The T34 was the first axial flow gas turbine engine designed and produced by Pratt & Whitney.
Pratt & Whitney had studied the possibilities of commercial and military transports powered by large, gas turbine-driven propellers. Funded by the U.S. Navy, Pratt & Whitney developed the PT2/T34 turboprop engine for large military cargo aircraft.
The T34 turboprop engine first flew in September 1950, installed in the nose of a B-17 flying test bed. The Boeing KC-97J, which later became the B-377 Super Guppy, was this engine's first application. The Air Force then selected it for the Douglas C-133A Cargomaster. Originally developing 5,700 shaft horsepower, later models delivered 7,500 shaft horsepower.