Abstract: An acoustic treatment technology of honeycomb sandwich stiffened structure to reduce cabin noise for propeller airplanes is presented briefly. The principle of the acoustic treatment technology to improve the environment quality of the cabin for propeller airplane with low frequency noise is introduced. Then, experimental data of noise transmission loss for both acoustics treated and untreated aircraft sidewall panels are given. Analysis of the data mentioned above shows that the technique of acoustic treatment of honeycomb stiffened structure to reduce the noise transmission of propeller airplane sidewall panels is easible and effective.

Key words: aircraft cabin, noise control, honeycomb panel.