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This type of noise increases with aircraft speed and also at low altitudes due to the density of the air. Jet-powered aircraft create intense noise from aerodynamics. 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 primary sources of jet noise for a high-speed air jet (meaning when the exhaust velocity exceeds about 100 m/s; 360 km/h; 225 mph) are "jet mixing noise" and, for supersonic flow, shock associated noise. Acoustic sources within the "jet pipe" also contribute to the noise, mainly at lower speeds, which include combustion noise, and sounds ...
However, Concorde's high noise levels around airports, time zone issues, and insufficient speed meant that only a single return trip could be made per day, so the extra speed was not an advantage to the airline other than as a selling feature to its customers. [34] The proposed American SSTs were intended to fly at Mach 3, partly for this reason.
The project resulted in the development of the prototype Miles M.52 turbojet-powered aircraft, which was designed to reach 1,000 mph (417 m/s; 1,600 km/h) (over twice the existing speed record) in level flight, and to climb to an altitude of 36,000 ft (11 km) in 1 minute 30 seconds.
While hush kits effectively reduce noise emissions from older aircraft, noise cannot always be reduced to the level of modern planes at a reasonable cost. [ 7 ] In 1999, this concern led to a regulatory dispute between the United States and the European Union , where the EU proposed a new noise ordinance which effectively prevented the use of ...
Landing quota count values are based on the certificated approach noise level at maximum landing weight minus 9.0 EPNdB. Aircraft were originally divided into six QC bands from 0.5 to 16, but following a review by the Department for Transport [1] a seventh category – Quota Count 0.25 – was added in March 2007 [2] and an eighth category ...
In the US, the Concorde noise was measured at DFW and Dulles airports: [17] Based on the data given in Tables 11 and 12, it appears that the approach noise of the Concorde is somewhat higher than that for present day commercial aircraft. The takeoff noise is, for locations close the airport, considerably higher than present aircraft.
Effective perceived noise in decibels (EPNdB) or Effective Perceived Noise Level (EPNL) is a measure of the relative noisiness of an individual aircraft pass-by event. It is used for aircraft noise certification and applies to an individual aircraft, not the noise exposure from an airport.