10. Getting the Bug to the target was a problem to be solved
For the Kettering Bug to work as planned, two problems had to be resolved. It had to “know” where it needed to go, and it had to also know how to get there. Level flight at a pre-planned altitude was relatively easy to achieve, or so its designers thought. Measuring the distance to the target was another problem posed to the designers. How could the machine know how far it had traveled? To resolve the problems of altitude, distance, and course of flight, Kettering and his team relied on the abilities of Elmer Sperry and his associates. The gyrocompass was reliable enough to ensure the flight would be on course. Altitude and distance were other issues.
An aneroid barometer – measuring air pressure – was developed by the engineers and technicians at Sperry. It was sensitive to the point that it could detect differences in air pressure from just a few feet. Sperry demonstrated it registering changes between the floor and the surface of Kettering’s desk. Detecting the change was not enough. The information needed to be transferred to the control surfaces, ensuring the Bug attained and remained at the desired altitude. Both Kettering and Midgley applied their talents to the problem of controls. Their first system used servos, which added weight to the aircraft and failed to respond rapidly enough to the input from the sensors. It was Midgley who came up with the idea of using the medium through which the Bug operated – air – to control its flight.