The Yeoman Cropmaster was an Australian agricultural aircraft developed from the CAC Wackett trainer of World War II.

KSA had obtained a number of Wacketts following the type's retirement from Royal Australian Air Force service and had converted four for agricultural use as KS-3 Cropmasters in the second half of the 1950s.

[1] The conversion involved little more than the installation of a hopper located in the rear cockpit of the Wackett, the cutting of a hole in the centre section of the Wackett's wooden wing to allow the dispersal of the chemical load, and re-routing controls to bypass the hopper.

Like its contemporary the CAC Ceres the Cropmaster was unable to compete with more modern types of agricultural aircraft.

An intermediate flying test-bed, the single Yeoman 175 was converted from CA-6 Wackett airframe C/N 257 for trials of a new all-metal empennage, and had the swept fin of later Cropmasters but retained the Warner Scarab radial engine and fabric-covered aft fuselage of the Wackett.

The tailwheel configuration was retained although new oleo legs to handle the heavier take-off weight were required.

The area from the hopper to the tail was to be of monocoque construction with an access hatch to permit loading of cargo/work equipment or (no doubt) the odd passenger.

In 1965 Air-Culture's VH-CXQ, with Richard Adams flying, struck a tree whilst entering a spray run at Highbury near Narrogin.