NACA microphone actuator at the Lewis Flight Propulsion Laboratory (now Glenn Research Center), c. 1955. Full caption: "MICROPHONE ACTUATOR ON HANGAR APRON"
Fullsize image: https://diqn32j8nouaz.cloudfront.net...r_fullsize.jpg
https://diqn32j8nouaz.cloudfront.net...e_actuator.jpg
Previously:
https://www.homemadetools.net/forum/...837#post179141
https://www.homemadetools.net/forum/...249#post176893
https://www.homemadetools.net/forum/...395#post177425
https://www.homemadetools.net/forum/...114#post176359
https://www.homemadetools.net/forum/...024#post176118
https://www.homemadetools.net/forum/...802#post171104
