B17 Gunship was an ill-conceived project that did not work out in the real life and was scrapped immediately.
B17 had an abysmal bombload as it was, considering the crew and its size. Putting many drones in the formation would not help any. Besides, they did not offer protection agains flak.
Their bigger problem was the folowing:
Once the regular B17s dropped their load and become much lighter, the gunship still had all that weight off ammunition and extra weapons to carry, so it's top speed on egress was much lower then a regular bomber.
They either had to fall out of formation and leave the formation without a cover and themselves vulnerable, or the whole formation had to fly slower and linger extra time in the enemy territory.
miko--