I guess you must be referring to Lawrence Hargrave, a pioneer in aerodynamics who invented the box kite, published his research, and whose literature was extensively read by the Wright brothers who then adapted his design to the Flier, which was essentially a scaled-up box kite, even though a few other things went into it. But I know nothing about the first powered flight taking place in Australia. You have any leads on that?
1894 Powered flight Lawrence Hargrave discovered that curved surfaces lift more than flat ones. He subsequently built the world's first box kites, hitched four together, added an engine and flew five metres. Hargrave corresponded freely with other aviation pioneers, including the Wright Brothers. Unlike the Americans who commercialised their ideas, Hargrave never patented his. Because it promised public access, Hargrave left all his research and prototypes to the Munich Museum. http://adb.anu.edu.au/biography/hargrave-lawrence-6563
In that case, Hargrave invented the principle of lift and produced a design which demonstrated this principle. On top of it, he may have achieved the world's first powered flight if his model was launched from a horizontal surface rather than elevation, lifted rather than glided, achieved a powered flight for a few seconds, and then landed on the same horizontal surface. The Wright Brothers then dublicated his design, scaled it up, attached a pair of engines as well as control and stability surfaces of their own invention, and achieved the world's first powered manflight.
