(Above) The completed prototype Lycoming powered Airtruk, fitted out for a crop-spraying demonstration. According to my (fairly unreliable) memory, this was Bathurst NSW Air Show, February 1979. In the background you can see the tail of Transavia-built Sopwith Pup replica VH-PSP.
(Below) A Continental-powered Airtruk being demonstrated at an air show in the late ’70s – early ’80s. I don’t remember where this was taken, unfortunately; it may have been Schofields, NSW.