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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Gyro sextant
From: Bruce Cutting
Date: 2019 Jan 26, 17:33 -0700
From: Bruce Cutting
Date: 2019 Jan 26, 17:33 -0700
NO the precession and centering happen for the same reason and is due to the same force (namely gravity). The problem visualizing this is because the force acting on the gyro is a cross product of gravity and the angular momentum vector (i.e. The force exerted on the gyro is at right angles to either angular momentum or gravity). Hope this helps. Here are 3 links explaining this: https://physics.stackexchange.com/questions/281291/why-does-a-spinning-top-get-back-upright-when-knocked http://www2.eng.cam.ac.uk/~hemh1/gyroscopes/spinningtop.htm https://www.askamathematician.com/2012/01/q-what-keeps-spinning-tops-upright/ On Sat, January 26, 2019 16:46, David Pike wrote: > > Even more thoughts on precession damping. > > > We seem to have this precession business cracked apart from explaining > why the spin axis works its way back to the vertical again after being > disturbed. Perhaps the bottom heaviness is a red herring and is there > simply to ensure the gyro is reasonably close to upright when it starts > to spin. If the gravity couple causes the gyro precess, then we must > look for a torque or couple applied in such a way to make the gyro > precess in such a way that the CG moves slowly back into line with the > spin axis. Could it be differential aerodynamic effects on the spinning > rotor, could it be the pivot walking around its cup in a circular motion > of small radius? Still working on it. Tried to make gyroscope this > evening but not very good. Just ordered a toy one from eBay. My head > hurts. DaveP > > [plain text auto-generated] > ---------------------------------------------------------------- > NavList message boards and member settings: http://fer3.com/NavList > Members may optionally receive posts by email. > To cancel email delivery, send a message to NoMail[at]fer3.com > ---------------------------------------------------------------- > ---------------------------------------------------------------- > > > > : > http://fer3.com/arc/m2.aspx/Gyro-sextant-DavidPike-jan-2019-g44119
