You mustn't forget that with the popular setup of having a little ant-torque rotor at the back, Mr Sikorsky had originally planted it facing up much like a tandem setup but spinning a little faster. Theoretically it should have worked but flying it in that configuration proved to be more exciting than is necessary so they bolted it back to point to one side.
Another concept for Bob's fancy is the intermeshing rotors of the K-Max. It'll knock your head off if you don't approach it from the front.
