Abstract
Abstract Resonant-whip tests were performed on two horizontal shafts having critical frequencies of 4000 and 6100 rpm and with pairs of bearings of various designs. Whip, when developed, was found to set in at speeds equal to about twice the first natural critical frequency of the shaft. With the heavier shaft, whipping stopped at speeds nearly equal to three times the first critical; with the light shaft whipping could not be stopped. The frequency of vibration in the whipping range is constant and equal to the first critical of the shaft. High loads, high viscosities, and flexible mounting gave greater stability. The load necessary to prevent whip at a viscosity of 70 centipoises is around 40 psi, but this value changes with speed and oil viscosity. The order of bearing stability is, starting with the most stable bearings, as follows: 3-lobe, tilting-pad, pressure, elliptical, 3-groove, and plain circular.
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