The RC Allen RCA11A-15 is a vacuum-driven directional gyro (DG) used in light aircraft instrument panels (commonly Piper and Cessna installations). It provides a stable 360° heading reference independent of magnetic compass errors by using a precision air-driven gyroscope mounted in a vertical azimuth gimbal.

The instrument is part of the RCA11A series, designed for long service life with minimal internal mechanical complexity. It operates on aircraft vacuum/pressure systems, where airflow spins the gyro rotor to maintain directional stability.

The “-15” configuration is the cardinal heading display version (N, E, S, W markings), optimized for general aviation cockpits. This specific unit is unlit, meaning it does not include panel lighting for night operations unless separately specified.

It is TSO-certified and built to maintain accurate heading indication even under moderate aircraft maneuvers (non-tumbling within approx. ±85° pitch/roll limits).

Key features include:

RC Allen model: RCA11A-15
Vacuum-driven directional gyro (DG)
3.125" standard instrument panel fit
360° azimuth heading indication
Cardinal heading display (N/E/S/W) – Piper/Cessna style
Non-tumbling up to approx. ±85° pitch/roll
Vacuum air-driven precision rotor system
TSO-C5c certified (aviation standard)
Unlit configuration (no internal lighting)
Approx. weight: ~2.3 lb (1.04 kg)
Designed for general aviation (Cessna, Piper, etc.)
Used as primary heading reference instrument in analog cockpits