Bomb and Bomb-Bay Sizes

Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules

No. The bomb was attached to the rack, the sway braces (crutches in RAF speak) adjusted to fit and then the complete assembly winched into the aircraft. As you can see in post 43 there is no way that you could get your arms between the bomb and bomb bay skirt to adjust the sway braces in situ.

This part of Fig 4 in post 41 shows the bomb and rack attached to the cable and hanging about a foot below the installed position.
View attachment 791924

This part shows the assembly pulled all the way up
View attachment 791925

and this shows the swivel locking hook engaged in the loading link. Once the link is fully engaged the adjusting screw is screwed down firmly and then the cable tension is released. and cable and pulley cradle are moved to the next location. The spring loaded control for the adjusting screw works a bit like the direction control on a ratchet wrench. Move it one way and you can only tighten, move it the other way and you can loosen the adjusting screw.
View attachment 791926

The manual describes it thus. In (iii) it makes more sense with a comma after the word bomb or it said Fit the carrier to the bomb, adjust the crutches, set the fuse units and links.
View attachment 791927


This diagram from the RAF manual may describe it better. View D shows the rack and bomb assembly when it has just cleared the trolley.
View attachment 791928
Hi
Images from 'Britain's Wonderful Air Force' of January 1942 showing methods of winching for bombing up of Stirling and Wellington:
Image_20240806_0001.jpg

Image_20240806_0002.jpg

Mike
 
G Geoffrey Sinclair

The B-17 sheet on sorties lists "ATK": Does that mean the number which attacked the target, or those which were launched at the target? I remember looking at some data on B-29 raids on Japan and it often listed the total number of aircraft, the number which attacked, and so on.
 
No. The bomb was attached to the rack, the sway braces (crutches in RAF speak) adjusted to fit and then the complete assembly winched into the aircraft. As you can see in post 43 there is no way that you could get your arms between the bomb and bomb bay skirt to adjust the sway braces in situ.
Okay, I understand: The layout is pretty well thought-out. I'm honestly surprised we didn't use a system like this.
 
Hi

In continuation of my previous post, here is a composite photo of winching a 4,000 lb HC into a Lancaster, with winch fitted inside cabin above bomb bay, from page 134 in 'Bombs Gone, The development and use of British air-dropped weapons from 1912 to the present day', by MacBean and Hogben:
Image_20240806_0003.jpg

Mike
 
Hi

In continuation of my previous post, here is a composite photo of winching a 4,000 lb HC into a Lancaster, with winch fitted inside cabin above bomb bay, from page 134 in 'Bombs Gone, The development and use of British air-dropped weapons from 1912 to the present day', by MacBean and Hogben:
View attachment 792006
Mike
Hi

The winch appears to be similar to this one from page 135 of 'RAF Ground Support Equipment Since 1918' by F J Adkin:
Scan_20240806.png

Mike
 
Note on Message 59, the H.E., I.B., Frag and Total are in short tons, average in pounds. ATK means credited with attacking the listed target. Following figures from Mighty Eighth War Diary number sent on mission, number attacked a Berlin target.
DateB-17 SentB-17 attackB-24 SentB-24 attack
4-Mar-44​
238​
30​
6-Mar-44​
262​
246​
226​
198​
8-Mar-44​
415​
320​
209​
183​
9-Mar-44​
361​
339​
22-Mar-44​
474​
460​
214​
197​
29-Apr-44​
446​
368​
233​
212​
7-May-44​
600​
514​
8-May-44​
500​
386​
19-May-44​
588​
495​
24-May-44​
616​
464​
21-Jun-44​
703​
559​
386​
47​
6-Aug-44​
154​
132​
12-Sep-44​
0​
0​
6-Oct-44​
418​
382​
5-Dec-44​
451​
404​
3-Feb-45​
1004​
937​
26-Feb-45​
823​
781​
361​
285​
18-Mar-45​
980​
916​
347​
305​
28-Mar-45​
446​
383​
Totals
9,479​
8,116​
1,976​
1,427​
Inevitably MEWD and Richard Davis have different definitions of Berlin and MEWD does more summarising than Davis. Some aircraft that did not attack Berlin attacked other targets.

Pathfinders flew Halifax, Lancaster and Stirling as well as Mosquito, marker types dropped for war
TypeMosquitoLancasterHalifaxStirling
1000 TI
347​
1,882​
1000 Smoke
0​
34​
500 Smoke
17​
20​
250 TI
16,632​
29,792​
3,272​
883​
250 Spot Fire
396​
538​
12​
250 Smoke
0​
2​
250 Float
32​
100 Smoke
10​
Stirling only dropped markers in 1943, Halifax dropped 2,508x250 pound TI in 1943. Mosquito dropped 8x4,000 pound incendiary in 1945.
 
Hi

The winch appears to be similar to this one from page 135 of 'RAF Ground Support Equipment Since 1918' by F J Adkin:
View attachment 792014
Mike
Hi
Other types of winch in use during 1938, loading bomb cells of Fairey Battle, from page 183 of 'From the Ground up, A History of RAF Ground Crew' by F J Adkin:
Scan_20240808.png

Mike
 
The B17 's bomb bay was stacked vertically like this
img_20240805_175220-jpg.jpg

Here is an engineering drawing that presents the same information as the above drawing, but in what I think is a more understandable format. It's for a B-17F, but should apply to the B-17G. Earlier versions of this drawing do not show a 1600 pound bomb loading.

In addition, here's a Data Card for the B-17F. The Data Card for the B-17G looks similar, but the Weight Data now resides in a Weight and Balance Handbook stored by the main entrance door or in the Navigator's compartment. That is also true for some later versions of the B-17F. The Data Card is mounted to the front of the door in Bulkhead 4, just above the Flight Reports holder.​

Finally here is a chart which is posted in the A/C, with the full title of: Maximum Airplane Glide & Climb Angles for Bomb Release. Not sure what it all means, but am sure someone in this forum will know.
 

Attachments

  • Bomb Release Angles.jpg
    Bomb Release Angles.jpg
    10.4 MB · Views: 14
  • Data Card B_17F.jpg
    Data Card B_17F.jpg
    2.1 MB · Views: 14
  • B_17F_Bomb_load_1.jpg
    B_17F_Bomb_load_1.jpg
    9.5 MB · Views: 12
An excellent post as it answers the un-asked but important related question of what the aircraft pitch angle limits were for safely releasing the bombs and partially answers the post 4 quetion on clearance angles.

This incidentally means the B-17 could not be used, like the Pathfinder Lancasters were, as a dive bomber for target marking. There may, of course, have been mods to those aircraft but because it is a long wide bay I would expect there were just limitations on which locations the markers could be carried.

I find the picture labelled B17F_bomb_load_1 most interesting as it infers that the B-17F had a maximum bomb capacity of just 2,000lb. I think that highly unlikely but I have never studied at the B-17 loads. Is this the load when carrying the maximum wing fuel load? Again I think no.

I will comment on one earlier claim, I cannot remember who from, that the B-17 had a minimum bomb load of 4,000lb. What utter rubbish. That suggests that any B-17 ferry flight required at least 4,000lb of bombs or ballast to be carried and I can promise you that it not correct. Just as well the Collings B-17 was not carrying bombs or ballast or that accident would have been far worse and I know from being there that the Planes of Fame B-17 did many flights in the early 70s without any such ballast without any accidents or incidents.
 
Last edited:
If you check the manual for the B17f with 6,000 lbs in the bomb bay and 8,000 on external wing racks (14,000lbs) she had a range of 1170 miles IIRC. I think this was enough to reach just about any target in Germany. So it'd be reasonable to assume with the 12,800 lb load she had enough range to be useful. However, to get this range it would have meant dropping the altitude and flying straight in and out of target area.
Single aircraft straight-line range (the 1,170 miles you cite) never was used with the B-17.

In real-life missions the aircraft took off, with the earlier aircraft holding until all were up (which took considerable time), then they formed into formations which flew a "least-threat" course to their target - cutting the actual range about in half.
 
Single aircraft straight-line range (the 1,170 miles you cite) never was used with the B-17.

In real-life missions the aircraft took off, with the earlier aircraft holding until all were up (which took considerable time), then they formed into formations which flew a "least-threat" course to their target - cutting the actual range about in half.

Book range divided by three is what IRL range was, so far as I understand it.
 
An excellent post as it answers the un-asked but important related question of what the aircraft pitch angle limits were for safely releasing the bombs and partially answers the post 4 quetion on clearance angles.

This incidentally means the B-17 could not be used, like the Pathfinder Lancasters were, as a dive bomber for target marking. There may, of course, have been mods to those aircraft but because it is a long wide bay I would expect there were just limitations on which locations the markers could be carried.

I find the picture labelled B17F_bomb_load_1 most interesting as it infers that the B-17F had a maximum bomb capacity of just 2,000lb. I think that highly unlikely but I have never studied at the B-17 loads. Is this the load when carrying the maximum wing fuel load? Again I think no.

I will comment on one earlier claim, I cannot remember who from, that the B-17 had a minimum bomb load of 4,000lb. What utter rubbish. That suggests that any B-17 ferry flight required at least 4,000lb of bombs or ballast to be carried and I can promise you that it not correct. Just as well the Collings B-17 was not carrying bombs or ballast or that accident would have been far worse and I know from being there that the Planes of Fame B-17 did many flights in the early 70s without any such ballast without any accidents or incidents.
N371G?
 
Hi
In the book 'RAF: The Second Year' of 1942, there is a photo of a Havoc night intruder being bombed up, this shows the bomb carrier already fitted to the bomb before being loaded, methods appear to depend on aircraft type:
Scan_20240809.png

Mike
 
Later in WW2, 500lb bomb being loaded on a Mosquito FB.VI wing rack. The bomb carrier was fitted to the aircraft within a fairing. Armourers attached hand powered winches each side to haul them up into position.

1723186156631.jpeg



But for those in the bomb bay the bomb carrier was still attached to the bomb and then hauled into the fuselage.

1723186463172.jpeg


All a question of access I suppose.
 
An excellent post as it answers the OP's


Cant remember the rego - over 50 years ago. Piccadilly Lilly or some name like that I think - or was that the other one flying then?
I hope to meet the Piccadilly Lilly. I think watching 12 O'clock High with my dad is why I love the B-17. The Piccadilly Lilly is my favorite plane of my favorite planes.
 

Users who are viewing this thread

Back