Wind Effect - Kazan Helicopters Mi-17-1V Flight Manual

MI1-17-1B. Flight manual
LW= EHW-GLF
The values of GF, TOF, GLF, TOO, LD and q are derived from the Tables as
instructed in 1.7.2, 1.7.3.
1.7.6.
Wind Effect
Because of the helicopter relatively low airspeed the wind direction and speed
have a pronounced effect on the flight range and duration.
To account for the wind effect the equivalent wind concept is introduced, the
equivalent wind, being only tailwind or headwind, changes the range in the
same way as an actual wind with its direction. The equivalent wind speed is
equal to the difference between the ground speed and the true air-speed. Ta-
ble
1.7
shows the equivalent wind speed versus the actual wind speed and di-
rection (for TAS within the range of 180 to 250 km/h).
The wind effect on the range is accounted for by means of the graph in Fig.
1.13,
the equivalent wind being the input value.
Before each flight the calculation should be refined with the use of the wind di-
rection and speed data for various altitudes taken no longer than 1 hour be-
fore.
Calculation of the range in wind (the range in no-wind condition assumed
known) is performed in the following way:
(a) With the actual wind speed and direction being known the equivalent
wind and its direction (tailwind or headwind) are derived from Table
1.7.
(b) On the graph in Fig.
1.13
from the point of intersection of the lines depict-
ing the range in no-wind condition and the equivalent wind draw a line
equidistant to the wind lines (tailwind or headwind) until it intersects the
R
axis and have the range in wind (tailwind or headwind).
Table
1.7
E . I tW d S d
.ouiva
en In
,pee
Wind angle, deg
Actual wind speed, krn/helicooter
Wind
direction Leftdrift Right
10
20
30
40
50
60 70 80
drift
Eauivalent wind speed, km/h
0 360 10
20
30
40
50
60 70 80
10 350 10 20 30 39 49 59 69 78
20 340 9 19 28 37 46 55 64
73
Tail-
30 330 9 17 25 34 42 49 57 65
40 320 8 15 22 29 35 42 48
54
wind
50 310 6
12
18
23
28
33 37 41
60 300 5 9 13 17 20
22
24
26
70
290
3
6
8
10
11
12 12 12
80 280 1 2
3
3 2 1 1 3
90
270
0
1 2 4
7
10 14 18
100 260 2 4 7 11 15
20 25 31
110 250 4 8 12 18 23 29 36 43
120 240
5
11
17
23
30
37 45
54
Head
130 230 6 13 21 28 36 44 53 62
wind
140 220 8 16 24 32 41 50 59
68
150 210 9 17 26 36 45 54 64
74
160 200 9 19 28 38 47
57 67
77
170 190
10
20
30
39 49 59 69 79
180 180 10
20
30
40
50
60 70
80
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