The B-18A was the radial engined (two 1,065 hp Swedish licence built Pratt & Whitney R-1830
                                           Twin Wasps) sister craft to the B-18B.   The A model preceded the in-line powered B and some
                                           60 or so were built.  These were initially bombers but were relegated to the reconnaissance role
                                           after the more powerful B-18Bs started coming on line. At that time the B-18A was redesignated
                                           the S-18A.