NavList:

During a recent flight, it was found that the trig figures on a normal 10" slide rule were too small to read, with propeller vibration and sun glinting through cockpit windows. The problem was later solved by adding a larger P scale to the rule's redundant rear face. The same trick was done with an E6b.

I think I have only ever used one side of the E6b's slide. It is an easy job to make a thinner aluminium slide, and glue on a scan of that useful side, leaving the reverse free to accept a copied 10" closed scale, with the essential P scale. 

The original function of each slide rule is not compromised. There is plenty of room left on the E6b to add necessary formulae and memos for multiple functions. If available, trig tables ease placing of decimal points, and can sometimes, but not allways, be quicker.

For tuppence-halfpenny, two slide rules have been upgraded to adequate Bygrave capability, and much more. No electrics.

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