Abstract: This invention relates to an improved pitot tube type flow measuring instrument for use in pipes and other conduits characterized by a generally diamond-shaped sensor portion constituting a bluff body for splitting the flow that includes at least a large-radiused leading edge in which three or more impact ports are located, a pair of planar portions diverging rearwardly from the leading edge to a transversely-spaced pair of much shorter-radiused side edges that cooperate therewith and the downstream-facing portion of the bluff body to define flow separation zones capable of stabilizing the flow coefficient over a broad range of flow conditions provided that the distance separating them is at least five times either of their radii.