The Saab B18 was originally designed in the late 1930s to be a reconnaissance plane. Swedish requirements kept changing so the first Saab-18 didn't appear until 1942. These requirements called for the aircraft to be able to do bombing and dive bombing.
The Saab-18 was of all metal construction.
The wings were positioned mid fuselage and were cantilevered.
The engines used in the B18A were unlicensed Pratt & Whitney R-1830-S1C3G Twin Wasps.