Stearman-Hammond Y-1 twin-boom monoplane from the 1930s. Around 20 were built.
https://diqn32j8nouaz.cloudfront.net...s_fullsize.jpg
Previously:
https://www.homemadetools.net/forum/...008#post213996
https://www.homemadetools.net/forum/...212#post203865
https://www.homemadetools.net/forum/...016#post160570
https://www.homemadetools.net/forum/...436#post189108
https://www.homemadetools.net/forum/...389#post161907
