John,
Dave, I had always heard that Mr. Kaman left Sikorsky over his pushing the servo-flap design approach, not intermeshing or coaxial main rotors. That not the case?
You are correct in that Charles Kaman's proposal to the Engineering Manager at United Aircraft was the servo flap. But the servo-flap may have been only part of his reason for leaving.
Perhaps the following two excerpts from his book 'KAMAN ~ Our Early Years' clarifies his reasons for leaving.
At first I was mainly concerned with stability and control forces, and I applied my aerodynamics training to a new concept for rotor control.
I felt that somehow we had to find a means of aerodynamically stabilizing the rotor, while at the same time making it easier to fly. Since that was not part of my daily job at Hamilton, I continuously worked on the problem on my own time.
Primary among those potential improvements was my idea for aerodynamic servo flaps on rotor blades. My initial thought was that such a flap would be mounted on the trailing edge of the main rotor blade and would be connected by mechanical linkages working through a swash plate to the pilot's controls. It would be a good while before I would understand that this system would not achieve the desired result, and that it would have to take the form of a true servo system to see success. But this is getting ahead of the story.
The use of intermeshing rotors-a feature I would later envision for the Kaman K-125 helicopter-promised a significant power saving and greater efficiency over tail rotor designs. A tail rotor, used to counter the torque of the main rotor, used precious power without providing lift. But proposing an alternative to the tail rotor would have been premature - and out of the question for United Aircraft - as Sikorsky was completely committed to the tail rotor configuration.
___________________________
"Erle, I'd like to develop this system for United . I'll continue to function with my own basic job, and I'll do this work on overtime or extra time, or however. All I ask is that you pick up the costs and provide me with the place and a technician to the basic spade work."
His answer was swift, decisive and clear. "Charlie, we have our inventor at United Aircraft. His name is Igor Sikorsky. We don't need another one."
I think that his first patent was US 2,455,866, and it shows the servo flap on an Intermeshing helicopter.
Dave