Here is an interesting and well-written piece about a type aircraft that fought in the Battle of Britain, that was fitted with a rotating turret. What I love most about the description is the 1938 memo:
The speed of modern bombers is so great that it is only worthwhile to attack them under conditions which allow no relative motion between the fighter and its target. The fixed-gun fighter with with guns firing ahead can only realise these conditions by attacking the bomber from dead astern. The duties of a fighter engaged in ‘air superiority’ fighting will be the destruction of opposing fighters … For these purposes, it requires an armament that can be used defensively as well as offensively in order to enable it to penetrate into enemy territory and withdraw at will. The fixed-gun fighter cannot do this.
This reasonable-seeming, technical-sounding argument condemned many men to a needless death, by putting them into a vulnerable aircraft. I wonder if it was written by a pilot.