The HOK-1 was the USMC version of the Kaman K-600. Developed in 1952. The cabin has a capacity of 5 passengers, including the crew. The designation to OH-43D was made as part of the 1962 change in designations for US military aircraft.
Source 1: Alex, Ralph P. "Helicopters from 'A to Z', Part III". American Helicopter Society Newsletter, Vol. 7, 1961. Page 4-5.
Source 2: Moorman, Robert W. "Coming Full Circle". Vertiflite July/August 2015. Published by AHS International. Page 19.
Source 3: Hirschberg, Michael. "The American Helicopter" (2000). Page 58.
Design authority: Kaman Aircraft Corporation
Primary manufacturer: Kaman Aircraft Corporation
Parent type: No type defined
Aircraft status: No longer flying
VTOL type: Helicopter
Lift devices: 2 in Synchropter configuration
Crew required: 1 in Side-by-side arrangement
Landing gear: Wheels (non-retractable)