Photograph of the Learjet 23 prototype undergoing a fuselage down-bending test, February 18, 1964.Text on sign: "Fuselage down bending static test / 0% ultimate / 18 Feb. 1964."Inscription on verso: "T58-2-O / 2-18-64."
Photograph of the Learjet 23 prototype undergoing a fuselage side-bending test, February 25, 1964. Text on sign: "Fuselage side bending static test / 67% ultimate / 25 Feb. 2964."Inscription on verso: "Gene Koenig / middle white shirt / T-58-4E /…
Photograph of the Learjet 23 prototype undergoing a fuselage side-bending test, February 25, 1964. Text on sign: "Fuselage side bending static test / 0% ultimate / 25 Feb. 2964."Inscription on verso: "T-58-4C / 2-25-64."
Photograph of the Learjet 23 prototype undergoing a fuselage side-bending test, February 25, 1964.Text on sign: "Fuselage side bending static test / 0% ultimate / 25 Feb. 1964."Inscription on verso: "T58-4A / 2-25-64."
Photograph of the Learjet 23 prototype undergoing a fuselage up-bending test, February 13, 1964.Text on sign: "Fuselage up bending static test / 100% ultimate / 13 Feb. 1964."Inscription on verso: "T58-1-C / 2-13-64."
Photograph of five Learjet aircraft (visible tail number N804L) under construction in a Lear hangar, Wichita, Kansas, circa 1960s. Inscription on verso: "Learjets in hangar in Wichita / Photo courtesy Lear Archives."