It’s a shame there’s no biography of Bensen. His story is unique.
I’ve heard bits and dabs; like the time he landed GE’s Kellett on a frozen lake and couldn’t get enough traction to spin up the rotor and had to be towed off.
The Kellett had a 100 HP prerotator and was used as a dynamometer to drive the Doblhoff* tip jet rotor for cold measurements. Most likely a Kellett XR-3 that had swash plate cyclic.
He was flying the Doblhof helicopter at GE’s flight test center in Schenectady, NY when it broke into air resonance, splattered and resulted in severe spinal injuries that led to Parkinson’s disease in later life.
Bensen served as chief engineer of Kaman Helicopters after leaving GE and before forming his own company.
Wish I knew more.
*Full report is here:
http://retromechanix.com/article/ro...f-342-v4-evaluation-by-general-electric-1948/