United Aircraft is a corporation that includes, among other companies, Pratt & Whitney, a major aircraft engine manufacturer.

-In the list of Spanish patents dated 10/23/1946, the UAC filed an application to include in the Registry the patent for an aircraft engine, entitled:
"A motive power plant for aircraft."

-This patent was granted in the Registry on 10/24/1946 and published in the December 1 issue of the same year.

-Analyzing the following drawing, we find a machine consisting of a group of free-piston engines, gas generators, and a turbine that drives the propeller. In other words, it was a predecessor of the PT-1, although the idea is the same.

"Drawing accompanying the patent"