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The Tu-154 was developed to replace the turbojet powered Tupolev Tu-104, plus the Antonov - 10 and Ilyushin - 18 turboprops. Design criteria in replacing these three relatively diverse aircraft included the ability to operate from gravel or packed earth airfields, the need to fly at high altitudes 'above most Soviet Union air traffic, and good field performance. In meeting these aims the initial Tupolev -154 design featured three Kuznetsov (now KKBM) NK-8 turbofans, triple bogey main undercarriage units which retract into wing pods and a rear engine T-tail configuration.
The Tupolev -154's first flight occurred on October 4 1968. Regular commercial service began in February 1972. Three Kuznetsov powered variants of the Tupolev -154 were built, the initial Tupolev -154, the improved Tupolev -154A with more powerful engines and a higher max take-off weight and the Tupolev -154B with a further increased max take-off weight. Tupolev -154S is a freighter version of the Tupolev -154B.
Current production is of the Tupolev -154M, which first flew in 1982. The major change introduced on the M was the far more economical, quieter and reliable Solovyev (now Aviadvigatel) turbofans. The Tupolev - 154M2 is a proposed twin variant powered by two Perm PS90A turbofans.
6.2 Noise Calculaions
Noise level at control points is calculated using the Noise-Power-Distance (NPD) relationship. In practice NPD-relationship is used in the parabolic shape:
,
where coefficients А, В, С are different for different aircraft types and engine modes. For Tupolev-154M the coefficients А, В, С are shown in the table 6.2 in respect to Tupolev-154.
Table 6.2 Noise-Power-Distance coefficients of similar aircraft.
|
Tupolev-154 |
Tupolev-154M | |||||
|
Engine mode |
A |
B |
C |
A |
B |
C |
|
Maximal |
145.45 |
-15.66 |
-0.81 |
142.53 |
-15.52 |
-0.83 |
|
Nominal |
142.14 |
-15.56 |
-0.82 |
137.58 |
-14.28 |
-1.09 |
|
85% of nominal |
140.50 |
-16.29 |
-0.76 |
142.84 |
-17.75 |
-0.78 |
|
Cruise |
140.23 |
-16.35 |
-1.15 |
137.56 |
-16.07 |
-1.10 |
|
2-nd cruise |
131.03 |
-10.38 |
-2.23 |
130.07 |
-11.54 |
-2.00 |
|
Descending |
126.84 |
-11.86 |
-1.93 |
128.57 |
-14.25 |
-1.39 |
|
Idle |
132.37 |
-16.36 |
-0.86 |
134.92 |
-17.13 |
-0.68 |
6.2.1 Take-off Noise Calculation
The aircraft begins the take-off roll at point A (Fig. 6.2), lifts off at point B, and initiates the first constant climb at point C at an angle β. The noise abatement thrust cutback is started at point D and completed at point E where the second constant climb is defined by the angle γ (usually expressed in terms of the gradient in percent). The end of the noise certification take-off flight path is represented by aircraft position F whose vertical projection on the flight track (extended centerline of the runway) is point M. The position of the aircraft must be recorded for the entire interval during which the measured aircraft noise level is within 10 dB of PNLTM. Position K is the take-off noise measuring station whose distance AK is specified as 6500 meters.
Реферат опубликован: 28/08/2007