Search Results

A processing system has been developed to meet increasing demands for detailed noise measurement of aircraft in wind tunnels. Phased arrays enable spatial and amplitude measurements of acoustic sources, including low signal-to-noise sources not measurable by conventional measurement techniques. The Microphone Array Phased Processing System (MAPPS) provides processing and visualization of acoustic array measurements made in wind tunnels. The system uses networked parallel computers to provide noise maps at selected frequencies in a near real-time testing environment. The system has been successfully used in two subsonic, hard-walled wind tunnels, the NASA Ames 7- by 10-Foot Wind Tunnel and the NASA Ames 12-Foot Wind Tunnel. Low level airframe noise that can not be measured with traditional techniques was measured in both tests.

The present study examined the degree of spatial awareness obtained using what has been called an Augie Arrow, enabled so that it could be displayed as either a “nearest horizon pointer” (NH) or an “up arrow” (UP) indicator. Another issue investigated concerned the usefulness of analog dials vice digital readouts of airspeed and altitude as an aid to recovery. During simulated flight, twelve subjects were required to recover from six unusual attitudes employing one of four HUD formats: (1) Standard HUD, (2) Augie Arrow, (3) Analog Dials, and (4) Augie Arrow with Analog Dials. Results revealed that the Augie Arrow produced the most rapid recovery time. The Augie Arrow configuration was optimal at the most severe unusual attitudes, especially for the NH mechanization. The Dials only HUD was not particularly helpful in recovery, and the Arrow with Dials HUD was rated as a significant clutter problem.