An instrument for indicating roll and pitch attitude of a host craft. The instrument comprises a support for attaching the instrument to the host craft and a terrain reference including a horizon line fixed relative to the host craft parallel to the transverse axis of the craft. A gyroscope is universally mounted in the support to maintain a stabilized datum reference perpendicular to the earth. The gyroscope is coupled through gears and linkages to a simulator which represents the host craft as viewed from the rear. The simulator is mounted adjacent the terrain reference for angular movement with respect to the horizon line to indicate roll and for radial movement relative to the horizon line center to indicate pitch. In one embodiment the simulator is a three dimensional representation of the host craft pivotably connected to the coupling mechanism for pitch movement relative to the horizon line in the same sense the host craft pitches relative to the natural horizon. As the host craft rolls or pitches relative to the stabilized datum gyroscope the rotation and movement of the gear and linkage coupling devices effect the various responsive displacements of the simulator for attitude indication.
Artificial horizon indicators are precise, gyroscopic flight instruments designed to furnish an aircraft pilot with an artificial indication of an aircraft pitch and roll attitude with respect to earth. Basically, such indicators include a gyro gimbaled within a frame which is fixed to the aircraft. Roll indicia is responsive to the gyro for rotation within a display window as a part of the frame about an axis parallel to the roll axis of the aircraft. A spherically shaped horizon indicating member is also responsive to the gyro for movement within the display window to remain parallel to the actual horizon during flight of the aircraft. The spherical horizon indicating member is pivotally mounted to the frame between the gimbal axis of the gyro and the roll indicia. The coupling of a horizon indicating member to the gyro includes a two stage three pin drive to present the aircraft pilot a uniform movement of the horizon indicating member for movement of the aircraft about the pitch axis.
