Abstract: A rotary mechanism such as a rotary combustion engine, compressor, expansion engine or the like in which the shaft has a first counterweight diametrically opposed to the shaft eccentric on which the rotor is journaled and in which the shaft has sleeve-type bearings on opposite sides of said counterweight and a second counterweight is provided outboard of said bearings and disposed ahead of said shaft eccentric by an angle of approximately 90.degree. as measured about the shaft axis in the direction of shaft rotation.

Abstract: A rotor for compressors, turbines or the like and having a plurality of circumferentially-spaced blades in which every other blade is modified so that the average natural frequency of said modified blades differs from that of the other blades by at least 4% but by no more than 15% so as to reduce the maximum amplitude of turbine blade vibration.

Abstract: A system and apparatus for controlling excessive vibration of a rotating shaft at critical speed or when a large imbalance suddenly occurs, comprising an emergency bearing having sufficient radial clearance that it does not normally engage the shaft, and located longitudinally at a portion of the shaft which is sensitive to excessive vibration, and where it will raise the critical speed of the shaft system when additional support is added at that position. The bearing is of inexpensive construction and of such design that it requires no lubrication during the period when the shaft is passing through the critical speed and the bearing is operative.