John T. Parsons (October 11, 1913 – April 18, 2007) pioneered numerical control (NC) for machine tools in the 1940s.
Together, they were the first to use computer methods to solve machining problems, in particular, the accurate interpolation of the curves describing helicopter rotor blades.
In 1948, Parsons' company, "Parsons Corporation" of Traverse City, Michigan, was awarded a contract to make the challenging tapered wings for military aircraft; they won the contract because they developed the computer support to do the difficult three-dimensional interpolation for the complex shapes, as well as the 800 steps long production cycle for the wing manufacturing.
Parsons was reinstated as president of the company after royalties on the patent had generated significant amounts of money.
In 1993, Parsons (but not Stulen) was inducted into the National Inventors Hall of Fame for inventing numerical control.