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## Re: [TowerTalk] Flexible coupler assembly

 To: , Re: [TowerTalk] Flexible coupler assembly "Chuck Lewis" Thu, 25 Jan 2007 16:15:52 -0600
 ```> Does a shock absorber in the mast like this really take any stress off the > rotor gears? The shock absorber will wind up allowing the antenna to twist > further than it would without the shock absorber and have much more > "travel" > when returning in the opposite direction thus increasing the force by > allowing more travel and the antenna to whip around more than without any > flexible joint. Yes, but: The donut helps because it spreads the impact over a longer time. Without the donut, the force is applied over a short time after the backlash in the gear train is taken up, and the gears absorb the total energy almost instantaneously. But the donut allows the same total energy to be applied over a much longer time, and the result is a much lower peak force on the system. Think of the donut as the physical equivalent of a capacitor. A capacitor smooths the sharp transients in a spikey waveform and lowers the peak voltage...the donut smooths the hard bangs in the rotor system and lowers the peak forces on the gears, etc. The issue of how another spring (donut) in the system affects the dynamics is really complex, and the donut could either help or hinder oscillations, depending on the mechanical resonances of the elements, mast flexion, etc. But in any case the above paragraph still applies. If you're so inclined, check: http://www.physicsclassroom.com/Class/momentum/U4L1b.html Here's an applicable excerpt: ---------------------------------------------------------------- "Impulse = Change in momentum One focus of this unit is to understand the physics of collisions. The physics of collisions are governed by the laws of momentum; and the first law which we discuss in this unit is expressed in the above equation. The equation is known as the impulse-momentum change equation. The law can be expressed this way: In a collision, an object experiences a force for a specific amount of time which results in a change in momentum (the object's mass either speeds up or slows down). The impulse experienced by the object equals the change in momentum of the object. In equation form, F * t = m * Delta v. " -------------------------------------------------------------------- With apologies to any REAL physicists (Rigor Gained is Clarity Lost)... 73, Chuck, N4NM _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
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