American military personnel using a paraboloid as a primary finder for locating airplanes at night during World War One. The paraboloid used sound to detect the aircraft, which were then illuminated by searchlights. This lightweight and portable device had an approximate range of 3-1/2 times the unaided ear. This image is for official use only.

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Size: 8457px × 5613px
Photo credit: © piemags/NSC / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: -aided, activities, aeroplanes, american, approximate, ear, engineering, finder, light, military, night, official, paraboloid, photographer, portable, range, reconnaissance, searchlights, sound, technology, war, world