The rotation of the propeller It is noticeable that the propeller is only quite loco On a wire pin with correspondingly wide Head sits. It is easy to suppose that these Feature something with the propulsion of the propeller has to do. We want this assumption with the help of a model. We do this A larger propeller of cardboard This with a hole so large that, for example, A pencil the roll of the wire pencil Can take. (Favorably, the hole diameter About twice the size of the pencil to choose). Now we set ourselves the task, To set the propeller in rotation. Well, one thing Everyone is successful after a few tries And the cardboard propeller thereby turning To bring the pencil gingerly into one Circling movement, so that the propeller Is finally "taken". The pencil Slides in this way on the inside of the hole And transmits due to the result A corresponding torque On the propeller. The rotation of the axis of rotation If this model is for the HuiMaschine Should be clarified Which way the wire pin in a rotary movement Respectively. On this same explanation But the spirits separate themselves from us Through literature. For example, Asserted by brushing over the scores A vibration in the diagonal direction is generated, Which is wavy in the direction of the Propeller spreads. Because of the inhomogeneity Of the wood, the two vibration components spread Parallel to the sides of the Staffs differed quickly and resulted The resulting phase shift To a circular or ellipsoidal oscillation [7]. Quite apart from this explanation Will be too difficult for most users Probably, makes them of some prerequisites Use, which i.a. not true. The fiberization Of the wood on which the inhomogeneity rests,
Is considered parallel to the sides of the square Staff accepted. Wood with a fibering Parallel to the diagonal would therefore also be unsuitable Be like a rod, at which the rippling Parallel or perpendicular to the fiber becomes. That is, however, i.a. not the case. This can be One can choose by means of randomly carved and notched Wood. Also leave As well as rods made of roundwood and for example Plastic. A widespread explanation is also emerging The first time, the works evaluated by us Back [1]. In this case, That in a rectangular rod two vibrations With the frequency of excitation and vertical Mutually driven oscillation planes will. Because of the different edge lengths The corresponding resonance frequencies differ. That is why the two Vibrations Excitation, are thus phase-shifted relative to one another And superimpose themselves to an elliptical Vibration. The reason for this reasoning is the Shape of the bar cross section, according to our experience Have no significant influence on the Behavior of the Hui machine has. Besides that Can thus only a very small phase shift To be justified. Both vibrations Are almost synchronized with the stimulus Because the resonant frequencies are much larger. Are greater than the excitation frequency. This can be done For example by demonstrating that The rod is clamped in a vice and Caused by plucking. The sound, Which results, sounds much higher than that at the Rubbing. The above-described function of the thumb pressure, In our experience Results is not possible here at all Has been considered. A simple explanation model