I don't know about the 53, but they definitely did that on the Sikorsky SHADOW. The concept didn't work all that great. The Comanche had no pedals, just a sidearm controller and collective. All of Sikorsky's later FBW efforts had separate controls like a traditional helicopter. I assume they covered the 4 axis control with patents.
Last edited by IFMU; 14th Apr 2021 at 17:08.