Vintage AIRADIO models SU-52A, SU-52B and SU-52C 5 tube, 2 band aircraft radio receiver. Original old Sams Photofact manual includes schematic, layout, alignment instructions, voltage & resistance test chart, repair parts list and description. 4 pages. Dated 1947. Airadio Inc., of Stamford, CT. This manual would make a sensational accompaniment to your classic retro radio equipment.