Armor protection on Striling and other bombers

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tkaniuka

Airman
60
6
Dec 11, 2015
Did British bombers have armor plating to protect fuel tanks and other vital components? I know there armor for some humans pilot mainly, but other places like fuel, oil, and hydraulic tanks etc?
 
Pilot armour early on was minimal but was added and improved later on all aircraft,

Fuel tanks were protected with a coating of various compounds starting in about 1940 but nothing before that. The addition of the coating required smaller tanks on most aircraft as the coating was roughly 12mm (1/2") thick making the tank roughly 25mm/1" smaller in all dimensions. This is why there are different fuel capacities on early and late aircraft manuals and other documents for the same aircraft (as in pre 1940 and post 1940) even though the space the tank(s) occupy is exactly the same.

The CIMA process used on some British aircraft consisted of
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Fuel tanks were only seen with armour very early on, before self-sealing tanks got into full swing -- and before the Stirling was in service (eg. a 1939 Wellington or Whitley would be sporting armour aft of the fuel tanks.).

The Stirling had:
  • armoured back and headpiece for both pilots
  • bulkhead across the fuselage aft of the main cabin which also protected the navigator and front gunner
  • armoured back for the wireless operator seat
  • small piece of armour for mid-upper gunner legs
  • small piece of armour for the rear gunner
  • self-sealing oil and petrol tanks
It may have also had extra bits of armour for the outboard engines and heavier gauge metal covering the engines but I can't be sure. My Stirling info isn't all that strong,
 
Pilot armour early on was minimal but was added and improved later on all aircraft,

Fuel tanks were protected with a coating of various compounds starting in about 1940 but nothing before that. The addition of the coating required smaller tanks on most aircraft as the coating was roughly 12mm (1/2") thick making the tank roughly 25mm/1" smaller in all dimensions. This is why there are different fuel capacities on early and late aircraft manuals and other documents for the same aircraft (as in pre 1940 and post 1940) even though the space the tank(s) occupy is exactly the same.

The CIMA process used on some British aircraft consisted of
View attachment 659425
View attachment 659426
I recall reading that RAF command (Bomber Harris) ordered armor plate removed from bombers, especially the Lancaster, so more bombing payload could be carried. I cannot find the reference just now, but it was later in the war when the bombing campaign was getting very intense.
 
Armour plating of RAF bombers is used as a canonical example in statistics and operational research.

During the ramping up of the 1942 campaign, the Center for Naval Analysis in New York was studying how to armour their bombers based on RAF statistics, work that they passed to the Statistical Research Group at Columbia. They would receive damage reports and produce graphics like this one (which is a post-war reconstruction if I'm not mistaken):

Plane-bullet-holes-survivor-bias-1.jpg


The white spots were the holes where the aircraft had been hit, mostly clustered in the mid-fuselage and outer wings.

Abraham Wald noted this was an example of survivor bias - the aircraft that returned to be included in the data were, obviously, not shot down. So these holes are the areas one should not armour, because a hit there did not lead to the loss of the aircraft. The areas around the pilots, engines and the oil coolers in the wings were deadly, getting hit there would lead to the bomber being lost. He published an extensive report on the topic in 1943.
 
I recall reading that RAF command (Bomber Harris) ordered armor plate removed from bombers, especially the Lancaster, so more bombing payload could be carried. I cannot find the reference just now, but it was later in the war when the bombing campaign was getting very intense.
Are you sure you're not thinking of the campaign over Japan? They removed everything they could from the B-29s, including the guns, to carry more incindiaries.
 
Are you sure you're not thinking of the campaign over Japan? They removed everything they could from the B-29s, including the guns, to carry more incindiaries.
I wasn't thinking of Japan, although I'm not surprised to know that the same tactic was used there. I really don't know much about that theater. I know that I read that Air Marshall Harris ordered armor stripped out of Lancasters, though.
 
I wasn't thinking of Japan, although I'm not surprised to know that the same tactic was used there. I really don't know much about that theater. I know that I read that Air Marshall Harris ordered armor stripped out of Lancasters, though.

I know that some were strippers in order to hoist Grand Slams or the bouncers, but were these fleet-wise orders or spec-ops mission squadrons only? Was this a general thing?

My understanding is that most Lancs flew into combat as they came off the assembly, without mods. Forgive, please, what might seem an ignorant question.
 
German NF without Schräge Musik tried to disable rear gunner first, then aimed for the outboard wing fuel tank/engine.
Those with SM usually went straight for the the outboard wing tank/engine.
Aiming for center fuselage was suicidal unless bomber was on its way home
 
Some bits re Lancaster protection & armour:

Mod 431 Introduction of 400-gallon self-sealing fuel tanks in bomb compartment (S.O.O.) , +30 lbs (fixed weight) +425 lbs/tank (removable weight)
Mod 439 Introduction of special armour (S.O.O.) +1,710 lbs (fixed weight)
Mod 500 Introduction of engine armour protection with new oil coolers +300 lbs (fixed weight)
Mod 575 CO2 gas installation for fire protection of fuel tanks +208 lbs (fixed weight)
Mod 690 Introduction of navigator's special armour to suit C and E electronics (S.O.O.) -14 lbs (fixed weight)

The armour mods were in addition to the normal armour the Lancaster was fitted with, but I have no details as to what they entailed.

I do not have any real dates as to when the mods became available and/or began to be implemented, although Mod 575 started to be implemented in early(mid?)-1944 and was discontinued for some reason.

Does anyone know what S.O.O. stands for?
 
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Special Operations Order I think. A mod was supposed to be carried out throughout the fleet, to keep to a common standard, hence the MU stage between manufacture and delivery to a squadron to allow a catch-up. A SOO was permission to only apply the mod to certain chosen aircraft, a bombing leader for example.
 
and another light bomber one for interest - note the comment on turret armour for British aircraft

It's interesting because it shows an aircraft (Hudson) without a turret and just an open gun position, as the aircraft was when first delivered as the A-29 to the USAAC. The BP turrets were fitted to RAF Hudsons following arrival in the UK, so perhaps the extra weight of the turret and the armour compromised handling?


From here.

 
The manual it comes from is interesting - it is a USAAF A-29/29A dash 1 and shows both the open gun and the BP turret on the page I posted. Your supposition on the CofG envelope makes sense and leaving the armour in along with the turret would probably put the CofG well past the aft limit unless the aircraft was ballasted.

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Contrary to my expectation the 29A is not a 29 with turret but a cargo version - and both require a minimum two man crew.
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As soon as I find the manual I will scan and post the B-25 C/D armour plating.
 

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