Those are B-17B Flying Fortresses. The side blisters may have been modified from original but the ventral blister isn't the "dust bin" type of the "C" and "D".
Loves me my shark tails.
All metal I-16 ?, hmmm.. everything was used to make this plane, but rarely metal. It's a shame that young aviation enthusiasts have to read such nonsense, and draw the wrong conclusions....