Реферат: Tupolev 154M noise asesment (Анализ шумовых характеристик самолёта Ту-154М)

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

6.2.2 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 R_N remains constant and is equal to 119.7 m.

Figure 6.5 Schematic of approach

Taking into account that the speed remains constant and airframe configuration is for landing, we can calculate the stall speed:

,

where G is airplane weight, r is air density, S is wing area, C_{y max} is maximum lift coefficient determined from Fig. 6.6.

Approach speed should be 30% greater that the stall speed:

Figure 6.6 Aerodynamic characteristics of Tupolev 154M.

Using the approach speed, we can calculate current lift coefficient:

.

Corresponding drag coefficient is determined from Fig. 6.6.

Some corrections must be made to calculated values of drag and lift coefficients. It is necessary to take into account the influence of the landing gear which creates additional drag and decreases lift. The influence of flaps and slats is little and can be neglected.

Necessary thrust is calculated using the following formula

,

where is drag and q is approach path angle which is equal to 3 degrees.

Calculated results for five different landing weights are shown in the table 6.3.

Table 6.3 Calculation results for Tupolev 154M at approach configuration.

Weight, % MLW	MLW	95%	90%	85%	80%
Weight, kg	80000	76000	72000	68000	68000
Vapp, m/s	74,8	72,91	70,964	68,965	66,91
Thrust, kg	8445,63	8024,67	7601,88	7179,66	6758,58
LA , dBA	96,74	96,05	95,35	94,66	93,97
EPNL, EPNdB	112,17	111,32	110,48	109,64	108,79
∆LA, dBA	0	0,69	0,7	0,69	0,69
∆EPNL, EPNdB	0	0,85	0,84	0,84	0,85
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