While I was a Navy pilot (early 1950s) we used the E6B quite a lot. It was a
circular slide rule with an attachment used to calculate drift (the effect
of wind on your true course). Crews of multi-engine aircraft also used the
bubble octant, which was more effective than a sextant, particularly when
there was no visible horizon. Even though we had Loran, the receivers would
sometimes crap out, and Loran coverage was not 100%. Many big aircraft also
had specialized slide rules for calculating weight and balance. Having a
center of gravity too far forward or too far aft could cause big problems,
like crashing.

Earl K. Dille
e.dille@...






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