| 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 |
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.
Figure 6.2 Take-off and climb path
The take-off profile is defined by five parameters -- (A) AB, the length of take-off roll; (B) β the first constant climb angle; (C) γ, the second constant climb angle; and (D) δ, and e, the thrust cutback angles. These five parameters are functions of the aircraft performance and weight, and the atmospheric conditions of temperature, pressure, and wind velocity and direction.
Under reference atmospheric conditions and with maximum take-off weight, the gradient of the second constant climb angle (γ) may not be less than 4 percent. However, the actual gradient will depend upon atmospheric conditions, assuming maximum take-off weight and the parameters characterizing engine performance are constant (rpm, or any other parameter used by the pilot).
In operational conditions the climb is performed without the cutback stage, and the aircraft flies over the control point at a lower altitude, which leads to higher noise levels.
Figure 6.3 Comparison between operational and certification trajectories
The climb path for Tupolev 154M was calculated using the following equation
where:
m is aircraft mass;
P is thrust;
a is the angle of attack, j is the angle of engine installation;
q is climb angle which is equal to b or g, depending on the climb stage.
Figure 6.4 Comparison between noise levels under different flight paths
Approach Noise Calculation
The approaches must be conducted with a steady glide angle of 3°±0.5° and must be continued to a normal touchdown with no airframe configuration change. Thus the distance from the control point to the glideslope RN remains constant and is equal to 119.7 m.
Дата: 2019-05-28, просмотров: 223.
