NASA NKC-135 research aircraft used to test winglets in the late 1970s.
https://diqn32j8nouaz.cloudfront.net...5_fullsize.jpg
Previously:
https://www.homemadetools.net/forum/...603#post174271
https://www.homemadetools.net/forum/...425#post169777
https://www.homemadetools.net/forum/...410#post154633
https://www.homemadetools.net/forum/...018#post125382
https://www.homemadetools.net/forum/...624#post216084
