NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Francis Upchurch
Date: 2014 May 6, 23:22 -0700
Greg,
I've been studying Chichester's 1931 Tasman flights. On page 122 of the "Lonely Sea and Sky, he says he had Logs( In Roper's 1840s book!)but made too many mistakes copying 6 figure logs, so preferred his Bygrave.
By 1940,however, he was teaching RAF navigators using the new short Air Tables, with no mention of the Bygrave, although some top navigators, such as AVM Bennett of pathfinder fame used one for most of the war. The Germans and Japanese had their versions throughout the war. I also wonder whether Chichester may have lost his Bygrave in one of his near death crashes 1932+
I've repeated lots of Chichester's sight reductions using my Bygrave, including the miraculous (and lucky!) 1931 Tasman trip. Get pretty well perfect results and much quicker than tables and even more so than haversines and logs.
I still do not understand why the Bygrave did not become standard RAF issue. the only weakness in design was the "slippage issue" , easily fixed with a simple lock as per Gary's design.
I'm still trying to figure out how to use it for clearing my lunars. Can do half of it but not the first part. Waiting for some maths genius to guide there?
Francis
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