> I want to build a counter-flow heat exchanger radiator (aka the P-51) radiator that is reputed to provide enough thrust to compensate for the nacelle drag.
> I have a simple but perhaps naive question. In a ramjet base design, how is the force of the heated expanding gas mechanically couple to the frame of the engine /aircraft and the heat exchanger? Does this require a constriction like a Venturi in the tube? I.e is mechanical force coupled only to the difference in the annular area of the Venturi? Or is their some mechanism I am not understanding? Does the heat exchanger in the. P-51 nacelle have a constriction or rely some kind of "S" shaped offset jog between the nacelle opening input and its output that couples a net thrust to the air frame?
> I have a simple but perhaps naive question. In a ramjet base design, how is the force of the heated expanding gas mechanically couple to the frame of the engine /aircraft and the heat exchanger? Does this require a constriction like a Venturi in the tube? I.e is mechanical force coupled only to the difference in the annular area of the Venturi? Or is their some mechanism I am not understanding? Does the heat exchanger in the. P-51 nacelle have a constriction or rely some kind of "S" shaped offset jog between the nacelle opening input and its output that couples a net thrust to the air frame?
