Present status of aircraft instruments

This report gives a brief description of the present state of development and of the performance characteristics of instruments included in the following group: speed instruments, altitude instruments, navigation instruments, power-plant instruments, oxygen instruments, instruments for aerial photography, fog-flying instruments, general problems, summary of instrument and research problems. The items considered under performance include sensitivity, scale errors, effects of temperature and pressure, effects of acceleration and vibration, time lag, damping, leaks, elastic defects, and friction.