The Revolution Will Not Be Televised wrote:

On Fri, 18 Jul 2003 01:04:53 -0400, (Peter
Stickney) wrote:

snip much

[Lanc altitude on ops]

While it doesn't get talked about much, the Lancaster was a fairly
height-limited machine. The usual heights on a raid into Germany were
between 15,000, and 20,000', depending on the amount of fuel burned,
and the particuar airplane.

By the winter of 1943-44, planned height bands for Lanc squadrons in 5
Group (which I have researched) were often 20-22,000 feet. The actual
bombing height was rarely much over 20,000 feet, and often a lot
lower, depending on weather and individual aircraft characteristics.
On operational conditions, with a full load, and winter weather to
deal with, they really did have difficulty getting over 20,000 feet.
The most common bombing heights (excluding exceptions like the
Peenemunde raid) seem to have been around 18,000 feet.

Odd that you should mention that, as Middlebrook ("The Nuremberg Raid") says
that a/c of all the Groups on the mission (with the exception of No. 1 GP;
see below), whether Lanc or Halifax, were evenly assigned to one of four
cruise heights -- 20, 21, 22, or 23 thousand feet. Naturally, some a/c were
unable to get that high or anywhere close to it. One crew flying a very sick
or tired Lanc couldn't struggle above 12,000 ft. but pressed on regardless;
as it turned out it probably saved them on that mission because the fighters
were up in the stream several thousand feet higher. A few a/c proved capable
of much better when the Jagdwaffe got into the stream and the experienced
crews decided that rigid adherence to assigned altitudes was stupid under the
circumstances, and decided to get the hell out of it by climbing (and more
than a few got rid of some bombs to lighten the a/c). One crew in a
brand-new Halifax (like all Halifaxes by that time, carrying an
all-incendiary and thus lighter load than the Lancs, to improve their
altitude performance) was delighted to discover that they were able to get up
to 26,000, and cruised happily along over the carnage a few thousand feet
below. The exception was 1 Group, whose philosophy was to carry max. bomb
loads on every mission, and who asked if they could fly at 13-16,000 feet to
take advantage of some predicted cloud at that level. They were granted
permission to do so until IIRR they reached the Rhine, at which point they
were supposed to climb to the same heights that everyone else was (supposed)
to be at. Unfortunately for them, the predicted cloud didn't show up.

After shedding the 5-7 tons that it was
delivering over the target, it would certainly have been able to
return at a much higher altitude than it went in.

Hence early jettisoning of bombs to reach bombing height, or climbing
after bombing. This is the sort of real context that tends to get
ignored in the interminable and ahistoric B-17 vs Lancaster
nationalist posturing. One of the trade-offs for the Lanc's higher
bombload was lower operating altitude [although this was also down to
the different engine outputs at different hieghts].

In addition to the engine differences, there's the considerable difference in
fixed weights (carried both to and from the target) due to extra crew, armor,
guns, turrets etc., and the extra fuel required for formation assembly (an
extra 1/2 to 2 hours before setting out), climb to higher cruise altitude and
flying in formation (throttle jockeying). When Pete and I went through the
exercise of turning the RAF heavies into day bombers a few years back, it was
apparent that using Lancs in formation by day against the same targets that
U.S. heavies were attacking, and with the same equipment, procedures and
tactics, would require a decrease in bombload of between 2,000-5,000 lb. to
reflect this, even assuming we refit them with two-stage Merlins to give them
sufficient power at altitude (and those engines each weigh ca. 200 lb. more
than the single stage jobs, which decreases the useful load for the same
MTOW, or requires an increase in MTOW and thus a decrease in climb
performance, higher accident rates, etc.). In short, design and equip them
to do the same job and they'll do it with payloads within a couple of hundred
pounds (either way) of each other. The whole Lanc vs. B-17 argument is just
ludicrous.

Guy