History
Combat
Boeing eventually took note of any design faults in the erly types and produced, what was in effect, a completely new bomber, the B-17E, with its distinctive large tail fin and much improved firepower. The company built 512 B-17E's and then progressed to the B-17F which was the first truly battle-ready Flying Fortress. The B-17F rolled off the production line in the summer of 1942 and Boeing were eventually to built 2,405 of them. The B-17F was to be the model that flew the US 8th Air Force daylight unescorted raids into Europe in 1943.
The next model, the B-17 G was the final development of the design. 8,680 B-17G's were built. In total, Boeing managed to equip 108 squadrons of the 8th Air Force, 20 squadrons of the 15th Air Force in Italy and provided 200 B-17's to be used by the RAF. Most of the men who had flown a B-17 knew, that it was a rigged plane.
It was calculated that the average life of a B-17 flown by the US 8th Air Force was 215 days: for 119 days the aircraft was non-operational, it was under repair for 49 days and flying missions for 47 days.
Such was the fury of aerial combat in the European theater of operations that it was notable if a B-17 survided 25 missions in its first year.
The first crew, who finished 25 combat missions in Europe was the crew of the "Memphis Belle"
The following table shows the outputs of the B 17 of the respective for manufacturer.
| Model | First Flight | Boeing | Douglas | Vega | TOTAL |
| 299 | 28.Jul.1935 | 1 | 0 | 0 | 1 |
| Y1B-17 | 02.Dec.1936 | 13 | 0 | 0 | 13 |
| Y1B-17A | 29.Apr.1938 | 1 | 0 | 0 | 1 |
| B-17B | 27.Jun.1939 | 39 | 0 | 0 | 39 |
| B-17C | 21.Jul.1940 | 38 | 0 | 0 | 38 |
| B-17D | 03.Feb.1941 | 42 | 0 | 0 | 42 |
| B-17E | 05.Sep.1941 | 512 | 0 | 0 | 512 |
| B-17F | 30.May.1942 | 2300 | 605 | 500 | 3405 |
| B-17G | 21.May.1943 | 4035 | 2395 | 2250 | 8680 |
| Sum | 6981 | 3000 | 2750 | 12731 | |
| Proportional | 54.8% | 23.6% | 21.6% | 100% |