c. early 1960's. 16x30 7/8" wood frame has mat with 10.25x25 1/8" opening revealing photo of large engine. The Pratt & Whitney J75 (company designation: JT4A) was an axial-flow turbo jet engine first flown in 1955. It was known in the civilian service as a JT4A. The engine was used on the Lockheed U-2, the Republic Aviation F-105 Thunderchief, and the Convair F-106 Delta Dart. It was also used in proto-type and experimental models. From its introduction in 1960, over 1,000 FT4s were sold, with many of them still in operation for electrical generation. Display was most likely designed for company office use or as a presentation piece to customers. Mat and white areas of image area have some age foxing. Mat is a bit worn at inside right edge. Near Fine appearance. Great display piece.