The B-17 was critical to the USAAF daylight precision bombing campaign and was armed with 13 machine guns, hence the name "Flying Fortress".
Flying in formation, the Fortresses battled through German defences in daylight raids, suffering heavy casualties until the addition of long-range escort fighters, the P-47 Thunderbolt and P-51 Mustang, and the introduction of the 25 mission limit.
Combat crews lives were measured in weeks rather than months but, despite the high casualty rate, B-17's became famous for returning home with terrible battle damage and were fondly regarded by their crews for this quality.
The B-17 is powered by four Wright Cyclone radial engines, each producing 1,200 horse power giving a top speed of 287mph at 25,000ft. With a bomb load of 6,000lbs the B-17 could fly 2,000 miles.