The noise generated from a 1/4-scale AH-1G helicopter configuration was investigated in the Langley V/STOL tunnel. Microphones were installed in positions scaled to those for which flight test data were available. Model and tunnel conditions were carefully set to properly scaled flight conditions. Data presented indicate a high degree of similarity between model and flight test results. It was found that the pressure time history waveforms are very much alike in shape and amplitude. Blade slap when it occurred seemed to be generated in about the same location in the rotor disk as on the flight vehicle. If model and tunnel conditions were properly matched, including inflow turbulence characteristics, the intensity of the blade-slap impulse s...
An investigation of helicopter rotor noise at model scale has been conducted in the Langley 4- by 7-...
A 2.1-m diam., 1/6-scale model helicopter main rotor was tested in hover in the test section of the ...
Helicopter impulsive noise tests were conducted in the Langley V/STOL tunnel with an articulated rot...
Models of both the advanced main rotor system and the standard or "baseline" UH-1 main rotor system ...
A 1/17-scale research model of the AH-1 series helicopter main rotor was tested. Model-rotor acousti...
The Army rotorcraft aeroacoustic programs are reviewed, highlighting the theoretical and experimenta...
Experimental and related analytical results on model rotor rotational and broadband noise obtained i...
The features of existing wind tunnels involved in noise studies are discussed. The acoustic characte...
The effects of impulsiveness on the noisiness of helicopters are examined by varying the main rotor ...
An investigation of helicopter rotor noise at model scale was conducted in the Langley 4 by 7 meter ...
The reduction of high speed impulsive noise for the UH-1H helicopter was investigated by using an ad...
In-plane impulsive noise radiating from a hovering model rotor was measured in an anechoic environme...
A wind tunnel test to study the effects of geometric scale on acoustics and to investigate the appli...
A 2.1 m diameter, 1/6-scale model helicopter main rotor was tested in hover in the test section of t...
Blade slap encountered in rotary wings and its effect on helicopter performance are reported. The re...
An investigation of helicopter rotor noise at model scale has been conducted in the Langley 4- by 7-...
A 2.1-m diam., 1/6-scale model helicopter main rotor was tested in hover in the test section of the ...
Helicopter impulsive noise tests were conducted in the Langley V/STOL tunnel with an articulated rot...
Models of both the advanced main rotor system and the standard or "baseline" UH-1 main rotor system ...
A 1/17-scale research model of the AH-1 series helicopter main rotor was tested. Model-rotor acousti...
The Army rotorcraft aeroacoustic programs are reviewed, highlighting the theoretical and experimenta...
Experimental and related analytical results on model rotor rotational and broadband noise obtained i...
The features of existing wind tunnels involved in noise studies are discussed. The acoustic characte...
The effects of impulsiveness on the noisiness of helicopters are examined by varying the main rotor ...
An investigation of helicopter rotor noise at model scale was conducted in the Langley 4 by 7 meter ...
The reduction of high speed impulsive noise for the UH-1H helicopter was investigated by using an ad...
In-plane impulsive noise radiating from a hovering model rotor was measured in an anechoic environme...
A wind tunnel test to study the effects of geometric scale on acoustics and to investigate the appli...
A 2.1 m diameter, 1/6-scale model helicopter main rotor was tested in hover in the test section of t...
Blade slap encountered in rotary wings and its effect on helicopter performance are reported. The re...
An investigation of helicopter rotor noise at model scale has been conducted in the Langley 4- by 7-...
A 2.1-m diam., 1/6-scale model helicopter main rotor was tested in hover in the test section of the ...
Helicopter impulsive noise tests were conducted in the Langley V/STOL tunnel with an articulated rot...