Herrick HV-2A Vertaplane. An early VTOL (vertical takeoff and landing) aircraft from the 1950s with both a helicopter rotor system and conventional airplane wings.
https://s3-us-west-1.amazonaws.com/h...vertaplane.jpg
Previously:
https://www.homemadetools.net/forum/...092#post157384
https://www.homemadetools.net/forum/...176#post138386
https://www.homemadetools.net/forum/...637#post102089
