The drawing to the right is a detail from a figure from my book, showing the harried flight engineer of a B-29 bomber. Click for the full image, which is the cover of an instruction book for using the “flight engineer’s computer.”¹

The “computer” is the slide rule that the flight engineer is holding. It was designed by physicist Alex Green (1919–2014) of the Twentieth Air Force’s Operations Analysis Section to aid in the management of fuel consumption over the course of long flights (see a picture of the slide rule here).²

In the drawing, the cause of the flight engineer’s stress is the complexity of the slide rule. Some years ago, Green replied to an inquiry I emailed to him concerning the illustration: “I instructed the artist of our topographical unit to show the flight engineer as the most hardworking member of the flight crew and to recognize that what we wanted him to do was impossible unless we gave him some extra arms. The flight engineers computer might have been the most complex slide rule in history with some six independent variables needed for a calculation of the fuel consumptions rate.”

One should also note that using such a slide rule was a task that came atop the flight engineer’s other, decidedly non-trivial duties. YouTube has increasingly become a treasure-trove of materials that would not previously have been readily available. Among materials that have recently appeared is the following training film for B-29 flight engineers, which nicely illustrates their typical responsibilities. An additional historical curiosity: one of the narrators is Ronald Reagan!