Boeing B-17C

B-17B, aka Model 299M {Two Frames}

-The first substantial purchases of the B-17 were staged in three lots of 13 aircraft beginning in October 1939. The B-17B was another upgraded version featuring design changes to accommodate the newer turbo superchargers, larger flaps, hydraulic brakes as well as streamlining of the nose all enhanced performance again.

**-It is interesting to note that even with these purchases Boeing incurred a loss over the course of the program to this point. This would all change quite rapidly in a short time.

-Army Air corps changes in the middle of production caused issues and reduced the profit.

**B-17C & D, aka Model 299H {Five Frames}

-The B-17C was another variation which incorporated changes that once again improved performance but most notably were the improved defensive capabilities. The bathtub lower gun position and flat teardrop waist windows were most notable.

**-This model had an upgraded Wright engine and could achieve 300 mph at high altitude

-This model was sent to England and served in the RAF 90 Squadron as Fortress I. This was the first combat use of the B-17…it was not a resounding success.

**-The initial order of July 1940 was for 80 B-17C, only 42 were produced when half way through the production the model was changed to B-17D in February 1941 addressing Army Air Corps requests.

**-An improved engine cooling system was incorporated featuring adjustable engine cowling flaps as was as an updated supercharger. A major upgrade was self sealing fuel tanks. Heavier machine guns were also fitted though the field of fire was still somewhat restricted.

**-Bomb load rating was 4000 pounds due in part to the 1000 hp engines, speeds over 310 mph at 25,000 feet were achieved.