At the outset of the Spanish Civil War both sides used what aircraft they could lay their hands on, regardless if they were military or civilian. And some of the civilian ones were converted into improvised combat aircraft.
The one that probably was the most important was the civilian DC-2, that were hastily converted into a bomber, and was used in action for the first time just tow days after the outbreak, when two DC-2 bombed Tablada. It had quite an effect because of its speed it was almost impervious to interception to the standard fighter used in those first nonths of the war: the Nieuport D.52.
I wonder - could anyone try and do a makeshift DC-2 bomber?
There is no 3d work involved. It just needs to be able to carry bombs. It also was equipped with two defensive MG's that fired out through the side windows on the sides. (On at least one, an MG was also installed in the font cabin window, and operated by the second pilot.) The bombs were not carried in racks, but inside the passengers compartment, and were simply pushed out of the open side door!
The bombs used were also of an improvised nature: 10 x 60kg bombs, sometimes combined with 12kg bombs and live mortar rounds (!) The largest projectiles that the converted DC-2's could carry in this way were 100kg bombs.
I don't think that this needs an open cargo door etc. Bombs just dropping underneath the bird, combined with two defensive MG's will do quite nicely!
Any takers?