To clarify, British experience with the B-17C and criticism of the fact the type had no armour plating, self-sealing tanks and inadequate defensive armament were transmitted to the Americans in time for B-17Ds to be modified with better armour protection, self-sealing tanks and improved armament, along with the same modifications to the remaining B-17Cs in USAAC service. This is common knowledge and can be found in most books on the B-17.
What? Do you think the British relied on carrier pigeons to relay their information across the Atlantic? There was ample time between May 1941 when 90 Sqn received its first B-17Cs through to production of the B-17E. While its structural and aerodynamic design had been settled on in late 1940, metal wasn't cut until later in 1941. The modifications made to the B-17C and D models in USAAC service were also applied to the B-17E; armour plating, self-sealing tanks, etc. At the time of the B-17E's design in late 1940, by and large, the USAAC did not have these innovations fitted to its in-service aircraft and the Americans did not have a production powered gun turret, although several manufacturers were investigating the issue - arguments had been had about the fact Britain had turrets on their bombers despite there being resistance to them in the USAAC.
From the outset the B-17E was to be fitted with one and it was from the British that a production gun turret for the type came. A tail turret was also proposed initially, but the weight of a turret below the massive new fin dangerously shifted the aircraft's proposed cg. Boulton Paul and Nash & Thompson sent examples of turrets to Wright Field in 1940, and these were extensively studied by the US turret manufacturers resulting in the Sperry company studying the Boulton Paul Type T top turret, which was rejected by the British Minister of Aircraft Production in 1940 because it was a 50 cal armed twin turret. The MAP wanted existing turrets in production and at that time the British did not have the 50 cal under licence production, which, it was argued would delay production bombers receiving gun turrets, but that's a different story. The Sperry A 1 top turret eventually fitted to the B-17E was a copy of the Boulton Paul Type T using the same electro-hydraulic operating system but built by US manufacturers, but I digress...
Throughout 1941, based on British experiences in combat since the beginning of the war, these innovations were applied to US combat aircraft, to the extent that at the time of Pearl Harbor, Grumman were hurriedly retrofitting F4F fighters with self-sealing tanks and armor before they were embarked on US carriers.
Last edited: