List of Boeing B-17 Flying Fortress variants

The following is an extensive catalogue of the variants and specific unique elements of each variant and/or design stage of the Boeing B-17 Flying Fortress, a heavy bomber used by the United States Army Air Forces and other Allied air forces during World War II. == Boeing Model 299 (B-17) == The Model 299 was the original aircraft built by Boeing to fulfill an August 1934 requirement by the United States Army Air Corps for a bomber capable of carrying 2,000 lb (910 kg) of bombs 2,000 mi (3,200 km) at 200 mph (320 km/h). The 299 was powered by four 750 hp (560 kW) Pratt & Whitney S1EG Hornet radial engines, giving a maximum speed of 236 mph (380 km/h) and a maximum gross weight of 38,053 lb (17,261 kg).

Source: Wikipedia — List of Boeing B-17 Flying Fortress variants (CC BY-SA 4.0)