John Halliwell wrote:

In article , Guy Alcala
writes
No, I'm saying that _if_ you followed US practises etc., the Lanc's performance
would be within a few % either way of the B-17's.

But why drag the performance of an aircraft down by using it in a way
that is clearly inefficient? All this discussion has confirmed to me is
how inefficient the big box formations actually were. Dragging the
performance of a heavy bomber down to the point where it is carrying a
similar load to a Mossie, whilst remaining considerably vulnerable (and
with a crew of ten), doesn't make much sense to me.

Who says it was inefficient, under the prevailing circumstances? Clearly, the RAF
heavies would have suffered much heavier losses than U.S. heavies if they had tried
to operate by day, in formation, in the same time frame (especially before air
superiority had been won). Out of formation, they would have been slaughtered on an
even more routine basis than the U.S. heavies were, because they had no effective
daytime defensive armament, lacked armor, altitude performance, co-pilots etc. etc.
And they would have been knocked out of formation much more easily, lacking all the
above.

A couple of Mossies with a light load, perhaps 2,000lbs each start to
sound more and more promising. Small, fast formations may have been very
effective.

Small 'formations' for point targets, sure. For large industrial targets covered by
smoke and clouds, almost certainly not. A Mossie could carry at most 6 x 500 lb.
bombs (2 external), while a B-17 could carry twice that internally, i.e triple the
bmb load you recommend. If the Mossie's extra speed prevents more intercepts and it
can bomb from a lower altitude, it may well be more efficient than carrying more
bombs and dropping from higher up, but it's by no means certain that's the case
(unlike some on the NG, I don't rule out the possibility, but the only way to find
out for sure would have been to actually try it, and that didn't happen).

Now, could a B-17's performance be improved by removing some or all of the defensive
armament? Sure, which was done starting mid-44. At first, they removed the radio
room gun and left one of the waist gunners behind; less ammo was usually carried as
well. By 1945, one combat wing ordered one of its groups to remove the ball turret
from their a/c, another group the chin turrets and the third group both waist guns
(and their gunners). A different group in '45 was given permission to remove the
chin turret, ball turret AND either both waist guns or the top turret (forget
which). It boosted cruise speed by about 25 mph, or allowed a tradeoff of fuel,
bombload, and/or height. But it was possible (and made sense to do so) because by
then the fighter threat was rapidly shrinking. Defensive armament doesn't help
against flak, which was the primary threat in that period, but speed and altitude
do.

Nowhere did I say that you
had
to do so, but that is the variable that is always left out of the Lanc vs. B-17
threads, so that they wind up comparing apples and oranges.

The B-17 bomb bay was not the best arrangement for carrying large loads.

Certainly (the same was true to a lesser extent with the B-24), but that was due to
the structural design decisions made, not an inherent effect of design for day vs.
night bombing. Just look at the B-29 and B-36. I don't know why U.S. heavy bomber
designers pre-war went for short and tall bomb bays rather than long and shallow
oones like the RAF's; FAIK it was considered to give a better bomb pattern, or maybe
there was some different reason. It certainly wasn't universal among U.S.
bomber/attack a/c, as I can attest having had to slide over the wing spar (just like
a Lanc) to go from fore to aft in a P-2 Neptune.


As such had it been used in night ops, the range/payload may not have
been able to be improved to compensate for lighter fuel (or fewer
guns/crew) loads. On that basis, it's easier to drag the Lanc down by
hampering it with US practises than boost the B-17 by using RAF
practises.

The question is, what was the typical load actually carried by Lancs? In 1943, it
was about 8,000 lb. (effective bombload was something like 7,450 lb. The difference
represents aborts and a/c shot down before bombing ). In 1944 and '45 it increased,
both because there were more short-range tactical missions (to more lightly defended
targets), the defenses were lighter, and because friendly terrain was closer
(allowing more fuel efficient flight profiles and more divert possibilities if low
on fuel, i.e. less reserve fuel needed to be carried). Can a B-17 carry 8 x 1,000
lb. bombs in the bomb bay? There seems some question about that - it could
definitely carry 6 (the B-24 could carry 8), and could carry a pair externally.
Could a British heavy carry more individually larger bombs internally? Yes (with
the possible exception of the Stirling), but again that was a design decision, not
an inherent effect of the type of bombing to be done.

Guy