I was chatting with an ex-Rhodesian Air Force Canberra navigator the other day. I asked him to check a TAS calculation; he told me that he was quite familiar with the good old Dalton whizz-wheel as "There was this computer thing in the Canberra with a whole load of pipes and cables - but it never really worked so we had to use the circular slide rule for working out our bombing calcs."
"Was that accurate enough?" I asked.
"Ag, well - put it this way. The 'customers' never complained!" was his reply.