Paul:

 

Wow! You are asking something that the best qualified person to answer would be a veteran Bomb Aimer and even so they might be pretty rusty.   I recall my Dad being a little startled that he'd forgotten the settings on a bombsight once.  It started to come back to him after a few moments and that was about 45 years after he'd last used one.  Now the average time lapse might be 66 years or so!

However, I did, after alot of searching, find Dad's training notes on Automatic Bombsights.  It's a fairly lengthy and complex document complete with diagrams and instructions.  It also is not likely entirely complete.

It appears that the differences between say Wellingtons, Halifaxes and Lancasters were relatively minimal.  Mostly it was the organization or lay out of this equipment that varied.   Still I believe most of the Bomb Aimers panel were located on the right side of the nose while the sighting computer and the bomb sight itself was generally mounted on the left.  Although, that said the big change was Dad switched from the Mk. IX C.S.B.S. in the Wellington to the Mk. XIV in the Halifax and Lancaster.  I believe this made his job much easier in terms of set up and inputting of altitude, air speed, course settings, etc.

I don't truly understand the exact procedure myself and really only have a vague idea of how it was all done but aside from the sighting component the Bomb Aimer had to set up the Automatic Bomb Distributor and/or the Selector Box to the Bomb Release Unit depending on the type or composition of the Bomb Load and the type of bombing pattern dictated by the target.

For example:  long, narrow targets such as bridges, railways or battleships would be bombed with a "stick" pattern and this required the Bomb Aimer to release a number of bombs with a set interval in between based on the aircraft's speed.

Different targets eg. factories or railway yards might be bomber with a more distributed cluster type bombing pattern.  Obviously in some cases individually aimed bombs such as the 12,000 lb.Tallboys or 22,000 lb. Grandslams or the Dambuster's "bouncing mine" were sighted for a single release.

A good Bomb Aimer and crew could lay their bomb load within a range of 100 to 200 yards of an intended aiming point and often those tolerances could be considerably improved.  Given that bombs were released from an altitude point often 3 - 4 miles above the accuracy was quite something. 

250 lb., 500 lb., 1000 lb. 2000 lb. the Cookies and Blockbusters (4,000 & 8,000 lbs respectively) as well as SBC with incendiaries all had different rate of fall characteristics and the timing interval had to be adjusted accordingly.  As well the aircraft had to be balanced with the release from the set attachment points so it wasn't totally thrown off kilter.

Here is a brief excerpt from these notes:

 

Bomb Aimers Panel

 

This is a 16 Point box on the end of which is a Drum Switch marked in 4 positions:

1. Safe Except for Jettison - with this setting bombs cannot be dropped by any operation of the selector or firing switches

2. Single and Salvo - with this setting the Distributor Unit is short circuited and bombs are released by selector and firing switches

3. Distributors -   with this setting the Distributor is the circuit and operation of the Firing Switch starts the arm of the Distributor moving which drops the bombs. The Carriers must be selected.

4. Container: As above but the contacts on the Distributor are joined together.  At the other end of the box are two Jettison Bars.  By pushing these bars in, the load is Jettisoned irrespective of the setting of the Drum Switch. 

 

Referred to as the MK VI - 16 contact Bomb Distributor. Also a detailed parts sketch diagram.)

 

If you are still interested let me know and I can probably photocopy and mail these docs to you on provison of an address or mailbox.  It's a bit hard to do a write up on the forum and as they are on legal paper size difficult to scan.  They are fairly faded and yellowed with age and a little dog earred, too but a good photocopy might clean that up.  You can contact me at roful at sympatico.ca (replace the at with the usual)

 

Hope that helps some.

 

Bob

Hi,

I have had  a DISTRIBUTOR 12 VOLTS TYPE VI REF NO.5D/663 in vgc. in its transit box.

 

I think this is from a bomb aimers station in a Lanc.

 

I plan to put it on ebay soon, anyone interested can email me,   Marc Young    rebeccayoung950@btinternet.com

Sorry to jump in on this thread.....

Bob, if its ok I would love to see the instructions you have - My Dad flew Lancs on his second tour with 75(NZ) (the first also being with 75(NZ) in a Stirling in '43). He passed away a year ago yesterday and we never spoke about the war. Since then I have been trying to piece together his time in the Squadron. He qualified as a category B bombing leader between tours and also instructed as No. 3 L.F.S.

my mail address is infoAT75nzsquadronDOTcom

many thanks in advance

Simon

Hello fellas, could you please tell me what A.m. actually stands for im guessing its an early mod supplier as i have a storage box for the above ref distributor with it on and ive had signal lamps and gauges wiyh a.m. with crown between the letters but i cant seem to finsd any info on A.m. please help men, cheers Ant