I'm curious as to what aerodynamic problem that design is trying to solve? Is a ducted prop more efficient than unducted? Would concentrating the prop wash over the elevator improve maneuverability at slow speeds?
Luigi Stipa came up with a theory that a tubular fuselage gave significant extra thrust to a conventional engine and propeller. His idea was to mount and engine and propeller inside of a fuselage that was a venturi tube and compressed the propeller's airflow and engine exhaust before it exited the duct at the trailing edge of the aircraft. He was applying Bernoulli's principle of fluid movements to make the engine more efficient.
While he showed his idea did increase engine efficiency, the plane had so much drag that any benefits from the design were negated.
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