Artificial horizon how does it work

The gyroscope is gimbaled at a lateral axis for pitch attitude and a longitudinal axis for roll. The gyroscope works by creating a rigidity in space while spinning and is placed to take into account the tilting of that instrument. An AI functions properly when its gyroscope remains vertically upright while the aircraft rolls and pitches around it.

The bearings in AIs must have minimum friction. Even a small amount places a strain on the gyroscope, causing it to tilt. To minimize this tilting, a mechanism inside the instrument applies a force when the gyroscope tilts from its vertical position. This force returns the gyroscope to its upright position. All mechanical gyroscopes have inner and outer bearings in a gimbal assembly in addition to the rotor assembly.

Bearings contain bearing oil for anti-friction and are made to operate at high RPMs. In the closed system of an AI, the gyroscope stands erect and banking of the plane will tilt it off the axis. When an outside force tries to tilt a spinning gyroscope, it responds as if the force had been applied at a point 90 degrees further around in the direction of rotation.

Precession occurs when the vacuum or electric motor of an AI operates outside the design limits, or when any excess frictional force disturbs the free rotation of the gyroscope at design speed.

This causes a slow falling out or sluggish movement of the indicator. Therefore, the instrument should be left uncaged in flight unless the limits are to be exceeded. Otherwise, the instrument will show false indications when first uncaged. This site was designed with the. Artificial Horizon. The essential components of the indicator are: "Miniature Airplane", horizontal lines with a dot between them representing the actual wings and nose of the aircraft.

How Does It Works. An artificial horizon instrument presents pitch and roll against a circularly-shaped, vertical, cross-sectional representation of earth and sky which is aligned perpendicular to the direction in which the aircraft nose is pointing. In respect of pitch, the fixed aircraft symbol will then effectively ascend into the blue sky if the aircraft nose is raised from the horizontal and will effectively descend into the light brown ground if the aircraft nose is lowered.

In respect of bank, the horizon line will deviate from the horizontal relative to the instrument if the aircraft banks left or right whilst the aircraft symbol will remain horizontal relative to the instrument. Superficially, the bank case may seem slightly odd since, as displayed, the horizon has moved rather than the aircraft. However, the relative movement is correct and the observed position of the horizon bar will be replicating the real horizon as it would be seen if it was visible ahead.

The degree marks on the upper periphery of the dial. The first 3 on both sides of centre are 10 degrees apart, then 60 degree bank marks, and 90 degree bank arks.

The adjustment knob is used to adjust the wings up or down to align with the horizon bar. This allows adjustment to the height of the pilot. Preferably, the adjustment should be made when level on the ground. When the wings are aligned with the horizon bar, the aircraft is in level flight. If the wings are above the horizon bar, the aircraft is in a climb. Wings below the horizon bar indicates a decent. The upper blue part of the ball represents the sky. The miniature airplane wings fixed to the case represent the wings of the aircraft.

When in a left turn, the blue portion of the ball will have rolled to the right, as though you were looking at the horizon over the nose of the aircraft.

In a right turn, the blue portion will have rolled to the left. The rotor, mounted in a sealed housing, spins in a horizontal plane about the vertical axis. The housing pivots about the lateral axis on a gimbal, which in turn is free to pivot about the longitudinal axis. The instrument case is the third gimbal necessary for universal mounting.

The horizon bar is linked to the gyro by a lever, attached to a pivot on the rear of the gimbal frame and connected to the gyro housing by a guide pin. When the attitude indicator is in operation, gyroscopic rigidity maintains the horizon bar parallel to the natural horizon. When the pitch or bank attitude of the aircraft changes, the miniature aircraft, being fixed to the case, moves with it.

These movements of the instrument case with respect to the gyro are shown on the face of the instrument as pitch and bank attitude changes of the miniature aircraft with respect to the horizon bar.