Southern Cross was a small Australian car-making venture initiated in 1931 by aviator Sir Charles Kingsford Smith, together with his flying colleague Jim Marks. The project grew out of an earlier design, the 1923 Marks-Moir, which had been created by Jim Marks's father and employed an unusual monocoque construction using laminated timber to form a single-piece frame and body. The updated car made its public debut at Mascot Aerodrome in…