Music acoustic and architecture

vii;586 hlm.;ill.;index;28 c

Acoustics

x+481hlm.;24c

Noise reduction

x, 752 p.; 24 cm

NACA Technical Notes

Note presenting a study that is part of a program to find practicable ways of reducing the external noise level of light airplanes. This particular report deals with noise measurements on a representative pusher-type amphibian airplane. Testing was made with a standard pusher-type airplane, the same airplane with a four-bladed propeller, a modified version with a geared engine and four-bladed propeller but no exhaust muffler, and a modified version with a geared engine, exhaust muffler, and propellers varying in number of blades from three to eight

NACA Technical Notes

"This report presents results of a research and engineering program performed during the first half of 1950 that resulted in an acoustical treatment for the 8- by 6-foot supersonic wind tunnel at the Lewis Flight Propulsion Laboratory" (p. 1)