Muffler Development for Light Aircraft and a Technique of In-Flight Data Acquisition and Analysis

This paper presents a summary of the application of basic muffler principles to the development of an efficient aircraft muffler.

Simple expansion chamber and resonator silencers were evaluated. The automotive tri-flow principle was also investigated for possible adaptation.

The resonator principle was found to offer the best attenuation of the engine firing frequency utilizing a minimum of chamber volume and low back pressure.

Acquisition of in-flight noise and vibration data is discussed with some examples of what is believed to be the most reliable way of analyzing the data.