The Magic Plastic Wheel

Ernest K. Gann, the aviation writer of the Twentieth Century, once wrote about the plastic E6-B flight computer that resided in his top pocket of his uniform shirt. Other pilots had other favorite places in or on their uniform for the storage of the magical plastic wheel; my favorite was the lower pocket of my right leg in my g-suit.

Today, many pilots use an electronic flight calculator. Few are the student pilots who rely on the old fashioned “whiz wheel.” To many, the whiz wheel represents something hard to use because it can be something difficult to learn. Once learned, however, the whiz wheel is one of the most simple devices to use—a very convenient and reliable tool in a pilot’s flight bag.

One of the great benefits of the whiz wheel is that it is, well, a wheel. As such, it is easy for anyone using or operating the wheel to see the relationships in the math. A pilot cannot do this with an electronic calculator.

If you look at the wheel, you can set the hour marker one the rate of speed. Then you can split the wheel in half by looking 180 degrees away from the hour marker. This point represents 30 minutes and it will tell you exactly hour far you will fly in half an hour. Similarly, you can quarter the wheel and determine the distance flown in 15 minutes.

It is different on the electronic calculators, though. More thinking is required to determine the calculations with the electronic E-6Bs. On the push button machines, pilots are unable to see those ratios plainly; they have to be able to do more math in their heads quickly. For instance, pilots have to know 120 knots divided by 2 is 60, divided by 4, it equals 30.  It seems simple enough and for the most part, it is.

When working with 120 knots, or 100 knots, it is easy.  This is simple math. Are pilots capable of the same mental math when the TAS is 174 knots? Or how about 266 knots?

The same holds true for fuel flow. On an airplane sucking down 16 gph, divided by 2 equals 8 and 16 divided by four (or 15 minutes) is four. Again, on the wheel, this is really simple—every 90 degrees around the wheel represents four gallons. It is very precise and simple to see—very quickly and easily.

Again, the same cannot be said of the electric machines.

When I was flying the A-7, other pilots asked why I carried an antiquated piece of equipment in an attack jet equipped with an onboard computer. The air data computer was capable performing many navigational tasks and the computer was capable of setting up and providing bombing solutions for many different types of weapons.

The important thing about carrying the old whiz wheel in an electric jet is that sometimes, the electricity might fail. Many pilots hate it when the electricity flops, some more so than others. When all of the electrical components quit working, the wise pilot can pull out and use those “antiquated methods” safely to handle the emergency and get the airplane on the ground in one piece.

In one of the “I Learned About Flying From That” columns in Flying Magazine from years ago, there was an account of a T-38 instructor pilot and his student flying through a front from Columbus AFB to Eglin AFB on an instrument training flight. In the nose cone of their airplane, a slight hole in the fiberglass began enlarging as they encountered rain. Soon, the avionics bay was awash in rainwater and the crew lost all communication and navigation radios. This happened in solid low IMC on the PAR approach. They were fortunate enough to maintain internal communications and the instructor simply told the student to climb and maintain 17,500 feet and set a course of 340 degrees.

Fuel was critical as it always is in tactical jets.

The IP pulled out his trusty plastic E-6B and with a few twists and turns, sweetened up the navigational problem. This put them back into VFR conditions right at Maxwell AFB where they flew a NORDO approach to a safe landing.

When teaching my students about the advantages of the old ways, I challenge them to a contest. Naturally, I can perform groundspeed problems lightning fast and some of the students can do other problems almost, if not faster than the old E-6B. I also admit to them that the electric devices are more precise with density altitude problems. But before I relent to the electric boxes being better than the old wheels, I challenge them to one last contest.

With a heave, I throw my wheel against the wall with great force. Then I reach down and pick it up.

“Look! It still works!”


©2012 J. Clark

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