Australian designed and built, based on the CAC CA-6 Wackett trainer. A new wing, tail, and engine were fitted and twenty-one were built between 1959 and 1967. The first flying in February 1960.
Production versions were the KS.3 Cropmaster 250 and Fieldmaster 285.
At least one was converted to three seats and, as a Yeoman Hanes 250, fitted with an extended glazed canopy to cover all seats.