el cid again
I do not entirely agree. There were indeed Axis heavy bomber designs and developments. A good case
can be made that some designers were leading the world in their concepts. In particular, the He-177,
which did eventually reach production, was a very sophisticated bomber in many ways well ahead of US
practice. It was the basis for numbers of Japanese designs by two companies, in two and four engine
configurations. Which is not to say there were not significant flaws: the original idea for four engines
in only two nacelles turned out to be a significant problem (which Japanese companies rejected on principle,
opting for either four separate engines, or to wait for more powerful engines to mount in a two engine version -
both choices resulting in delays that were too long to cope with during WW2). To which add the outrageous
requirement imposed by Hitler that the machine be a dive bomber, which was utterly impractical, and which had
tragic results. It is, however, misleading not to admit it was a very sophisticated aircraft, for which there is
nothing comparable in its design year, or for several years thereafter. It is not unique. The Me-264 was
without peer, ever, although it only reached prototype form - one of these did cross the Atlantic in a test run.
It is true that most Axis heavy bombers were improvised variations of commercial aircraft, as indeed was the first
US bomber to achieve modern mass production (the Hudson - originally adapted from an airliner for the British -
and the pioneer in true mass aircraft production). The Hudson was very Axis like - with a maximum load equal to its
normal load - rather than the heavy bomber practice of max load, normal load and an extended range, minimum load.
This is because airliners were not designed to carry truly heavy loads. But it isn't as if the US didn't use the same
design concepts - it did - and it was able to do that faster than it could develop the B-17 or B-24. It also
needs to be noted that the British achieved real heavy bombers of unique capabilities, including the largest
of bomb loads, which US heavies could not equal. The British regarded their designs as superior, and only used
US bombers because they were available in greater numbers. I tend to sympathize with that view. Never mind I worked
at Boeing Renton, and both my parents flew B-17s during WW2 (pretty unusual in my mother's case), which is how they
met. My mother's story might be worth telling - never thought of that before. My grandmother built B-24s, her
"tool" being a sewing machine (used on canvas which was part of the internal materials). I also used to go to
Willow Run when it was an airport (formerly the largest airplane factory in the world building B-24s when my grandmother
worked there). I grew up more or less inside the US Auto industry, which is very proud of its wartime bomber
production (and believes myths like Japan did NOT use auto plants to build airplanes: I learned in Japan that
they DID that TOO MUCH! - resulting in more planes than they could crew or fuel - and not enough tanks - a mistake
understood too late). US wartime bombers were not perfect (B-24s in particular were dangerously flawed,
and yet operationally more important than B-17s in PTO - the tanker versions were so dangerous I won't fly in one -
generally leaking aviation fuel). My father was a tail gunner and my mother was a photographer, both on B-17s.
I later worked for both GM and Boeing, and even on the B-1B bomber project. I thought I would probably be the
last advocate of the manned bomber (but am not - I no longer believe it is safe to fly manned combat aircraft -
nor necessary - because of the lethality of missiles and because unmanned aircraft can maneuver better not to
mention have more range if they do not need to have humans on board). I got this view working in a USAF R&D
activity in the 1980s - THEN USAF developers did NOT expect what we see today - plans for yet another manned bomber
being advocated for post 2030 use.
However, I am not sure the Axis should have developed heavy bombers. In spite of my USAF books about how it was
a bad mistake not to field them, I think for Germany at least it made geographic sense to go with two engine aircraft.
For Japan, it is only slightly more iffy: they really are cheaper and Japan did achieve oceanic range with
two engine solutions. I would have focused on a G7N two engine solution to replace the G4N - but that decision
was not taken in time. A variation of the He-177, it was still quite advanced by the time it might have achieved
production. Armed with torpedoes or missiles or bombs, it might have been superior to the Ki-67, which did demonstrate
utility with two of those weapons. Its success in raids on Saipan and Guam was classified Top Secret until this century,
and was the reason Iwo Jima was not bypassed, but invaded. Japan used it in JOINT raids, brilliantly timed to
catch armed and fueled bombers on the ground (we never understood how - but they noticed our use of weather planes
in a consistent pattern before a major raid), and they were never able to be opposed by fighters because they bombed
at night (making one wonder why we did not set up radar picket ships and night fighters on carriers?). They
did NOT need to see their targets - they were good enough to hit the fields - amazing for the navigation techniques
of the period. Imagine those raids with a rather better bomber, with more load and more defensive armament, and more
No Axis country had anything like the Fortress or the Liberator. These were different aircraft with different design assumptions, the benefit of a large and aggressive aviation industry.
Here's the bomb loadout for the B-17 and B-24D, all loaded into the bomb bay. Note the greater load capability of the B-24, although its greater flammability made it less popular that the rugged B-17. The slab-sided B-24 also had more room in the bomb bay than the svelte B-17.
2 x 2,000lb
2 x 1,600lb
2 x 1,000lb
12 x 500lb
16 x 300lb
16 x 250lb
24 x 100lb
4 x 2,000lb
8 x 1,000lb
8 x 500lb
12 x 300lb
20 x 100lb
Larger bombs were used against hardened and point targets (factories, bunkers) while smaller bombs were used against area targets such as airfields, troops in the open, etc. A string of 500lb bombs could destroy hangers, tanks and dispersed aircraft more easily than one or two 2000lb bombs.
Drag-inducing external bomb racks may have been an option for short range missions but would have not been the norm.
For example, the 8th Air Force missions into Germany which were full combat radius missions used only bomb bay mounted racks for their bombs. Conversely some heavy bomber attacks around D-Day in Europe used external racks onto which very heavy 4,000lb bombs could be fitted. These cut range but that wasn't a factor for these short-haul missions.
Bombs on external racks have to be armed before takeoff, normally at the end of the runway. Bombs in bomb bays are armed by the bombardier on the way to the target. Safer for plane and crew.
Incidentally the C-47 also had external bomb racks available on some variants, mainly to drop supply cannisters.
These racks only needed a separate electrical circuit to trigger bomb release.
These racks would have to be plumbed for external fuel tanks. This would require additional pipes and pumps.
The only reference to external fuel tanks (sometimes called "drop" tanks) on the B-17 or B-24 I have found was for two Navy B-17G which were rebuilt as PB-1W early warning aircraft late in the war. This mod required adding the aforementioned plumbing but only to the two B-17G aircraft modified.
I spent 10 years and two wars in an A-10 wing. Like the B-17 and B-24 the A-10 has a large internal fuel capacity and great range. We had the capability to carry external fuel tanks, but used them only for ferry missions across the pond. NEVER for combat.
"Tokyo" tanks were not external to the aircraft. "Tokyo" tanks were additional internal tanks in the wings fitted to the B-17F and G models. This was extra fuel internally carried that did not affect bomb load. Few if any went to the B-17E seeing depot maintenance in 1942. I think pretty much the B-17E was the predominant model used in the Pacific 1942-1943, being replaced by the longer-legged B-24 as they became available.
So adding extra fuel by adding extra tanks means a 410-gallon "ferry" tank in the bomb bay, cutting the payload of bombs in half. This added 700 miles to the range, about 230 miles to the radius. These were self-sealing later in the war, not sure about 1942. Not sure how this would affect the "durability" number for the sturdy B-17.
The B-24 was already vulnerable to battle damage to its fuel system so I don't think its durability would be further reduced.
Also, due to geometry not sure anything larger than 500lb bombs would load with a ferry tank in the bomb bay.