Torque on a hinge to a gate that is 69 inches long

[ewhite17]

I have a gate that is 69 inches long and it takes 50 lbs of force to lift at the end of the gate when it is extended at a little over a 90 degree angle. How many foot pounds of torque in a torsion spring will be needed to lift the gate or at least offset the majority of the weight?

 

[SteamKing]

Draw a free body diagram.