After making a new drawing of the DC-4, and modifying the DC-3's cockpit, I ended up updating the DC-1, 2, 5, and the Showa Tabby too, as well as drawing the Li-2.
So I decided to show the complete Douglas Comercial family and its relatives I have done so far.
DC-1
DC-2
DC-3
DC-4
DC-5
DC-8
Lisunov Li-2
Showa L2D Tabby