0071 00
TM 1-6625-724-13&P
0071 00-40
TASK 5 – ISOLATE IRREGULAR VIBRATIONS
Table 3. AH-64 Frequency Data
AH-64A
100% Nr Frequency (Hz)
AH-64D
101% Nr Frequency (Hz)
Source
4.8
4.87
Main rotor 1/REV
9.6
9.74
Main rotor 2/REV
14.4
14.61
Main rotor 3/REV
18.7
18.87
MGB G3 shaft
19.3
19.48
Main rotor 4/REV
23.4
23.62
Tail rotor 1/REV
38.4
38.96
Main rotor 8/REV
46.8
47.25
Tail rotor 2/REV
57.6
58.44
Main rotor 12/REV
60.6
61.21
Tail rotor vertical drive shaft
73.2
73.91
MGB G1 shaft
79.8
80.07
MGB G2 shaft
80.2
81.02
AGB Idler shaft
80.3
81.06
Tail rotor drive shaft
82.2
83.00
AGB Idler
93.6
94.49
Tail rotor 4/REV
127.1
128.33
ECS compressor (2)
137.5
138.89
APU shaft
164.0
165.66
Nose gearbox shaft
189.8
191.67
ECS condenser fan (4)
204.2
206.24
AC Generator
210.6
212.68
Hydraulic pump
349.2
352.69
Engine shaft
379.5
383.33
APS Blower
384.5
388.33
ECS Fan (4)
384.5
388.33
Crew station fan
408.4
412.47
AC Generator 2/REV
665.3
672.03
SUN gear clash, MGB
1330.6
1344.06
2x SUN gear clash, MGB
1333.1
1346.53
Tail rotor gearbox clash
1895.0
1914.13
Hydraulic pump 9/REV
2634.1
2660.73
G1/G3 clash, MGB
2969.1
2999.10
Intermediate gearbox clash
4756.1
4804.09
MGB clash
6499.6
6565.59
GB/TR drive shaft clash
6737.7
6805.80
ACC gearbox clash
10824.1
10933.45
Nose gearbox clash
