Gyroscopic Instruments in Aircraft

Even the most basic aircraft trainer includes gyroscopic instruments, due to their overwhelming importance for flight and navigation. The three most critical of these instruments are the artificial horizon, heading indicator, and turn indicator. If used properly, these indicators allow a pilot to fly using instruments alone, even if the view outside the cockpit is completely obscured by weather.

Gyroscopic instruments work on the principle of gyroscopic inertia. Inside a gyroscopic device is a spinning wheel or disc, whose inertia, once the wheel has been accelerated, keeps the disc stable about its axis of rotation. Once the instrument is stabilized, any deviation in the aircraft’s flight path will try to deflect the gyroscopic wheel in its gimbal mount. This movement, which is actually the instrument’s case changing position in relation to the gyro wheel, is translated to the movement of a needle or card on the instrument’s face.

While the three main gyroscopic instruments use the same basic principles, there are significant differences between them. The artificial horizon, or attitude indicator, has the gyroscopic wheel spinning on the vertical axis, and stays parallel to the natural horizon of the Earth. This means that as the aircraft banks, turns, climbs, and dives, the artificial horizon will reflect these changes as well, showing pitch and roll information in one instrument.

The heading indicator places its gyro spinning on the horizontal axis, with the pivot aligned with the aircraft’s centerline. Its gimbal allows only one axis of freedom, vertical, and connects the mount to the card on the instrument’s face through bevel gears. When the aircraft begins to turn, the compass card will turn only when the gyro reacts to the yawing of the airplane during the turn.

Lastly, the turn coordinator mounts its gyro wheel on the horizontal axis, but the pivot is oriented transversely, parallel to the wingspan.  Meanwhile, the turn coordinator’s gimbal mount runs along the aircraft’s longitudinal axis. In turns and banks, this gimbal axis is perpendicular to the instrument face, meaning that the needle will only show movement in the yaw axis.

At Just NSN Parts, owned and operated by ASAP Semiconductor, we can help you find all the gyroscopic instruments, for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at or call us at +1-714-705-4780.


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