Sprocket
It will be difficult to tell more. The helicopter was
so "far ahead of its time" that most of the five page article had to be blacked out; even though 60 years has passed.
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OK. A little more;
That the intermeshing configuration results in a slow helicopter is a misconception.
The intermeshing Flettner FL-282B, which flew just before the single rotor Sikorsky R-4B, had a maximum speed 24% faster than the R-4B.
The intermeshing Kellett XR-8, which flew just after the single rotor Sikorsky R-4B, had a maximum speed 39% faster than the R-4B.
Kaman elected to produce a high lift, slow speed helicopter, and thereby created the misconception.