Abstract: An improved airspeed transducer for rotorcraft is disclosed having a pitot tube connected with a differential capacitive pressure sensor. The pressure differential from the pitot tube is a function of the airspeed squared. A diaphragm in the capacitive pressure sensor deflects when the dynamic pressure exceeds the static pressure from the pitot tube. This diaphragm deflection is sensed by electronics which provides an electrostatic attractive force between the diaphragm and a fixed plate such that the diaphragm is brought back to an undeflected, "at rest" position. The electrostatic force between the diaphragm and fixed plate is a function of the square of the voltage applied to the plate that creates this electrostatic force. Since the pressure differential from the pitot tube varies with the airspeed squared, the relationship between airspeed and feedback voltage is linear. Thus, the feedback voltage is a direct indication of sensed airspeed.

Abstract: A variable frequency vibration absorber adapted to be fixedly mounted in a fixed vibration prone system to coact with the system principal vibration excitation source to control system vibration. The vibration absorber is bifilar in construction and the natural frequency thereof is varied in proportion to the frequency of the vibration being generated by the principal system excitation source.