Whiz wheels

This is when Philip Dalton enlisted in the U.S. Naval Reserve to become a naval aviator. Dalton was also a research physicist and a consulting engineer who, in 1933, discovered the need for and developed a pocketsize time-speed-distance computer based on the principle of a circular slide rule. This was aviation’s first “whiz wheel.”

Dalton next developed his Mark VII wind-triangle computer that enabled pilots to determine the predicted groundspeed and heading required to maintain a desired true course during any given wind condition. This was the forerunner of what was to become the venerable Dalton Dead Reckoning E6B computer, which has been in worldwide use since its introduction near the beginning of World War II.

Although early E6Bs were constructed of aluminum, the scarcity of metal during the war led to the widespread use of plastic computers. A small number of wartime units were made of brass, and these are highly prized by collectors (of which I am one).

I became fascinated by the E6B the first time I saw one. This was after my first flying lesson, in 1952. It was such a status symbol, and I felt so proud to be seen with one. It was similar to the manner in which engineering students used to enjoy strutting around campus with slide rules dangling conspicuously from their belts. This is why I bought a used E6B so early in my career. The computer looked so cool and identified me as a pilot.

Although various other types of wind-triangle computers were developed in other countries for use by their military pilots during World War II, not one continued to be manufactured much beyond war’s end, which proves the success and popularity of Dalton’s E6B. I have been fortunate to have been able to collect some of these rare computers. Those shown here are a part of my collection and were made for and used by pilots of the German Luftwaffe, the Imperial Japanese Army Air Force, the Royal Air Force (Britain), the Soviet Air Forces, and the U.S. Navy. Not one of the foreign models is as accurate or as easy to use as the E6B. (The one wartime computer missing from my collection is the one developed by Italy for its Regia Aeronautica.) Also shown here is Dalton’s first wind-triangle computer, the Mark VII.

A unique aspect of the E6B is that it combines a wind-triangle computer on one side with a time-speed-distance computer on the other. The E6B has remained largely unchanged since its introduction and continues to be used in training today.

There are several reasons that explain why so many pilots prefer the E6B over its microchip counterpart. The most significant is the elegant simplicity with which a pilot can construct a wind triangle. The required plotting consists only of making a small pencil mark on the computer to represent the wind velocity. The pilot then needs only to adjust the slide to the appropriate airspeed and rotate the compass rose to the desired true course. The pilot can then visually verify that the solution is reasonably correct.

Plastic E6Bs, however, can warp and become junk when left on the glare shield of a parked airplane on a hot, sunny day. This is one reason why I am so fond of my brass version, the most enduring product of Philip Dalton’s ingenuity.

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