I've now got a mental image of racing B17s retaining their waist guns and blasting chunks off each other as they tear round the course.
Maybe four engine racing bombers would be allowed to retain two of their defensive guns. Which two being left to the team to decide.
Ball and top turrets would be better choices
For field of fire considerations maybe. But in terms of drag?
Depends what model of the B-17.
I'd have thought the nose gun of the F model would be the 'slipperiest' - and you'd want to take out the guy in front of you, no?
If you're going with the G model, then the two cheek guns would be the least drag inducing.
Rule 1: No nose or tail guns!
Rule 2: All allowable turrets must have a physical inhibitor preventing the firing of weapons in a 45
0 arc to the left & right of the aircraft's centre-line!
Rule 3: Two (2) only self-loading rifles of not greater than 12.7mm (.50cal), or two (2) only automatic machine guns of not greater than 7.62mm (.30cal), or a combination of one (1) self-loading rifle of not greater than 12.7mm (.50cal) & one (1) only automatic machine gun of not greater than 7.62mm (.30cal) may be carried aboard at any time!
This means a more strategic approach needs to be taken towards overtaking & being overtaking, rather than just blasting away with a bunch of .50cals/20mm's at the opposition immediately ahead or astern of you.