Which design for the Wirraway?

Before deciding which design to build locally as the Wirraway, CAC were asked by the Air Board to import two different prototypes from North American Aviation (NAA) for evaluation in a “fly-off”.

Here’s a quick summary:

The first aircraft imported was the NA-16-1A (also known by its NAA accounting code, NA-32), a fixed-gear trainer with a direct-drive Pratt & Whitney Wasp R-1340 driving a two-bladed propeller. The newspapers of the day commonly referred to it as the “NA-16” (however this was a little misleading, since the NA-16 was actually a different aircraft, but they didn’t really understand that, and the name stuck in popular usage).

The second aircraft imported was the NA-16-2K (NAA accounting code NA-33), a retractable-gear trainer with a geared Pratt & Whitney Wasp R-1340 driving a 3-bladed prop. It was commonly known as the “NA-33”.

The drawing below shows these two aircraft compared with the Mk I Wirraway.

The RAAF held a “fly-off” between the two aircraft and decided that the NA-16-2K was a more capable aircraft.

Therefore the Wirraway was based on the NA-16-2K, but with numerous modifications added to meet RAAF requirements.