The RCA22 Series of vacuum artificial horizon are controlled by air driven precision gyros to present the pilot with pitch and roll information. The attractive color scheme of blue sky and brown ground presents a realistic spherical display of flight. Unless otherwise indicated, all RCA22 instruments have a dark blue/brown display, fixed pointer and are unlighted.

All R.C. Allen vacuum gyros run off of 4.5 inch Hg, erect time is 3 min. Instruments equipped with a warning flag will let you know when vacuum has dropped below 3.8 inch Hg. Flag re-tracts from view at 4.3 inch Hg. The instrument fits in a standard 3 1/8 panel cutout. A ¼ -18 NPTF nylon tube slip fitting is recommended for vacuum hose installation. A 1/8 – 27 NPTF nylon tube slip fitting is recommended for vacuum gauge installation.