NACA 11-foot valve installation, c. 1955. Full caption "11 FOOT DIAMETER VALVE AT VARIOUS POSITIONS FOR ALTITUDE EXHAUST LINE IN REAR OF PROPULSION SYSTEMS LABORATORY PSL EQUIPMENT BUILDING - THIS VALVE MANUFACTURED BY W S ROCKWELL COMPANY"
Fullsize image: https://diqn32j8nouaz.cloudfront.net...e_fullsize.jpg
https://diqn32j8nouaz.cloudfront.net...11ft_valve.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/...281#post177015
https://www.homemadetools.net/forum/...114#post176359
