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Low-flying, high-speed military aircraft produce especially loud aerodynamic noise. The shape of the nose, windshield or canopy of an aircraft affects the sound produced. Much of the noise of a propeller aircraft is of aerodynamic origin due to the flow of air around the blades. The helicopter main and tail rotors also give rise to aerodynamic ...
Sound sample ⓘ An 1860s-era siren. [2] A siren is a loud noise-making device. There are two general types: mechanical and electronic. Civil defense sirens are mounted in fixed locations and used to warn of natural disasters or attacks.
Helicopter noise reduction is a topic of research into designing helicopters which can be operated more quietly, reducing the public-relations problems with night-flying or expanding an airport. In addition, it is useful for military applications in which stealth is required : long-range propagation of helicopter noise can alert an enemy to an ...
The auditory warnings produced by these systems usually include a separate attention-getting sound, followed by one or more verbal commands to the pilot/crew. Perhaps the most widely known example, encountered in many video games and movies, is the "Pull up! Pull up!" command. Other common spoken warnings are "Terrain, terrain", "Windshear ...
The investigation determined that the helicopter lost yaw control due to failure of flight control computer. On 29 May 2001, a Republic of Korea Army (ROK Army) CH-47D installing a sculpture onto Olympic Bridge in Seoul, South Korea failed to unlatch the sculpture. The helicopter's rotors struck the monument; then the fuselage hit and broke ...
Airwolf is the helicopter from the 1980s American television series of the same name. Its fictional features included stratospheric ceiling, stealth noise signature, a wide range of weapons and supersonic speed. The Airwolf helicopter was a conventional Bell 222 helicopter modified by attaching some film props.
A stealthy RAH-66 Comanche (foreground) flying in formation with a non-stealthy AH-64 Apache (background). Stealth helicopters are helicopters that incorporate stealth technology to decrease an enemy's detection ability. [1]
A long-range acoustic device (LRAD), acoustic hailing device (AHD) or sound cannon is a specialized loudspeaker that produces sound at high power for communicating at a distance. It has been used as a method of crowd control , which has caused permanent hearing damage , having an extremely high decibel capacity (up to 160 dB measured at one ...