Table 1: Bell 206 gears, speed, and data acquisition parameters.

ParameterValueReduction ratios

Shaft input speed (Hz)100
Number of stages2
Number of teeth of the bevel pinion19First-stage reduction ratio:
3.73 : 1 (71/19)
Number of teeth of the bevel gear71
Number of teeth of the sun gear27Second-stage reduction ratio:
4.67 : 1 (99/27 +1)
Number of teeth of the planet gear35
Number of teeth of the ring gear99
Overall reduction ratio:
(1st stage times 2nd stage)
17.45 : 1
Carrier (arm) output speed (Hz)5.73
Sampling frequency (Hz)51200
Length of records30 seconds