Jim, it was Sergei Sikorsky's youthful enthusiasm which i found really refreshing.
Dave, you have to admit that TsAGI 1-EA with it's 4 tail rotor's is a massively complicated compared to the single MR/TR config. I would say Igor Sikorsky's major innovation was to correctly identify the compromise required for the machine purpose. This compromise naturally changes as the machine speed goes up.
Mart