By Mike Davenport, EAA 89102, Langley, British Columbia
Back in the day, computers were simple things that didn’t require batteries, had no memory, and required a certain manual and mental dexterity to use.
Fifty years ago, I bought a Jeppesen CR-1 Computer. The retailer assured me that it was easy to use, and with it, I could solve all my aviation problems. Even back then there was no truth in advertising.
Sometimes called “whiz wheels” or more correctly “circular slide rules,” they were an essential part of one’s flight bag. Every pilot had one, but I doubt many could actually use the thing in a busy cockpit because that required the use of both hands. It did have its place in flight planning, and it worked well in conjunction with the appropriate paper charts.
With it I was able to calculate time, speed and distance, convert nautical miles to statute miles, U.S. gallons to Imperial, find density altitude, and even do trigonometric functions — though I avoided that as much as possible, including something called sine and cosine as we had never covered that in grade 10 math. However, if I turned it over to the ‘wind side,’ I could calculate true course and magnetic course, heading and ground speed, and something called variation and deviation — though that means something different today.
An assortment of whiz wheels otherwise known as Circular Slide Rules
As my faithful reader knows, I will stick with paper maps until they stop cutting down the trees to make them. However, I have cheerfully entered the computer age. I have found the perfect replacement: a Garmin Aera 500 portable GPS that I can use in the aircraft and even in my car. I just have to remember to update the software occasionally.
