As I have studied the construction of the early B17Ls, I have noticed considerable variation in some of the construction details. This page is an attempt to document the differences that I have noticed. If you have any thing to contribute, please get in contact with me.
Gear Doors (updated 6-13-2016)
Engine Cowl (updated 6-13-2016)
Wing Faring (updated 6-13-2016)
Fuel Tank Vent (updated 6-13-2016)
Tube Rivets? (updated 7-31-2015)
Cessna turnbuckles on a Beech? (updated 7-31-2015)
Flaps and Ailerons changes on sn3 (updated 1-25-2017)
Internal wing fitting changes after serial number 21 (updated 4-18-2017)
Emergency Exit on serial number 21 (updated 4-8-2017)
Changes in I-Strut after serial number 21 (updated 5-26-2019)
Landing Gear Countershaft changes (updated 3-7-2020)
Wing attach bolt size. 1/4" to 5/16" after serial number 38 (updated 2-13-2020)
Tail Wheel Fork (updated 7-4-2020)
Change in brace at fuselage station 107 (updated 12-4-2021)
Change in aileron pulley location (updated 12-4-2021)