In this article we show why flying and rotating beer mats, CDs, or other flat disks will eventually flip in the air and end up flying with backspin, thus, making them unusable as frisbees. The crucial effect responsible for the flipping is found to be the lift attacking not in the center of mass but slightly offset to the forward edge. This induces a torque leading to a precession towards backspin orientation. An effective theory is developed providing an approximate solution for the disk’s trajectory with a minimal set of parameters. Our theoretical results are confronted with experimental results obtained using a beer mat shooting apparatus and a high speed camera. Very good agreement is found.

在本文中，我们将展示为什么飞行和旋转的啤酒垫、CD 或其他平面圆盘最终会在空中翻转并最终以后旋飞行，从而使它们无法用作飞盘。发现负责翻转的关键效应是升力攻击不是在质心，而是稍微偏移到前缘。这会引起扭矩，导致向后旋方向进动。一个有效的理论被开发出来，它提供了一个具有最小参数集的磁盘轨迹的近似解。我们的理论结果与使用啤酒垫拍摄设备和高速相机获得的实验结果相对。找到了很好的一致性。