Ronald "Duffy" Hambleton (b. 1937) worked as a stuntman in the 1970's and early 80's. He appeared in films including, "Cleopatra Jones" (1973), "Bring Me the Head of Alfredo Garcia" (1974), "Race with the Devil" (1975), "Midway" (1976), and "Bound for Glory" (1976).
Below: Duffy performed a spectacular motorcycle crash for George Lucas' "THX 1138" (1971). Everyone at the location was stunned and immediately ran in to ensure that Duffy was alright. Although Duffy flew over the handlebars, was hit by the airborne motorcycle, landed in the street on his back, and slammed into a crashed car, he was uninjured.
Here is the stunt.
Below: Duffy appeared in "Jackson County Jail" (1976)
and had a terrific fight scene with Tommy Lee Jones.
Below: In the 1970's, Duffy (right) was married to famous stunt woman Kitty O'Neil.
Below: A TV movie was made about them called, "Silent Victory: The Kitty O'Neil Story" (1979). Duffy was played by James Farentino (left) and Kitty was played by Stockard Channing (right).
Below: In 2005, Duffy testified that Robert Blake solicited his help in killing Blake's wife.