb casing indicated TNT or Aurotal [sic] filling."

On page 153 of the same book, in a section about the B-17F, it says this:

"The B-17F had the capability to lift much heavier loads if external wing racks were used when it was possible but not practicable to attach 4000 lb bombs. With the prospect of increasing bomb loads to short-haul targets, in August 1943 B-17 stations received kits for installing external racks on their aircraft. A few missions were flown during the next month where, in addition to a normal internal load, two 2000 lb bombs were carried externally by each Fortress. With the adverse effect on climb and high altitude performance making formation flying even more difficult and considerably reducing endurance, VIII BC soon decided that high altitude bombing was sufficiently difficult without this added burden. Underwing racks were removed, thereafter to be used only for special tasks."

 

[wuzak]

The US AN-M56 4,000lb. general purpose bomb was developed in 1941.

This was something the RAF built on with their "HC" series of bombs, often called "cookies".

How can the RAF have built on the US AN-M56 with their HC series when the first HC bomb was dropped in April 1941 and, by your reckoning, the AN-M156 was developed in 1941?

btw the AN-M56 was a "light case bomb".

 

[drgondog]

And this is the reason why taildraggers went away on the majority of aircraft produced after WW2, especially on military aircraft.

You "fly" a taildragger the minute the engine(s) start turning.

I was on a program where you had USAF IPs with minimal or no tail wheel time attempt to fly a motorized tail dragger glider. Many ground loops and damaged aircraft, thank god no one was killed. A bird Colonel saw the light and killed the program.

I was privy to a great story by Lt Marshall Knox (Navy Cross) who flew ADs in combat during Vietnam. Somewhere (I 'disremember' where) in Pacific or even San Diego, beverages were consumed and a cluster of clueless A-4 drivers alleged that flying a tail dragger should not be a problem for a 'real' aviator. Bets were placed re: no incidents/damage'. The next day, the 'real aviators' drove the first three ADs into the weeds on left side of runway, and wiser heads prevailed. Bets were paid, butts were chewed by higher authority. Marshall told me 'Thank God' they didn't attain actual flight condition and have to watch them land'.

 

[Reluctant Poster]

Hey GrauGeist,

Sorry, but those are not 4000 lb bombs on the external racks. The 4000 lb bomb was as ~long as the external rack, the ones in the phots you posted are only ~1/2-2/3 the length of the rack. Also the sway braces are in the wrong position for the 4000 lb bomb. By the position and spacing of the sway braces it looks like the bomb in the photos with the words "You To Joseph . . " on the side is the 1000 lb. The 2000 lb and 4000 lb used wider spacing for the sway braces with the forward one farther forward. The lower diagram in the link to your post#62 in the Fake B-26 photo? thread shows the required sway brace spacing and positions, as well as the relative size of the bombs to the bomb rack.

Here is another diagram of the rack and sway brace position and spacing, with the relative size of the 1000 lb and 4000 lb bomb in comparison to the length of the rack. Note the spacing of the sway braces.
View attachment 666821

Of further interest attched are the B-17 bomb hoisting arrangements. Note that the USAAF got the captions for the 1600 lb and 2000 lb bombs reversed. Figure 417 showns the external rack

Also note the restrictions on 1600 lb AP bombs which do not apply to the others

 

[Reluctant Poster]

Quite a shape! From the attached article

 

[Reluctant Poster]

Everything you ever wanted to know about US bombs (and more)

 

[Reluctant Poster]

Size comparison for US bombs

This is from the attached file. I had a clearer version of this figure, but I cannot locate it.

 

[FLYBOYJ]

I was privy to a great story by Lt Marshall Knox (Navy Cross) who flew ADs in combat during Vietnam. Somewhere (I 'disremember' where) in Pacific or even San Diego, beverages were consumed and a cluster of clueless A-4 drivers alleged that flying a tail dragger should not be a problem for a 'real' aviator. Bets were placed re: no incidents/damage'. The next day, the 'real aviators' drove the first three ADs into the weeds on left side of runway, and wiser heads prevailed. Bets were paid, butts were chewed by higher authority. Marshall told me 'Thank God' they didn't attain actual flight condition and have to watch them land'.

My god! no experience flying a taildragger and then ballsy enough to attempt a first flight in a Skyraider!!!! Ensign Darwin!

 

[drgondog]

My god! no experience flying a taildragger and then ballsy enough to attempt a first flight in a Skyraider!!!! Ensign Darwin!

You can tell a Fighter pilot, but not tell him much, Dad and several other pilots took a dare from Doc Savage (Cpt USN and Ace) that USAF pilots at Eglin couldn't all make a carrier landing in 'soft' seas with some training at Pcola. They did with one wave off and land on second try - circa 1952 - so USAF lost the bet. I think T-28s were the beast of choice.

 

[FLYBOYJ]

Great stuff Bill - "remember, it's better to die than look bad"!!!!

Hey - take a look at the thread and tell us what you think! - Identifying new WW2 wreck off Pt Loma, San Diego

 

[Jugman]

I believe six 1600lb bombs was either the original intended load out or was set by the availability of B-10 shackles and later it was expanded to eight. I Have seen that same bomb loading chart in the E&M manuals for the B-17F and the B-17G. In ALL cases the more authoritative bomb hoisting diagram show eight. It also shows that the station numbers differ between the two configurations.
7/28, 10/31, 18/39
8/29, 11/32, 16/37, 20/41
The bombs at stations 16/37 had to be rotated 10° fin down so that the bombs at 11/32 would have adequate clearance.
The maneuvering restrictions specifically apply to the use of B-7 shackles.

In terms of actual bomb weight the heaviest loads were:
B-17
12,720lbs = 8x1600lb AP
10,250lbs = 10x1000lb AP
10,144lbs = 16x600 AP
7960lbs = 8x1000lb SAP
7,552lbs-7,904lbs = 16x500lb SAP
6,120lbs-6420lbs = 12x500lb GP
5,784lb-6240lbs = 6X1000lb GP
4,692lbs-4,968lbs = 8X600lbs Dem
4,444-4564lbs = 4X1100lb Dem
4,080lbs-4,384lbs = 16X250PG or 300lb Dem
3,982lbs-4,280lbs = 2X2000lb SAP or GP
~3,600lbs = 24X150lb class bombs
B-24
12,720lbs = 8x1600lb AP
11,940lbs-12,300lbs = 12X SAP or AP
7712lbs-9128lbs = 8X1000lb GP or 1100lb Dem
3,060bs-7,608lbs = 12X250 GP to 600lb Dem or AP
~3,000lbs = 24 X 150lb class bombs

The B-17 had a small but very space efficient bomb bay.

 

[JDCAVE]

I'm just a stupid non-pilot. WTF is a "Tail-Dragger"?

Jim

 

[FLYBOYJ]

I'm just a stupid non-pilot. WTF is a "Tail-Dragger"?

Jim

an aircraft with a tail wheel

 

[Geoffrey Sinclair]

The nominal meaning of the "design useful bomb load" is pretty much the same as the requirement to carry a specific weight of wombs to a given distance. Similar in idea to the requirement that a the Air Ministry Specification resulting in the Fairey Battle required it to carry 1000 lbs to a radius of X miles.

I think it is mostly to make the B-17 not look anemic compared to the British 4-engine heavies. If you do not use the 1600 lb AP bomb load, for the US normal operations it only carried a max of ~6000 lbs

Interesting term for a specified range figure with a given bomb load. Next, Australian Official histories online, Second World War Official Histories

Not sure about the bomb load figure to make the B-17 look better, it definitely started early though, the first of the RAAF Official Histories were published in 1954, the first half of the war against Germany, Appendix 1 aircraft performance has this about the B-17 and B-24. Performance, still air range with bomb loads.

Aircraft	Crew	Miles	Bombs (lb)	max speed mph/feet	serv. Ceil. Ft.	Guns	Remarks
B-17
Mk I B-17C	6​	3,000​	nil	300 at 25,000	35,000​	6 x .5-in & 1 x .3-in	As used by RAF
Mk I B-17C	6​	2,000​	5,000​
Mk II	6 to 10	2,050​	6,000​	290 at 25,000	27,500​	9 x .5-in	As used by RAF
Mk II	6 to 10	840​	12,800​
Mk IIa	8​	1,900​	7,000​	295 at 25,000	32,000​	9 x .5-in	As used by RAF
Mk IIa	8​	1,650​	9,600​
Mk III	9​	2,740​	3,500​	280 at 20,000	31,500 (a)	13 x .5-in	As used by RAF (a) min . Weight
Mk III	9​	1,140​	12,800​	n/a	26,500 (b)	13 x .5-in	(b) max. weight
B-17G	11​	2,350​	4,000​	295 at 30,000	36,000​	13 x .5-in
B-17G	11​	2,250​	6,000​
B-24
Mk I	6​	3,100​	nil	320 at 16,500	36,000​	4 x 20-mm & 5 x .303-in or
Mk I	6​	2,000​	4,000​	n/a	n/a	or 6 x .5-in & 1 or 2 x .3-in
Mk I	6​	1,500​	8,800​
Mk II B-24C	6 to 10	2,100​	5,000​	?	34,000​	7 x .5-in or 11 x .303 -in
Mk II B-24C	6 to 10	?	8,000​
Mk III B-24D	8​	2,470​	3,500​	275 at 20,000	33,000​	8 x .5-in & 4 x .303-in
Mk III B-24D	8​	1,290​	12,800​
Mk VI	8​	2,290​	4,000​	270 at 20,000	32,000​	10 x .5-in	As used by RAF
Mk VI	8​	990​	12,800​
B-24G, H & J	10​	2,500​	3,000​	300 at 30,000	34,000​	6 or 10 x .5-in	American . Max . bomb load 16,000 lb

By 1962 the performance table had added, in the volume on the first part of the war against Japan,

B-17E	6 to 10	2,500​	nil	295 at 30,000	27,500​	8 x .5-in and 1 x .30 in
B-17E	6 to 10	1,415​	2,500​
B-17E	6 to 10	1208​	4,000​
B-17G	11​	1,100​	12,800​	295 at 30,000	36,000​	13 x .5-in	External racks could increase bomb load to 17,600 pounds

The US AN-M56 4,000lb. general purpose bomb was developed in 1941.

US AN-M56A1 4,000 pound bomb, first production in January, then some in March, April and October 1942, then production April 1943 to March 1944, all up 6,225 made. Superseded by the HC Mk V, production from April 1944 to August 1945 at least, 38,805 made. USAAF Statistical Digest has 1,220 x 4,000 pound dropped in theaters against Japan in 1945.

Roger Freeman's Mighty Eighth War Manual on page 223 has the same photo of the aircraft on the ground with the bombs on the underwing racks; note the image on your linked post is cropped tighter. The caption for the photo reads:

"M-44 1000 lb GP slung on a 303rd BG B-17F's wing racks, 18 Sept. 1943, ready for a mission to France. Single yellow band round rear and front of bomb casing indicated TNT or Aurotal [sic] filling."

And the plot thickens, using the Mighty Eighth War Diary the 303rd had flown a mission to France on 16 September, dropping 500 pound bombs, then the group's next mission was on 23 September, again France, again 500 pound bombs. Then on 26 September the 3rd Bomb Division mission to France, only the 96th (19 a/c) and the 388th (21 a/c) bombed, with 38x1000 pound, 228x500 pound HE and 840x100 pound Incendiary, the 94th and 385th groups aborted. The accompanying photograph is a shot of the 94th group with a pair of 1,000 pound bombs on external racks, the numbers suggest the 96th also carried the external load, even so at 5,900 pounds per attacking bomber they are not big loads, perhaps the external load was to compensate for the loss of bomb weight carrying the incendiaries.

On page 153 of the same book, in a section about the B-17F, it says this:

"The B-17F had the capability to lift much heavier loads if external wing racks were used when it was possible but not practicable to attach 4000 lb bombs. With the prospect of increasing bomb loads to short-haul targets, in August 1943 B-17 stations received kits for installing external racks on their aircraft. A few missions were flown during the next month where, in addition to a normal internal load, two 2000 lb bombs were carried externally by each Fortress. With the adverse effect on climb and high altitude performance making formation flying even more difficult and considerably reducing endurance, VIII BC soon decided that high altitude bombing was sufficiently difficult without this added burden.

Mighty Eighth War Diary usually lists the number and types of bombs dropped by the heavies in August and September 1943, a pair of 2,000 pounders on Bonn 12 August, another pair on French airfields on the 15th, 368 dropped on Watten France on 27th from 187 B-17, 7 September 116 dropped on Watten from 58 B-17, the B-17 could carry 2x2,000 pound HE internally.

The evidence is there for 1,000 pound bombs dropped from external racks on a small number of missions, but not 2,000 pound.

 

[33k in the air]

And the plot thickens, using the Mighty Eighth War Diary the 303rd had flown a mission to France on 16 September, dropping 500 pound bombs, then the group's next mission was on 23 September, again France, again 500 pound bombs. Then on 26 September the 3rd Bomb Division mission to France, only the 96th (19 a/c) and the 388th (21 a/c) bombed, with 38x1000 pound, 228x500 pound HE and 840x100 pound Incendiary, the 94th and 385th groups aborted. The accompanying photograph is a shot of the 94th group with a pair of 1,000 pound bombs on external racks, the numbers suggest the 96th also carried the external load, even so at 5,900 pounds per attacking bomber they are not big loads, perhaps the external load was to compensate for the loss of bomb weight carrying the incendiaries.

Yeah, I looked at that too and noticed the group didn't fly on the 18th. I presume it's either (a) the B-17s were prepped with external bombs but the mission was later scrubbed; or (b) the date printed in the book is a typo.

 

[FLYBOYJ]

Found another photo of that gear collapse from my earlier post (312).

 

[spicmart]

Which assessment did the PB4Y-2 Privateer get? Any significant improvement over the B-24?
Did it have better accident rate, Was it safer to fly and be in, in case of a crash/ditch?

 

[FLYBOYJ]

View attachment 667406

Which assessment did the PB4Y-2 Privateer get? Any significant improvement over the B-24?
Did it have better accident rate, Was it safer to fly and be in, in case of a crash/ditch?

I think in the bigger picture it would have a lower accident rate but then again it was performing a different mission