The Yeoman YA-1 Cropmaster was a development of the Kingsford Smith Aviation Services KS-3 Cropmaster (which was an agricultural conversion of the CAC Wackett Trainer), featuring a major redesign and retaining only the steel-tube fuselage frame of the CAC Wackett Trainer.
The Cropmaster went through several developments during its service life, the final version featuring an all-metal wing and all-metal empennage.
This set of detailed drawings (originally drafted at 1:48 scale) shows the development of the Cropmaster from its initial YA-1 configuration through to the final YA-250R production version.
Plate 1. Side elevations
The first plate shows side elevations of several versions of the cropmaster:
- YA-1 Cropmaster 250 (first version with the Wackett trainer empennage, wooden wing and fabric-covered aft fuselage sides)
- YA-1 Cropmaster 250 (production version with all-metal wing, all-metal empennage, fibreglass aft-fuselage sides and Lycoming engine)
- YA-1B tricycle undercarriage proposal (never constructed)
- YA-1 Cropmaster 250R (production version with Continental engine)
Click on the thumbnail above to open a PDF file.
Plate 2. Plan view
The second plate shows a plan view of the YA-1 Cropmaster 250 production version (Lycoming engine) as well as several scrap views showing extra details.
Plate 3. Structural details
The third plate shows a front elevation of the YA-1 Cropmaster 250 (Lycoming engine) as well as structural details.
Plate 4. Additional side elevations
The fourth plate shows a front elevation of YA-1 Cropmaster 250R (Continental engine) as well as side elevations of several different version:
- Yeoman 175, a modified Wackett Trainer used as a test-bed for the new cockpit canopy and all-metal empennage
- Yeoman-Hanes 250, a 3-seat modification of the Cropmaster
- Yeoman Cropmaster 300, a proposed larger and more powerful version of the Cropmaster which was never constructed
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