This is our last installment with the theme of "Fathers" for September. We are concluding with Lawrence Hargrave, another of Australia's aviation pioneers who also graced the paper $20. Hargrave had been interested in experiments of all kinds from an early age, particularly those to do with flying machines He chose to live and experiment with his flying machines in Stanwell Park where he invented three particularly significant designs - curved aerofoils, the box kite and work on the rotary engine.