Stroukoff YC-134

The Stroukoff YC-134, designed in 1956, was based heavily on the Fairchild C-123 Provider, itself designed by Michael Stroukoff. The United States military contracted with Stroukoff Aircraft Corporation to develop an improved version of the aircraft, combining features that the company had developed for the YC-123D and YC-123E.
History.
Stroukoff's work with the C-123.
In 1956, Stroukoff had already gained much experience working on the C-123 Provider, having completed two contracts based on that airframe.
Its YC-123D had introduced a Boundary Layer Control (BLC) system to the C-123B. This system forced pressurized air over the upper wing surfaces of the airplane, making the wing work as if it were flying at much greater airspeed. 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. This gave the YC-123E the ability to operate on water, as well as ice and snow, and with the BLC from the previous YC-123D, the new aircraft could effectively be operated from almost any runway surface available, and airstrips of shorter length.
The YC-134.
The product of a US Air Force contract in 1956, a single C-123B from the -CN production block (serial 52-1627) was modified by Stroukoff Aircraft to become the YC-134. This aircraft was heavily modified with the following new features:
These features gave an empty weight increase over the C-123B from to , and a maximum loaded weight increase from to . The aircraft's cruising speed was , compared to the C-123B's , and the YC-134 had a range with a payload. The BLC allowed the YC-134's take-off distance to decrease from to , very similar to that of the YC-123D. 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.