ZERO-GRAVITY MANEUVER INSTRUMENTS AND INSTRUMENTATION.

The type ARU-2BA Attitude Director Indicator ADI system was evaluated as a pilot aid in flying a JC-131B aircraft on a ballistic trajectory to produce a zero- or reduced-gravity field. To provide an unburdened display to the pilot, all information necessary to fly a complete zero-G maneuver was presented on the ADI, except airspeed. A Parabola Control Panel was designed to provide six modes of presenting normal acceleration data to the ADI i.e., zero-G, sub-G, super-G, decay, float, and program modes. The modes were effective, except for the float and program modes which are still experimental. Data from 385 maneuvers at various gravity levels from 0 G to 0.75 G revealed that when flying gravity levels below 0.25G an accuracy of 0.05G could be maintained. This is generally considered an acceptable parabola. However, when flying gravity levels greater than 0.25G the errors became greater than 0.05G. As the desired gravity level is increased, the parabola time is increased and a high degree of accuracy is more difficult to maintain. In addition, the system errors were greater at the higher gravity levels. These two facts account for most of the errors at increased sub-gravity levels. The ARU-2B ADI system proved to be an effective aid in flying various sub-G, super-G, zero-G, and decay maneuvers. Author