Peter Stickney wrote:

snip

I've just come across my notes from the Day Bomber Lanc thread, and
here's some stuff that didn't make it into the thread that may be
germane to this discussion. With reference to armor weight.
Wartime Lancasters didn't have a whole lot of armor. The only armor,
in fact, was the Pilot's seatback, and a bulkhead over the main wing
spar, where it crosses the fuselage. Figure about 150# of armor.
It did have self-sealing tanks. (I don't know if it was for all
tanks, though. If not, you lose about 7% fuel capacity, and 3/4# for
every gallon protected.


U.S.A.A.F. day bombers carried armor at all crew positions, except
Bombardier 9Can't se through armor, after all) and the rule of thumb
was 100# per position, doubled in the case of the cockpit, which was
armored both to the rear, and to the front.

Later, they removed much of the crew armor and replaced it with flak curtains, as the
latter was considerably lighter and only slightly less effective.

Each oil cooler or
radiator that was armored cost 80#, Turret weights, less guns, are
about the same. A .50 cal gun weights as much as 2 .30s, so the tail
turret doesn't change, but the nose and top turrets gain 65#.

Mo 65 vs 24lb (some sources give 22, but that may be the fixed variety).

A ball
turret, with guns, or its equivalent in a remotely sighted turret,
plus the extra crewman to operate it, is 1200#.

So - added weight for a day-bomber Lanc. (This will have to come out
of fuel or bombs), we'll assume similar ammunition wieghts

Armor for nose, tail, and top turrets: 300#
Armor for cockpit, pilot only 200#
Addition of lower turret 1200#
upgrade guns to .50 cal 130#
Armored Oil Coolers 320#
Armored Radiators 320#
That's a total of 2470#

Note that a co-pilot is a good thing
if adding a copilot, add 370#
(170# crewman, more armor)
Total oe 2840#

And then you can add all the extra fuel for formating, close formation, climbing higher,
and hauling all of it there and back.

I've read it somewhere that the single-pilot B-25s and B-26s saved about 300 lb., but
ISTR that the inference was that this was due to the emoval of dual controls/instruments
plus the armored seat, i.e. not counting the co-pilot's weight or any other armor.
There's also some minor additional weight for the extra oxygen tanks/regulators/lines
and the intercom lines for each additional crewman. And then there's the ammo weight.
I've seen 'typical' loads quoted as 13,000 rounds for a Lanc, 6,500 rounds for a B-17.
Belted .50 cal. weighs roughly three times as much as .30 cal. For long, deep daytime
missions beyond fighter range in 1943, that 6,500 rounds might grow to 10 or even 12,000
depending on the crew's inclinations and what the pilot would allow (some crewmen were
wont to build 'cocoons' for themselves out of extra flak vests; tail gunners who did
this could cause serious Cg problems). BTW, I don't recall seeing a photo or reading
that the Brit bomber crews wore flak vests and helmets, at least by night. I imagine
they might have adopted them if they went over to day bombing, but does anyone know for
a fact?

Guy