A Small-sized Wind Turbine is schematically shown in Fig (a), and is delivering a maximum rated power of ( 50 KW ). This Wind Turbine is using " A Single-Stage- Spur- gearbox " to speed up the main Drive shaft speed from 20 rpm to 1400 rpm ( see Fig (b) ). In order to absorb shock loads , such gear box is suspended in space by two torque arms -as shown in Fig ( c ); which is attached to the turbine housing by a Bolted Joint, of 6 equally spaced Hexagonal bolts. requirements:

1- The Standard Design Procedure

2-Design of Torque arm,

3-Design of the Bolted Joint

4-Design of the used Spur gear Pair

5-Design of main Input Shaft together with its KEY

6-Select the Right Deep Groove Ball bearings; which are supporting the main input Shaft, and Finally

7-The Configuration of the Main Input Shaft (Product Concept, DFM, DFA, Dimensions, Fits, and Tolerances for mating parts)