Abstract: A propulsion device and its method of use, the device having a forward foil and a rearward foil adapted for alternate transverse reciprocal and alternate pivotal movement in opposed direction about parallel axes. The forward and rearward foil axes are perpendicular to the chords of the forward and rearward foils and the rearward foil is positioned to the rear of, and in a nested relationship with, the forward foil. The axes of the forward and rearward foils are positioned a distance of less than one-quarter of the chord length from the leading edge of the forward and rearward foils, respectively.

Abstract: Axial flow turbomachinery having an impeller with a plurality of contoured blades mounted within a diffuser throat and about a central rotatable hub. This blade shape is defined by the ratio of the blade root and tip chords to the minimum midsection blade chord, which is between about 1.25 and about 2.25. The ratio of blade pitch at the root and tip sections as compared with the blade midsection pitch is preferably between about 1.0 and about 1.4.This configuration of a preferred diffuser is described by the following relationship: ##EQU1## Where A.sub.t is the diffuser cross-sectional area at the diffuser throat, A.sub.o is the diffuser cross-sectional area at the outlet, 1 is the diffuser length from the diffuser throat to the diffuser outlet, x is a distance along the diffuser measured from the diffuser throat toward the diffuser outlet, A.sub.x is the diffuser cross-sectional area x distance from the diffuser throat and n is a value between about 2 and about 4.

Abstract: A fluid control valve which avoids wear, cavitation, and high noise level operation and yet is substantially non-clogging. The valve includes one or more nozzles through which fluid is passed, thereby producing a fluid jet, the fluid subsequently being spun tangentially within an annular whirl chamber, and then being passed through a labyrinth passageway comprising a series of inwardly spaced concentric sleevelike annuli.