A great article on RCUniverse.com about flutter and how to prevent it. Click the link at the end of the short blurb to read the full article.

 Most of us are familiar with the term "Flutter". For those of you who aren't, it is when a surface or control surface of an airplane suddenly and often violently vibrates, frequently resulting in a catastrophic failure. However, the more I read and talk to others, the more I realize how little this phenomena is understood. With that in mind, I hope to shed some light on this subject and hopefully, dispel some myths.

 

Simply put, Flutter is a Harmonic Vibration. A harmonic vibration is really quite easy to comprehend, but describing it is a bit more complicated. So I will try my best to put it in terms that are easily understood.

 

What you must first realize is that everything in the universe will vibrate at a given frequency. That frequency depends on many factors, such as size, weight and a host of others, AND in most cases, that frequency can be changed. I'm sure that as school kids we've all slapped a ruler that is hanging over a desk to make it vibrate, and if you slide the ruler so that less of it hangs over the edge, the vibrations get faster. By the same token, a string on a guitar will vibrate at a certain frequency, but if you tighten it, or make it shorter by holding it against a fret, the frequency will change.

Read the full article