In the US Army Air Force during WWII, did experienced B25 and B26 pilots get moved up to the B17 or B29 (depending on the theatre) as the new planes became available or were fresh pilots trained for them?
On the one hand, I suppose you’d want your most experienced pilots in the best planes. On the other, maybe the B17s/B29s were so different from earlier models that it was thought better to simply train new pilots in the task.
A quick google gives results that don’t seem to address the question.
Note that the B-17 was in service before the war started; the B-25 came in about the beginning of the war; and the B-29 in the middle of the war. The B-24 (which you did not mention) came in about the same time as the B-25. (And there was no WWII bomber designated B-26, at least as far as Wikipedia knows.) So if crews did transition, it would likely have been B-17 –> B-24/B-25 –> B-29 or something like that.
About the OP, afaik there were different missions assigned to medium and heavy bombers and different skills needed to conduct them successfully.
Both B25 and B26 had forward pointed machine guns for strafing ground targets, or ships. Some variants of the B25 even had a 75mm gun in the nose, though I’ve heard that they were often removed and replaced with even more forward pointed MGs. Generally mediums attacked at lower height than heavies, Google “skip bombing” for an extreme example.
So I followed my own advice and read the Wikipedia article:
And it turns out the first successful skip bombing attacks were in fact flown by B17s even if the most well known attack (during Battle of the Bismark Sea) were by B25s.
This has been touched on in other responses but in a little more detail, the B-25/26/17/24 were all in or near operational service when the US entered WWII, all saw combat by spring 1942. There wasn’t any particular pattern of moving pilots from twin to four engine bombers of that generation.
The B-29 only entered service in 1943 with combat debut in mid 1944. So in that case many, initially most pilots had flown the earlier generation bombers, particularly four engine.
The first operational B-29 unit was the 58th Bomb Wing, which bombed Japan from bases in China from mid 1944, later moving to the Marianas. It received more previously experienced personnel than the later units. A goal was that pilots have two years previous service and 400 hours previous 4 engine (ie B-17/24) flight time. However, due to delays in B-29 production this unit did a good deal of its stateside training in the B-26.
The second B-29 wing, the 78th, the one which initiated bombing operations from the Marianas in November 1944, got a lesser allotment of previously experienced pilots but had more time to train before being deployed. But still most pilots had previous experience, and the unit used B-17’s in training to fill in for a shortage of B-29’s. Some pilots in both wings were men who’d finished training earlier in the war and become instructor pilots, as opposed to having previous combat experience, but others had previous combat experience.
By the third B-29 wing, 313th, entered combat early 1945, 50% of the pilots were direct out of training school and that % can be assumed to have risen further in the 314th (entered combat ca. Mar 1945) and 315th (June 1945) BW’s.
Sources are ‘Blankets of Fire’ by Werrell, ‘Twentieth AF Story’ by Rust and anecdotal evidence of various B-29 crew first hand accounts.
The same thing was true for the rest of the aircrew as well; they often raided the lighter bomber crews in order to fill out B-17 squadrons with gunners and flight engineers. (how my grandfather went from A-20s to B-17s after the 1st Schweinfurt/Regensburg mission).
And they retrained them for B-29s once they were finished with their 25 missions, at least enough to serve as gunnery instructors for incoming B-29 crews. (what my grandfather did once his 25 were complete).
My Father did maintenance on B 25s in Australia and New Guinea. He told me the cannons were removed because they bent the airframe. I’ve wondered if this is why the B 25H replaced the M4 75 mm cannon with the T13E1 light weight cannon, a lightweight version of the M3 with a lighter thin-walled barrel and a different recoil mechanism.
Oops. Somehow I missed the Marauder on the Wiki-disambiguation page when making my post. I saw the post-WWII bomber with the B-26 designation, but not that one.
The a/c redesignated B-26 under the USAF system of the late 1940’s served late in WWII as the A-26, then a major USAF Type in the Korean War as B-26 and in Southeast Asia in the 1960’s (eventually again designated A-26). But the WWII B-26 was a fairly major type. It saw limited service in the Pacific mainly in 1942/3 before the B-25 became de facto standard medium bomber there, but the B-26 was the main medium bomber of the 9th AF in NW Europe and shared those duties with the B-25 in the 12th AF in the Mediterranean theater.
Related to OP question of smaller bomber pilots going to bigger bombers, it again wasn’t typical (unlike big airliner pilots who often fly smaller ones first) but the first B-26 group to see action, the 22nd BG which flew in New Guinea from April 1942 eventually became a B-24 unit in mid 1944 which involved some personnel retraining on the larger a/c. It as because its operations by then required a longer range a/c. It had earlier become mainly a B-25 unit, concentrating its remaining B-26’s in one sdn from early 1943. Such a unit conversion from 2>4 engine was unusual though.