NavList:

Paul,

Agreed. Remarkable accuracy, suitable for pre-planning Hs . I have said before that a dedicated navigator could achieve adequate results in an aviation context, using a 10" rule in the right setting. This may not be good enough for operating a plane alone.

You make some comments: 
 Reading tiny trig scales on most 10" rules needs above average sight. On my modified E6 the figures are twice as large, and normal vision suffices. If a P scale is available, small angle cosine values are shown, without the need to find the complement of the sine. That scale is on my 10" as well.

Decimalising inputs is easier on a circular rule, and notes on use can be added; it is all-too-easy to forget things not done regularly.  It is also a shame the Bygrave method requires accurate azimuth calculation before comimg up with Hs.

 Picture is of a test, hand flying on 4 Nov 24.

In passing, none of the Boeings I flew, nor the Airbuses my son flies, nor the Garmin 1000 in shot,  possess a keyboard to allow +,-,/,x. This is needed  to work out litres of fuel to buy, to reach take-off gallons, and how many travellers' cheques to cash to give the bowser driver greenbacks before he will pump. A circular rule can do this.

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