[2] Stipa spent years studying the idea mathematically, eventually determining that the Venturi tube's inner surface needed to be shaped like an airfoil in order to achieve the greatest efficiency.

He appears to have intended the intubed propeller for use in large, multi-engine, flying wing aircraft—for which he produced several designs—but saw the construction of an experimental single-engine prototype aircraft as the first step in proving the concept.

[3] Stipa published his ideas in the Italian aviation journal Rivista Aeronautica ("Aeronautical Review"), then asked the Air Ministry to build a prototype aircraft to prove his concept.

However, Stipa viewed the Stipa-Caproni as a mere testbed, and probably did not believe that the intubed propeller's aerodynamic drag problem would be significant in the various large, multi-engine flying wing aircraft he had designed.

[8] Despite the lack of Regia Aeronautica interest in developing the intubed propeller concept further, the Italian government publicized the success of Stipa's idea.

Some aviation historians do at least partially agree with Stipa, noting that the modern turbofan engine has features which show it to be the descendant of his intubed propeller concept.