Sikorsky H-2 coaxial rotor helicopter - photo

Built in 1910, the H-2 coaxial rotor helicopter was the second helicopter designed by Igor Sikorsky. It was powered by a 25 hp Anzani engine and equipped with two counter-rotating three-bladed rotors. However, the craft could barely lift itself, let alone the added weight of a pilot.

https://diqn32j8nouaz.cloudfront.net/sikorsky_heli2.jpg


Previously:

https://www.homemadetools.net/forum/...910#post133618
https://www.homemadetools.net/forum/...944#post129552
https://www.homemadetools.net/forum/...220#post134788
https://www.homemadetools.net/forum/...580#post128257

It may not have lifted off properly but was a great start: could have been creating a 1910 in c minor but someone else was doing that.