In 1956, Stroukoff had already gained much experience working on the C-123 Provider, having completed two contracts based on that airframe.

This greatly improved landing and take-off performance, gross weight capability, and lowered the C-123's stall speed.

The YC-123E had been another experiment in improving the C-123's ability to operate wherever it might need to, introducing Stroukoff's own Pantobase system: two high-stress skis fitted to the lower fuselage, wingtip mounted floats, along with sealing the fuselage itself.

The U.S. Air Force, however, deemed that the YC-134 did not offer substantial improvement over the C-123, nor did it have a requirement for a piston-engined amphibious assault transport, and decided to purchase the Lockheed C-130 Hercules.

[citation needed] Data from Jane's All the World's Aircraft 1958–59 [1]General characteristics Performance