Hi engineers and future engineers!
I have a project given by my lecturer which is to design just the gearbox in a wind turbine.
The goal of this project is to design a prototype conceptual gearbox that will power a generator on a wind turbine. The blades are about 25ft in diameter and are held in the air by a 60 foot tall tower. The turbine blades spin the input shaft of the gearbox which increases speed and decreases the torque.
Specs for the gearbox: Weight and size is minimized

Gear ratio Max 33:1 and min 28:1
Shaft arrangement Co linear input and output shafts(reverted gear train)
Input shaft protruding 4" out of the front gearbox
Output shaft protruding 2" out of the rear gearbox
Provide adequate key slots on the input and output shafts

We need to find the loading and to calculate the input torques. The turbine speed is constant at 120rpm. Weight of the turbine blades and generator will be carried on separate bearings. These component will be connected to the gearbox with flexible couplings. THE LOADING TO THE INPUT AND OUTPUT OF THE GEARBOX IS TORQUE ONLY.

The design life is 10 years. continuous operation and the loading mention above(which needs to be calculated)
I am desperate for help that's why i decided to seek help here.

I just need some guidance on how should i proceed after knowing the wind profile. Thanks!

I guess a god place to start is working out what power is generated from the wind. I have seen an interesting thread on the physics forum site.