11.08.2009, 14:53
There were a total of 21 YB-40s built/converted. The original prototype and 20 more which were Vega-built B-17Fs converted by Douglas. There were also 4 TB-40s, though I'm not certain what differences there were from the YB-40.
From Joe Baugher's excellent pages:
XB-40: Conversion of B-17F-1-BO 41-24342
YB-40: Conversions of B-17F-10-VE 42-5732/5744, B-17F-30-VE 42-5871, and B-17F-35-VEs 42-5920, 5921, 5923, 5924, 5925, and 5927.
TB-40: Conversions of B-17F-25-VEs 42-5833 and 5834, B-17F-30-VE 42-5872, and B-17F-35-VE 42-5926.
From Joe Baugher's excellent pages:
XB-40: Conversion of B-17F-1-BO 41-24342
YB-40: Conversions of B-17F-10-VE 42-5732/5744, B-17F-30-VE 42-5871, and B-17F-35-VEs 42-5920, 5921, 5923, 5924, 5925, and 5927.
TB-40: Conversions of B-17F-25-VEs 42-5833 and 5834, B-17F-30-VE 42-5872, and B-17F-35-VE 42-5926.