Lockheed CL-475 light helicopter from 1959. Only one was built.
https://diqn32j8nouaz.cloudfront.net...5_fullsize.jpg
Previously:
https://www.homemadetools.net/forum/...384#post204560
https://www.homemadetools.net/forum/...709#post232099
https://www.homemadetools.net/forum/...107#post214380
https://www.homemadetools.net/forum/...312#post218683
https://www.homemadetools.net/forum/...906#post190921
