At the same time I gained over 1,000 rpm. By contrast, the muffler that came with the engine reduced dB by only about half that much, had no noticeable effect on the rpm, and did nothing to smooth out the sound quality. I am convinced that most complaints about noise have nothing at all to do with dB, but rather with the quality of the sound our models make. But I digress. I'll now explain how you can get these benefits with little or no tinkering.
Many fliers think of a tuned pipe as a cylindrical chamber filled with voodoo magic.
They're scared to use one because they think you need a Ph.D. to understand it. The kit sits in the tub, leans forward a little, back a little, and forward again. A small wave starts traveling from one end of the tub to the other, back and forth. The kid soon discovers that the wave always goes the same speed, so rocking faster doesn't help it along. But, by rocking at just the right speed, the kid adds a little energy each time the wave passes, building it up into a real tsunami that slams into the end of the tub, spraying water everywhere.