I got a mail from Kenneth Ketner:
"In your site, you mentioned the Langley tandem didn’t fly. That isn’t
correct. His smaller models flew well, and their success caused an
international excitement because many famous scientists had stated
bluntly that heavier-than-air powered machines were impossible.

Even Langley’s man-carrying tandem was later rebuilt by Alexander Graham
Bell and Glenn Curtiss and successfully flown by Curtiss and others in
1910. In 1907, Louis Bleriot had flown a Langley configuration successfully."

http://aerostories.free.fr/precurseurs/langley/page2.html

Later I will try to get approval to use some drawings or photos. Or I will make some drawings myself.

Also go see for some other early year tandem:

http://www.flyingmachines.org/mont.html