Lancaster bomb loads

From my recollection the nose and tail fuses were installed by the armourers when loading the bombs.

Usually there would be an arming wire run from each fuse and this was attached to the aircraft. When the bombs were released the arming wires were pulled out and the fuses then started to arm themselves by the small propellors on each fuse. The bombs had to fall a specified distance before they were armed. This then allowed the aircraft to dump the bombs on takeoff, should they lose an engine, without destroying friendly folks and potentially themselves.

Unlike the B-17’s and 24’s there was no access to the bomb fuses in the bomb bays of the Lanc and the Halifax once the aircraft took off.

Deryck is right, the arming wire was fed from a spool on each bomb rack with a quick release pin on the end as the bombs fell, the wire was pulled out and released the pin in the fuse and the wire retracted back into the spool.

The bombs had to fall a specified distance before they were armed. This then allowed the aircraft to dump the bombs on takeoff, should they lose an engine, without destroying friendly folks and potentially themselves.

But bombs (except HC type such as the 4000lb ‘cookie’) could be jettisoned safe from any altitude.

Deryck is right, the arming wire was fed from a spool on each bomb rack with a quick release pin on the end as the bombs fell, the wire was pulled out and released the pin in the fuse and the wire retracted back into the spool.

How were bombs actually ‘armed’ in flight; were the ‘spools’ dropped with the bombs if they were jettisoned ‘safe’?

This is probably where the confusion in the translation occurred.

The spools or reels are part of the bombracks not sure how they were dropped safe maybe others will be able to advise.

Unfortunately, if the current thinking is true, Major Glen Miller wishes that they could have been jettisoned “safe”. I am only familiar with the US type of bombs so I cannot speak for the HC types.

In the B-17, and probably the B-24, it would have been possible to unhook the arming wires from the bomb racks and bend the part of the wire that was fed through the fuses so that it could not fall out and then dump the arming wires with the bombs. That way the propellors would not spin and the fuses would not arm. You would have to be quite agile in order to reach all the four bomb racks and it would not be a pleasant exercise!

In the 8th Air Force the bombs were loaded with two 48″ long (or so) lengths of wire connected to a ring in the middle. The ring was hooked onto the bomb rack. When the aircraft landed the bomb bay was a tangled mess or arming wires, all of which were disposed of. We never wanted for bits of wire! If the RAF figured out a better way, good for them!

Here is spool that pulled the pin from the bomb once it was clear of the bomb bay and recoiled back. And a pic of the Lanc Bomb bay at Duxford.

Unfortunately, if the current thinking is true, Major Glen Miller wishes that they could have been jettisoned “safe”.

Wasn’t it speculated that it was either the splash or even a direct hit (rather than explosion) that brought his aircraft down?

I seem to remember some speculation about a 4lb incendiary (one of thousands being jettisoned) being responsible.

The spools or reels are part of the bombracks not sure how they were dropped safe maybe others will be able to advise.

I do remember reading how a Bomber Command pilot could see 4000lb ‘cookie’ bombs exploding in the channel on the way to the target, jettisoned by crews who were desperate to gain the safety of additional height. I can’t remember who it was (Don Bennett?) but his speculation was that other parts of the bomb-loads were being jettisoned ‘safe’ in similar manner but that the ‘cookie’ couldn’t be dropped safe as it would explode when it hit the sea…..whether it was ‘armed’ or not.

Makes you wonder why they had (three) fuses at all! :confused:

Anyway, the point being that Bomber Command aircraft could ‘arm’ bombs in the air without access to the bomb-bay.

The other thing is the ratio between bomb load and range. Mindful crews noted the amount of fuel as well as the bomb load and could determine where they would be heading to. Were there “typical” bomb loads if one would be bombing f.e. Essen in the Ruhr Valley compared to a faraway target like Nuremberg or Berlin?

I suppose it would depend on the routing; not all raids were straight in, straight out, but it should be possible to work-out an approximate range or to exclude targets that couldn’t be reached.

Here are a couple of graphs to work-out range / bombload from ‘The Lancaster manual’.

Thank you, these diagrams are really helpful. I presume “W/T” means “take-off weight”?

Yes, maximum take-off weight is listed as 63,000lb (unless certain modifications have been carried-out when it is 65,000lb) in the Pilot’s Notes reprinted in ‘The Lancaster Manual’.

Bomb release, safe or live.

HI.
The spools mentioned are normally locked and the pins are pulled out when the bomb is dropped. To jettison bombs safe, the bomb aimer puts the fusing switch from ‘live’ to ‘safe’. the spools are free to revolve allowing the bombs to fall with the pins in situ.

Ken

I do remember reading how a Bomber Command pilot could see 4000lb ‘cookie’ bombs exploding in the channel on the way to the target, jettisoned by crews who were desperate to gain the safety of additional height. I can’t remember who it was (Don Bennett?) but his speculation was that other parts of the bomb-loads were being jettisoned ‘safe’ in similar manner but that the ‘cookie’ couldn’t be dropped safe as it would explode when it hit the sea…..whether it was ‘armed’ or not.

Makes you wonder why they had (three) fuses at all! :confused:

Anyway, the point being that Bomber Command aircraft could ‘arm’ bombs in the air without access to the bomb-bay.

I’m new to this forum but that is easy to answer/explain. The black object shown earlier is known as a “Fuzing Unit”. Internally it functions much the same a retractable tape measure would. The fuzing unit was normally in the safe/unarmed mode which allows the fuzing wire (steel bowden cable similar to that on bike brakes) to be withdraw against spring tension. When bombs were released live, the drum would be locked by a solenoid (when fuzing is selected) and the locked system arms the fuze by removing its safety device which is retained until landing. If dropped is a safe condition (no fuzing selected), the fuzing wire is pulled out of the fuzing unit and is lost with the weapon. Although we are talking WW2 era, similar fuzing units remained in use in most bomber aircraft up to and including the V bombers.

So when dropped fused (armed) the cable reels out of the fusing unit (spool) but stops when fully extended, removing the pin from the bomb (arming it), and the cable then retracts. But when dropped safe the cable doesn’t stop when fully extended.

Thanks for the explanations everybody; it is nice to know the actual mechanics of the operation…

Here is spool that pulled the pin from the bomb once it was clear of the bomb bay and recoiled back.

…and thanks also for posting that photograph of the spool fusing unit…..are these things difficult to get hold of?

I’m new to this forum…

Excellent first post…..welcome to the forum!

You can fit 4 x 500lb across the bomb bay as shown in Night Bombers here.
ie: the middle station holds 2 bombs.

http://youtu.be/z-cVw7Xb6Nk?t=15m16s

cheers,
Greg

What a great film, I have not seen this before, thank you for the link.

I didn’t know that some Lancs fitted 0.50cal in the rear turret as an ‘up grade’. Must have been bloody cold with the plexi glass cut out.
And the average of 40 hours before getting shot down, most Lancs didn’t have to have replacement engines fitted as they never had a chance to wear them out.

Lest we forget.

No worries Paul!

Great photo BobKat!

The box tails are the US supplied ones.

edit: I see you show the bombs dropped. I’m surprised the 500lb are presumably not the last row (if the photo shows tumbling 500lbers). The one dead centre looks like 1000lb, I guess the others are US 1000lbers. Never appreciated the difference in shape before.

Yeah, Ive seen a few mistakes on the ORBs.

Thanks again for sharing the pic.

lanc35, a fascinating video clip – many thanks for providing this.

I agree with you that ‘GF’ is probably a mistype for ‘GP’ and yet the ORB states: 16 x 500 GF, 2 x 500 GP. The two types of bomb were clearly intended to be different!

With the consent of the copyright holder, I attach a picture of bombs dropping from ED908 on 19 July 1944 – the last mission from which it returned. At first sight this looks like a ‘standard’ 14 bomb load, but the ORB says that 1 x 500lb hung up because of a faulty carrier. From what you say this must have been in the fourth group which would have been loaded four abreast. The bombs dropped were 7 x 1,000lb MC, 4 x 1,000lb GP, 3 x 500lb MC. It is interesting to note the two types of tail fin in the third group of two bombs, which were presumably loaded 3-3-2-4-3.

ED908’s 18 bombs on 20 July would presumably have been loaded: 4-4-2-4-4.

You can fit 4 x 500lb across the bomb bay as shown in Night Bombers here.
ie: the middle station holds 2 bombs.

http://youtu.be/z-cVw7Xb6Nk?t=15m16s

cheers,
Greg

Thanks Greg,
Mystery solved
I enjoyed the Utube clip very interesting & detailed look at wht happened on an op in a Lanc.
Cheers Paul

BombKat, regarding your GF entry. I expect it to be a mistaken entry for GP/General Purpose bomb.