A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Tony Oz
Date: 2019 Feb 7, 00:55 -0800
Dear Bill, thanks for the answers.
I asked about gyro's [in]sensitivity to sideways accelerations because it is interesting to see how the apparent coincidence of the gyro's mass center and its' point of support provide for the simultaneous static AND dynamic balance. In that case the gyro is indeed VERY insensitive to any (reasonable) disturbances. I played with that (the static and dynamic balance) when upgrading my turntable (a.k.a. "der Plattenspieler"). Because the tonearm is far from being symmetrical - with weights alone one cannot achieve both the static and the dynamic balance, making a statically-balanced pick-up sensitive to rumble and external vibrations. I had to use springs to statically-balance the tonearm that was first dynamically-balanced with weights. The spring is keeping the tonearm horizontal (and provides the proper stylus pressure) while the weight (actually - the mass) of the other end of tonearm is in the length·mass proportion with the pick-up side of the assembly. When subjected to an external shock/vibration the turntable moves as one piece, the pick-up is almost isolated from all the disturbances.
It is MUCH easier to achieve all that for a spherically-shaped body as in this sextant.