The above image is with the notebook folded open placing it at about 30 degrees from horizontal. The notebook has provision for details of the flight with columns for time and observation.
The top dial is used to make altitude and air speed corrections.
The Navigational Computer was designed for attaching to the navigators leg. The straps are original and the elastic has not lost its properties.
This RAAF example was made by White & Gillespie in Melbourne. I'm currently looking for details of the firm.
I've had a few requests for the instructions so I've uploaded them
RAAF Publication 317.
Cheers from the cellar
A link to: Royal Australian Air Force Watches
Updated February 2006